December 2008 Edition

grinding

Needle Sharpener Keeps Phoenix On Point

A medical manufacturing shop takes the sting out of shots by keeping its needles sharp

Phoenix Medical Products, Mountain City, TN, is a contract manufacturer of various devices used in the thoracic, laparoscopic, arthroscopic, gastrointestinal, cardiovascular, soft, and hard tissue biopsy areas of the medical and research markets. As such, its watchword is precision at every turn.

In addition to mold design, injection molding, and various machining services such as milling, turning, grinding, and drilling, Phoenix also maintains a complete Class 10,000 cleanroom packaging and labeling facility. It offers its customers a competitive edge by being a turnkey operation, from CAD through rapid prototype, validation, production, and packaging. Even product printing, etching, and laser marking are done here, along with catheter tipping and Nitinol wire forming and crimping, making Phoenix a one-stop shop for most customers.

In any operation, bottlenecks at any stage can create upstream and downstream problems. With a variety of demanding customers and diverse jobs that all require precision handling, this 20-year-old, 107,000 ft² shop is on the lookout for newer, better means of creating its products.

One Phoenix department is devoted to needle design, production, sterilization, and packaging. This work has a set of challenges and concerns facing many shops in the medical field.

"Our former method for a type of needle production involved sharpening with a 5-axis CNC grinder and manual fixture. We had to end-swage the needles down to a specific diameter, not a very precise process. When we’d set up the CNC grind, we’d often need to run some parts two or three times to get the desired edge because the swage did not leave us enough usable material," David Hannah, general manager for needle production, said.

“In a short time, we were able to track a 40 percent increase in our production plus a five to 10 percent decrease in scrap”

Finding the Needle in a Haystack

Hannah and Chris Blake searched for an answer from the multitude of companies touting possible solutions. Blake, engineering manager at Phoenix, and Hannah first did a web search and, after some calls, found Advanced Machine & Engineering – AME – Rockford, IL.

"After speaking to AME engineers, I knew we had a good match," Hannah said. "The process was simple and straightforward. They sent an engineer to see our manufacturing process, which we appreciated."

AME’s Dan Lapp, vice president of sales for the company, was the engineer who visited. After his first visit, the AME design department went to work. A series of discussions resulted in a SolidWorks model ready for review. Only minor modifications were required by the Phoenix team.

Once the first machine was built, it underwent testing on Phoenix needle products, using an in-house grinder at AME to test accuracy, surface finish, part-to-part time, and the machine assembly. Upon shipment and commissioning at Phoenix, the machine was put into production. To the Phoenix production team’s satisfaction, the needle sharpener was productive from the outset.

"With the fixture, we were able to set up the products on our manual grinder and a surface plate. Using our video system, the operator observed each needle being ground and achieving the correct point on the first cycle, every time. In a short time, we were able to track a 40 percent increase in our production plus a five to 10 percent decrease in scrap," Hannah said.

No Reservations

Since the raw material for such needles is typically an expensive 304 or 17-7 stainless steel, the decrease in scrap achieved was beneficial. Hannah said the entire operation was simpler and easier for the operator, with less setup time and reduced maintenance. Since its start-up at Phoenix, the needle sharpener has needed one routine cleaning.

In production, the AME needle sharpener machines a double loup conical point. It also was designed to let Phoenix change cam plates and grind a variety of style points. The needle sharpener provides simultaneous workpiece rotation and axial motion – oscillation. A dustproof, watertight gear motor provides rotation through a drive system. Oscillation is provided through the built-in cams.

The typical needle workpiece oscillates twice for 0.025"/0.028" per rotation. The spindle assembly tilts from 0° to 40° around the pivot point – the shoulder bolt screw – and locks in any position for an optimum sharp edge on the workpiece. Tolerances are held to ± 0.001" on straight grinds, ± 0.002" on double loup grinds.

The original machine purchased was designed for a line of Phoenix needle products that was modified, but the needle sharpener was adjusted and back in production in a short time, according to Hannah. He said he would have "zero reservations" about recommending AME for future work. Advanced Machine & Engineering Co.

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