Thickness and Clearance Analysis of 3D Object Using Maximum Inscribed CubesMasatomo Inui; Ryo Ohno and Nobuyuki Umezu3, Lead, Machine designers must have an accurate understanding of the thickness distributions of parts. In this study, a novel thickness evaluation method for polyhedral objects is proposed in which the thickness at a point on the object’s surface is determined by the size of the maximum cube inscribed at that point. Considering a three-dimensional object with the inside and outside inverted, the thickness definition can also be used to evaluate the amount of clearance on the part surface or between parts. The interior of a polyhedral object is converted to an equivalent voxel model, and a “cuboid distance field” consisting of inscribed cubes centered at each voxel is defined. The maximum inscribed cube tangent to any point on the surface of the object was obtained by analyzing the cuboid distance field along a half-line extending from the point to the interior of the object. We devised a fast algorithm to compute the cuboid distance field using a hierarchical bounding box structure of surface polygons in combination with the parallel processing function of the graphics processing unit. The effectiveness of the algorithm was verified through computational experiments.
Computer-Aided Design & Applications, Jan. 2024,
[Reviewed] Analysis of Contact Positions of Inspection Toool for Motorcycle Safety Verification
Masatomo Inui; Nobuyuki Umezu, Lead, We propose a method for automatically detecting shapes that may be dangerous to pedestrians in the event of a collision using a motorcycle’s CAD model for its safety verification. A columnar inspection tool comprising a conical surface and cylindrical surface with a diameter of 300 mm, imitating an upright person, was prepared for this verification. The shape of the contact of the motorcycle with inspection tool is recognized as a shape that can cause severe injury to a pedestrian in a collision, which is modified at the designer’s discretion. The proposed technique detects the location of the inspection tool in contact with the motorcycle. It then detects the surface portions of the motorcycle that establish contact with the tool placed at that location. The former process involves slicing the CAD model of the motorcycle into several horizontal planes placed at small intervals, expanding the resulting cross-sectional figures by the radius of the inspection tool, overlapping the expanded figures, and calculating their Boolean union shape. To accelerate these processes, we developed an algorithm that leverages the parallel processing capabilities of a graphics processing unit. Computational experiments confirm the effectiveness of the proposed method., The American Society of Mechanical Engineers
Proceedings of the ASME 2023 International Mechanical Engineering Congress and Exposition IMECE2023, 02 Nov. 2023, [Reviewed]
Fast simulation of machining error induced by elastic deformation of tool system in end millingKazuki KANEKO; Masatomo INUI and Isamu NISHIDA, In end milling, tool deflection can often be a main cause of machining error. Therefore, in our previous study, a,method to simulate the machining error due to elastic deformation of the tool system was proposed because,simulation is an effective tool to optimize cutting conditions and machining accuracy. However, the large,computational time needed for machining error prediction is unacceptable for practical use. Thus, this study,proposes a fast simulation of the machining error for end milling based on our conventional method. To,accelerate the simulation and reduce the computational time, the multiple analysis steps that are sequentially,calculated in our conventional method are parallelly processed using a graphics processing unit because each,step can be treated as an independent phenomenon. In addition, to improve the efficiency of geometric,calculation, the workpiece and tool are respectively represented by a dexel model and polygon model that,correspond to the swept shape of cutting edges. To verify the validity and effectiveness of the proposed,method, a machining error simulation was performed based on both our conventional and proposed methods. It,was confirmed that the simulation results based on both methods are in good agreement, and the proposed,method can reduce the calculation time significantly., 日本機械学会
Journal of Advanced Mechanical Design, Systems, and Manufacturing, 23 May 2023,
[Reviewed] Graphical Assistance for Determining Cutter Axis Directions in 3+2-Axis MachiningMasatomo Inui; Shutaro Taguchi; Nobuyuki Umezu, Lead, Recently, the use of 3+2-axis machining, in which machining is performed by tilting the direction of the cutter spindle axis, has increased in the machining of parts with complex shapes, such as impellers and airplane parts. This paper describes a novel interactive software technique for assisting 3+2-axis machining. This software computes a range of cutter postures without interferences with the machine part for each point in the cutter path. The possible cutter postures for all points are examined, and the number of the machinable points is determined for each cutter posture. The obtained results are color-coded in the Gauss map. By referring to the color information of the map, cutter postures required for machining can be efficiently selected. By repeating the selection of the cutter posture based on the color display, the operator can semi-automatically generate the numerical control (NC) data for the 3+2-axis machining. Computational experiments were then performed to verify the feasible applicability of the software., CAD Solutions
Computer-Aided Design & Applications, Jan. 2023,
[Reviewed] Geometric Simulation of 5-axis Milling without Using Cutter Swept Volume
Shogo IUCHI; Masatomo INUI; Nobuyuki UMEZU, Geometrical milling simulation which computes the workpiece shape obtained as a result of 5-axis machining is an important technology of the CAM software. In this simulation, it is common to generate a swept volume of a moving cutter and subtract it from a solid model of a workpiece shape. In this paper, we propose a milling simulation method w ithout using the cutter swept volume. Our method obtains the machining result shape of the workpiece by defining the shape models of the cutter whose position and posture are changed in a very small amount along the path, and by repeatedly subtracting them from the workpiece model. By properly controlling the arrangement interval of the cutter shape models and by using the parallel processing function of the graphics processing unit (GPU) , we succeeded in obtaining sufficiently accurate milling result model at high speed., The Japan Society for Precision Engineering
Proc. 19th International Conference on Precision Engineering (ICPE 2022), Nov. 2022, [Reviewed]
Various Daubechies Wavelets for Compressing Z-map Models
Nobuyuki Umezu; Masatomo Inui, We propose an algorithm for lossy compression of CAD models in a Z-map representation while keeping the compression artifacts within a specified value (the maximum difference designated by the user). We employ the Daubechies,wavelet functions smoother than the Haar wavelet used in the previous work for lossy compression of shape models. A significant reduction in the data amount of the compressed shape model is achieved with our lossy process to delete higher frequency components of the wavelet synopsis. We conducted a series of experiments with sample shape models with 512×512 -,8192×8192 resolution to evaluate our technique with various wavelet functions. The proposed method reduced 75 to 85% of the output binary size compared to those compressed by the previous method. We also found that some of Daubechies wavelets,such as D4 and D6 are superior in lossy compression with non-linear filtering according to the order of magnitude of wavelet coefficients., The Japan Society for Precision Engineering
Proc. 19th International Conference on Precision Engineering (ICPE 2022), Nov. 2022, [Reviewed]
SHAPE MODELING OF POTENTIAL SINK MARKS FOR AESTHETIC DESIGN OF PLASTIC PARTS
Masatomo Inui; Nobuyuki Umezu, Lead, Shallow depressions, called sink marks, may form on the surface of plastic parts produced by injection molding. These depressions are caused by partial differences in the amount of shrinkage of plastic parts during the solidification process. The appearance of such depressions in the exterior of the product degrade its aesthetic quality. In this study, we propose a shape modeling technique of possible sink marks. The input data of the method is a polyhedral model of a part. This model is transformed to another polyhedral model of the same shape and whose surface polygons have a sufficiently small size. For each vertex of the part, the amount of shrinkage is determined using the result of the thickness analysis at the vertex of the model. The position of the vertex is then modified according to the shrinkage value to obtain a solid model with shallow depressions on its surface. By properly visualizing the model using the computer graphics technique, it becomes possible for the designer to evaluate the influence of sink marks on the part appearance., The American Society of Mechanical Engineers
Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition IMECE2022, Oct. 2022, [Reviewed]
IMPROVED METHOD FOR EXTRACTING DIFFICULT-TO-MACHINE SHAPES USING MULTIPLE MILLING SIMULATION RESULTS
Masatomo Inui; Qi Chen; Nobuyuki Umezu, Lead, We previously developed a software technology for assisting the design of machine parts with high machinability. Our system is milling-simulation-based and detects shapes that cannot be machined using the available cutters by repeatedly executing milling simulations with the cutters. This paper describes an enhanced software technology that improves the extraction and visualization of difficult-to-machine shapes. Contrary to our previously reported software, the current software is equipped with a recognition function for the shape features. By controlling the milling simulation process according to the recognized features, more accurate simulation results can be obtained. The current software can visualize the extracted difficult-to-machine shape by superposing and displaying the shape left unmachined after milling simulations on the CAD model of the part. By examining this shape, the reason for the difficulty in machining can be visually understood. We implemented the software and applied it to CAD models of machine parts to evaluate its practicality.
Proceedings of the ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference IDETC/CIE2022, Aug. 2022, [Reviewed]
VISUALIZATION OF THICKNESS DISTRIBUTION IN SOLID OBJECTS
Masatomo Inui; Nao Oki; Nobuyuki Umezu, Lead, To appropriately proceed with a machine design, it is important to define the part shape while confirming the thickness distribution throughout the part as needed. In this study, we developed a novel method to visualize the thickness distribution in a solid object using a translucent point cloud. In this method, numerous points are randomly placed inside a solid object, then the volumetric thickness value at each point is computed. Efficient computation is realized using hierarchical axis-aligned bounding boxes to manage the maximum inscribed spheres inside the solid and parallel processing technology of a graphics processing unit (GPU). To improve the performance, a cell structure based on an orthogonal grid is introduced to efficiently detect the axis-aligned bounding boxes (AABBs) commonly indicated by close points and store them in high-speed shared memory. By rendering the translucent points that are color-coded according to their thickness values, the thickness distribution inside a solid object can be represented in an easy-to-understand manner. Numerical experiments are performed to verify the effectiveness of the proposed algorithm.
