medical polysulphone parts | cryogenic deburring

Cryogenic Deburring for Medical Polysulphone Parts


Polysulphones (PSU) are a group of high-performance thermoplastics that provide toughness and stability at high temperatures. They are available in medical grades and can withstand repeated cleaning with disinfecting chemicals. With their very low rate of water absorption, medical PSUs can also withstand superheated steam. In addition, these engineering polymers provide excellent resistance to high-energy radiation and combine good dimensional stability with high impact strength.

Medical injection pens, or injector pens, are used to deliver medications in pre-determined doses under the skin. They are easier-to-use than vials and syringes and are often prescribed to patients who need to inject repeated doses over a short period of time or on a regular basis. Applications for medical injection pens include the delivery of insulin or insulin analogs (i.e., insulin pens), growth hormones, cholesterol medication, and monoclonal antibodies.

Whether they’re disposable or reusable, injector pens include a needle, an internal locking mechanism, and an assembly that a patient can grasp in the hand. Polysulphone is a good choice for the assembly because it withstands the radiation that’s used for sterilizing single-use devices, and the chemical cleaning or steam sterilization that’s used for reusable devices. To acquire the net shape for the injector pen assembly, machining is used. However, this can create raised areas (burrs) that are hard-to-reach.

When a medical device manufacturer asked Nitrofreeze® to deburr injector pen assemblies, we analyzed the part geometry, performed initial trials, and determined that the part was a good fit for our cryogenic deburring technology. A two-pass process with varying media sizes eliminated exterior burrs while protecting the integrity of a slotted opening that was required for proper assembly. This customer-specific deburring solution saved the medical device manufacturer time and money while delivering on quality.

What is Cryogenic Deburring?

Cryogenic deburring is an automatic, computer-controlled batch process that provides a safe, clean, cost-effective alternative to hand trimming. During cryogenic deburring, your parts are cooled to cryogenic temperatures so that the burrs become brittle. Your parts are then impacted with a special non-abrasive media so that there’s little dust and no mess as the burrs are removed without affecting surface finish or dimensional tolerances.

The Nitrofreeze® cryogenic deburring process is very efficient at removing burrs from blind holes, cross-drilled holes, and other hard-to-reach features and geometries. The non-abrasive polycarbonate media that we use ranges from 0.015” (smallest) to 0.060” (largest) so that Nitrofreeze® can choose just the right size for your parts deburring project. Because your medical polysulphone parts are specific to your application, we can also develop the right “recipe” for burr removal and store it for future use.

At our Worcester, Massachusetts facility, Nitrofreeze® can develop low-cost custom fixtures to ensure burr removal from blind holes, through holes and other recessed areas in machined medical parts. Our cryogenic burr removal process can accommodate thin-walled parts as small as 0.025” and larger, inch-based parts with greater mass. Compared to hand trimming, Nitrofreeze® cryogenic deburring delivers greater part-to-part consistency and repeatability.

Ask Nitrofreeze® About Deburring Medical Polysulphone Parts

What’s the best way to deburr machined medical parts like PEEK implants and PSU injector pens? Contact the experts at Nitrofreeze® to discuss your requirements. No job is too large or too small, and our standard turnaround time is two days after receipt. If your medical polysulphone parts are a viable candidate for cryogenic deburring, we can perform sampling to demonstrate our process. The consultation is free of charge, so send us your part drawings, photos, or actual part samples.

To get started, contact Nitrofreeze® at the phone number and email listed below.

(508) 459-7447 x109 |