Medical Precision and Customization

Medical Engineering

Always looking for a chance to innovate, the Northfield team were excited to bring their years of work holding expertise to the medical industry, creating parts for joint replacement.

Brief:

Deliver the appropriate tolerances requested, including: concentricity, accuracy, and repeatability from part to part. Achieving this was the priority whilst allowing easy operation and quick tooling change overs. The Northfield team created two separate solutions:

• The first, a collet chuck solution that holds shoulder joint inserts to ‘finish-turn’ the outside.

• Secondly, a 'Power Block' for holding multiple knee-joints simultaneously with a very specific grip force. Also, allowing clearance for the milling tools and part sensing ports. This allows the machine to acknowledge that parts are correctly loaded and ready to be manufactured.

Challenge:

1. Holding the half sphere shoulder parts from the inside with only a minimal surface area, to allow the finishing operation on the outside. 2. The knee joints required custom air chucks to clamp various part sizes at the same time for finish milling. 3. Ensure the correct jaw force was applied to the delicate parts throughout the entire process.

Solution:

1. Northfield offers a large range of standard precision collet chucks, that grip a part internally. This job was unique as we developed a special contoured collet with a specific shape. Finish milled to enable holding several different part sizes. We also added a locating surface that uniquely has a small surface area, although robust and accurate enough to allow a long tooling lifetime. 2. Four different sized parts need to be held at the same time, therefore multiple Northfield chucks are in use simultaneously. Our customer wanted to finish the second operation of all the parts at once, achieved by creating a base plate with easy air porting. 3. Finally, we also delivered a force analyser that works together with our custom tooling, creating a turn-key solution with specific grip force. Do you have a special working holding requirement? Our sales team are always available to answer your questions. https://www.northfield.com/contact/ Northfield is a custom work holding solutions company based in Island Park, New York.