Mothers don't let your sons grow up to be mold makers. Plastic injection mold making can make you grow old fast. If you have the temperament, the brains and the skill to build plastic injection molds then you deserve to be paid well for your services. Modern machinery, no doubt, has simplified the mold maker's job; still there is little room for error or sloppy work in mold making.

Although I've worked on many molds and been on teams constructing molds, I don't consider myself an expert. I shy away from mold work simply because I find it too demanding. The way I see it, mold makers live in the worst of all worlds. They work on projects that require the most precision machining on one-of-a-kind expensive parts while being pressured to get things done by people who may not understand the difficulties mold makers face.

Here are a few mold making tips I've collected over the years.

1. Start with a part print.

   Seeing a mold drawing package for the first time can be an intimidating experience even for a hardened mold maker. Having a part print to study at the beginning of a project can greatly reduce the mysteries of a new mold drawing package. As a mold maker, you should always ask for and expect a part print.

2. Continue the drawing review by studying core and cavity details.

   The core and cavity details are the heart of the mold. Much of the complication you see in...