Water assist Injection Technology (WIT) has been discussed, analysed and evaluated by research scientists and engineers at various conferences for the last 4-5 years. However, this technology has not yet been used commercially.

Water, due to its superior incompressability is considered better to create cores in moulded parts. Water, compared to gas offers some advantages such as faster cooling due to higher thermal conductivity against Nitrogen gas. Water, however, due to efficient cooling can create problems for semi crystalline polymers like PP. With water, semi crystalline polymers form a skin layer. This skin formation would create higher shrinkage or voids in thicker sections. WIT therefore has been found more suitable for amorphous polymers such as Nylons.

Gas assisted injection moulding has seen wide usage, but water assisted injection moulding is slowly catching the 'niche' market. Infact, the first commercial application of automobile ducts for engine cooling system from Nylons are likely to commercialize in 2002.