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Plastic Mold Steels

Porcerax II


The benefits molders derive from using Porcerax II are primarily, but not limited to, 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. Porcerax II provides a location-specific method of venting gas in a targeted area. Since it is 25% 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.

Prevention of Burning
Burning is a condition caused by compressed gases trapped by the flow of molten resin in a cavity pocket. Using Porcerax II venting steel, gases are permitted to evacuate through the steel to the outside atmosphere, thus eliminating the burning condition.

The enhanced venting capabilities of Porcerax II are illustrated below. The illustration is taken from a current production application:

In a typical automotive console application, gases have a tendency to settle in areas such as the cup holder recess area or the CD/cassette storage compartment. This causes short shots and/or material burning. The illustration above shows Porcerax II inserted in the problem area and properly vented to the atmosphere.

The scrap rate on this part prior to installation of the Porcerax II insert was over 45%. Upon completion of the installation, the documented scrap rate dropped to 9% and was unrelated to the previous burning problem.

Prevention of Knit Lines
Minimizing or eliminating flow and knit lines is an additional benefit for using Porcerax II.
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. The failure of resin to sufficiently fuse due to the drop in temperature after flowing over long distances.
  2. The presence of residual air at the resin flow convergence point at the cavity obstruction, prohibiting the proper fusion of the flows.

The permeability of Porcerax II prevents defects arising from residual gases normally trapped inside the mold cavity. Also, using Porcerax II reduces back pressure and improves the flow rate, allowing the resin flows to merge while still hot.

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 Porcerax II on the trapped air side of the cavity will eliminate shrink in most cases.

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. Porcerax II reduces back pressure, therefore, less injection pressure is needed, and because it vents trapped gases, both causes of short shots are eliminated.


Conventional Molding

Porcerax II

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

Automotive Speaker Grill

Gloss Reduction
When using Porcerax II 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.

Conventional Molding


Tool Simplification and Cost Reduction

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.

Aiding in Part Ejection
In many situations, an air poppet is needed to help eject the molded part from the cavity. Inserting venting steel in the cavity with an air blow setup accomplishes the same result. This helps break the vacuum seal and aids the ejector pins in doing their job.

Important Warning:

It is imperative that anyone coming into contact with Porcerax II during the mold building or molding operations understand the characteristics and sensitivity of this material. Any questions should be directed to International Mold Steel at 859.342.6000.

NOTE: All technical and engineering data and suggested procedures, specifications and applications contained in this publication are for general information only. Sintokogio, Ltd., International Mold Steel and/or their distributors disclaim any and all express or implied warranties of merchantability, suitability for any particular purpose or use, or freedom from infringement of any patent, trademark or copyright. Porcerax II® is a registered trademark of International Mold Steel, Inc. and Sintokogio, Ltd..





Recommended Reading

Unique Characteristics


General Properties

Post-Machining Treatments

Water Line Sealing

Design Guidelines

Cleaning, Maintenance, and Resin Removal

Porcerax II Insert Installation

Porcerax II Pin Installation

Discussion Forums



  International Mold Steel, Inc. 
1155 Victory Place
Hebron, KY 41048 USA 
Tel: 859.342.6000
Fax: 859.342.6006
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