Precision Metal Machining, Inc. - Making Your Concepts Real MADE IN AMERICA

Plastics Machining of a Surgical Positioner for the Orthopedic Industry

Glenosphere Positioner
Glenosphere Positioner

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At Precision Metal Machining, Inc., we played a key role in the development and manufacture of a Glenosphere Positioner, which is used in shoulder surgery by orthopedic surgeons to orient and insert the humeral implant. The handle of this assembly also contained the working mechanism that allowed the surgeons to grasp, manipulate, and insert the implant into the shoulder during arthroplasty. The challenge presented to us was to recommend the proper grade of plastic and machine it so that it retained flexibility, but would not snap under pressure.

After recommending Radel 5500, Delrin, and 17-4-SS for the device, they were machined using CNC milling and turning. The positioner was then assembled by welding. Ten inches long in various diameters, the devices were machined to precise tolerances of ±.001", and received a finish of 32 Ra, all verified with dimensional and visual inspections. Redesign of the "fingers" on the handle was particularly thorny, as a method had to be created that allowed the finger to increase in thickness, without losing the flexibility for their required grasp. Ultimately, the design intent was met. Prototyping for a project such as this requires between one and two weeks. We also met ISO 13485:2016 standards while manufacturing 150 of the completely assembled devices for delivery in Florida. We worked closely with the customer's design engineer to bring this project to completion, resulting in an extremely pleased client.

Our knowledge of plastics properties and machining were clearly highlighted by this project. We worked hand-in-hand with the customer to develop the prototype, and then delivered the production quantities on time for release to market. For further information, contact us directly.

Glenosphere Positioner Project Highlights

Project Name
Glenosphere Positioner
Project Description
Used in Shoulder Arthoplasty by orthopedic surgeons, the Glenosphere Positioner aids with the orientation and insertion of the Humeral implant.
Capabilities Applied/Processes
Plastics Machining
Engineering Plastic Applications
Medical Grades of Plastics Recommendations
Equipment Used to Manufacture Part
CNC Milling
CNC Turning
Swiss Screw Machine
Overall Part Dimensions
10” long with various diameters
Tightest Tolerances
Material Used
Radel 5500, Delrin, 17-4 SS
Material Finish
32Ra or better
Industry for Use
Medical (Orthopedic)
In Process Testing/Inspection Performed
Dimensional / Visual (Aesthetic)
150 complete assemblies
Delivery/Turnaround Time
1-2 weeks for prototypes
Delivery Location
Standards Met
ISO 13485:2016

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