Research Of Special Fixture CAFD System Based On SolidWorks Secondary Development

Machine special fixture is an indispensable craft equipment in machinery manufacturing. However, the repetitive model of parts in the design wastes designer a lot of energy and affects the design efficiency; The calculation of traditional fixture location error needs to derive the formula, which is complicated and difficult to understand. To improve design automation and intelligent level,the special fixture CAFD system is studied using Visual Basic6.0 programming tools based on SolidWorks 2009.General design idea of CAFD system is proposed and the core technologies are explored, including parametric technology, macro recording, database technology etc. Using Access relational database to manage part parameters, three-dimensional component models are established by parameter-driven technology trough interactive interfaces.The implementation characteristics of automatic assembly are analyzed. According to the structural features of special fixture components, automatic assembly is completed by establishing reference geometry as auxiliary assembly features and constructing the selection set in the feature design tree.A new method of local error aided calculation is put forward.Using SolidWorks virtual assembly function, three-dimensional assembly models of positioning device are set up. According to the thought of traditional "limit position method" calculating location error, using assessment tools to measure the distance between process benchmark and reference base in the limit state, the outcome of two synthetic measurement data is location error. As to facilitate the system program management, the position error aided calculation add-in is created, as an independent module integrated under the SolidWorks assembly environment.A rotary drilling fixture is successfully designed, which illustrates the developed system has practical value in the actual fixture design.