Proceedings of the 2022 International Symposium on Flexible Automation,ISFA2022, Jul. 2022, [Reviewed]
〔Major achievements〕Visualization of 3+2 Axis Machining Result by Combining Multiple Z-map ModelsMasatomo Inui; Qi Chen; Nobuyuki Umezu, Lead, Geometric NC milling simulation is usually performed before the actual cutting process to visualize the machining result and detect potential errors during the machining process. Recently, 3+2 axis machining, in which machining is performed by tilting the direction of spindle of the tool, has been used increasingly in the mold and die fabrication. In this paper, a novel method to visualize the milling result of the 3+2 axis machining operations is proposed by combining multiple Z-map models into a single triple-dexel model. This method can correctly visualize the result of 3+2 axis machining operations at high speed by using the rapidity of the Z-map based milling simulation and the expressiveness of the triple-dexel model. The effectiveness of the technology is demonstrated using software and via computational experiments., CAD Solutions
Computer-Aided Design & Applications, Jan. 2022,
[Reviewed] 〔Major achievements〕Fast Cutter Accessibility Analysis Using Ray Tracing Cores of GPUMasatomo Inui; Kohei Kaba; Nobuyuki Umezu, Lead, In the cutter path computation for the five-axis machining, it takes much time to determine proper cutter postures in machining. We propose a novel method for calculating all possible cutter postures that can be used in machining mold’s surface without collisions in a short time. In determining the cutter postures for each cutting point, intersection detection between a line segment and a set of polygons is frequently carried out. Latest graphics processing units (GPUs) are equipped with a hardware called ray tracing (RT) cores dedicated to image processing in the 3D computer graphics. We use this RT core technology for accelerating the intersection detection and consequently reduce the time and cost necessary in the cutter posture determination. We also present the numerical experiments conducted to verify the effectiveness of the proposed method., Fuji Technology Press
International Journal of Automation Technology, Nov. 2021,
[Reviewed],
[Invited] 〔Major achievements〕Comparison of Two Parallel Offsetting Algorithms Free from Conflicts Between ThreadsMasatomo Inui; Daiki Ishii; Nobuyuki Umezu, Lead, object by offset radius is a fundamental geometric process frequently used in manufacturing applications. This process combined with the triple-dexel representation solid model has become popular because of its robustness and compatibility with parallel processing using a graphics processing unit (GPU). In the parallel geometric processing, conflicts between threads must be avoided. Thus, we propose a novel parallel offsetting algorithm free from conflicts between threads. Triple-dexel model is a combination of x-, y-, and z-axes-aligned dexel models. Each dexel model is defined based on an orthogonal grid given on a coordinate plane. We subdivided the grid into several sub-grids of a fixed size in advance. For each sub-grid, a block of GPU threads was assigned. As each GPU thread always processes different dexel elements in this method, no conflict occurs. Our research group previously presented a parallel offset computation algorithm of a polyhedral solid model, which also uses a triple-dexel representation model and GPU. In the previous algorithm, surface polygons of the model were classified into several groups in advance. Parallel offset computation of multiple polygon groups was realized by selecting the polygon groups in which offset processing did not affect each other. In this method, the selection process of the polygon groups is time-consuming. Computational experiments were performed to analyze the performance difference between the current algorithm and our previous algorithm. In our experiments, the software using the current algorithm achieved speedups from 1.4 times to 3.2 times higher than our previous offsetting software., Fuji Technology Press
International Journal of Automation Technology, Nov. 2021,
[Reviewed],
[Invited] Parallel Contour-Type Cutter Path Computation Using GPU
Issei WATANABE; Masatomo INUI; Nobuyuki UMEZU, Corresponding, In the contour-type cutter path computation of a machine part, Minkowski sum shape of the part CAD model and an inverted cutter model is sliced by a horizontal plane at a specific height. The cutter path can be obtained by tracing the boundary curve of the cross-sectional figure on the slicing plane. Since the tracing operation is inherently a serial process, it is generally difficult to apply the parallel processing to the tracing operation. In this paper, we propose a novel algorithm for computing the contour-type path using the parallel processing function of the graphics processing unit (GPU). Computational experiments are performed to verify the practical applicability of the algorithm., JSME
Proc. of The 10th International Conference on Leading Edge Manufacturing in 21st Century (LEM21), Nov. 2021, [Reviewed]
FAST CUTTER LOCATION SURFACE COMPUTATION USING RAY TRACING CORES
Daiki Ishii; Masatomo Inui; Nobuyuki Umezu, Corresponding, By using the cutter location (CL) surface, fast and stable computation of the cutter path for machining complicated molds and dies can be realized. State-of-the-art graphics processing units (GPUs) are equipped with special hardware named ray tracing (RT) cores dedicated to image processing (called ray tracing) for 3D computer graphics. Using RT cores, it is possible to quickly compute the intersection points between a set of straight lines and polygons. In this paper, we propose a novel CL surface computation method using the RT core. The RT core was originally designed to accelerate 3D computer graphics processing. For the development of software using RT cores, it is necessary to use the OptiX application programming interface (API) library for computer graphics. We demonstrate how to use the OptiX API in the development of software for CL surface computations. Computational experiments were carried out, and it was confirmed that it is possible to obtain the CL surface based on a very high-resolution Z-map several times faster than the depth buffer-based method, which has been considered to be the fastest to date., ASME
Proceedings of the ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference IDETC/CIE2021,August 17-20, 2021, DETC2021-68081, Aug. 2021, [Reviewed]
〔Major achievements〕Fast Computation of Volumetric Thickness of 3D Objects Using GPUMasatomo Inui; Sinnosuke Naganuma; Nao Oki; Nobuyuki Umezu, Lead, We proposed a novel definition for thickness, termed “volumetric thickness” to clearly visualize thickness distribution in solid objects. Because our proposed method analyzes the thickness at internal points of an object, the computational complexity for its implementation is significantly higher than that of the conventional ray and sphere methods, which analyze do so only at points on the object’s surface. This paper describes a fast analysis technique for volumetric thickness of 3D objects. To realize the computation in a realistic timeframe, we utilize a culling technique with hierarchical bounding boxes and a parallel processing function within the graphics processing unit (GPU). In the culling process, the necessary data is collected for appropriate utilization of the fast shared memory of GPU. We also present the numerical experiments conducted to verify the effectiveness of the proposed method., IEEE
IEEE ROBOTICS AND AUTOMATION LETTERS, 22 Jul. 2021,
[Reviewed] Thickness evaluation of solid model in triple-dexel representation
Yu HUANG; Masatomo INUI; Nobuyuki UMEZU, The Japan Society for Precision Engineering
Proc. of 18th International Conference on Precision Engineering, A-4-3, 2020, Nov. 2020, [Reviewed]
Parallel offset computation free from conflicts between threads
Daiki ISHII; Masatomo INUI and Nobuyuki UMEZU, The Japan Society for Precision Engineering
Proc. of 18th International Conference on Precision Engineering, A-4-2, 2020, Nov. 2020, [Reviewed]
MILLING SIMULATION-BASED METHOD TO EVALUATE MANUFACTURABILITY OF MACHINE PARTS
Masatomo Inui; Tong Zhang; Nobuyuki Umezu, Lead, ASME
IDETC IDETC2020-22124, Proceedings of ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference IDETC/CIE2020, Aug. 2020, [Reviewed]
Accessibility Map for Assisting Cutter Posture Determination in Five-Axis Mold Machining
Masatomo Inui; Kouhei Nishimiya; and Nobuyuki Umezu, Lead, IEEE
Proc. of International Conference on Automation Science and Engineering CASE 2020, Aug. 2020, [Reviewed]
Geometric simulation of power skiving of internal gear using solid model with triple-dexel representation
Masatomo Inui; Yu Huang; Hideaki Onozuka and Nobuyuki Umezu, Lead, Elsevier
Procedia Manufacturing, May 2020, [Reviewed]
Visualizing Thickness and Clearance of 3D ObjectsMasatomo INUI; Shinnosuke NAGANUM; Kouhei NISHIMIYA; Nobuyuki UMEZU, Lead, Thickness and clearance are two of most fundamental parameters during design processes of mechanical products. In this paper, we propose novel definitions of these two parameters about a three-dimensional object, named “volumetric thickness” and “accessibility clearance.” These new definitions have a range of applications in design processes. For example, the interior part of a solid object can be classified according to our volumetric thickness. Visualization based on such classification results allow us to better understand the thickness distribution of the three-dimensional object. In terms of clearance, this attribute in current industrial practice is typically measured as the distance between two shape elements. This definition, however, is basically incomplete for evaluating the clearance during assembly tasks that also require the depth information. Our accessibility clearance handles both the width and depth simultaneously and its visualization offers intuitive understanding about assembly capability of that product., NIST
Proc. Model Based Enterprise Summit, 2020, 31 Mar. 2020,
[Reviewed] CLEARANCE MEASUREMENT OF 3D OBJECTS USING ACCESSIBILITY CONE
M.Inui; K.Nishimiya and N.Umezu, Lead, In this paper, we propose a novel definition of clearance for the surface of three-dimensional objects. Unlike the typical methods used to define clearance, the proposed method can simultaneously handle the relationship between the width and depth in the clearance, and thus, obtain an intuitive understanding regarding the assembly and manufacturing capability of a product. Our definition is based on the accessibility cone of a point on the object’s surface; further, the peak angle of the accessibility cone corresponds to the clearance at this point. A computation method of the clearance is presented and the results of its application are demonstrated. Our method uses the rendering function of a graphics processing unit to compute the clearance. A large computation time necessary for the analysis is considered as a problem regarding the practical use of this clearance definition., ASME
ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference IDETC/CIE2019, 18 Aug. 2019, [Reviewed]
Milling simulation-based approach for determining optimal milling direction of ejector pin
Tong ZHANG; Masatomo INUI; Nobuyuki Umezu, In the injection molding, ejector pin is used to push out the molded product from the mold core. Since the top surface of the ejector pin is a part of the mold surface, it must be machined to have the same curved shape of the mold surface. Fixed 5-axis milling method is usually used for fabricating the ejector pin. Determination of a proper milling direction of the ejector pin is important in the fixed 5-axis milling. In this paper, the authors propose an algorithm for automatically determining the optimal milling direction of the top part of the ejector pin. Our algorithm extracts the top part of the pin-shape as a target shape of the machining. Some candidate cutter axis directions are selected based on the geometric property of extracted target shape. For each candidate direction, a CAM software is applied to generate a cutter path for machining the target. Cutting simulation system is further applied to obtain the result shape of the machining. The optimal milling direction is determined as a direction whose corresponding milling result has the maximum machined area in the target shape.
International Congress and Conferences on Computational Design and Engineering 2019 (I3CDE 2019), Jul. 2019, [Reviewed]
Contour-Type Cutter Path Computation Using Ultra High Resolution Dexel ModelMasatomo Inui; Nobuyuki Umezu, Lead, We propose a novel algorithm for computing a contour-type cutter path for a mold CAD model in the polyhedral representation. Our algorithm uses a Minkowski sum shape of the mold model and a cutter model in the inverted orientation. To realize robust Minkowski sum computation, a grid-based shape representation named two-directional dexel model is used. This method can represent the 2D object with much smaller amount of the memory than the regular square mesh-based method. Utilizing this advantage, we realize two-directional dexel models based on an ultra-high-resolution grid. Parallel processing with many cores of graphics processing unit (GPU) is also introduced for reducing the computation time. An experimental path computation software is implemented and its accurate and robust performance is demonstrated., CAD Solutions, LLC,,, ,,,,,,CAD Solutions, LLC,,, ,,,,LLC CAD Solutions, LLC
Proceedings of CAD’19, Jun. 2019,
[Reviewed] GEOMETRIC APPROACH FOR EVALUATING MANUFACTURABILITY OF PARTS PRODUCED WITH INJECTION MOLDING AND DIE CASTING
Masatomo Inui; Nobuyuki Umezu, Lead, Cost and time reduction of mold and die production is a critical issue for any manufacturing company. Machine part designers are not always manufacturing experts; therefore, they often design parts with various problems for manufacturing using injection molding and die casting. These problems are usually detected by manufacturing engineers in later production stages. Problems are reported to the part designer, and they are resolved by modifying the part shape. The reduction of such reworks would aid the efficient production of the mold and die and, consequently, efficient part production. In this work, a software system, named “manufacturability assistant”, that reduces the number of reworks is explained. This system detects the shape elements of a part with potential manufacturability problems by applying various shape extraction procedures to the computer-aided design model of the part. By using this system, designers can evaluate the quality of a part from the perspective of manufacturability. They can reflect the evaluation result in the part design to obtain a part with higher manufacturability, NIST
Proc. of Model Based Enterprise Summit, 2019, Apr. 2019, [Reviewed]
Study on Efficient Development of 1D CAE Models of Mechano-Electrical Products
M.Inui; T.Fujinuma, Lead, To promote the use of 1D CAE model in the mechano-electrical industry, it is necessary to resolve the issues associated with the model and reduce the cost of creating it. We are in the process of developing the guidelines for creating proper 1D CAE models that will help reduce the modeling cost. A mechano-electrical product is generally a complex system of mechanical, electrical/controlling, and software components. In the industry, Modelica and MATLAB/Simulink are emerging as popular tools for modeling the mechanical and electrical/controlling components, respectively. Programming languages derived from C are usually used for describing the software necessary in the mechano-electrical product. For example, SystemC is recognized as a standard tool for describing a hardware behavior in the design of electronic circuits to be incorporated in the product. In this study, we investigated a method for the combined use of these tools. We explain our findings in our experimental construction of 1D CAE models of a mechano-electrical product using Modelica, MATLAB/Simulink, and SystemC simultaneously.
13th International Modelica Conference, Mar. 2019, [Reviewed]
GPUによる工具工作物接触面積検出の高速化
乾正知; 小林正佳, Lead, 日刊工業新聞社
型技術誌, 2018年12月号, Dec. 2018
Visualization of Thickness of 3D Object Using Reversed Distance Field
S.Naganuma; M.Inui; N.Umezu, Thickness is a basic parameter in machine design. In this paper, we propose a novel method for visualizing the thickness of three dimensional objects. In this method, a three dimensional field named “reversed distance field” is used in the visualization. Consider a skeleton structure in the object. Reversed distance field is constructed based on the Euclid distance between the points in the object and the skeleton. This field enables proper visualization of the thickness of the object, especially thin shapes in the object. A system based on this algorithm is implemented and some computation results are demonstrated.
Proc. International Conference on Precision Engineering, ICPE 2018, Nov. 2018, [Reviewed]
Detection of Sphere Colliding Step Shape in Automobile Parts
S.Nikaido; M.Inui; N.Umezu, In this paper, we propose a novel method for evaluating the safety concerning the corner shape of the mechanical product. Instead of the corner angle, we propose “opening angle” as a new measure for evaluating the injury risk at the corner shape. We propose an algorithm for computing the opening angle of the edges by using the offset shape of the part. We found that there are some exceptional cases in the evaluation of the sharpness of the corner, which are narrow gap exception and low step exception. In our offset-based method, these exceptional cases can be handled in a uniform way.
