Injection - compression molding provides some major advantages, when compared to conventional injection molding. The injection compression molding (IPM) process allows the flow of material into much thinner walled cavities than conventional injection molding. In addition to reducing warpage and residual stress, the downsizing of molding machines and tonnage can be realized.
Unfortunately, in the past use of this technology meant very costly machine modification was needed for hydraulic presses, while most toggle presses did not allow for further modification. Often the purchase of a specialized machine was necessary at a high cost to the end user. Many times this machine could only be used for injection compression molding, thus further costing the end user in productivity.
Idemitsu Petrochemical Corporation has developed a new compression unit that fits easily into the injection press. The unit is slim and portable and fits between the machine platen and the mold. The unit provides smooth parallel travel. The IPM unit provides an inexpensive means to accomplish injection compression molding. Good success has been achieved producing two types of automotive door panels. One panel is completely covered with a leather substrate, and the other panel which is partially covered with leather or cloth.
The purpose of this paper is to reveal and explain experimental data that compares injection compression molding to conventional injection molding. Additionally, parts produced using the injection compression molding unit will be introduced.