Research On The Rapid Design And Error Evaluation Technology Of The Clamping Scheme

For improving the efficiency of fixture design, shortening the preparing time of fixture, achieving rapid evaluation of position error and clamping deformation, a system of rapid design on fixture and error evaluation has been programmed. This system can achieve parametric design and modular design of fixture as well as fast errors evaluation. The main research of this thesis is as following:(1) Through the study of the fixture program a fixture case base is built using parametric design philosophy, including parametric components library and component libraries. Based on the built case base, the rapid reuse method of fixture design knowledge was studied according to case-based reasoning (CBR) technique.(2) Through the analysis of the causes of positioning error, and the use of the principle of homogeneous coordinate transformation of rigid body, a positioning error evaluation mathematics model is established, and a rapid error evaluation is achieved using computer program, The maximum machining error of arbitrary machining position due to positioning error has been derived by the manufacturing tolerances of both fixture positioning components and work piece positioning feature.(3) Through calculating the 3D error variation caused by the clamping deformation of work piece by finite element analysis, and analyzing the results of both clamping deformation and positioning error, a comprehensive evaluation method for profile normal error is established. Using the established profile normal error as unified evaluation indicators, the work piece positioning error and clamping deformation error has been evaluated.(4)Utilizing Microsoft Visual Studio 2008 development platform, C++programming language and secondary development method for CATIA a system of rapid design off fixture and error evaluation is programmed. The overall structure of system development its related are also introduced using diagrams and examples.The system of rapid design of fixture and error evaluation has been studied through parametric design, modular design, CBR and secondary development method, The efficiency and quality of program design could be improved.