Just as in the classic injection molding process, the plasticized thermoplastic is injected into the injection mold. At a certain point, an inert gas (nitrogen N2) is also injected at high pressure into the still viscous plastic mass.
Because of the high pressure of the gas the melt is displaced and this creates a void in the component. The displaced material is pressed out of the mold and into a collecting channel and can be reused later.
The advantage of this process lies, among other things, in the very low weight (up to 30% less part weight).