By using this venting material in appropriate areas, the molder can eliminate gas buildup, reduce injection pressure, lower cycle times, gloss levels and substantially reduce scrap and reject rates.

1) Eliminates Trapped Gas Problems
The benefits molders derive from using gas permeable mold steel include the elimination of trapped gas problems that occur in inadequately vented areas within the mold. Frequently it is difficult, if not impossible, to provide adequate venting in these hard-to-mold areas. Traditional methods of venting—such as parting line vents, vent plugs and pins—often do not provide sufficient surface area to accommodate the large volumes of gases that can be generated. By inserting gas permeable mold steel, you provide a location-specific method of venting gas in a targeted area. Since it is 25 percent air by volume, one-fourth of the surface area becomes a vent. The larger the surface area of the piece installed, the greater the venting capacity.

 2) Prevents Burning
Burning is a condition caused by compressed gasses trapped by the flow of molten resin in a cavity pocket. By using this venting mold steel, gasses are permitted to evacuate through the steel to the outside atmosphere, thus eliminating the burning condition.

 3) Prevents Knit Lines
Minimizing or eliminating flow and knit lines is an additional benefit. Knit lines occur at points where resin flows converge after molding around an obstruction or protrusion within the mold, usually away from the gate area. There are two primary reasons for this occurrence: (1) failure of resin to sufficiently fuse due to the drop in temperature after flowing over long distances and (2) presence of residual air at the resin flow convergence point at the cavity obstruction, prohibiting the proper fusion of the flows. The permeability of this venting mold steel prevents defects arising from residual gases normally trapped inside the mold cavity. Also, using this material reduces back pressure and improves the flowrate, allowing the resin flows to merge while still hot.

4) Reduces Cycle Time
Because of the reduction in back pressure within the mold, the plastic fills the cavity faster, thus allowing for reductions in temperatures, which shortens cooling and cycle times.

5) Eliminates Shrink
Trapped air bubbles between the resin and mold steel surface can cause shrinkage or sink that shows as a ripple in the otherwise straight plastic surface. Using gas permeable mold steel on the trapped air side of the cavity will eliminate shrink in most cases.

6) Eliminates Short Shots
Short shot is another condition caused by too low of an injection pressure, or trapped gases, in pocket areas of the cavity. This results in the part not being completely filled out. Gas permeable mold steel reduces back pressure; therefore, less injection pressure is needed, and because it vents trapped gases, both causes of short shots are eliminated.

7) Enhances Part Appearance
Webbed, ribbed and other difficult-to-fill, thin-walled designs are greatly enhanced and cosmetically defined using gas permeable mold steel in the mold. Molding high detailed, thin-walled and aesthetic parts is easily accomplished with reduced back pressure and added venting.

8) Reduces Gloss Levels
When using this venting steel as a cavity in an injection mold, the air typically trapped between the cavity and the resin (causing a gloss to show on the part) is allowed to escape through the pores, thus leaving a dull matte finish. This often eliminates the need for costly secondary spray painting operations

9) Simplifies Tool Design and Reduces Cost

When back pressures, injection pressures and cycle times are lowered, fewer drops are needed to assure proper filling of the cavity. Lowering the number of drops needed to fill a cavity simplifies design while saving tool costs. In some cases the entire hot runner manifold is eliminated.                       

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