Machining by the Numbers

As machining technology advances, tolerances are growing tighter and OEM expectations of quality are rising. (Photo courtesy of LaVezzi Precision).

Faster, smaller and more intricate: these qualities are what OEMs demand of contract manufacturers today.

Driven by shorter product cycles, device makers are shaving months off development time and years from the life cycle. And while speed to prototyping and full-scale production are important, contract manufacturers say OEMs are also struggling with tight budgets and increasingly smaller, complicated products. That’s one reason why the relationship between OEMs and their contract manufacturers has become more of a partnership; it’s also why device manufacturers are raising expectations for their suppliers.

“OEMs definitely expect more from their suppliers,” said Brad Rosenkranz, sales manager for Marox Corp. in Holyoke, MA. “They’re more and more stringent in terms of what quality programs their suppliers must have in place, and they’re requesting more value-added services. For example, in addition to just machining product and then shipping, we also provide packaging and labeling so that we can streamline their production process.”

“OEM expectations today are very high,” Tanya DiSalvo, operations manager for Criterion Instruments in Brook Park, OH, agreed. “The difficulty of machining the parts is greater—they’re getting so tiny and precise, and tolerances are so tight. FDA requirements are also increasing as is the need for documentation.”

Higher expectations are translating into expanded capabilities for many contract manufacturers. In addition to traditional machining work, vendors often have to provide assembly, packaging and other value-added services. Al LaVezzi, president of LaVezzi Precision, Inc. in Glendale Heights, IL, said that to differentiate as well expand its capabilities, the company is installing a class 10,000 cleanroom.

With increased pressures on medical device OEMs—from shorter product life cycles, to smaller budgets and devices to heightened regulatory and reimbursement concerns—they are seeking help from those in the know. Indeed, contract manufacturers across the board expect to see growth ranging from 8–25% in 2004. Here are four reasons why:

More precise capabilities have kept pace with a more demanding customer base, machining providers say. (Photo courtesy of LaVezzi Precision)

Contract manufacturers offer creative, cost-cutting solutions. “OEMs’ priorities today are to get the product to market fast, fine-tune the manufacturing process and identify cost savers to increase margins,” explained Jack Fulton, vice president of sales and marketing for Specialized Medical Devices in Lancaster, PA. As partners, contract manufacturers often make recommendations to OEMs on adjusting product design to save big bucks or time during the production process.

“It’s not unusual for us to see drawings in the early design phase today,” LaVezzi said. “Years ago, we might not have seen drawings until they were final, but now designers are asking more questions about manufacturability earlier in the process. We have more input today. In the end, it saves a lot of time and money for both of us.”

“We frequently take a look at the design and discuss modifications that won’t affect the device’s function but will cut costs significantly,” Fulton added. “Sometimes designers hit a default key on tolerances or finishes—those are the two biggest areas we make recommendations in.

A slightly different tolerance or finish can make a big difference in manufacturability and speed cycle time.”

“A larger radius, changed finish line or being allowed to put in a tooling hole that won’t affect the product’s function but will let us make it quicker are other changes that can help,” said Moe Feldman, president of Aeromed, Inc. in Hatfield, PA. “Reducing the number of parts helps, too. For a recent assembly job, one of the key elements was made out of two pieces so the OEM could save material costs. We suggested that they make it one piece. Even though the material cost a little more, the labor cost was significantly less.”

Choosing Materials Wisely

Using materials that are easier to work with can reduce labor time and increase savings also, said Kevin Noble, executive vice president for process engineering at Norman Noble, Inc. in Cleveland, OH. “The No. 1 thing OEMs can do to save time and money in machining is examine the material they’re using,” he said. For example, he pointed out, 303 grade stainless steel will cut much easier with fewer burrs than a 304 grade. Also, many OEMs require .0001- to .0005-inch tolerances in certain geometrical dimensions and shapes that are difficult to hold and serve no purpose to the device’s function. If an OEM can change some of its dimensions and tolerances, it can benefit from a less costly and more efficient manufacturing process.

Materials make a difference. Material selection makes a world of difference not only in product functionality but also in manufacturability. While stainless steel and titanium remain popular choices, there is a trend of moving from titanium to implantable-grade plastics like PEEK, noted Fulton.

Greater Alloy Use

“Polymers such as PEEK are now replacing titanium in spinal cages,” added Rosenkranz. He pointed out that more polymers are being developed for this purpose because medicine is increasingly using MRIs, and polymers are more radiolucent and easier to view by x-ray. Polymers also feature better porosity so that bone can grow into them and adhere better than to titanium. In the spine sector, cobalt and titanium are used in conjunction with polymers. Adoption of bioabsorbable polymers is also on the rise. Device manufacturers are taking advantage of the fact that such polymers will fully dissolve during the healing process.

