3-D printed molds used for short-run injection molding

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Stratasys 3-D printing can replace traditional prototype injection mold tooling in some cases.

DETROIT — Gaining steam as a time-saving alternative to aluminum and steel molds, plastic injection molds created on a 3-D printer can replace traditional tools for some short-run items and prototypes.

Stratasys Ltd., a major supplier of 3-D printing machines and materials, displayed molds made with the company’s Digital ABS material at the Rapid 2014 Conference Exposition June 9-12 in Detroit.

Using technology it acquired through a 2012 merger with Objet Ltd., another 3-D printer manufacturer, Stratasys was able to improve the finish of the molds and produce a better product than previous efforts, a Stratasys representative said at the show.

3-D printed molds can be created much more cheaply than traditional molds, but they are also more fragile. They work with lower-heat, lower-pressure materials than metal molds can withstand, and the molded item has to be able to release easily, because prying it out could damage the plastic tool.

“You can’t bang on it like you can with an aluminum tool,” said Steve Gunderson of Protojet LLC.

Though plastic tools won’t last as long as metal tools, they can be used for prototyping and short-run products of a couple hundred shots. Used to produce prototypes, 3-D printed molds can help identify design problems before an expensive aluminum or steel tool is built.

Using a 3-D printed injection mold successfully can mean reworking the manufacturing process, something many companies are hesitant to do, experts told Plastics News.

“It’s a disruptive technology,” said George Russell Jr. of Stratasys.

Stratasys is working with one of the Detroit 3 automakers to promote 3-D printing education within the automotive industry, which has been particularly slow to embrace the technology, Russell said.

Gus Breiland of Proto Labs said that while he thinks molders should be aware of the technology, he doesn’t consider it to be an attack on the industry.

“It’s more than making parts from nothing,” he said. “There are resin limitations, manufacturing limitations. … We’re not there yet, but it’s pretty darn cool that they’re trying.”