Higher Gas Pressure for Counterpressure Molding

A gas counterpressure control module for structural-foam or standard injection molding, introduced in 2001 by the consulting firm Caropreso Associates, Becket, Mass., has been upgraded to deliver higher gas pressure.

A gas counterpressure control module for structural-foam or standard injection molding, introduced in 2001 by the consulting firm Caropreso Associates, Becket, Mass., has been upgraded to deliver higher gas pressure. The module controls delivery of air or nitrogen to the mold to pre-pressurize the tool prior to injection of resin. It now provides a working gas pressure up to 1500 psig, vs. up to 280 psig previously. The module itself is also more compact and features a color touchscreen.


Gas counterpressure can improve part quality by ensuring more balanced mold filling and packing, reducing the packing pressure and packing time. It improves part flatness, reduces swirl lines in structural foam, and cuts down on splay when molding undried resin.