Research On Computer-aided Tolerancing Optimization Design Based On SolidWorks

With the implementation of Industrie 4.0 and Made in China 2025,digital design and intelligent manufacturing become the main direction of industry development.Computer-Aided Tolerancing(CAT),as an important part of CAD/CAM integration,plays a significant role in improving design efficiency and accelerating intelligent manufacturing.However,CAT is far behind the development of CAD.Aiming at this problem,CAT is researched in this paper,and a CAT plug-in integrated into SolidWorks is developed,to realize a higher efficiency of tolerance optimization design by interacting with 3D models.The main research work of this paper is as follows.Firstly,the method to integrate CAT into the SolidWorks platform using the secondary development tool API SDK is discussed.The link and data exchange between the plug-in and SolidWorks and the method to realize specific functions of the plug-in are investigated,by analyzing the interface model structure of SolidWorks API and the framework code generated by API SDK.The principle to build dimension loop automatically is researched using some API,which can obtain the information of components and fits in the dimension loop.New methods are put forward for judging positive or negative character of each composing loop and making it easier for loop searching,based on the position data of fits from API interfaces.Secondly,the main methods of tolerance allocation and tolerance analysis are compared.Process of tolerance analysis calculation is studied deeply using Monte Carlo method.The tolerance standard data are obtained automatically by the database technology,and the efficiency of tolerance design is improved.Finally,theories and principles of tolerance optimization allocation are investigated,and the C-T model is discussed emphatically with different restricted conditions,including the conditions in the extremum method and the statistical method.The multi-objective optimization method is studied by combining the C-T model and Taguchi quality model.An example is employed to inspect the different tolerance optimization methods,and the reason leading to difference results is discussed.The CAT plug-in designed in this paper is integrated into the SolidWorks 3D CAD platform.It can directly obtained related data from 3D assemble models,automatically generate dimension loop,and realize several methods of tolerance analysis and tolerance allocation.The tolerance optimization design and verification can be easily carried out using this plug-in,and the efficiency of tolerance design is greatly improved.