A medical device designer might look up a polymer's physical properties and game out how a part made of the polymer will withstand stress. But start molding the part, and it might not hold up anyway.

3D printing is all well and good for prototyping, and it can even produce useful parts. If you want real strenght in plastics, though, or to produce a LOT of parts, you probably want to step up to ...

The following is an edited excerpt from The Business of Injection Molding, by Clare Goldsberry. The book is the first title in the IMM Book Club Injection Molding Management Series, published by IMM.