The Prescription For Making Orthopedic Parts

In the film "The Graduate," a neighbor gave one hushed word of business advice to Dustin Hoffman’s character: "plastics." That screenplay was written more than 30 years ago. If it were written 15 years later, that word might have been "medical." The exploding growth in the market for medical components, such as metal joints, bone screws and laparoscopic tools, has helped many job shops survive when orders from other industries lessened or disappeared in the late 1990s. The medical market is expected to continue to be strong as life expectancy lengthens, the Baby Boom generation crosses into senior citizenship, and orthopedic and microinvasive surgical advancements continue to evolve.

Before a shop seeks out medical customers, there are factors to consider to help ensure the shop’s success in the medical market. These have to do with the nature of orthopedic parts, the optimum way to produce them efficiently, quality requirements by both medical companies and the government, along with labeling and packaging.

JKB Tool in Milford, Connecticut, is a company that made a leap to medical machining about 6 years ago. The shop made its reputation in the 1980s as a designer and builder of sophisticated automatic assembly and test systems. An adjunct to that business was a small contract production shop and, later, a stamping business. Jason Blake, son of the founder, has worked with his dad since the business started, deburring parts in the family’s basement.

"When I graduated from college, I came to work at JKB full time," Mr. Blake says. "That was 1994, and by 1997, the automation projects were getting bigger and more complex, but were less profitable. We were making money in the stamping business, but more jobs were going to China and Mexico, so the future in that was questionable." As Mr. Blake tells it, the company was on the verge of despair by 1998.

"We had one hopeful spark going for us," he says. "We had a small machining contract for a laparoscopic tube running on our CNC milling machine. We saw a future in medical parts and made a commitment to do whatever was necessary to go after more of that business; we had to become more efficient if we wanted to be successful at it."

Mr. Blake was particularly interested in the orthopedic segment and understood that the shop would have to invest in new multifunction equipment to be competitive. In a typical bone screw, for example, the operations are thread whirling, broaching, gundrilling and micro-milling. If conventional equipment is used for each operation, then three or four machines would be required.

"I went to the EASTEC trade show in '98 and looked at CNC screw machines for the bone screw parts that we wanted to attract, plus additional laparoscopic parts," Mr. Blake says. "I knew that these were multifunction machines, but that’s all I knew. I had never worked on one, nor had any of our employees."

JKB purchased a "Deco" Swiss-type sliding headstock turning center from Tornos Technologies (Brookfield, Connecticut) in 1999. The machine was 60 percent faster (41 seconds) in a competitive test involving the laparoscopic tube part. Today, 6 years later, Mr. Blake and his crew produce that part even faster (36 seconds) as a result of gaining expertise in the technology.

First Machine
Once the machine was on the floor, the shop employees began working to master bone screw manufacturing. Titanium bone screws are used for spinal corrective surgery, trauma, and other types of bone repair and correction. Other bone screws are made of 316 stainless steel. They are produced by the millions in the United States to strict demands for tolerance, surface properties, cleanliness and packaging. The titanium screws range in length from 6 mm to 80 mm and have ODs from 2 mm to 8.5 mm. They typically require a 0.4-micron to 0.8-micron surface finish and dimensional tolerance of ±0.025 mm. Customer specifications also often include the addition of an anodized coating for color coding different sizes and types of screws. Surface finishes and tolerances must take into account the coated layer, allowing for additions or reductions in material.

"It was a difficult time," Mr. Blake says. "Remember, this was a new discipline for us, using a new technology in a new market. This was our very first screw machine."

It was a challenge for JKB to adapt to the large volume of parts coming off the machine.

"If we made a mistake in programming or setup or tooling, it set us back in production time," Mr. Blake says. "The bone screw machining process is not very forgiving."

Mr. Blake and his staff also had never worked with titanium, which is a tough, flammable material. If a tool breaks, the material’s temperature is so high that it can ignite the cutting fluid. It’s necessary to have fire extinguishers at every machine. According to Mr. Blake, he and his employees worked 14-hour days, 7 days a week for about 4 months to learn how to make the parts.

"But we were driven. We were hungry. We persevered," he says. "The only thing we didn’t worry about during that learning phase was threading, which is usually the big problem for people requiring expensive, dedicated equipment. The Deco has a thread whirling attachment that puts the thread on so easily. They come out burr-free; we can put any shape we want into it; and we get tremendous life out of the tooling inserts."

First Contract
JKB won a bone screw contract in 2000. The company sold off its press equipment and bought another Deco.

"We got the business because we could produce it for less than our competitors and with better quality and faster delivery," says Mr. Blake.

Armed with confidence and experience in the technology, and driven by the spirit of survival and perhaps also by youth (Mr. Blake is 34; most of his employees are younger), the orthopedic part business grew.

