End Mills Give Medical Manufacturer a Leg Up on Automated Production

Emuge solid carbide end mills feature select sub-micron grain carbide construction and advanced cutting geometries.What do you do when you have a part that takes up to 24 hours to machine and only one eight-hour day shift? You find a way to automate the process and speed production. However, what do you do when the tools you are using fail after just three or four hours, making automation extremely difficult? This is precisely the predicament Micron Integrated Technologies found themselves in when they wanted to take their knee implant machining operation lights out.

Located in Fitchburg, MA, Micron Integrated Technologies is a wholly owned subsidiary of Arrhythmia Research Technology, a provider of state-of-the-art hardware and software solutions for comprehensive cardiac care. Micron offers outsourcing solutions including engineering services, precision metal and plastic component manufacturing, finished goods assembly, and complete supply chain management. With approximately 100 employees, Micron has more than 94,000ft2 of environmentally-controlled manufacturing and warehouse areas with Class 10,000 cleanroom capabilities. Micron prides itself on providing low cost turnkey manufacturing services to the medical, aerospace, petrochemical, and defense industries, but about 80% of all the production at the Fitchburg facility is for the medical industry.

Micron's precision metal manufacturing division is capable of producing tight tolerance components from forgings, castings, and bar stock. They machine materials such as stainless steels, nickel based alloys, titanium, brass, cobalt chrome, and other specialty metals. Using state-of-the-art technologies, Micron offers the precision needed to handle the most challenging machining applications, including those required by the medical industry. Examples of medical products they manufacture include components for blood analyzer equipment, heart pump parts, orthopedic devices/implants, custom knee braces, fetal heartbeat monitors, and more.

Customized Knees
Micron currently manufactures tibial trays, inserts, and femoral components for surgical knee implants, supporting more than 200 parts per month.Micron currently manufactures tibial trays, inserts, and femoral components for surgical knee implants, supporting more than 200 parts per month. Each implant is custom-produced, with the first step being an MRI of the patient's knee done at the hospital. Then, creation of a CAD model from the MRI enables the manufacturing of a unique part, specifically for the patient. Alternatively, a standard-sized knee implant could be used and portions of the patient's bone would be removed to create a better fit. However, a custom-fit implant requires very little bone removal on the patient, which means a much quicker recovery period. It can also extend the life of the implant by up to ten years.

In the manufacturing process, Micron uses approximately ten different end mills, including ballnose and torus (radius corner) in diameter ranges from 1/16" to 1/2". Running on 3- and 5-axis vertical machining centers, each part takes anywhere from six to 24 hours to machine. Micron was trying to run these jobs lights out, but the tools they were using kept prematurely wearing down and breaking.

"We were using four end mills to create femoral knee implants on our 3-axis vertical machining centers. Because each part took so long to machine, we were trying to automate operations," states Dan Dorion, lead programmer and machinist at Micron. "However, tools were regularly breaking and were pretty beat up by the end of the cycle. We were lucky to get two parts completed before the tool would fail. With only a day shift on staff, it was impossible to run things 24/7 with the tools we were using."

Because of the demanding stock removal requirements, most end mills Micron was using would not last through more than two or three parts. Dorion knew he had to address the problem and research possible solutions. On some previous jobs, Dorion has used Emuge tools for hard milling, being impressed with their performance. He thought that given the demanding manufacturing process and the fact that they were machining challenging cobalt chrome, Emuge might be a good fit for this application.

Micron talked to an Emuge applications engineer, explaining the problem they were having with tool life. The engineer then traveled to Micron's manufacturing facility in order to execute a series of test cuts, after which it was determined the best solution was to use an Emuge 1/2" torus tool to rough out the parts.

Emuge solid carbide end mills feature select sub-micron grain carbide construction and advanced cutting geometries. Tools are available for application-specific machining for demanding situations as was the case with Micron, and the tool designs vary depending on the material used: such as aluminum, titanium, graphite, stainless steels, and specialty materials. In addition, specially engineered coatings provide maximum cutting performance and tool life.

Savings, Efficiency
Micron realized immediate results after using Emuge end mills in their machining centers. "Our tool life and part production has more than doubled," says Peter Rezuke, custom machining manager at Micron. "The Emuge tools can last through more than six parts and some cycles can run up to ten hours without failing. We are now running successful weekend lights out operations. On Friday, several machines are loaded and set to run. When Monday morning arrives, the parts are all ready for inspection and shipping. We are now machining more than 200 implants per month, whereas before we could only manufacture 100 parts per month."

Besides doubling their tool life, the Emuge end mills substantially minimize chatter and provide a much better finish in heavy cutting. Feedrates have doubled, and in some cases tripled. Because of the dramatic increase in tool life and productivity since switching to Emuge tools, Micron has saved considerably on their tooling costs.

The Emuge tools are performing much more efficiently than the previous tools. They are more resistant to wear and have eliminated the breakage problems that thwarted Micron's automation efforts. For example, with the best performing 3/16" ballnose end mill they were previously using, the chipload was 0.0005" and spindle speed was 5,000rpm running at 10ipm. The Emuge 3/16" ballnose tool ran at 4,700rpm, with a chipload of almost 0.002", the feedrate was 35ipm.

"Surface finish quality has improved considerably as well. We eliminated 10 to 15 minutes per part in our secondary polishing operations," Dorion comments.

"Making the decision to switch to Emuge cutting tools radically improved our machining operations," adds Sal Emma, general manager at Micron. "With a unique ability to understand their customers' challenges, Emuge was able to provide the most effective solution to our tooling issues. Emuge tools provided longer tool life, increased speeds, and feeds and gave us the advantage and benefits of lights out manufacturing."

Emuge Corp.
West Boylston, MA
emuge.com

Micron Integrated Technologies
Fitchburg, MA
micronintegrated.com