Water assist injection molding is a hot topic within the plastics industry because of the ability to mold hollow or partly hollow parts. With this process, water is used to core out the hollow sections, then flows through the part to cool the plastic. Unlike the gas injection process, cooling is provided from the exterior of the part by the tooling and from the interior channel by the water.

Direct cooling inside the part is a big advantage of this molding method because, the thermal conductivity of water is 40 times greater than gas and the heat capacity is four times greater - so cooling cycle times can be reduced to up to 50% that of traditional gas assist.

To date BASF has had development success using WAIM with their product lines of Ultramid® B polyamide 6 (PA6), Ultramid® A polyamide 6/6 (PA6/6), Ultradur® polybutylene terephthalate (PBT) and Petra® polyethylene terephthalate (PET).

Water assist injection molding is well-suited for the following types of potential applications - automotive components such as handles; fluid handling tubes; office furniture components; appliance handles; and other structural components.

Water Assist Injection Molding – Potential Benefits Versus Gas Injection Molding:

Up to 50% shorter cooling time More uniform wall cross sections Smoother interior surface appearance with certain formulations

BASF and Cinpres are working jointly to assess and develop WAIM applications in the North America region.

For more information on water assist injection molding at BASF contact:

• Randy Fleck, Senior Process Engineer at 1-973-426-5414

For more information on water assist injection molding equipment at Cinpres contact:

• Lee Pereces, General Manager at 734-449-8301