Proc. International Conference on Precision Engineering, ICPE 2018, Nov. 2018, [Reviewed]
Shape Modeling of Possible Sink Marks on Plastic Part
S.Onishi; M.Inui; N.Umezu, Sink marks are unwanted shallow depressions on the part surface due to localized shrinkage in the hardening process of the injection molding. Sink marks in the exterior appearance impair the aesthetic quality of the product. In this paper, we propose a shape modeling method of possible sink marks on the part surface. The input data of the method is a finely tessellated polyhedral model of the plastic part. The amount of the shrinkage is basically proportional to the thickness of the part. For each vertex of the part, its amount of the shrinkage is computed, then the position of the vertex is modified according to the shrinkage value to obtain the part model with shallow depressions in the surface. By properly visualizing the model, it becomes possible for the designer to evaluate the influence of the depressions on the part appearance. An experimental system is implemented and some computational tests are demonstrated.
2018 Asian Conference on Design and Digital Engineering (ACDDE2018), Nov. 2018, [Reviewed]
Bounded Distance Field for Assisting Interactive Layout Design of Water CircuitsM.Inui; T.Imai; N.Umezu, Lead, The idea of a “bounded distance field” is proposed, which is a distance field in a limited region around the boundary surface of a solid object. Gaps generated during parts placement that are too narrow can be detected by checking the distance value at the surface polygon of the object in the field. Based on a placement of new objects or a position change of objects, the distance field in the modeling space must be updated. To reduce the update cost, we introduce the idea of a “lazy evaluation” into the distance computation. In this method, a thickness and clearance evaluation is performed by using individual fields associated with the objects, and the computation of the combined distance field of all objects is postponed for as long as possible. To evaluate the practical application of the bounded distance field and the lazy evaluation of the distance value, an interactive system to assist in the layout design of water circuits in a mold cavity is demonstrated.
2018 Asian Conference on Design and Digital Engineering (ACDDE2018), Nov. 2018,
[Reviewed] Visualization of potential sink marks using thickness analysis of finely tessellated solid modelMasatomo Inui; Shunsuke Onishi; Nobuyuki Umezu, Lead, Sink marks are unwanted shallow depressions on the molded plastic surface caused by localized shrinkage during the hardening process of injection molding. Sink marks appearing in the exterior impair the aesthetic quality of the product. In this study, a novel method for extracting potential sink marks that can occur on the part surface is proposed. The thicker portion of the part shrinks with a greater amount than that of the thinner portion. This difference in the shrinkage amount is the main cause of the sink mark. In the plastic part design practice, engineers often check the thickness distribution to predict potential sink marks in the part surface. Our method can be considered as an automated technique of such manual inspection task. A polyhedral solid model of the part with sufficiently small triangles of nearly the same size is prepared. The amount of shrinkage at each polygon is estimated based on its thickness and the shrinkage ratio of the part. The developed algorithm extracts the potential sink marks by analyzing the shrinkage distribution on the part surface.
Journal of Computational Design and Engineering, Oct. 2018,
[Reviewed] Fast computation of accessibility cones for assisting 3 + 2 axis millingMasatomo Inui; Shinji Nagano; Nobuyuki Umezu, In this paper, we propose an algorithm for computing all appropriate cutter postures in the 3 + 2 axis milling of the mold part. As a measure of the appropriateness of the cutter posture, the peak angle of the accessibility cone (AC) is used. We use the polygon rendering function of the graphics processing unit for computing the AC. In this method, the necessary cost in the computation is basically proportional to the number of polygons to render in generating an image of the offset shape. A novel technology named “visible surface offsetting” is developed for reducing the rendering cost of the offset shape. An experimental system is implemented and some computation results are demonstrated. Our system can determine the cutter postures appropriate for 3 + 2 axis milling of the mold part in a few minutes., Taylor and Francis Inc.
Computer-Aided Design and Applications, 03 Sep. 2018,
[Reviewed] Geometric Simulation of Infeed Grinding Process of Silicon Wafer Using GPU
M.Inui; Y. Ebina; T.Maezaki; L.Zhou, Lead, Performing grinding before polishing is a widely used method of realizing large silicon wafers with high flatness . The variations in the size of the abrasive grains of a grinding wheel affect the surface quality of a ground wafer. We propose a simulation-based approach for analyzing the effect of the variations in grain size on surface quality. Rapid and accurate geometric simulation of the wafer grinding process is a key technology of the analysis. In this paper, we propose a novel method for simulating infeed grinding. Grinding is simulated with many abrasive grains of different sizes by executing geometric milling simulations with micro ball-end cutters of various radii. The polygon rendering hardware of a graphics processing unit is used to accelerate the simulations.
2018 14th IEEE International Conference on Automation Science and Engineering (CASE), Aug. 2018, [Reviewed]
Radial Ray Representation for Fast Analysis of Optimal Cutting Direction in 3+2 Axis Milling
M.Inui; S.Nagano; N.Umezu, Lead, In this paper, we propose a novel 3D shape representation method called “radial ray representation (3R)”. In this method, a solid shape is recorded by a set of dense rays radially expanding from a single point. This representation is especially useful for determining the optimal cutter posture in the 3+2 axis milling of a mold part. As a measure of the appropriateness of the cutter posture, the peak angle of the accessibility cone (AC) is used. In the appropriate postures, we select the optimal one as the tool posture with possible shortest cutter length without holder collisions. We developed 3R model based algorithms for computing the AC and for selecting the optimal cutter posture. We also propose a fast method for obtaining a 3R model using the polygon rendering function of the graphics processing unit. An experimental system is implemented and some computation results are demonstrated.
Proc. 2018 ISFA 2018 International Symposium on Flexible Automation, Jul. 2018, [Reviewed]
実験とシミュレーションによる砥粒径のばらつきがウエハ研削面に与える影響の調査蛯名 雄太郎; 前崎 智博; 周 立波; 清水 淳; 小貫 哲平; 尾嶌 裕隆; 乾 正知, In general, abrasive grain size is determined by mean diameter of abrasive grain. However, the abrasive grains in a grinding wheel are randomly scraggly in size and shape. There is no particular aspect to regulate the grain size variation in JIS (Japanese Industrial Standards). This paper investigates the effect of grain size variation on the ground surface topography by actual grinding on silicon wafers and analysis based on grinding simulation. The results reveal that the standard deviation of grain size is a very important index to characterize the grinding performance of a wheel. Smaller standard deviation leads to larger density of effective cutting-edge under the same volume percentage of abrasive grain contained in the wheel. This fact significantly contributes to not only achieve a better surface roughness and more uniform surface integrity, but also shorten the finishing time.
精密工学会誌, Jul. 2018,
[Reviewed] Cutter Engagement Feature Extraction Using Triple-Dexel Representation Workpiece Model and GPU Parallel Processing FunctionM.Inui; M. Kobayashi; N.Umezu, Lead, For an accurate analysis of the cutting force, the cutter engagement feature (CEF) representing the contact area between the cutter and workpiece must be extracted for each small feed motion of the cutter. We previously proposed a method for accelerating the CEF computation using the parallel processing function of a graphics processing unit. To improve the stability in the CEF computation, we propose a novel CEF extraction algorithm using an intersection analysis between the cutter and the workpiece shape. A triple-dexel model is adopted to represent the workpiece shape to realize a highly accurate computation. The algorithm is extended to compute the CEF, not only for the cylindrical surface portion of a cutter but also for the flat area of a flat-end cutter and the spherical surface area of a ball-end cutter. Our cutting simulation system based on this algorithm can compute a single CEF in 0.12 ms to 0.25 ms.
Proceedings of CAD’18, Jul. 2018,
[Reviewed] Toward The Standardization of Digital Verification Technology, Development of Guidelines for Creating 1DCAE Models of Mechano-Electrical Products
M.Inui; T.Fujinuma, Lead, Although 1DCAE is considered to be effective for supporting the conceptual/functional design of mechano-electrical products, 1DCAE is not popular in the mechano-electrical industry in comparison to the automobile and aircraft industries. To promote the use of 1DCAE, it is necessary to eliminate the obstacles associated with the use of 1DCAE, and to reduce the cost required to create models of mechano-electrical products. In the attempt to reduce the modeling cost, we have started to develop guidelines for creating proper 1DCAE models of mechano-electrical products. In this study, we briefly explain our guidelines and use part of them to develop a specific mechano-electrical component . We also explain our findings in the use of 1DCAE in the mechano-electrical industry., NIST
Proc. of Model Based Enterprise Summit, 2018, Apr. 2018, [Reviewed]
Study on the effect of grain size variation on ground surface roughness
Tomohiro Maezaki; Yutaro Ebina; Teppei Onuki; Hirotaka Ojima; Jun Shimizu; Masatomo Inui; and Libo Zhou
Proc.The 7th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN 2017), Nov. 2017, [Reviewed]
Quad Pillars and Delta Pillars: Algorithms for Converting Dexel Models to Polyhedral ModelsMasatomo Inui; Nobuyuki Umezu, In the geometric simulation of multi-axis milling, a dexel representation solid model is frequently used. In this modeling method, the object shape is defined as a collection of vertical segments (dexels) based on a two-dimensional regular square grid in the XY plane. In this paper, the authors propose the quad pillars algorithm and its enhanced version named the delta pillars algorithm for converting a dexel model to an equivalent polyhedral stereolithography (STL) model. These algorithms define a series of vertical pillar shapes for each square cell of the grid to represent the object shape as a bundle of pillars. The final polyhedral model is obtained by performing a simplified Boolean union operation of the pillar shapes. Unlike prior methods, the proposed algorithms are simple and fast and are guaranteed to generate a watertight polyhedral model without holes, gaps, or T-junctions. An experimental system is implemented and conversion tests are performed. The system converted a dexel model based on a high-resolution grid to a polyhedral model in a practical amount of time., ASME
JOURNAL OF COMPUTING AND INFORMATION SCIENCE IN ENGINEERING, Sep. 2017
Visualization of Possible Sink Marks using Thickness Analysis of Finely Tessellated Solid Model
Masatomo Inui; Shunsuke Ohnishi; and Nobuyuki Umezu, Lead, Sink marks are unwanted shallow depressions on the part surface due to localized shrinkage in the hardening process of the injection molding. Sink marks in the exterior appearance impair the aesthetic quality of the product. In this paper, we propose a novel method for extracting possible sink marks on the part surface. The input data of the method is a finely tessellated polyhedral model of the plastic part. The amount of the shrinkage is basically proportional to the thickness of the part. For each surface polygon of the part, its thickness at the center of gravity is computed. Our algorithm extracts the possible sink marks by analyzing the thickness distribution in the part surface. This method is simple and fast compare to traditional flow-simulation based method. An experimental system is implemented and a computational test is demonstrated. Our system can extract possible sink marks within a minute.
Asian Conference Design and Digital Engineering, Aug. 2017, [Reviewed]
Fast Extraction of Cutter Engagement Features by Using the Parallel Processing Function of a GPUMasatomo Inui; Masayoshi Kobayashi; and Nobuyuki Umezu, Lead, For an accurate analysis of the cutting force, the cutter engagement feature (CEF) representing the contact area between the cutter and workpiece must be extracted for each small feed motion of the cutter. In this paper, we propose a novel algorithm for accelerating the CEF computation by using the parallel processing capability of a graphics processing unit. In a milling simulation, the results of a prior cutting operation affect the subsequent CEF computations. This dependency on the cutting sequence can be ignored in a cutting operation along a linear trajectory. Based on this consideration, a new parallel CEF computation algorithm is developed. Our cutting simulation system using this algorithm can compute the CEF at 100,000 cutting positions in a few seconds., IEEE Computer Society
2017 13th IEEE Conference on Automation Science and Engineering (CASE), Aug. 2017,
[Reviewed] Extraction of Vertical Cylinder Contacting Area for Motorcycle Safety VerificationMasatomo Inui and Nobuyuki Umezu, Lead, Japanese motorcycle manufacturers define a safety regulation regarding the motorcycle shape to prevent injury to pedestrians in the event of a crash. To satisfy the regulation, the external surface of the motorcycle must have a sufficient degree of roundness if there is any chance that it could contact a vertical cylinder having a diameter of 300 mm approximating the human body. In this paper, we propose a novel method for assisting in the safety regulation inspection. This method extracts the surface regions of the tessellated motorcycle body where the vertical cylindrical column contacts and the surface region radius is less than 4 mm. The parallel processing capability of a graphics processing unit (GPU) is used to accelerate the extraction task of identifying the column contacting area. A system using our algorithm can detect surface areas on the motorcycle body where the safety regulation is not satisfied.
