Development of CAM system installed in CNC controller to achieve flexible and dynamic machining operations

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13650278
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Intelligent mechanics/Mechanical systems
• Research Institution: Osaka University
• Principal Investigator: SHIRASE Keiichi Osaka University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (80171049)
• Project Period (FY): 2001 – 2002
• Keywords: NC machine tool / Autonomous machining / Intelligent NC machine tool / Operation planning / CAM / Machining feature / Machining shape simulator / End milling operation

Research Abstract

For the target CAM system installed in CNC controller, (i) The operation planning module to adapt operation sequence and cutting tools, (ii) The simulation module to recognize machined shape during machining operation, and (iii) The real time tool path generation module to achieve flexible and dynamic machining operations, are developed in this study.
(i) The operation planning module to adapt operation sequence and cutting tools
The total removal volume is detected from 3D CAD models of a raw material shape and a final machined shape. The total removal volume is divided into several machining features in three ways for different geometrical consideration. The operation sequence is derived from the geometrical relations among the machining features. The cutting tool is selected according to the machining feature detected. The cutting conditions are determined by referring the past cutting case data.
(ii) The simulation module to recognize machined shape during machining operation
A machine d shape during machining operation can be detected by successive Boolean subtractions between 3D solid models of a workpice and a tool swept volume. The tool swept volume equals the space occupied by the cutting tool in motion. In case of cutting trouble such as tool breakage, the machined shape during machining operation is available to use as a raw material shape for a new operation planning.
(iii) The real time tool path generation module to realize flexible and dynamic machining operation
Tool paths can be generated in real time by the digital copy milling system which is developed for this module. In the digital copy milling system, a stylus and a master model are defined as geometrical surface models of 3D CAD, the stylus motion corresponding to the tool motion is generated based on copy milling principle. The tool motion can be changed dynamically during machining operation without any NC program.
NC programless milling of sculptured surface has been achieved by the CAM system which consists of those three modules. Based on a 3D CAD model of machined shape, suitable tool paths and cutting conditions can be determined without any NC program to achieve flexible and dynamic machining operation.