With Plastic Crate Mould, the custom plastic parts come out hollow and thin-walled. When the plastic part needs to have a homogeneous wall thickness, this approach is ideal. It is very similar to the process of glass blowing. When the raw plastic is heated enough to become liquid, the machine inflates it with air like a balloon. The plastic is blown into a Plastic Crate Mould and as it gets bigger it presses against the mold walls and it starts to take its shape.