Proceedings of CAD’17, Aug. 2017,
[Reviewed] 2D Wavelet Transform Data Compression with Error Level Guarantee for Z-Map ModelsNobuyuki Umezu; Keisuke Yokota and Masatomo Inui, Last, Most of workpiece shapes in NC milling simulations are in Z-map representations that require a very large amount of data to precisely hold a high resolution model. An irreversible compression algorithm for Z-map models using a two-dimensional Haar wavelet transform is proposed to resolve this tight memory situation for an ordinary PC. A shape model is first transformed by using Haar wavelet to build a wavelet synopsis tree while the maximum errors caused by virtually truncating high-frequency components are simultaneously calculated. The total amount of the shape data can be reduced by truncating particular sections of the wavelet components that satisfy the error threshold given by the user. Our algorithm guarantees that any error due to its irreversible compression processes is smaller than the specified level measured against the original model., Elsevier Ltd
Journal of Computational Design and Engineering, Jul. 2017,
[Reviewed] Extraction of Sliding Collision Area of Knee-Form for Automobile Safety Inspections
Masatomo Inui; Kenta Gunji; and Nobuyuki Umezu, Lead, The United Nations Economic Commission for Europe defines a safety regulation based on the possible collision between the driver’s knee and an automobile’s interior parts. The “knee-form” apparatus is used to evaluate compliance with this regulation. Current software for analyzing possible collisions of the knee-form is not applicable to the part whose surface is vertical and near parallel to the knee-form approaching direction. In this paper, we propose a novel algorithm named “push-and-slide” for extracting the knee-form colliding area on the console part and door panel. In the first step of the algorithm, the target surface of the part is transformed to grid-like points in a high resolution. The knee-form models in various positions and orientations are prepared in the second step. Each knee-form model is pushed to the grid-like points. The model is then moved along the part surface to detect possible collisions between the knee-form and the grid-like points. An experimental system is developed and some computational experiments are performed.
Proc. 25. International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision, WSCG 2017, May 2017, [Reviewed]
Simple offset algorithm for generating workpiece solid model for milling simulationMasatomo Inui; Nobuyuki Umezu; Masashi Tsukahara, In the milling simulation of a large stamping die for an automobile part, a workpiece solid model is necessary as an input data. The initial shape of the workpiece is generally equivalent to an offset shape of the stamping die CAD model. Accurate offset shape is not a requirement on the workpiece solid model for the milling simulation. In this paper, we propose a novel method named "Simple Offset" for fast and stable generation of a simplified offset shape of a polyhedral solid model. In this method, surface points of the offset shape are sampled using 3 mutually perpendicular grids in the model space. The final offset shape is obtained by properly connecting the sampled points. Simplification level of the offset shape can be controlled by changing the resolution of the grids for sampling the surface points. An experimental system is implemented and some computation results are demonstrated., JAPAN SOC MECHANICAL ENGINEERS
JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING, 2017,
[Reviewed] Reduction of Reworks by Detecting Possible Manufacturing Problems of Plastic and Diecasting Parts in Early Design Stage
Masatomo Inui and Nobuyuki Umezu, Lead, Reworks generally need a lot of time and cost. Reduction of the rework is indispensable for realizing the efficient production of the mold and die. In this paper, we propose a novel software system named “manufacturability assistant” for reducing the reworks. This system can detect possible manufacturability problems in early part design stage. By using this system, designers can evaluate the quality of a part in the manufacturability view point. They can reflect the evaluation result in the part design to obtain a CAD model with higher manufacturability. An experimental system is implemented and some computation results are demonstrated.
Proc. 2016 Asia Design Engineering Workshop (A-DEWS 2016), Dec. 2016, [Reviewed]
Extraction of Thin Shape of Part Using Distance Field
Masatomo INUI; Takuya IWANAMI; and Nobuyuki UMEZU, Lead, We propose a novel method for extracting the thin shape of a part in the sphere-based thickness definition. This method extracts the thin shape as a set of surface points covering the shape. It employs the minimum inscribed sphere (MIS) computation algorithm with the distance field of the part. We develop a new algorithm for distinguishing the voxels corresponding to the thin shape from other voxels in the distance field. Erosion and dilation operations of the voxel model are used for the distinction. It distributes many points on the object surface in high density and computes the MIS contacting the point for all points. MISs whose center point locates in the voxels of the thin shape are selected. Surface points corresponding to the selected MISs are recognized as the points covering the thin shape.
Proc. of 16th International Conference on Precision Engineering, ICPE 2016, Nov. 2016, [Reviewed]
GPU-Based Visualization of Knee-Form Contact Area for Safety InspectionMasatomo Inui; Shunsuke Nakano; Nobuyuki Umezu; and Tetsuya Asano, Lead, The United Nations defines a safety regulation based on the possible collision between the driver’s knee and an automobile’s instrument panel. The “knee-form” apparatus used to evaluate compliance with this regulation can be modeled as a Minkowski sum shape of a vertical equilateral triangle and a horizontal cylinder with a radius of 60 mm and a thickness of 120 mm. The knee form contacting condition is geometrically equivalent to that of an equilateral triangle contacting a Minkowski sum shape of the instrument panel and a horizontal cylinder. Based on this concept, we propose a novel algorithm for extracting the knee-form contacting area on the instrument panel. With the parallel computation capability of a Graphics Processing Unit, our system can detect and output the knee-form contacting area in a practical time period., Taylor and Francis
Computer-Aided Design and Applications, 17 Oct. 2016,
[Reviewed] Recognition of Narrow and Deep Slot Features of a Part Using External Distance FieldMasatomo Inui; Tomohiro Imai; and Nobuyuki Umezu, Lead, Injection molding is commonly used for fabricating plastic parts of consumer products. In this method, melted hot material is highly pressurized and forced into a space between the mold core and cavity. Thin wall shapes in the mold core are often deformed in the injection process, and plastic parts with defective shapes are produced. Detection of such problems in the manufacturing process causes costly rework of the part design. A fast inspection method that allows the part designers to check for possible problems in the later manufacturing stage is desired. Thin-walled shapes in the mold core correspond to narrow and deep slot features in the part. Our method can detect such slots by using the external distance field of the part. An experimental recognition system is implemented using the proposed algorithm. Our system can recognize all narrow and deep slots on a part in 5 to 15 min., IEEE
Proceedings of ISAM 2016, IEEE International Symposium on Assembly and Manufacturing, Aug. 2016,
[Reviewed] MILLING RESULT VISUALIZATION FOR ASSISTING PROCESS PLANNING OF MOLD PARTS WITH COMPLEX POCKET FEATURESMasatomo Inui and Nobuyuki Umezu, Lead, In the machining process planning of plastic molds, an estimation of the machining result that is realizable with a specific cutter is frequently needed. In this paper, we propose a novel method for computing the result shape using geometric models of the part, the workpiece before machining, and the cutter. This method is especially useful for mold parts with complex pocket features. The machining of a pocket uses a milling method with a cutter gradually approaching the pocket by following a downward slope. In this method, a gap distance is required between the cutter and the wall surfaces of the pocket. We have developed an inverted-offset-based method for evaluating this geometric constraint in the determination of the maximum milling depth of the pocket. Because this method does not consider any shape descriptions from the form feature database, it is applicable to any form features with certain depressions, like slot features., IEEE
Proceedings of ISFA2016, 2016 International Symposium on Flexible Automation, Aug. 2016,
[Reviewed] Shrinking sphere: A parallel algorithm for computing the thickness of 3D objectsMasatomo Inui; Nobuyuki Umezu; Ryohei Shimane, An interactive system is required to enable machine designers to precisely visualize the thickness of a machine part. The thickness of a 3D object at a surface point is given by the diameter of the maximum inscribed sphere (MIS) touching that point. In this paper, we propose a novel iterative algorithm, namely, the shrinking sphere algorithm, for computing the MIS at a specific surface point. The convergence speed of the proposed algorithm is very high, and several iterations are usually sufficient for obtaining the MIS. The parallel execution of the algorithm with a graphics processing unit (GPU) is presented for further improving the computation speed. On the basis of the proposed algorithm, an experimental thickness visualization system is implemented using Compute Unified Device Architecture (CUDA). This system can visualize the thickness of a complex object with nearly two million polygons in several minutes using a PC (Core i7 CPU, 32GB memory and GTX-980 GPU), which is sufficiently fast for practical purposes., Taylor and Francis Inc.
Computer-Aided Design and Applications, 03 Mar. 2016,
[Reviewed] Wavelet transform data compression with an error level guarantee for Z-map modelsNobuyuki Umezu; Kazuki Asai; Masatomo Inui, This paper proposes an algorithm to compress CAD models in a grid-based Z-map representation while keeping the compression artifacts within a specified value (the maximum difference allowed by the user). A wavelet transformis used for decomposing the input shape into lower and higher frequency patterns. A significant reduction in the data size can be achieved by deleting higher frequency components. We employ a tree structure called the error range (ER) tree to manage error occurrences and determine where to prune branches without increasing the resulting errors in the data compression. The widely used reversible compression method, gzip, is then used to obtain the final compressed model data output. We conducted a series of experiments with 12 sample shape models on a 512 × 512 grid. With a maximum error of 10 μm (a typical value specified for NC milling), the proposed method reduces the data by 90.9% on average and the computational cost of 19 ms is extremely low. The proposed method can be extended to larger CAD models in real applications., Fuji Technology Press
International Journal of Automation Technology, 2016,
[Reviewed] Thinning Algorithm of Front Grille Part Shape for Air Flow Analysis
Masatomo Inui; Nobuyuki Umezu; and Masahiko Tadaki, Lead, In order to avoid thermal problems, the automobile engine room designers repeat the air flow analysis in the compartment. Computation cost of the air flow analysis is generally proportional to the number of polygons of the tessellated component models. Various shape simplification techniques are applied to the models before the analysis to achieve a precise result in a limited time period. In this paper, the authors propose a novel method for simplifying the CAD model of the front grille part, which is a shield of the air intake for avoiding small obstacles coming into the intake. Front grille parts usually have a cell structure or a honeycomb structure with many through holes. In the air flow analysis, the front grille shape is often simplified by thinning the wall part of the cells. Proposed method projects the original shape on a plane to obtain its silhouette picture. The skeleton of the picture is derived as a set of segments by applying thinning and segmentation operations to the picture. The thinned model of the front grille is finally obtained by vertically sweeping the segments of the skeleton.
Proc. of 2015 Asian Conference on Designing and Digital Engineering, ACDDE 2015, Nov. 2015, [Reviewed]
Thickness and clearance visualization based on distance field of 3D objectsMasatomo Inui; Nobuyuki Umezu; Kazuma Wakasaki; Shunsuke Sato, This paper proposes a novel method for visualizing the thickness and clearance of 3D objects in a polyhedral representation. The proposed method uses the distance field of the objects in the visualization. A parallel algorithm is developed for constructing the distance field of polyhedral objects using the GPU. The distance between a voxel and the surface polygons of the model is computed many times in the distance field construction. Similar sets of polygons are usually selected as close polygons for close voxels. By using this spatial coherence, a parallel algorithm is designed to compute the distances between a cluster of close voxels and the polygons selected by the culling operation so that the fast shared memory mechanism of the GPU can be fully utilized. The thickness/clearance of the objects is visualized by distributing points on the visible surfaces of the objects and painting them with a unique color corresponding to the thickness/clearance values at those points. A modified ray casting method is developed for computing the thickness/clearance using the distance field of the objects. A system based on these algorithms can compute the distance field of complex objects within a few minutes for most cases. After the distance field construction, thickness/clearance visualization at a near interactive rate is achieved., Society for Computational Design and Engineering
Journal of Computational Design and Engineering, 01 Jul. 2015,
[Reviewed] Visualizing sphere-contacting areas on automobile parts for ECE inspectionMasatomo Inui; Nobuyuki Umezu; Yuuki Kitamura, To satisfy safety regulations of Economic Commission for Europe (ECE), the surface regions of automobile parts must have a sufficient degree of roundness if there is any chance that they could contact a sphere of 50.0 mm radius (exterior parts) or 82.5 mm radius (interior parts). In this paper, a new offset-based method is developed to automatically detect the possible sphere-contacting shape of such parts. A polyhedral model that precisely approximates the part shape is given as input, and the offset shape of the model is obtained as the Boolean union of the expanded shapes of all surface triangles. We adopt a triple-dexel representation of the 3D model to enable stable and precise Boolean union computations. To accelerate the dexel operations in these Boolean computations, a new parallel processing method with a pseudo-list structure and axis-aligned bounding box is developed. The possible sphere-contacting shape of the part surface is then extracted from the offset shape as a set of points or a set of polygons., Society for Computational Design and Engineering
Journal of Computational Design and Engineering, 01 Jan. 2015,
[Reviewed] Data Conversion From Dexel Model to B-reps Solid Model
Masatomo Inui, Lead, In the geometric simulation of multi-axis milling, dexel representation solid model is often used. In this modeling method, the object shape is defined as a collection of vertical segments (dexels) based on a 2 dimensional regular square grid in the XY-plane. In this paper, the author proposes a new algorithm for converting a dexel model to an equivalent polyhedral STL model. This algorithm computes a series of vertical thin cubes for each square cell of the grid to represent the object shape as a bundle of cubes. The final polyhedral model is obtained as a result of Boolean union operation of the cubes. Proposed algorithm is simple, fast, and smaller memory consumption than other methods and it is guaranteed to generate the water-tight polyhedral model without holes and gaps.
