Multistep methods

Multistep method is generally used in the production of multilayer products, it works and two steps are similar. If you have foam on the inner wall of a non-foaming layer, then use the second input into bags, boxes or more thermoplastic, has formed a foam inner core release non-foamed resin on the surface, forming a foam layer.

Two-step and multi-step remains complex, old rotational molding equipment needs to be a lot of reconstruction process is difficult to control, and so on. In order to maximize the use of the original rotational molding equipment, people developed a one-step rotational foaming molding technology.