Research On The Injection-Compression Processing Technology Of Large-Scale Polycarbonate Workpiece

PC (polycarbonate, PC) is an engineering thermoplastics with good transparency, weather ability, flexibility, high impact strength and a smaller density. These integrated performance makes PC become the first replacement choice for traditional glass used in building, aeronautics, automatic and so on. With the rapid development of these fields, the need of large size workpiece is rapid increasing such as auto glass, bubble canopy for the aircraft and so on. However the traditional method for processing PC products can not meet the quality requirements because they would induce high residual stress and large dimension error during the processing. Injection-compression molding is a good method for producing low stress and accurate thin walled plastics products under low injection stress. The design of molds and processing parameters based on practice can not guide processing because it would result in large errors .First, This paper introduced the technology and the machine of injection-compression molding, then introduced the research progress in domestic and abroad, pointed out the significance of simulating the process of injection-compression molding. This paper used the software MOLDFLOW to simulate the injection-compression process of a small size PC product. Compared the numerical simulation results with the experiment results, they are in good agreement that proving the finite model for injection-compression is accurate. The effect of the processing parameters including melt temperature, mold temperature, compression force, compress distance and velocity were analyzed.Based on the research of small size PC product, this paper takes PC auto glass as object and sets Finite element models with different running systems and cooling systems for its injection-compression processing. According to the numerical simulation results using warpage, weldline, bubble evaluate the running models while the cooling systems compared were based on warpage and cooling effect, the best model was selected.Seven processing parameters including melt temperature, mold temperature, injection velocity, compress force, compress waiting time, compress distance and compress velocity were selected using orthogonal optimization. The prominence of process parameters were analyzed through variance analysis and range analysis, which provide a reference for the actual processing. Selected the most important processing parameters for the warpage to analyze their effort by single factor method.