Proc. of 15th International Conference on Precision Engineering, ICPE 2014, 24 Jul. 2014, [Reviewed]
Parallel Distance Field Computation with GPU and Its Application for Evaluating Part Thickness
M.Inui; N.Umezu; and K.Kobayashi, Lead, A parallel algorithm with GPU for constructing the distance field of a solid model is proposed. This algorithm is fast, precise, and applicable to complex models with huge number of polygons. In the distance field construction, the shortest distance between a point and surface polygons of the model is computed many times. An OBB tree based culling operation is implemented for selecting polygons sufficiently close to the point. Close points usually refer similar set of polygons as their close ones. By using this spatial coherency, proposed parallel algorithm is designed to compute distances between a cluster of close points and the polygons selected by the culling operation so that the fast shared memory mechanism of GPU is fully utilized. As an application of the distance field, a thickness evaluation and visualization algorithm of a solid object is also developed. A program based on this algorithm can compute the distance field of a complex object and visualize its thickness in a few minutes.
Proc. of ISCIE/ASME 2014 International Symposium on Flexible Automation, 14 Jul. 2014, [Reviewed]
Automatic detection of the optimal ejecting direction based on a discrete Gauss mapMasatomo Inui; Hidekazu Kamei; Nobuyuki Umezu, In this paper, the authors propose a system for assisting mold designers of plastic parts. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with minimum undercuts. Since plastic parts are generally very thin, many rib features are placed on the inner side of the part to give sufficient structural strength. Our system extracts the rib features from the CAD model of the part, and determines the possible ejecting directions based on the geometric properties of the features. The system then selects the optimal direction with minimum undercuts. Possible ejecting directions are represented as discrete points on a Gauss map. Our new point distribution method for the Gauss map is based on the concept of the architectural geodesic dome. A hierarchical structure is also introduced in the point distribution, with a higher level “rough” Gauss map with rather sparse point distribution and another lower level “fine” Gauss map with much denser point distribution. A system is implemented and computational experiments are performed. Our system requires less than 10 seconds to determine the optimal ejecting direction of a CAD model with more than 1 million polygons., Society for Computational Design and Engineering
Journal of Computational Design and Engineering, 01 Jan. 2014,
[Reviewed] Manufacturing Assistance by Specifying Additional Geometric Information to CAD ModelsGunji Hiromichi; Inui Masatomo; Umezu Nobuyuki, 設計段階にCADモデルを用いて，製品機能だけでなく，製品の加工性や組み立て性を評価することが一般的になっている．これらの作業では，簡易な加工シミュレーションや組み立て解析を行うことが多い．本研究では，このような解析時に用いた図形情報を，CADモデルに積極的に付加し製造工程へ送ることで，後工程の作業を軽減し，製造プロセスの一層の効率化実現を目指す．曲面加工や放電加工用データの作成に有用なデータの付加を例に本研究の考え方を示す．, The Japan Society for Precision Engineering
Proceedings of JSPE Semestrial Meeting, 2013
A Comparison of Two Methods for Geometric Milling Simulation Accelerated by GPUMasatomo Inui; Nobuyuki Umezu; Yuuki Shinozuka, Lead, For detecting potential problems of a cutter path, cutting force simulation in the NC milling process is necessary prior to actual machining. A milling operation is geometrically equivalent to a Boolean subtraction of the swept volume of a cutter moving along a path from a solid model representing the stock shape. In order to precisely estimate the cutting force, the subtraction operation must be executed for every small motion of the cutter. By using GPU, the required time for the subtraction can be drastically reduced. In this paper, the computation speed of two known GPU accelerated geometric milling simulation methods, which are the depth buffer based method and the parallel processing based method with CUDA language, are compared. Computational experiments show that the implementation with CUDA is several times faster than the depth buffer based method when the cutter motion in the simulation process is sufficiently small., AMER SOC MECHANICAL ENGINEERS
Proc. of the ASME 2012 International Symposium on Flexible Automation, ISFA2012, 2013,
[Reviewed] Fast detection of head colliding shapes on automobile partsMasatomo Inui; Nobuyuki Umezu, In the ECE regulation, any surface of the interior part of automobiles must have sufficient roundness where a sphere of diameter 165mm, which is equivalent to the average head size of infants, may collide. A system for automatically detecting sphere contacting shape on the automobile part is developed. In the current practice, some Japanese automobile manufactures detect the shape by using the virtual milling method. In this method, a milling simulation with a ball end cutter of diameter 165mm is executed on the part to detect the sphere contacting shape. The method generally needs a lot of computation time for the detection. In this paper, the authors propose an improved virtual milling method for fast detecting the sphere contacting shape. Our algorithm initially generates points sufficiently covering the visible surface of the model. For each point, the contact condition of the cutter is evaluated by using the inverted offset surface of the part. An inverted offsetting method accelerated with the depth buffer mechanism of GPU is introduced. An experimental system is implemented and some computational experiments are performed. Our system can detect the sphere contacting shape on the part surface with approximately 1 million polygons in a few seconds. © 2013 by JSME.
Journal of Advanced Mechanical Design, Systems and Manufacturing, 2013
Automatic Detection of Ejecting Direction of a Part with Minimum Undercuts
Masatomo Inui; Hidekazu Kamei; Nobuyuki Umezu, Lead, In this paper, the authors propose a system for assisting mold designers of plastic parts. Plastic parts are usually produced by the injection molding. In this method, the formed part must be removed from the mold in a single ejecting direction. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with the minimum undercuts. Since plastic parts are generally very thin, many rib features are placed in the inner side of the part to give sufficient structural strength to the part. Each rib feature strictly constrains the possible ejecting direction. Our system extracts the rib features from the CAD model of the part, and determines the range of the possible ejecting direction based on the geometric properties of the features. The system then selects the optimal direction with the minimum undercuts. The undercuts detected in the selection process are visualized to the mold designer for assisting the sliding core mechanism design. Such information is helpful for further improving the part design with less undercuts. An experimental system is implemented and computational experiments are performed.
Proc. of 2012 Asian Conference on Design and Digital Engineering, ACDDE 2012, Dec. 2012, [Reviewed]
Cutter Engagement Feature Extraction by Using Dexel Representation Solid ModelMasatomo Inui; Nobuyuki Umezu, Lead, Computer simulation of the cutting force change in a milling process is important for realizing more stable, precise, and efficient metal cutting. In the latest cutting force simulation method, a cutter engagement feature representing a contact area between the milling cutter and the workpiece must be extracted for each small motion of the cutter. In this paper, a new algorithm is proposed for computing a cutter engagement feature based on the dexel representation of the workpiece. Most prior studies compute the feature based on the cutter removal volume of the workpiece. Differently from them, our technology computes the cutter engagement feature based on the contact analysis between the cutter and dexels representing the workpiece shape. An experimental system is implemented and computational experiments are performed. Our system can complete the cutter engagement feature extraction of a complex 3-axis NC milling process in a few minutes., TRANSACTION PUBLISHERS
Proc. of 14th International Conference on Precision Engineering, ICPE 2012, Nov. 2012,
[Reviewed] Fast Estmation of Milling Result with GPU
Masatomo Inui; Nobuyuki Umezu; Marie Fushimi, In this paper, the authors propose a new method for estimating the result shape of the milling operation. The automation of the process planning is strongly requested for realizing faster and more economical production of the mold and die. Our developed technology is expected to be used as a basic tool for the process planning automation. Milling result estimation is realized in 3 steps, initial cutter path generation, modification of the cutter path for avoiding holder collisions, and milling simulation. In the last step, some portions of the workpiece are removed, therefore the cutter can mill the workpiece more deeply without holder collisions. Our system thus modifies the cutter path according to the updated workpiece shape and executes the milling simulation again. This simulation and path modification processes are iterated until the workpiece removal by the cutter does not occur. The cutter path generation and the milling simulation are generally time-consuming. Our system realizes the fast computation with good use of the hardware acceleration with GPU. The developed system can visualize the milling result in a minute even for a large mold of an automobile bumper.
Advanced Science Letters, 2012
Clearance Verification between Stamping Dies by Using Virtual Die Machining MethodMasatomo Inui; Yuji Hasegawa; Nobuyuki Umezu, In the press-working of sheet metal parts for automobile bodies, two stamping die CAD models with mutually inverted curved surfaces are necessary. They are designed to have some clearance between them when they are assembled so that they can properly hold a sheet metal within. Since these two models have very similar curved surfaces, engineers usually design a single CAD model only. The other model is obtained by copying, partly modifying, and inverting the designed model. The modification is generally very small and limited, and the visual inspection of the modified shape is difficult. False modifications often cause bad results in the later trial press-working process and expensive design reworks become necessary. In order to assist the stamping die designer, the authors developed an algorithm for visually inspecting the clearance between the designed model and virtually machined model of its modified counterpart. A fast clearance inspection between 2 models is achieved by using the hierarchical structure of OBBs and the multiple-threading technology., The Japan Society for Precision Engineering
Journal of the Japan Society for Precision Engineering, 2012
The Optimal Cutter Length Determination for Fixed 5-Axis MillingWenli Huang; Masatomo Inui; Zhihui Shi, Fixed 5-axis milling machining has been the most preferred method in fabricating dies and molds with very deep shapes. In the process planning of such machining, determining of the cutter length is a time consuming task. In this paper, an algorithm for automatically determining the optimal cutter length for the fixed 5-axis milling operation is proposed. The optimal length can be derived by computing the distance between the cutter location points and an offset shape of the workpiece by the inverted zero-length cutter. These computations of the offset shape can be accelerated by using the depth buffer mechanism of GPU which is now installed on most PCs. An experimental system is implemented and some computational experiments are performed., TRANS TECH PUBLICATIONS LTD
Advanced Material Research, 2012,
[Reviewed] Fast Estimation of Milling Result with GPU
Masatomo Inui; Nobuyuki Umezu; Marie Fushimi, Lead, In this paper, the authors propose a new method for estimating the result shape of the milling operation. The automation of the process planning is strongly requested for realizing faster and more economical production of the mold and die. Our developed technology is expected to be used as a basic tool for the process planning automation. Milling result estimation is realized in 3 steps, initial cutter path generation, modification of the cutter path for avoiding holder collisions, and milling simulation. In the milling simulation, some portions of the workpiece are removed, therefore the cutter can mill the workpiece more deeply without holder collisions. Our program thus modifies the cutter path according to the updated workpiece shape and executes the milling simulation again. This simulation and path modification processes are iterated until the workpiece removal by the cutter does not occur. The cutter path generation and the milling simulation are generally time-consuming. Our program realizes the fast computation with good use of the hardware acceleration with GPU. Developed program can visualize the milling result in a minute even for a large mold of an automobile bumper.
Proc. of 2011 Asian Conference on Designing and Digital Engineering, ACDDE 2011, 27 Aug. 2011, [Reviewed]
Fast Estimation of Milling Result with Geometric Processing UnitMasatomo Inui; Nobuyuki Umezu; Marie Fushimi, Lead, In this paper, the authors propose a new method for estimating the result shape of the milling operation. The automation of the process planning is strongly requested for realizing faster and more economical production of the mold and die. Our developed technology is expected to be used as a basic tool for the process planning automation. Milling result estimation is realized in 3 steps, initial cutter path generation, modification of the cutter path for avoiding holder collisions, and milling simulation. In the milling simulation, some portions of the workpiece are removed, therefore the cutter can mill the workpiece more deeply without holder collisions. Our program thus modifies the cutter path according to the updated workpiece shape and executes the milling simulation again. This simulation and path modification processes are iterated until the workpiece removal by the cutter does not occur. The cutter path generation and the milling simulation are generally time-consuming. Our program realizes the fast computation with good use of the hardware acceleration with GPU. Developed program can visualize the milling result in a minute even for a large mold of an automobile bumper.
