THE ENGINEERIST: Designing with Moldability in Mind

Editor’s Note: The Engineerist is a three-part blog series written by Michael Corr, founder of Los Angeles-based manufacturing consulting firm, DuroLabs. This is part three. The first two installments can be found here.

Intelligence does not automatically equate to experience, and in hardware, product development experience goes a long way.

I was recently hired to take over management of an engineering team at an early-stage company. A team of mechanical, electrical, and firmware engineers was already in place, and while I noticed they were younger than most teams I’ve managed before, I was incredibly impressed with their intelligence and creativity. That energy of young and enthusiastic engineers was a convincing factor for me to accept the position.

An Introduction to Manufacturability
Since the team had already released products to customers, I took a passive approach and just observed the established processes while they worked on the next version of the product. I injected comments and feedback on occasion, but trusted them to repeat their existing methods as they prepared for production. However, the more I got involved in reviewing the designs, I realized there was a common theme across the younger engineers—moldability was not factored into their designs. Many of the mechanical prototype parts coming off the Stratasys desktop 3D printer were designed to satisfy the performance requirements, but would at best, be expensive to manufacture, and at worst, impossible.

Adding draft angles to design helps facilitate ejection of a part from a mold, and improves overall moldability. The exact degrees of draft angles are dependent on part geometries.

I took several of the MEs aside and asked a few direct questions challenging them on how they envisioned an injection mold being designed for their parts. Blank stares were the only answers I received. I pointed out that one design had an undercut and another had no draft angles for clean part ejection. Again, blank stares. That’s when I realized that these engineers had become trained on producing parts using 3D printing tools only. While 3D printing has a made tremendous impact in prototyping and even production-grade parts, it also has its caveats. Continue reading

THE ENGINEERIST: Fail Fast, Succeed Faster

Editor’s Note: The Engineerist is a three-part blog series written by Michael Corr, founder of Los Angeles-based manufacturing consulting firm, DuroLabs. This is part two.

Certification testing is expensive, especially when your product fails.

I was managing an engineering team several years ago when we submitted a new product with an injection-molded enclosure to UL for certification testing. The tests included a mechanical stress test with some rather extreme impact forces. This product was a deviation to a predecessor and therefore had legacy requirements which constrained our design options. With the time pressure we had to get the product to market, the mechanical engineering team and I were hoping a few modest changes to the existing legacy injection mold would be sufficient to pass the new certification testing and go into production. They weren’t.

Logo Image: PR Newswire

Prototype Prep Before UL Testing
After a humbling blow to our egos and sizeable invoices from both the molder and UL, we took another approach. The ME team reviewed the points of failure of the plastic enclosure and came up with a few design improvements. But we didn’t want to risk failure again, and UL required testing parts fabricated from the actual production mold. It would be too expensive and risky if we were to modify the tool and fail again. Continue reading