Normally, it is difficult to produce thick walled plastic parts by standard means of injection molding. However, with the introduction of gas injection, large hollow articles may be formed. Structural foam and blow molding fulfill some of the requirements for thick moldings, but when it comes to high quality surfaces and dimensional stability, parts produced by these means do not compare to gas-assist injection molded parts. Material savings, cycle time reductions, warp free and stress free parts without sinks are possible benefits of the gas injection process.