Proc. of 2011 Asian Conference on Designing and Digital Engineering, ACDDE 2011, 27 Aug. 2011,
[Reviewed] A Hybrid Collision Detection Method for Anti-Crash
Masatomo Inui; Nobuyuki Umezu; Yuji Hasegawa, Lead, In this paper, a new CPU/GPU hybrid algorithm is proposed for detecting collisions between rigid objects. This algorithm is developed as a collision detection engine of a new Anti-Crash system. The proposed algorithm is fast, precise, and applicable to large and complex objects with huge number of polygons. In our broad phase collision detection, a culling program based on the OBB tree is executed on CPU to efficiently exclude apparently non-colliding polygons. In the following narrow phase collision detection, parallel processing capability of GPU is used for detecting mutually penetrating polygons. The authors develop a new penetration detection program for GPU based on ERIT’s method. A sample program is implemented and tested with complex examples. Our program needs only a few milliseconds for detecting all collisions among free falling objects whose total number of polygons is approximately 10 million.
Proc. of 2011 Asian Conference on Designing and Digital Engineering, ACDDE 2011, 27 Aug. 2011, [Reviewed]
Fast Safety Verification of Interior Parts of AutomobilesSatoru Yamazaki; Takahiro Baba; Nobuyuki Umezu; Masatomo Inui, Last, A program for automatically verifying safety regulations specified on the interior part of the automobile is developed. In the ECE regulation, any surface of the interior part is requested to have roundness larger than R3.2 where a sphere of diameter 165mm can collide. Our developed program initially generates points sufficiently covering the visible surface of the model. For each point, sphere-object intersections associated with the regulations are evaluated. If the surface portion around the point cannot satisfy the geometric condition of the regulation, red color is painted to the point. As the result, corner shapes of the CAD model with possibly injuring the driver and passenger in the car crash are extracted and displayed.
Proc. of 2011 IEEE International Conference on Mechatronics and Automation, ICMA 2011, 07 Aug. 2011,
[Reviewed] Fast Thickness Evaluation of Solid Models by Using Parallel Processing Function of GPUSatoru Yamazaki; Nobuyuki Umezu; Masatomo Inui, In the current manufacturing practice, injection molding is widely used for fabricating plastic parts of various consumer products, such as digital cameras, printers and other electric appliances. In designing a plastic part, thickness of the part is defined to be constant all over the surface, otherwise some deformations happen in the molding process which deteriorate the aesthetic quality of the product. In this paper, the authors propose a fast algorithm for evaluating the thickness of the solid model. Existing commercial CAD systems provide some thickness measuring functions of solid models. These functions are, however, not appropriate for evaluating thickness of the complex shape. In this paper, a new definition of the thickness of the solid model is proposed. Using the definition, a fast thickness evaluation algorithm with the oriented bounding box (OBB) and the parallel processing capability of GPU is developed. A system is implemented and some computational experiments are performed., The Japan Society for Precision Engineering
Journal of the Japan Society for Precision Engneering, 05 Aug. 2011,
[Reviewed] A Dexel Based Algorithm for Evaluating Thickness of Solid Models
S.Yamazaki; N.Umezu; and M.Inui, Last, In the current manufacturing practice, injection molding is widely used for fabricating plastic parts of various consumer products such as digital cameras, printers, and other electric appliances. In designing a plastic part, thickness of the part should be constant all over the surface, otherwise some deformations happen in the molding process which deteriorate the aesthetic quality of the product. In this paper, the authors propose a fast algorithm for evaluating the thickness of the solid model. Most commercial CAD systems provide some kinds of thickness measuring functions of solid models, these functions, however, are not appropriate for evaluating thickness of the complex shape. In this paper, a new definition of the thickness of the solid model is proposed. Based on the definition, a dexel based thickness evaluation algorithm is developed. A depth peeling based method for converting a boundary representation solid model into a solid model in the dexel representation is also proposed. A system is implemented and some computational experiments are performed.
2010 Asian Conference on Designing and Digital Engineering (2010 ACDDE), 25 Aug. 2010, [Reviewed]
GPU ACCELERATION OF 5-AXIS MILLING SIMULATION IN TRIPLE DEXEL REPRESENTATION
Masatomo Inui and Nobuyuki Umezu, Lead, In the triple dexel model, object shape is represented by 3 groups of axis aligned segments named X-axis dexels, Y-axis dexels, and Z-axis dexels. Triple dexel model is known as compact and precise representation compared with other discrete solid representation schemes. Based on the triple dexel representation, a new 5-axis milling simulation system is developed. Differently from prior systems, this system uses GPU technologies for accelerating 3 important processing steps in the milling simulation, which are (1) cutter swept volume generation, (2) subtraction of the swept volume from the workpiece solid model, and (3) update of the workpiece picture for achieving fast animation of the milling process. An experimental system is implemented and some computational experiments are performed. Our system can realize a geometric simulation of a complex 5-axis milling process in a few minutes. The animation speed is generally more than 100 frames per second.
Proc. of 2010 International Symposium on Flexible Automation, 12 Jul. 2010, [Reviewed]
An Algorithm for Determining The Optimal Cutting Direction in Rough Milling of Impellers
W.Huang and M.Inui, Fixed 5-axis milling method is usually a good choice for rough milling of impellers, because of higher stiffness of the cutter and simpler cutter path generation. Determination of the proper cutter posture in machining is, however, a time-consuming task at present. In this paper, a novel method is proposed to automatically determine the optimal cutter posture for the rough milling operation of impellers. The important characteristics of the algorithm are: (1) selection of candidate cutter axis directions based on some geometric properties of the impeller and (2) determination of the optimal cutter axis direction from the candidates based on the estimation of the remained material after the milling operation. In the remained material estimation, the cutter path generation and milling simulation are executed for each candidate cutter axis direction. These computations are accelerated by using a graphics processing unit (GPU) in the developed program. An experimental system is implemented and some computational experiments are performed to verify the practical applicability.
International Symposium on Factory Automation (2010 ISFA), 12 Jul. 2010, [Reviewed]
Implementation of a 5-Axis Milling Simulation System Using Triple Dexel ModelsMasatomo INUI and Nobuyuki UMEZU, In the triple dexel model, object shape is represented by 3 groups of axis aligned segments named x-axis dexels, y-axis dexels, and z-axis dexels. Triple dexel model is known as compact and precise representation compared with other discrete solid representation schemes. Based on the triple dexel representation, a new 5-axis milling simulation system is developed. Differently from prior systems, this system uses GPU technology for accelerating 3 important processing steps in the milling simulation, which are (1) cutter swept volume generation, (2) subtraction of the swept volume from the workpiece solid model, and (3) update of the workpiece picture for achieving smooth animation of the milling process. An experimental system is implemented and some computational experiments are performed. Our system can realize a simulation of a complex 5-axis milling process in a few minutes. The animation speed is generally more than 100 frames per second., The Japan Society for Precision Engineering
journal of the Japan Society for Precision Engineering, 05 Mar. 2010,
[Reviewed] Algorithm for Determining the Optimal Cutter and Shank Length for Fixed 5-Axis MachiningWenli HUANG and Masatomo INUI, Dies and molds with very deep shapes are often fabricated using a fixed 5-axis milling machine. In the process planning of such machining, determination of the cutter and shank length is a time consuming task. In this paper, an algorithm for automatically determining the optimal cutter and shank length for fixed 5-axis milling operation is proposed. The optimal length can be derived by comparing a Minkowski sum object of the workpiece and the inverted zero-length cutter, and another Minkowski sum object of the part shape and the inverted cutter. These computations of Minkowski sum objects can be accelerated by using the depth buffer mechanism of GPU which is now installed on most PCs. An experimental system is implemented and some computational experiments are performed. Our system can determine the optimal cutter and shank length for milling a complex mold in a minute., The Japan Society for Precision Engineering
Journal of the Japan Society for Precision Engineering, 05 Feb. 2010,
[Reviewed] Data Conversion Technology between Triple Dexel Model and Polygonal ModelMasatomo INUI; Takashi SAKURAI and Nobuyuki UMEZU, In the triple dexel model, an object shape is represented with 3 groups of axis aligned segments named X-dexels, Y-dexels, and Z-dexels. In this paper, the authors propose a data conversion method from a conventional polygonal model such as STL to a triple dexel model, and vice versa. In this method, the following technology is employed; (1) Data conversion from a polygonal model to a triple dexel model is realized by multiple applications of “depth peeling”. This process can be accelerated by using the depth buffer and stencil buffer mechanisms of GPU. (2) Data conversion from a triple dexel model to a polygonal model is realized by gathering and classifying polygons attached to the end point of neighboring dexels. An experimental conversion program is implemented and some computational experiments are performed. Our program can convert a polygonal model with 3,000,000 polygons to a triple dexel model with 1024 x 1024 resolution grids in 8 seconds. Reverse conversion from a triple dexel model to a polygonal model is realized in a second., The Japan Society for Precision Engineering
Journal of the Japan Society for Precision Engineering, 05 Feb. 2010,
[Reviewed] Cutter Accessibility Analysis of a Part with Geometric UncertaintiesMasatomo Inui; Kazuhiro Maida; Yuji Hasegawa, In designing a holder part of a large stamping die, designers must consider not only the functional property of the part, but also its manufacturability. The holder part is usually produced by cutting and engraving table, wall, slot and pocket features into a raw cast object. The raw cast object has inevitable large shape errors. It generally has 5 to 10mm shape difference from the nominal CAD model. This shape uncertainty causes various manufacturability problems in the milling process. The most serious problem is unexpected collisions between a cutter and raw cast object. They cause possible tool breakages and become obstructions to the cutter access to some regions on features. Since such features are not properly machined, costly re-designing the holder part is necessary. In this paper, the authors propose a manufacturability analysis system which can detect such un-machinable features caused by the shape uncertainty of the raw cast object. Proposed system computes a geometric model of a holder part with the maximum shape error by modifying the CAD model. Inverted offsetting and cutting simulations are successively applied to the model to extract the un-machinable region on the features. A system is implemented and some computational experiments are performed., SPRINGER-VERLAG BERLIN
FRONTIERS OF ASSEMBLY AND MANUFACTURING, 2010,
[Reviewed] Cutter Accessibility Analysis of a Part with Geometric UncertaintiesMasatomo Inui; Kazuhiro Maida; and Yuji Hasegawa, Lead, In designing a holder part of a large stamping die, designers must consider not only the functional property of the part, but also its manufacturability. The holder part is usually produced by cutting and engraving table, wall, slot and pocket features into a raw cast object. The raw cast object has inevitable large shape errors. It generally has 5 to 10mm shape difference from the nominal CAD model. This shape uncertainty causes various manufacturability problems in the milling process. The most serious problem is unexpected collisions between a cutter and raw cast object. They cause possible tool breakages and become obstructions to the cutter access to some regions on features. Since such features are not properly machined, costly re-designing the holder part is necessary. In this paper, the authors propose a manufacturability analysis system which can detect such un-machinable features caused by the shape uncertainty of the raw cast object.
