"... over 25 years of experience in the
development and application of
assisted moulding processes."

External Gas Moulding (EGM)

External Gas Moulding (EGM)

Process Operation:

> The mould closes

> Plastic is injected to fill the cavity

> Plastic packing as required

> Gas is injected onto the ‘B’ surface

> Gas pressure is applied to pack the plastic

> Gas pressure is released




The gas pressure compresses the surface of the plastic. Gas flows to areas of low pressure and high temperature compensating for the volume shrinkage of the material. The gas packs ribs and thick sections avoiding sink marks of the 'A' surface.


> Combinations internal and external gas

> Warpage problem resolved

> Painting process eliminated

> 40% reduction in IM machine size to 3000 to 1800 US tons

> 33% material saving in the gas channel

> 10% material saving in the wall section

EGM Customer

“With external gas, we can produce a large cosmetic part that is structurally strong at a lower cost. We are able to use larger rib-to-wall ratios with external gas ...and we can locate ribs where we want them, and in general, we are enjoying more design freedom. The result is a solid part with no gas holes, no voids and no potential read-throughs... We were also able to reduce cost on the project with a smaller press, more efficient material usage and less design/engineering man-hours.”


For more information please contact us.

Additional Comments

>  EGM can be applied to exisiting moulds (tool alteration cost) as well as new moulds, where the most benefits can be derived. 

>  Potential cost savings rise dramatically with part size and shot weight.