The Development Of The Calculation Software Of Fixture Planar Location Error

The automatic and stepwise computation for fixture planar location error is benefit for the efficiency and veracity of fixture-design, thus it can reduce the defective index of the corporate production, improve benefit.. Up to now, people do not pay enough attention to the automatic computation for fixture planar location error, and there is not an automatic computation software which fit for all the fixture planar location. This article aims at this problem, developed a calculating software based on the distributed computing.The distributed computing means to complete the calculatin of positioning error step by step, the steps are mutual independence, and associated with each other by some specific parameters. In the consideration of the static error, the workpiece&fixture system has four elements that related to the position error:fixed element, fixed position basis, process benchmark and the finished surface. The distributed computation that suggested in the article is to do the research in the relationship between these four elements. The research contents includes:(1) Calculate the range of the fixed position basis. Do the research in the geometry relation between the fixed position basis and the fixed workpiece in all of the planar location circumstances, especially in two holes positioning. Then differential the formulas according to the variation of the dimension parameters in margin of tolerance, and calculate the subtle range of fluctuation of the fixed workpiece.(2) Calculate the range of the process benchmark. The range that relative to the fixed position basis has been known, then do the research on how to calculate every type’s process benchmark that relative to the range of the fixed elements, and get the range of the process benchmark in the fixture coordinate system.(3) Calculate the position error. The range of the process benchmark in the fixture coordinate system has been known, then use the geometrical relationship to reverse calculate the range of the process benchmark that relative to position of the finished surface, which could also be called:the position error. When the geometry types of the process benchmark and the finished surface are the straight line, the depth of parallelism, verticality or the gradient between the two lines could be calculated by the relationship of them.On the basis of the theory above, the article developed the calculating software to calculate the fixture planar location error. In the sofrware. the computational process that introduced above have been designed as several program modules, the user could choose to call different program modules to complete the calculating of the position error. The software is designed in the development environment of VC++6.0, and use the development tool Pro/TOOLKIT to do the secondary development to Pro/E2.0. The softeware realizes the distributed computing and also satisfies the users’requirements.In addition, the article developed a detecting device to detect the location error of two holes positioning. The detector could imitate the integrated positioning of round pin and diamond pin, and get the related dimensions’variation in margin of tolerance, it could also calculate the position error by multiple metering.The article also do the summarize and the prospect to the research at last.