Thermosets: they're plastics that can only be molded once. They are heated and made into a particular condition, and the moment they harden, they can not be remolded.
Plastic injection molding has become the oldest https://socialmediainuk.com/story18698386/how-much-you-need-to-expect-you-ll-pay-for-a-good-china-plastic-injection-molding