A Critical Application in Medical Molding

Plastic medical parts are sometimes machined, but frequently they are produced using plastic injection molding instead. SyBridge Technologies is one company that manufactures the injection mold tooling to mass produce plastic medical parts, as well as plastic parts for other markets such as automotive. “Most of our molds are class 101 molds that are guaranteed to produce one million shots,” said Aaron Liefveld, general manager of SyBridge Technologies, which is headquartered in Rancho Cucamonga, California. The company was founded in 2019 through the acquisition of 15 manufacturers across North America, Europe and Asia.

Liefveld noted that the company has two separate divisions: life science, which includes medical and health care, and mobility, which deals mainly in automotive. “Completely different worlds as you can imagine.” Various plastics are available and injection-molded medical parts come in a host of shapes and sizes.

SyBridge Technologies

According to SyBridge, the company’s precision engineering ensures consistent part quality and extended mold life. By knowing the plastic and part shape, SyBridge begins the moldmaking process with the design for manufacturing (DFM) methodology, said Daniel Schoelmberger, SyBridge’s business unit director. “Knowing the material and the part, there are often changes that we suggest, knowing that this would make a better part, with better quality and often at a better price.” That process might involve changing part features that are difficult to extract from the mold without major actions or part damage, he added.

“Just because the steel is right doesn’t mean the plastic part will be. The molded part is never a perfect replica of the cavity. At the end of the day, the goal isn’t steel that measures right, it’s a part that meets tolerance and performs in the real world.” The company reports that it embeds manufacturability into the heart of its injection mold tooling design process, proactively identifying and resolving issues early on.

In addition to DFM, SyBridge’s design for excellence approach considers all critical factors, ensuring tooling is optimized for performance, reliability and cost-effectiveness. Schoelmberger said dimensions that are critical for fit and function — and what the part is supposed to do in the application — are particularly targeted, and those dimensions typically tie in with a Cpk number, a statistical measure used to assess a manufacturing process’s ability to produce output within specified limits. For example, a Cpk of 1.33 corresponds to a process where 99.994% of products fall within specification limits and is more information about the author For more information about SyBridge Technologies, call 833-824-1116 or visit www.

sybridge.com. Alan Richter, a 40-year veteran journalist, has spent the last 25 years covering the metalworking industry for Cutting Tool Engineering and currently serves as its editor-at-large. Contact him at alanr@ctemedia.com.

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3/19/26 10:09 AM

A Critical Application

considered acceptable in most industries because it provides an effective balance between process capability and defect rates. “When you achieve the required Cpk, you’ve proven the process is stable and capable, which means you can reliably produce in-spec parts for years to come from that mold.” The vast majority of the molds SyBridge produces, said Liefveld, are made of the “highest end” 420 stainless steel that is heat treated to achieve a hardness of 50 to 54 HRC. “We do build some aluminum molds for rapid prototyping,” he noted, “but that is not our specialty. That makes up 2% of the molds that we build.”

Tight Tolerances

Using CNC machine tools, EDMs and other machining equipment, SyBridge cuts the steel workpieces to the needed shapes, Liefveld explained. Besides building a mold that must achieve the specified Cpk value, it must meet the required tolerances. The shutoffs where two pieces of steel come together to close the plastic part off, for example, have a tolerance of ±0.0051 mm (±0.0002").

To measure machined dimensions, the moldmaker uses dial indicators with a 0.0025 mm (0.0001") resolution and two Hexagon CMMs that are accurate to within ±0.00127 mm (±0.00005").