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Adoption of 3D printing for cores/cavities remains low in spite of advantages

While 3D printing (aka additive manufacturing) has advanced dramatically in recent years, making possible myriad parts - both prototype and production - moldmakers remain reluctant adopters of the technology. However, as usual, OEMs seem to be catching onto the advantages of 3D printing for a number of applications including building single-cavity pilot molds quickly and cheaply.

Clare Goldsberry

November 24, 2014

3 Min Read
Adoption of 3D printing for cores/cavities remains low in spite of advantages

While 3D printing (aka additive manufacturing) has advanced dramatically in recent years, making possible myriad parts - both prototype and production - moldmakers remain reluctant adopters of the technology. However, as usual, OEMs seem to be catching onto the advantages of 3D printing for a number of applications including building single-cavity pilot molds quickly and cheaply.

The whole idea of a "pilot" mold or "pre-production" mold is to test out the design and manufacturability of a component. While machine tool technology has advanced to provide faster production of soft (aluminum or P20) cores and cavities (some in less than a week), 3D printing offers even faster builds of a core/cavity set - in a day in some cases - that give part designers a real-world look at far less cost.

Recently, Stratasys announced a partnership with Worrell Design Inc., a medical product design and development firm, to help promote injection molds built using Stratasys' PolyJet-based 3D printers. The partnership will educate OEMs and promote the use of these 3D printed molds in the medical device industry as a way to improve time and costs to get products to market.

Building a core and cavity set from PolyJet materials allows parts to be molded in the actual plastic materials in which the production parts are spec'd. This is a huge leap forward from the prototype parts that were 3D printed 20 years ago that were little more than "touchy-feely" parts to examine for form, fit and function. Today, by molding components from the actual materials OEMs get not only form, fit and function but they can get actual end-use parts to test under real-world conditions.

3D-Printed_Prototype.jpeg"With 3D printing, we can print three different mold sets on the same tray [in the build box] that account for different shrink rate factors if the customer wants to try out three different materials for their product, for example," Nadav Sella, senior manager of Manufacturing Tools at Stratasys, told PlasticsToday. "We can also print three different molds for small design variations of the same product in a matter of hours. The whole idea here gives customers and especially medical device customers which are short in time and have a long, regulatory process more flexibility in their manufacturing options when they need a small number of parts from the real end product material for testing before investing in costly and time consuming metal tools."

While the Worrell-Stratasys partnership focuses on the medical device industry, there are other industries that have long part-approval processes for which 3D printed core and cavity sets would be a huge benefit. The automotive industry, for example, is one in which the part approval process can take many weeks or even months. "Definitely the automotive industry," Sella concurred. "We also see examples in the defense and consumer electronics industries.

"I think another key factor here is the need to have tests with the final production material quite early in the design phase to capture elements like safety and behavior under extreme conditions which cannot be tested on non-production materials," he added.

The reluctance of mold manufacturers to adopt 3D printing technology could be due to several factors: the cost of many of the industrial-sized additive manufacturing machines, the learning curve to operate these machines, and even perhaps seeing 3D printed core and cavity sets as a disruptive technology to traditional machined cores and cavities. However, Sella said that he doesn't see 3D printing technology as disruptive to moldmakers at all.

"I see this as an extension of the mold shop capabilities and a way to do things faster and cheaper when possible," he stated. "However, it all depends on the number of parts required, the material type and the level of accuracy."

About the Author(s)

Clare Goldsberry

Until she retired in September 2021, Clare Goldsberry reported on the plastics industry for more than 30 years. In addition to the 10,000+ articles she has written, by her own estimation, she is the author of several books, including The Business of Injection Molding: How to succeed as a custom molder and Purchasing Injection Molds: A buyers guide. Goldsberry is a member of the Plastics Pioneers Association. She reflected on her long career in "Time to Say Good-Bye."

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