Numerical Simulation And Mold Design Of Injection-compression Molding Process

With the continuous improvement and development of modern design methods and macromolecule numerical simulation technology,, computer-aided technology has become increasingly mature and gradually becomes an effective way to solve technical problems in the field of plastic processing. Depending on different processing methods, plastic molding processes are divided into injection molding, hollow blow molding, extrusion molding, compression molding and thermal forming, etc. Injection molding can mold batches of high precision parts with complicated geometrical shapes quickly and is the most extensive processing means in plastic industry. Compression molding, due to a simple structure and strong adaptability to thermosetting plastics with poor flow properties, occupies an important position in molding. Injection molding fully combines the advantages of plastic molding and compression molding. It can mold CDs, lens, automobile windows and other products whose quality requirements are difficult to meet for common injection or compression processes. Injection-compression composite molds and the design of process parameters need to be based on the CAD/CAE simulation of molds, make an integrated use of the experience of mold engineers and the processing ability of computer analysis, shorten the development cycle and reduce production costs. Based on an thorough investigation and analysis of injection-compression molding principle as the theoretical basis, with thick-wall optical components door side lights and thin optical components-CDs as the research object, this paper determines the structures and process parameters of molds through simulation, carries out a mold design and secondary development. The main content of work includes:1. To establish a CAE mathematical model for injection-compression molding. Based on a numerical analysis theory of the combination of finite element/finite difference, it starts from fluid continuity, motion and energy equations, makes a full analysis of the viscosity of melts in stress field and temperature field, heat-transfer characteristics and flow state and sets up a mathematical model that describes all stages in the injection-compression molding.2. The numerical simulation and mold design of the injection-compression molding of door side lights. Aimed at the structural characteristics of thick-wall optical components- door side lights, it applies a mold flow analysis software Moldflow2014 to carry out an initial mold filling analysis of plastic parts and then uses volume shrinkage and buckling deformation when plastic parts are ejected as a quality standard. Later, it applies the built-in DOE technology of the software to carry out an optimization experiment, determines the effect level of the process parameters on optimizing standard, inputs three of the most influential variables again to conduct a response experiment and finally determines the optimal molding condition. Combined with the results of mold flow analysis, it uses the drawing software Auto CAD to design the injection-compression molds of door side light designs and describes the working process and advantages of this set of molds.3. Simulation and mold design of CD injection-compression molding. Aimed at the technical problems encountered in the process of thin-wall optical components-CDs in the molding process, this paper makes an integrated use of the mold flow analysis function of Moldflow and the mold design function of UG software. It focuses on optical birefringence results-phase shift as the experimental standard and gets a reasonable molding process parameter. Finally, according to the results of finite element analysis, it carries out a mold design and probes into the structure of key parts and components.4. The secondary development of CD injection-compression molds based on UG. It takes the injection-compression molds of CDs as an example and conducts a secondary development of injection-compression composite molds and uses Visual Basic 6.0 to set up a secondary development program interface. Based on the powerful secondary development function of UG, using its development tools UG/Grip and UG/Open Menu Script, this paper completes modeling, routine calls and customization of menu. This technical route is simple and mature and provides certain guidance for the establishment of a typical mold standard library for injection-compression molding.