Injection Mold Cad System Developed By The Theoretical Research And Applications

After analyzed the main design tasks of injection mold, a frame todevelop three-dimensional CAD system for injection mold is supposedon the basis of existing PC software, and several problems related closelyto software development are studied. In order to select a suitable moldframe for a given injection part and determine the parting direction of themold, the concept of convex-hull for a random polygon is introduced. Aminimum bounding rectangle algorithm is developed on which theminimum bounding box algorithm is presented for a random givenpolyhedral. Based on the idea of part parameterized-drawing and table-driven, the concept of parameterized assembly drawing is also putforward. Its principle and method are discussed and applied to theparametric generation of the 3D assembly drawings. According to theprinciple and method mentioned above, the assembly relationships ofthirteen usually used mold frames are analyzed and their parameterized-assembly drawings are established respectively, which include bothassembly models and the definitions of global variants table with localvariants table. The program for the data communication between MDT,Access and Excel is developed and the 3D parametric assembly drawingsare generated when keeping the assembly relationship constant. In orderto generate the main menu of the injection mold CAD system, thestructure of menu file of MDT is analyzed and reedited. The Windowsstyle human-machine interfaces for every module are developed with theDCL language and Autolisp language. Based upon the theoretical research works, a injection mold CADsystem frame is supposed. Some programs are developed and integratedinto the frame. The CAD system includes seven modules, such as theinitial design, the parts design of the mold, the cooling system design,injecting system design, mold frame design, database management andthe drawing generation. The initial design module provides the plasticperformance parameters and injection machine parameters used in theother modules. On the basis of the minimum bounding box algorithm, themodule for the mold parts design gets the minimum bounding box of theinjection part, which gives the basis of selecting the standard mold frameand the parting direction of the mold. Eight primary cooIing circuits aresummarized and presented through the way of icon menu in the cooIingsystem design module, and the system can generate the corresponding3D cooling-tube models. In the injection system design moduIe, severalkinds of injection systems are summarized and their human-machineinterfaces are provided. The mold frame design module utilizes theprinciple and method ofparameterized-assembly drawing to generate the3D parametric drawing of the mold frame. The database managementmodule has two subfunctions. One is the file management function tomanage the plastic parameters and injection machine parameters. Theother is the speciaI database management system to manage the standardmold frame data as well as standard parts data.The results of the theoretical research and softWare developmentmentioned above lay a foundation to develop a perfect three-dimensionalinjection mold CAD system.