Motion System Design
Field Report: Scalpel...clamp...actuator?

Field Report: Scalpel...clamp...actuator?

Medical equipment designers look for a miniature linear solution

Problem: When engineers at a medical equipment manufacturer in Switzerland were designing a new robotic sampling station, they needed an accurate, miniature linear actuator that would comply with rigorous worldwide medical requirements.

Solution: The Swiss company approached engineers at Reliance Gear Co. of Huddersfield, U.K., because of their expertise in this field. Reliance then developed a revolutionary new type of miniature actuator based on a combination of their round and tubular racks with integral bearing support and pinion drive system.

The new Reliance Tubular Rack actuator is a stainless-steel linear tube with helical teeth ground into one external surface. It is both a drive component and a bearing surface in one. By using it for the Z-axis of the machine, more pipetting heads could be achieved in the same space. Attaching the pipetting head to the Tubular Rack didn’t pose a problem, as a variety of interfacing methods were available, such as screw threads, bores, and slots.

The Swiss engineers also needed to avoid possible human contact with sampling materials or reagents when the machine was in use. The Tubular Rack provided the ideal solution, because both vacuum and electrical lines could be routed through the actuator’s relatively large inner bore.

Additional benefits: Reliance’s range of standard products, coupled with rapid prototyping and test facilities, was significant for the medical manufacturer. Proof of principle for the design was easy to establish using off-the-shelf products, which eliminated the need for expensive tooling and testing during the prototype stage.

Once proof of principle was established, Reliance worked closely with the Swiss engineers to source the most cost-effective raw material to manufacture the tubular rack — without loss of performance.

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