"There were bumps and challenges along the way, of course," he says. "One part comes to mind—a fixed-angle bone screw. We worked on that part for 2 years to make it successfully. We use all 20 tool positions on the Deco to make this part complete in one setup. The elliptical shape of the head posed unique challenges, such as part holding and the many operations that have to be performed in the machine’s counter spindle. The Deco gives you eight tool positions for counter operations, all of which can be live tools."

JKB’s goal is to always make a part in what it calls "done-done" in the machine. The shop always tries to avoid secondary operations.

Art Deco
The ten-axis Deco machine can use two turning tools at the same time, completing rough and finish cuts in the same operation. One of the machine’s cross slides accepts up to four live tools for operations such as cross milling and off-center drilling. A gundrilling and high-pressure coolant attachment can be mounted on the end-working unit. This feature is a plus when producing cannulated bone screws, which are screws with a 1.5-mm to 2.5-mm hole through the entire length. JKB prefers to gundrill the hole rather than to buy cannulated stock, which is often unavailable. Polygon milling of flats or contours can be accomplished using the machine’s optional C axis on the main spindle.

While the bar in the main spindle is machined, operations are performed on the previously parted piece mounted on the counter spindle. For example, the counter spindle can present the part’s cut-off end to as many as four live tools or turning tools. In effect, the user gets these operations at zero time because they occur while the part in the main spindle is machined. Users such as JKB can minimize part cycle times by balancing operations between the main and counter spindles. As many as ten axes can be controlled simultaneously on the Deco, and up to four tools can be operating simultaneously.

"The programming is a different approach," Mr. Blake says. "Tornos calls it PNC, parallel numerical control, because so much is happening simultaneously, but it’s the control and dedicated software that give you the productivity. The machine goes from operation to operation before you finish an eye blink. The payoff is worth learning it."

The machine’s software automatically calculates real machining times, taking into account tool paths, operation sequences and other cutting data entered by the user. It also incorporates canned cycles that speed programming, such as barstock advance, cut-off and pick-up by the counter spindle. It also displays the part’s production rate.

Quality Control
There are other aspects to consider when getting into the medical business besides efficient and advanced manufacturing technology. Not only must a shop be certified to ISO 9001/14001 for most medical OEMs, but there is also a myriad of U.S. Food and Drug Administration requirements involving inspection, reporting, labeling and packaging.

"It was an overwhelming prospect when we first got into the medical market; however, we plowed our way through to do all the right things for our new customers," says Mr. Blake. "We invested heavily in inspection equipment, because each and every part we make must be viewed under a microscope for physical characteristics, such as marks on the bone thread or any burrs on the part. We also check dimensional accuracy. We achieved our ISO 9001/2000 certification and are registered with the FDA. The regulations are somewhat of a moving target at times, but if a shop wants to be in this business, which we do, you do whatever it takes to be successful.

"Our next goal is to run a paperless shop and documentation system. Our customers and the FDA require very accurate record keeping called Device History Records, which are often kept for up to 30 years."
Labeling and packaging is another area with particular requirements in the medical industry. Each part or assembly must be individually marked with vendor code and lot code. JKB uses a quality-approved vendor to laser etch each part and also anodize the parts if required by the customer. When the parts return to JKB, they are packaged and shipped per customer specifications.

"If we are shipping more than one lot, they are segregated by lot," says Mr. Blake. "The most important thing is accurate documentation. It’s everything in the medical business."

Putting It All Together
"Generally speaking, the main difference between the medical industry and the others we have been in is that we have to be more careful, more precise," Mr. Blake says. "All aspects have to be as close to perfect as humanly and technologically possible—the parts, the inspection, the documentation—but if a shop is as motivated as we were, it’s rewarding. We’re in the black. The work is interesting and challenging. And we like the idea of making products to improve a person’s quality of life."

Mr. Blake is a strong believer in reinvesting. He says he invests 80 percent of the profits back into the business. The company now has 12 Decos on the shop floor, and will order four more this year. He says the company buys the most expensive tooling, and it has switched to a vegetable-based oil that is double the cost of conventional oils. According to Jason, his tool life savings makes up the difference. He has also developed his staff and takes a sports team management approach.

"I see myself as a coach who has 55 talented players, and I do whatever I can to keep them happy and performing at peak levels," he says. "I pay them well and we all work very hard because we want to win. Many of them were with me when the business was struggling. They don’t want to go back there. Neither do I. We do whatever it takes to maintain our competitive edge. We’re always in R& D mode, you might say, always trying new things to grow and keep that edge razor sharp. If we don’t, someone else will."

About the author: Lynn Gorman is a communications and marketing specialist in Bethlehem, Connecticut. Tornos Technologies U.S. Corp. is one of her clients.