Alloy enhancement continues to be significant, according to Dave Vincent, director, business development, with Johnson Matthey. “Enhancements to existing and next-generation alloys also attract a high level of interest in the industry,” he said. The trend is to improve strength characteristics, fatigue life, miniaturization, radiopacity and MRI-compliance. Miniaturization and intricate machining have become critical capabilities for contract manufacturers. Nitinol, a super-elastic, shape-memory alloy, continues to grow in popularity as well.

Machinery advancements enable production of increasingly intricate products more quickly. As machines become more sophisticated, end products have become more sophisticated as well. Today’s more automated machines allow for tighter tolerances and faster production cycles than possible just five years ago.

“Tolerances continue to tighten as devices keep getting smaller,” noted Bob Lamson, vice president of business development for Micro Group in Midway, MA. He said that five years ago, tolerances of .001-inch or greater were standard. Today, customers want to reduce those numbers by half. In addition, many parts have become more complicated because of the number of features they must have and their relationships with one another. Contract manufacturers are using more CNC machinery for its ability to achieve high tolerances.

Myriad Tooling Options

Further aiding the trend is a growing number of tooling options. Live tooling capabilities allow complex parts to be produced on one machine. This is a step forward from past practices, when a product may have been sent to other facilities for secondary operations. Swiss turning centers are now capable of turning, milling and manufacturing unique features such as offset holes and offset slots on one machine.

“Equipment is improving more [quickly] than materials are. Previous technologies required multiple setups, which translated into increased costs,” Fulton added. “Now a part can be almost completely manufactured on milling and turning machines, which greatly reduces cycle times.”

The drive toward miniaturization is fueling an increased interest in micro-machining. Drilling, cutting and finishing can achieve even smaller parts, but handling requirements of these small products can complicate production. However, measurement and analytical techniques have improved, so machining shops can meet the tougher requirements associated with smaller parts.

Advances in laser machining capabilities are allowing OEMs to make very intricate patterns from flat stock or tubing more easily than with milling or wire cuts. Laser cutting is helping to reduce burrs and may eliminate a manufacturing step, which speeds manufacturing times and reduces costs.

However, some engineers have been hesitant to use the technology simply because they’re not familiar with it. Noble said one customer had specified that its rings be wire cut in a series of hook shapes. When the company switched to laser cutting, it achieved higher-quality rings in less time.

Machining also is being performed with waterjet cutting, which is ideal for some very high-volume runs for tubing and lumens. An abrasive is mixed in high-pressure water to cut stainless, aluminum, tile and marble—just about anything but carbide—at 10,000–60,000 psi. The process even allows cutting around curves as well as materials too thick for lasers. However, it’s unable to meet tight tolerance requirements.

Enhanced quality programs mean better products. “OEMs today are more cognizant of companies that have quality systems and validating processes, and those that don’t,” Lamson said. “They’re also more conscious of statistics.”

For example, one study of Six Sigma, a manufacturing process improvement mechanism, has shown that 99.379% accuracy may no longer be acceptable, said Randy Bormann, general manager of the development center for UTI in Collegeville, PA. (See The drive toward Six Sigma: cost savings from less variation and product waste) “For a device that has more than 40 components, all of which have achieved Four Sigma (a 99.379% perfection rate), the stack up of the tolerances would result in a good finished product only 86% of the time,” Bormann explained. “That’s huge in terms of cost and significance to the patient.”

 

Laser machining capabilities allow device manufacturers to create intricate patterns than other methods. (Photo courtesy of Norman Noble).

Quality systems are a top priority also because FDA requirements continue to become more stringent. Contract manufacturers’ internal controls can offer other benefits as well. “When you ship products to your customer, it sits in a queue, waiting for the OEM’s inspector to inspect it,” Rosenkranz explained. “If your quality is high and consistently on target, it may meet dock-to-stock requirements. If the OEM supports this program, your product can go right to stock. That would eliminate cost and save time since there’s no duplication of the inspection process.”

As medical device manufacturers face growing competition, a domino effect occurs. The product cycle continues to shorten, and machining vendors have to abide by more-demanding schedules. At the same time, they are employing new techniques and equipment to help them meet these deadlines.

“When you consider that a few years ago, it took two weeks to move some components through all phases of manufacturing, and today it can be done in days, it’s exciting to think where we’ll go from here,” said DiSalvo. “Imagine what technology in machining will allow us to do in another 10 years. The future looks bright.”

Stacey L. Bell is a freelance writer based in Tampa, FL, who specializes in marketing and business issues.