Choosing steel for a production mold

Mold steel is chosen against three things: how many shots the tool has to make, what resin it will run, and what surface finish the part needs.

Volume

Short runs and long runs do not need the same steel. A steel that is easy to machine is often the right answer for a low-volume tool; a high-volume tool usually justifies a harder, more wear-resistant grade.

Resin

Glass-filled and other abrasive resins wear gates and cavity surfaces faster than unfilled resins, which changes what the tool needs to be made from.

Finish

A part that needs a high-gloss or optical surface calls for a steel that can take a high polish and hold it.

Specific steel grades and hardness values are pending confirmation from the factory.