Mold-steel vents gas

Trapped gas has long been the bane of plastic molders. It causes incomplete fills, gas burns, and knit lines, and can ruin product quality. A new porous steel, called Porcerax, vents trapped gasses through the plastic mold's walls, while retaining the resin in the mold.

According to Tom Schade, VP at International Mold Steel, "Porcerax eliminates the need for complex venting systems normally required for fine hair-like parts such as speaker grills or large complex assemblies such as car doors. You don't have to build the entire mold from Porcerax," explains Schade. Usually a small piece (or pieces) in the right place, vents trouble-causing gas. The material comes in two shapes--flat plates and bars--providing a variety of design options for mold makers.

According to Schade, choosing the right steel for the mold is the most cost effective way to improve productivity and quality. To this effect, the company offers several new materials. One example is a new pre-hardened H-13 type, 40 RC mold steel called DH2F. The material reportedly cuts fabrication costs for die and mold makers because it machines about 30% faster than other H-13 steels of similar hardness. "It also eliminates the need for heat treatments," adds Schade.

Another example is PX5, a replacement for P-20, that also machines about 30% faster, according to Schade.