Medical Instruments, Part 3 – Adjusting Surface Finishing Alongside Medical Advances

All medical technology requires precise surface finishing to ensure safety, strength, and longevity. The specific surfacing goal and technique vary though.

From stainless steel dental drill heads that require deburring and

surface smoothing to stainless steel tweezers that require surface cleaning and

texturing after forging/grinding and induction welding, the specific treatments

are the key to surface finishing success.

In our last medical instrument blog, Rosler Metal Finishing discussed the merits of mass finishing and shot blasting for medical instruments.

This blog will address a particularly challenging form of material in need of surface finishing and answer the question: What specific surface finishing challenges are there in the medical field?

Media & Compounds Matter

In any machining operation, good tooling is essential for producing quality parts. For mass finishing processes, the finishing media are the “precision” tools that guarantee the specified finishing results. Especially in the field of medical devices with its zero-defect requirements, only top-of-the-line media and compounds will ensure that the quality requirements are met.

The

rapid development of tougher and more wear-resistant materials for medical

devices frequently demands the development of new, innovative mass finishing

media and processes that can cope with the surface finishing challenges of

these new materials.

Good examples for these challenges are the increased use of ceramic materials in the medical field and work pieces made with additive manufacturing.

Adaptive Technology

The new materials are generally a lot tougher and harder than previously used materials. This makes the finishing tasks much more difficult. Especially with the increased use of additive manufactured work pieces, which have a much rougher surface than cast, forged or machined work pieces.

Suppliers of mass finishing and shot blasting equipment and consumables

have met these challenges head-on by modifying existing equipment designs or

developing brand-new machinery. However, the biggest progress has been made in

the field of mass finishing media.

There is now media on the market, which allow placing a high-gloss

finish on work pieces made from cobalt-chrome or titanium after CNC grinding.

And these media even allow mirror polishing of ceramic work pieces.

Likewise, additive manufactured work pieces can be finished from initial surface readings of >800 micro inches down to less than 10.

To date, additive manufacturing has been mainly a prototyping method. For example, scientists developed a computer model of the stinger of bees to produce an additive manufactured prototype of an innovative hypodermic needle.  Additive manufacturing is rapidly evolving into a low- to mid-volume manufacturing technology in the medical and aerospace industries and beyond.

Unfortunately, printed parts have a much higher initial surface

roughness than, for example, forged or cast work pieces:

• Initial surface roughness of additive manufactured parts – Ra = up to 800 micro inches
• Initial surface roughness of forged or cast parts – Ra = 120 – 320 micro inches

To go from an Ra of 800 micro inches down to 10 or lower can be a daunting

task!

The Rosler Way

Whatever your medical instrument finishing needs are, you can count on Rosler Metal Finishing to help you find a better way and the best results. We listen, learn, develop, and deliver mass finishing and shot blasting technology in step with medical advances. Learn more in our Surface Finishing for Medical Devices guide (pdf) and contact us today to discuss your unique challenges.

The complete Medical Instrument Series includes:

• Part 1 – Surface Finishing Requirements for Medical Instruments.
• Part 2 – Mass or Shot: Which Technique is Best for Medical Instruments.
• Part 3 – Adjusting Surface Finishing Alongside Medical Advances.

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