Studies On The Design And Manufacturing Of Plastic Injection Mold With Conformal Cooling Channels

Injection molding is one of the most effictive techniques for plastic production. The design of the cooling system of injection molds directly affects both productivity and the quality of the final part. Compared with conventional drilled cooling channels, conformal cooling channels have demonstrated simultaneous improvements in cooling efficiency and cooling uniformity. However, because there is no methodology for the design of conformal cooling channels, designers have to use convetional methodology to design them. This is the major bottleneck for the application of conformal cooling system.The transient heat-transfer process of the plastic injection molding is reaserched by the means of heat tranfer theory and numerial simulation software. On the base of those conclusions, the heat transfer mathematic model for conformal cooling is built. In this model, the shape factor is used to correct the calculate result. Not only is this heat transfer model suitable for the circule corss-section cooling channels, but also for other section shapes, such as ellipse, U shape etc.The SLS rapid tooling technology is also studied. Green shape of injection mold with internal conformal cooling channels is formed using the composite metal powders developed in this work and optimal forming parameters. After decomposition, vacuum sintering,dropping infiltration of liquid bronze (or infiltration of epoxy and curing) and being simply machined, the mold can be used for plastic injection.Conformal cooling system design methodology and design rules are developed after reaserching the features of the conformal cooling system. Some new concepts are used in this mehodology, such as cell cooling technology, minium cooling time and suitable temperature of cavity walls etc. By the guide of this methodology, designers can design optimal coformal cooling system efficiency. Finally, the injection mold of pomander with the designed optimal conformal cooling channels is fabricated by using the SLS technique. The production efficiency of the injection mold of pomander with conformal cooling channels is improved 30%, and the warpage is only 20% as much as the conventional injection mold.