Mold cooling pulse

While machine control is important, it is the polymer state (pressure, temperature, and morphology) that directly determines the molded part quality. As such, recent technology developments have focused on closing the loop between the machine parameters and the polymer state. Conformal cooling and pulsed cooling are two molding technologies that have been... 

The uneven heat baiance in the moid is often a reason for distorted parts. Using thermal imaging cameras, which are now affordable, hot spots in the mold, can be seen and valuable support for the optimization, not only for the warpage, is provided. The intensification of the temperature control, by pulsed cooling or sintered mold inserts, for example, often leads to significant cycle time reductions. 

Pulse cooling is a method where mold temperatures are monitored, and cold water is introduced to control the steel temperature. A variation of this technique delivers water immediately after mold closing for variable pulse times. Using this approach, better distribution of surface temperature on injection molded parts may be achieved compared to traditional cooling with a thermolator. Thermocouples and a thermal camera were used to evaluate mold and part surface temperatures respectively. 

The authors would like to thank Mr. Bradley Johnson for his help and guidance throughout this experiment. They also thank Rick Coon for the mold tooling, and Brian Young for assistance with mold assembly and setting. Thanks are also given to Kistler for the donation of sensors, Cito Products, Inc. for the donation of the pulse cooling unit, RJG, Inc. for donation of data acquisition equipment, and Infrared Solutions, Inc. for donation of the infrared camera. 

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