Structural Plastics Processes

Nitrogen assisted alternatives to high pressure injection molding of large pieces are explored- Structural Foam, Counterpressure, Gas Assist, and External Gas Molding. Plastic flow and resin shrinkage are considered. There is something about bubbles of…

Cashiers Plastic Corporation

Cashiers Plastic was a leading custom molding manufacturer from 1969 to 2006. Located in an unlikely resort town in the Blue Ridge Mountains, it provided a unique background for excellence. One Man’s Vision- Fifty Years…

External Gas Molding

External gas molding represents the latest advanced method of injection molding thin walled parts with large surface areas. The process involves the injection of a blanket of gas assist to one surface of the molded…

Design for Function (White Paper)

STRUCTURAL PLASTICS- DESIGN FOR FUNCTION Steve Ham Steve Ham Plastics, Highlands, North Carolina Abstract A methodology in producing highly functional designs is discussed. The family of injection molding processes referred to as Structural Plastics offers…

Structural Foam

Structural Foam molding has been around since the sixties but remains unknown to many product designers. It is a way to injection mold very large parts. Traditional thermoplastic resins are used along with a blowing…

Gas Assisted Injection Molding

Gas Assisted Injection Molding was one of the fastest growing new injection molding technologies in the 1990’s. And yet, less than 20% of all currently active injection molding machines are equipped with this feature. Here’s…

EGM White Paper

Measuring In-Mold Pressures with the External Gas Molding Process (2006) Jim Hendry, Brian Brookshaw, and Kamal Vinning  – Cinpres Gas Injection Steve Ham – Steve Ham Plastics Abstract External Gas Molding (EGM) is an emerging…

Design Guidelines

Piece part designers must have an understanding of the molding process being employed.  Design for function and optimization require that every potential benefit of a given resin/process be exploited. At the same time there are…

Counterpressure Structural Foam

Counterpressure Structural Foam is a variation of the structural foam process. The purpose is to control the pressure drop at the leading edge that occurs during resin injection. Normally the pressure drop allows the blowing…