Proc. of 2009 IEEE International Symposium on Assembly and Manufacturing, 17 Nov. 2009,
[Reviewed] Study on Computer-Aided Process Planning of Mold Part Machining,- Automatic Subdivision Algorithm of Machining Region for Inclined Cutting using Cluster Analysis -Masatomo INUI; Hideki AOYAGI, Large molds with very deep shape are used in producing plastic parts such as bumpers and inner panels of automobiles. In order to realize the precise and stable machining of the deep mold, 3-axis milling with inclined cutters is often applied in Japanese manufactures. Some machining regions are difficult to process with a cutter in a single orientation. Such regions must be subdivided into several smaller regions, so that each region can be processed with a single orientation cutter. The authors propose a new algorithm for automatically subdividing a machining region. A machining region is represented as a set of points covering the region. For each point, all accessible directions of a cutter are computed. Points are then classified into some groups based on the distribution pattern of accessible directions using our improved cluster analysis method. The classification result corresponds to the milling region subdivision., The Japan Society for Precision Engineering
Journal of the Japan Society for Precision Engineering, 01 Sep. 2009,
[Reviewed] An Algorithm for Determining the Optimal Cutter Length in 3-Axis MillingWenli HUANG; Masatomo INUI, Last, Fixed 3-axis milling has been the most popular method for the die and mold fabrication. Determining the optimal cutter length is a time consuming and critical task in process planning, especially for milling deep and complex molds for bumpers, inner panels and lighting components of automobiles. In this paper, the authors propose an inverted offset based method for automatically determining the optimal cutter length. Inverted offsetting is one of Minkowski sum operation with a solid model and an inverted shape of a milling cutter. In the 3-axis milling, the optimal cutter length can be derived by comparing two inverted offsetting results: an object from the part shape and the inverted cutter, and another object from the workpiece shape representing the prior machining result and the inverted zero length cutter. An experimental system is developed and some computational experiments are performed to confirm the practical applicability of the method., IEEE
Proc. 2009 IEEE International Conference of Mechatronics and Automation(2009 ICMA), 12 Aug. 2009,
[Reviewed] Development of Manufacturability Verification System for Assisting Mold Design,- Computation of Shape Modification Range to Resolve Unmanufacturable Features -Masatomo INUI, In designing a holder part of a large stamping die, designers must consider not only the functional property of the holder, but also its manufacturability. The holder part is produced by cutting and engraving table, wall, slot and pocket features into the raw cast shape. Since designers do not always have enough knowledge about the manufacturing method, they sometimes design a part with some unmanufacturable features. The author develops a new system for suggesting a design modification method to eliminate such unmanufacturable ones. This system automatically determines some optimum positions of a cutter for completely machining the unmanufacturable feature. Such cutters in the optimum positions have interferences with the holder part. Our system visualizes the interference volume between the cutter and the holder part. The designer can determine the design modification method of the holder part based on the interference volume., The Japan Society for Precision Engineering
Journal of the Japan Society for Precision Engineering, 01 Jul. 2009,
[Reviewed] 金型加工における機械加工検証システムの開発（第１報）－鋳物形状誤差を考慮した加工困難形状の検出－
乾正知; 大友祐二, 自動車のプレス用金型の構造部は，鋳物を削り出して製造する．鋳物には数ミリの形状誤差が避けられない．この誤差の影響を考慮し忘れて，加工困難な形状を設計してしまうことが問題になっている．本研究では，ＣＡＤモデルに鋳物誤差分の修正を加え，修正後のモデルに基づいて加工シミュレーションを行うことで，誤差に起因する加工困難形状を自動抽出する技術を開発した．
精密工学会誌, Mar. 2009, [Reviewed]
Automatic Subdivision of Milling Region for 3-Axis Milling Machine with Inclined Cutter
Masatomo INUI; Kuninori MORIMOTO, Lead, Large molds with very deep shape are used in producing bumpers and inner panels of automobiles. In order to realize the precise and stable machining of such deep molds, 3-axis milling machines with a cutter in a fixed inclined orientation are often used in Japanese manufacturers. Some milling regions are difficult to process with a cutter in a single orientation. Such regions must be subdivided into several smaller regions, so that each region can be properly processed with a single orientation cutter. In this paper, the authors propose a new algorithm for automatically subdividing such an unmanufacturable milling region. The milling region is represented as a set of points in our study. For each point, all accessible directions of a cutter are computed. Neighboring points with similar cutter accessible directions are then combined, and some groups of points with common accessible directions are obtained as a subdivision result. Proposed algorithm is implemented and an experimental program using this technology is demonstrated.
Proc. 2008 International Symposium on Flexible Automation, Aug. 2008, [Reviewed]
Kuninori Morimoto, Masatomo Inui
Study on Computer-Aided Process Planning of Mold Part Machining -Automatic subdivision algorithm of machining regions for inlcined cutting-, 金型加工の傾斜加工において，一つの工具軸方向からだけでは加工が困難な領域が与えられた時，その領域を一つの工具軸方向から加工可能な複数の領域に自動分割するアルゴリズムを開発した．
Journal of the Japan Society for Precision Engineering, 01 Feb. 2008, [Reviewed]
A GPU based Algorithm for Determining the Optimal Cutting Direction in Deep Mold MachiningKuninori Morimoto and Masatomo Inui, Last, Large molds with very deep shape are well used in producing bumpers and inner panels of automobiles. In order to realize the precise and stable machining of such deep molds, 3-axis milling with inclined cutters are often applied. In this paper, we propose a new algorithm for determining the optimal cutting direction in such inclined machining. We introduce a concept of accessibility cone as a measure for evaluating the stability and safety in the inclined machining, and we define the optimal cutting direction as the direction whose corresponding accessibility cone has the maximum peak angle. An accessibility cone for a specific cutting direction can be derived by rendering a silhouette picture of the offset shape of the mold. This computation can be accelerated by using a graphics processing unit (GPU) which is now equipped in most PCs. Proposed algorithm is implemented and an experimental process planning assistance program using this technology is demonstrated., IEEE
Proc. IEEE International Symposium on Assembly and Manufacturing, ISAM 2007, 22 Jul. 2007,
[Reviewed] Using a GPU to Accelerate Die and Mold Fabrication
M.Inui and A.Ohta, 自動車の金型製造において重要な役割を果たす逆オフセット面の計算と加工シミュレーションを，GPUの機能を用いて劇的に高速化するアルゴリズムを開発した．さらにそれを実際の金型製造に適合するように改良する技術を紹介した．
IEEE Computer Graphics and Applications, Feb. 2007, [Reviewed]
金型加工の工程設計支援技術に関する研究（第二報）－安定した金型加工のための最適な工具姿勢の決定アルゴリズム－森本國文; 乾正知, 深い金型を精度よく切削するために，多くの自動車メーカは，工具の主軸を傾けて加工する手法を採用している．工具の傾斜角度や傾斜方向は慎重に定めないと工具と金型が干渉する問題が発生しやすい．この問題解決を実現するために，金型のオフセット形状の透視投影によるシルエットを描き，そこから最適な工具姿勢を抽出する技術を開発した．, The Japan Society for Precision Engineering
精密工学会誌, Feb. 2007,
[Reviewed] Data Compression Method of Z-Map Model Representing Milling Result Shape
Masatomo INUI; Riaki ISHIZUKA, Lead, Zマップ形式の立体モデルが，デジタル表現されたグレースケール画像と類似の形式であることに着目し，Zマップモデルを画像圧縮の一形式であるウェーブレット縮退により高効率かつ高品質に圧縮する技術を示した．
Proc. 2006 International Symposium on Flexible Automation (2006 ISFA), Jul. 2006, [Reviewed]
金型加工の工程設計支援技術に関する研究（第一報）－削り残り領域の逆オフセット面への投影アルゴリズム－Masatomo INUI, 金型製造の工程設計支援を目的に，削り残り領域を逆オフセット面へ投影するアルゴリズムを開発した．粗加工では，大径の工具を用いて素材を除去するため，製品の凹形状の部分に削り残りが生じてしまう．削り残りは，次の中仕上げにおいて，より小径の工具を用いて除去することになる．中仕上げ加工のための工具経路は，製品形状を工具の逆形状分膨らませた逆オフセット面上に生成される．そこで粗加工での削り残り部が，中仕上げ加工のための逆オフセット面のどの部分に対応するのかを高速かつ安定に計算するアルゴリズムを開発した．, The Japan Society for Precision Engineering
精密工学会誌, Feb. 2006,
[Reviewed] Inverse Offset of Z-map Model for Process Planning Assistance
Masatomo INUI; Tomoyuki MIYASHITA, Zマップ形式で離散的に表現された立体モデルを効率的に逆オフセットする手法を開発し，それを金型加工の工程設計支援に適用する技術を紹介した．
Proc. 2005 IEEE International Symposium on Assembly and Task Planning (ISATP 2005), Jul. 2005, [Reviewed]
ボロノイ図とタブーサーチを融合した配電計画評価手法
Yasuhiro HAYASHI; Jyunya MATSUKI; Masaki NOSE; Masatomo INUI, 配電計画の評価法としてボロノイ図を用いた手法を提案した．（ボロノイ図を高速・安定に計算するアルゴリズムを開発した．）
電気学会論文誌Ｂ, Oct. 2003, [Reviewed]
Fast Inverse Offset Computation using Polygon Rendering HardwareM.Inui, Mold and die parts are usually fabricated using 3-axis numerically controlled milling machines with ball-end, flat-end or round-end cutters. The cutter location (CL) surface representing a trajectory surface of the cutter's reference point when the cutter is slid over a part is important for preventing the gouging problem. This surface is equivalent to the inverse offset shape of the part, which is the top surface of the swept volume of the inverse cutter moving around the part surface. The author proposes a fast computation method of the inverse offset shape of a polyhedral part using the hidden-surface elimination mechanism of the polygon rendering hardware. In this method, the CL surface is obtained by simply rendering the component objects of the swept volume. An experimental program is implemented and demonstrated. (C) 2002 Elsevier Science Ltd. All rights reserved., ELSEVIER SCI LTD
Computer-Aided Design, Feb. 2003,
[Reviewed] Distribution System Planning Evaluation Method Using Voronoi Diagram and Tabu SearchYasuhiro Hayashi; Junya Matsuki; Masaki Nose; Masatomo Inui, Distribution planning must be carried out by considering (1) geographic information such as allocation of loads and feeders, (2) operational conditions such as line current capacity, voltage drop limit and distribution loss, and (3) facility cost and so on. In order to systematically support the above work by computational approach, optimization techniques are available. In this paper, a computational method to support distributional planning systematically is proposed by introducing (1) geographical optimization technique and (2) configuration optimization technique. The geographical optimization is to determine which of sectionalized lines should supply power to future appeared loads so as to maximize availability ratio of feeders. The configuration optimization is to determine states of sectionalizing switches (opened or closed) so as to minimize distribution loss under the constraints such as the line current capacity, voltage drop limit and radial structure. In the proposed method, after the geographical optimization is carried out to determine future section loads, operational conditions are evaluated by the configuration optimization. If the operational constraints are not satisfied, previously prepared expansion plan candidates are evaluated quantitatively, and then the best candidate is decided. Voronoi diagram is applied to realize the geographical optimization, and tabu search is used to accomplish the configuration optimization. In order to check the validity of the proposed method, numerical results are shown for a distribution system model. © 2003, The Institute of Electrical Engineers of Japan. All rights reserved.
