Acceleration of Geometric Computations in CAD and CAM by Using Polygon Rendering Hardware

点击翻译按钮获取中文摘要

In order to follow frequently changing customer preferences and to quickly distribute products with high market competitiveness, Japanese manufacturing companies make efforts to shorten the production preparation time after the design completion. Most time period of the production preparation is consumed for making dies and molds for stamping, casting and plastic molding of parts. Dies and molds are usually fabricated using 3-axis numerically controlled (NC) milling machines with various shape cutters. Computation of the reliable cutter path is still a difficult problem. Several hours are often needed for computing whole cutter paths for milling a complex die. Members in this project jointly develop a new technology for fast generation and verification of the cutter path for NC milling. Our technology uses graphics processing unit (GPU) which is currently equipped in most computers, for accelerating the geometric computation in process planning, NC path generation and path verification. As the result of the project, the following technologies are realized ; (1) a practical GPU accelerated CAM system is developed. This system is currently running as a kernel system of one Japanese automobile manufacturer, (2) an algorithm for projecting the machining remained area in a prior machining to the cutter location surface for the next machining is proposed. This projection is useful for automating some process planning task of mold machining, (3) some GPU accelerated algorithms for defining the curved surface and evaluating its geometric quality are developed, (4) several algorithms for accelerating geometric computations in non-manufacturing fields are developed also. Proposed algorithms are implemented and an experimental CAD/CAM/CAPP programs using this technology are demonstrated.