Getting an Edge on Super-Robust Surgical Blades

Hutchinson Technology has counted super-precise photochemical etching as a core technology in its evolution over the decades into a $250 million-a-year maker of computer disk suspensions.

Now Hutchinson (Hutchinson, MN) is preparing to use the same technology to produce thousands of tiny stainless-steel surgical blades less than an inch in length, about the same size as the disk suspensions that have been Hutchinson's bread and butter.          

An undisclosed major medical device company recently received FDA approval for a surgical device that uses Hutchinson's blades, and the company is working on securing more major customers, says Dan Roach, business development manager at Hutchinson.

Roach declined to divulge details of the process, but the blades are created not through grinding but through a modified version of the photochemical etching process in which Hutchinson already has plenty of expertise and capability.

The process can result in serrated blades with only about 25 microns between each tooth. Roach and others at Hutchinson think the process is much more precise than grinding because it avoids heat from friction and the resulting material softness that can then take place. The result is a more robust blade. And because the blade edge is sharpened in the same process step as the perimeter and other features, there is more precise registration.

One has to wonder whether Hutchinson has hit on a new process for producing more precise and durable medical blades, and all of the related innovations that could then follow.

Get a tour of the plant at corporate headquarters, and one will notice plenty of rooms with yellow light meant to prevent altering the green, photoresist chemical sprayed on sheet metal at the plant.

The green pieces of metal are exposed to white light on each side in a way that "prints" exactly where the etching will take place. The metal is then "developed," with the unexposed photoresist washed away. (Or in other cases, Hutchinson uses a photoresist that instead "hardens" after light exposure, with the unexposed area washing away.) Metal is revealed and then etched when it is sprayed with metal.

The major medical device manufacturer contract was the result of years of prototyping and development, Roach says. A major challenge involved the shape of the blade, which needed to be pointed enough to have the sharpness needed in a laparoscopic-type surgery, but also with a wide enough edge that it could be used repeatedly during a surgery without dulling.

Hutchinson gamed out multiple blade shapes to come up with one that was optimal for the OEM. It is but another example of how suppliers are increasingly becoming involved in early stage development with the large medical device companies.

Chris Newmarker is senior editor of MPMN and Qmed. Follow him on Twitter at @newmarker and Google+.