1. Overmolding

Various names and expressions are used in the literature to designate overmolding, both in French (surmoulage, surinjection, injection multiphasée de polymères, moulage pris sur un autre moulage...) and in English (overmolding, two shot molding...).

The principle of the overmolding process is simple: a part A (or insert) is placed in the cavity of an injection mold, and a material B is injected. By filling the cavity, part A is overmolded with material B (figure 1 ).

There are several types of A-piece or insert:

• metal insert ;

• plastic insert molded with a different or identical polymer.

For reasons of chemical compatibility and adhesion, polymers...