IEEJ Transactions on Power and Energy, 2003,
[Reviewed] NC加工命令の高速な生成手法 ―逆オフセット法の高精度化―乾正知; 崔原己, 従来の逆オフセット法では，形状表現にZマップを用いることが一般的であった．Zマップでは，垂直に近い形状を正確に表現できないため，等高線状に移動する工具のNC命令の生成に問題があった．ボクセル表現を導入し，マーチング・キューブ法を併用することで，逆オフセット法を高精度化する技術を開発した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
精密工学会誌, Oct. 2002,
[Reviewed] Hardware Acceleration of NC Milling Simulation
M.Inui, Lead, 論文19の内容を拡張し，複雑なフラットエンドミル加工やラウンドエンドミル加工の結果も，グラフィックス・ハードウェアの機能を用いることで，高速に可視化できることを示した．
Proc. Asia-Pacific Forum on Precision Surface Finishing Technology, Nov. 2001, [Reviewed]
Physically-Based Geometric Constraint Resolution
M.Inui; H.Tohyama and M.Miura, Lead, 図形の配置に関する制約を寸法制約と領域的な制約の二つに分類し，その両者が図形間の非干渉条件の特殊な場合として表現できることを示した．この条件を満たす図形配置を自動決定する手法として，バーチャル・リアリティの分野で開発された力学的なシミュレーション技術を用いることを提案した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Proc. 2001 IEEE Int. Symp. on Assembly and Task Planning, May 2001, [Reviewed]
Fast NC Milling Animation Using Partial Redrawing Technique
M.Takano and M.Inui, Last, 切削加工が安全に実行できること確認するために，多くのCAMシステムは加工アニメ－ション機能を用意しているが，現在の技術ではアニメーション速度と得られる画像の品質に問題があった．切削加工にともなう工作物の形状変化が局所的であることを利用して，高速かつ滑らかな加工アニメーションを実現する手法を開発した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Journal of Information Processing Society of Japan, Mar. 2001, [Reviewed]
Fast Inverse Offset Computation Using Graphics Acceleration Hardware乾正知; 垣尾良輔, 金型切削用のNC命令を自動生成する手法の一つに，製品形状と工具の逆形状のミンコウスキ和を計算する逆オフセット法がある．逆オフセット法における主要な計算は，デプス・バッファを用いた立体の隠面消去演算に置き換えられる．この考え方に基づいて，逆オフセット法をハードウェア処理する技術を開発した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）, The Japan Society for Precision Engineering
Journal of the Japan Society for Precision Engineering, Dec. 2000,
[Reviewed] NC加工結果の高速な可視化手法 ―離散的に表現された切削加工面の高品質な表示―乾正知; 垣尾良輔, Zマップ表現された立体モデルを描画すると，垂直に近い壁面部において，不自然な凹凸が生じてしまう．切削シミュレーション中に，加工面の法線方向を適切に記録することで，Zマップ表現された工作物モデルを正確に描画する技術を開発した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）, The Japan Society for Precision Engineering
精密工学会誌, Jul. 2000,
[Reviewed] Fast Bending Sequence Planning for Progressive Press-Working
M.Inui and H.Terakado, Lead, 板金製品の多くは順送加工により製造される．この加工の工程設計において最も手間を要するのは，その曲げ手順の決定である．順送加工に関する様々な幾何制約を考慮することで，全ての可能な曲げ手順を高速に決定するアルゴリズムを設計し，試作プログラムによりその有効性を検証した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Proc. 1999 IEEE Symp. or Assembly and Task Planning, Jul. 1999, [Reviewed]
Fast Simulation of Sculptured Surface Milling with 3-Axis NC Machine
M.Inui; M.Kaneda and R.Kakio, Lead, NC切削加工のシミュレーションでは，工具の移動形状と工作物モデルの集合演算が頻繁に繰り返される．この処理を高速化するために，移動形状を包含するボックスに基づく，ラフチェックがよく用いられる．移動形状の幾何的な特徴に基づいてボックスを非常にタイトに定義することで，シミュレーションを従来技術と比較して数倍高速化することに成功した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Journal of Information Processing Society of Japan, Apr. 1999, [Reviewed]
Fast Evaluation of Geometric Constraints for Bending Seguence Planning
M.Inui and H.Terakado, Lead, 板金製品の工程設計問題では，曲げ作業における板金の自己干渉や，製品と工具や取り付け具の干渉を頻繁にチェックする必要がある．板金製品の幾何的な特徴に注目することで干渉判定を高速化し，可能な全ての曲げ加工手順を効率的に生成するアルゴリズムを開発した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Proc. of IEEE Conference on Robotics and Automation, ICRA 1998, May 1998, [Reviewed]
A Physically-Based Method for Assisting Intevactive Polygon Layout
三浦政宏; 乾正知, 図形の配置設計を計算機支援する手法として，図形の位置，姿勢に関する各種制約を図形間の非干渉条件により統一的に表現し，力学的なシミュレーション技術により解く手法を開発した．アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Journal of the Japan Society for Precision Engineering, Oct. 1997, [Reviewed]
A Robust Algorithm for Slicing Polyhedra乾正知; 寺門宏明, 多面体の集合演算のうち，特に凸多面体の積集合の計算は，多面体を幾つかの平面で切断する処理に帰着する．この計算を安定に実現するために，論文Ⅱ―15に説明した技術を，多面体処理に拡張した手法を開発した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）, Information Processing Society of Japan (IPSJ)
Journal of Information Processing Society of Japan, Aug. 1997,
[Reviewed] Robust Boolean Set Operation of Polygons with Consistent Tolerances
乾正知, 多角形の集合演算を安定化するための新手法として，頂点，辺，面の一致を判定するための公差条件を，互いに整合的に定義する技術を開発した．集合演算において行われる全ての幾何判定を，この整合的な公差条件に基づいて行うことで，決して破綻しない多角形の集合演算プログラムを実現した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Journal of Information Processing Society of Japan, Jun. 1996, [Reviewed]
Cutting and Pasting Constrained Boundary Features
M.Ranta; M.Mantyla; M.Inui and F.Kimura, 立体モデルの一部を切り取り，他の立体モデルへ貼り付ける手法を拡張し，切り取る部分形状に寸法や公差，形状特徴などの制約が付加されている場合にも，適切に処理が行えるようにした．（アルゴリズムの開発の一部を担当した．）
Proc. of 5th IFIP Conference on Computer Applications in Production and Engineering, CAPE '95, Sep. 1995, [Reviewed]
Relative Positioning of Assembled Parts with Small Geometric Deviations by Using Hierarchically Approximated Configuration Space
M.Inui; M.Miura and F.Kimura, Lead, オクツリー表現された配位空間を用いて，微小な形状誤差をともなう部品を組み立てた際に生じる，ノミナルな位置，姿勢からの部品のズレを評価する手法を開発し，実験的な解析プログラムを試作した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Proc. 1995 IEEE Int. Conf. on Robotics and Automation, May 1995, [Reviewed]
Extended Formulation of Geometric Tolerances based on Parametric Modifications of Form Features
M.Inui; N.Matsuki and F.Kimura, Lead, 形状特徴のパラメトリック修正という技術に基づく，立体モデリング向けの新しい幾何公差方式を開発した．この手法は，既存の幾何公差方式と互換性を持つ．この手法を用いると，これまで扱うことが困難であった複雑な形状特徴にも公差を指示できる．（公差方式の定式化，論文の執筆を担当した．）
Proc. IFIP Int. Conf. on Feature Modeling and Recognition in Advanced CAD/CAM Systems, May 1994, [Reviewed]
Algebraic Interpretation of Geometric Tolerances for Evaluating Geometric Uncertainties in Solid Modeling
M.Inui; H.Otto and F.Kimura, Lead, 立体モデリングにおいて幾何公差に相当する機能を実現するために，現行の規格の幾何公差の定義を，立体モデリング向けに拡張する手法を示した．さらにこの拡張された定義を代数的に表現する一手法を示した．（代数的な公差表現の検討，論文の執筆を担当した．）
Proc. of 2nd ACM Symposium on Solid Modeling and Applications, May 1993, [Reviewed]
Cut and Paste Based Modeling with Boundary FeaturesM.Ranta; M.Inui; F.Kimura and M.Mantyla, 立体モデリングの新技術として，モデルの特徴的な部分形状を切り取り，他の立体モデルへ貼り付ける手法を開発した．実験的な処理システムを実装し，その有効性を検証した．（アルゴリズムの検討と，論文の一部執筆を担当した．）, ACM Press
Proc. Second ACM Symp. on Solid Modeling and Applications, May 1993,
[Reviewed] Using a truth-maintenance system to assist product-model construction for design and process planningM.Inui and F.Kimura, Assistance with product-model construction is a fundamental task for computer-aided-design systems. A general mechanism for recording and manipulating model-construction process in computers is proposed in the paper. The model-construction process is considered as a series of model state transitions realized by modeling operations. This process can only be properly recorded with dependencies between the operations. The dependency information is automatically detected on the basis of the conditions necessary for the execution of an operation. An assumption-based truth-maintenance system is used as a tool for recording and manipulating the dependency. Two basic functions for assisting with model-construction activities, an undo function and a model-maintenance function, are realized by using the dependency in a uniform manner. The applicability of these functions is verified using interactive-solid-modeling and machining process-planning examples., ELSEVIER SCI LTD
Computer-Aided Design, Jan. 1993,
[Reviewed] Representation of Modeling Processes by Data Dependency and Its Application for Variational Solid Modeling
乾正知; 木村文彦, 設計作業の進行にともない詳細化されていくモデリング作業の履歴を，計算機を用いて管理する手法として，操作間の依存情報に基づく手法を提案し，ソリッドモデリングの管理に適用した．その結果，モデリングパラメータの一部を変化させることでモデル形状を操作する可変ソリッドモデリング機能を，容易に実現できることを示した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Journal of Information Processing Society of Japan, Jul. 1990, [Reviewed]
A Process Planning System for Producibility Feedback to Designers
M.Ranta; M.Inui and F.Kimura, コンカレント・エンジニアリングを実現するためには，設計変更に起因する工程設計や加工手順の変更を，整合的に管理する仕組みを用意する必要がある．設計作業と工程設計作業の依存情報を管理することで，そのような整合性維持が可能となることを示した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Proc. Third Int. IFIP Conf. on Computer Applications in Production and Engineering, CAPE'89, Oct. 1989, [Reviewed]
製品特徴記述に基づく切削加工情報の自動生成松田三知子; 乾正知; 木村文彦, ポケットを構成する特徴的な部分形状に注目し，ポケットを加工するに最適な切削工具と，その利用手順，そしてNC加工命令などを自動決定する手法を開発した．（アルゴリズムの開発を担当した．）
精密工学会誌, Jul. 1989,
[Reviewed] 製品設計と工程設計を統合する形状特徴モデリング松田三知子; 乾正知; 鈴木宏正; 木村文彦, 複雑なポケット形状特徴を含むプロダクトモデルに対して，幾何推論と呼ばれる手法を適用することで，ポケット形状を適切に分類し，それらの加工順序を自動決定する手法を開発した．（アルゴリズムの開発を担当した．）
精密工学会誌, Dec. 1988,
[Reviewed] Automatic Process Planning for Sheet Metal Parts with Bending Simulation
M.Inui; A.Kinosada; H.Suzuki; F.Kimura and T.Sata, Lead, 板金製品のプロダクトモデルに対して，曲げ加工をシミュレーションする操作を適用することで，曲げ作業の工程設計を自動化する手法を開発した．（アルゴリズムの開発と論文の執筆を担当した．）
Journal of Japan Society of Precision Engineering, Nov. 1988, [Reviewed]
Product Modelling for Flexible Integration of Design and Manufacturing Activities
F.Kimura; H.Suzuki and M.Inui, Last, 設計製造における情報処理環境の基礎として，従来の立体モデリングシステム代わりに，プロダクトモデリングシステムを用いることで，より柔軟な製造作業支援が可能になることを，特にコンカレント・エンジニアリングの視点から論じた．（プログラムの一部実装を担当した．）
Proc. the Second Toyota Conf. on Organization of Engineering Knowledge for Product Modelling in Computer Integrated Manufacturing, Oct. 1988, [Reviewed]
A Product Modeling System for Constructing Intelligent CAD and CAM SystemsH.Suzuki; M.Inui; F.Kimura and T.Sata, 知的なCADシステムを実現するためには，製品の形状情報に加えて，設計者が設計において利用する寸法などの製品情報が，計算機によって適切に自動処理できる必要がある．述語論理をベースとするプロダクトモデリングシステムにより，これらの製品情報が適切に処理できることを示した．（製造の進行にともなう工作物モデルの製品情報の変化を，述語論理に基づいて記述する技術について執筆した．）, PERGAMON-ELSEVIER SCIENCE LTD
Robotics and Computer- Integrated Manufacturing, Oct. 1988,
[Reviewed] Representation and Manipulation of Design and Manufacturing Processes by Data Dependency
M.Inui and F.Kimura, Lead, プロダクトモデルの構築プロセスを記録する方法として，従来のモデリング作業の履歴に基づく手法ではなく．作業間の依存情報に基づく手法を提案した．またATMSとよばれる依存情報管理システムを用いた，モデリングプロセスの管理・処理システムを実装した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Proc. IFIP TC 5/WG 5.2 2nd Workshop on Intelligent CAD, Sep. 1988, [Reviewed]
加工向きプロダクトモデルに基づくマシンニングセンタ用加工命令の自動生成若原剛人; 志村庄司; 乾正知; 佐田登志夫; 木村文彦, 切削加工作業の効率化には，粗加工の自動化が最も効果的である．そこで従来のソリッドモデルに，形状特徴の記述を付加した加工向けプロダクトモデルを考え，その情報を用いて粗加工のためのNC加工命令を自動生成するアルゴリズムを開発した．（アルゴリズムの開発と論文の一部の執筆を担当した．）, The Japan Society for Precision Engineering
精密工学会誌, Jul. 1987,
[Reviewed] Generation and Verification of Process Plans Using Dedicated Models of Products in Computers
M.Inui; H.Suzuki; F.Kimura and T.Sata, Lead, 完成製品の製品情報だけでなく，加工途中の工作物の製品情報も利用することで，従来は困難であった，複雑な機械部品の工程設計が自動化できることを示した．（アルゴリズムの開発，プログラムの実装，論文の執筆を担当した．）
Proc. ASME Symp. on Knowledge- Based Expert Systems for Manufacturing, Dec. 1986, [Reviewed]
Manufacturing Preparation by Use of Product Model in Computer
T.Sata; F.Kimura; H.Hiraoka; H.Suzuki; S.Shimura; Y.Taguichi; M.Miki; and M.Inui, 機械設計や生産の自動化を実現するために不可欠な技術であるプロダクトモデリングの概念を，機械設計，寸法処理，ロボットプログラミング，加工工程設計などの例とともに議論した．（工程設計自動化のためのプロダクトモデルの役割について執筆した．）
Robotics and Computer-Integrated Manufacturing, Oct. 1984, [Reviewed]
