Technical Features

Machining Miniature Medical Marvels

By Stacey L. Bell | January 23, 2008

Machining and Laser Processing Companies Are Introducing New Capabilities and Services as Minimally Invasive Surgeries Fuel Demand for Increasingly Tiny, Complex Instruments and Devices

Women who would like to make their wrinkles disappear. Men who have learned their arteries are severely clogged. Hospitals that must shrink budgets even as their patient loads increase. And medical device companies that face escalating demands from regulatory agencies and Wall Street in a tightening economy, and then look for help from their outsourcing partners to make matters better.

Everyone who touches the healthcare industry is under tremendous pressure these days. In recent years, the pressure women have felt to erase years from their face-and both sexes have experienced when they've learned they require surgery-has been alleviated in part by spectacular advances in medical technology that have allowed minimally invasive procedures to become the norm. From repairing and replacing heart valves and arteries to replacing knee joints, surgeries across the board are becoming less invasive.

Such procedures also have helped to ease the pricing pressures all medical providers face while opening new opportunities to medical device firms' product developers and outsourcing service providers. Minimally invasive techniques not only shorten patient healing times and hospital stays-and in many cases allow surgeries to be performed on an outpatient basis-but they also are dramatically changing the design and manufacturability of the advanced, increasingly tiny and complex instruments, delivery devices and medical devices required.

"More devices are being designed for the minimally invasive arena, which means smaller moving parts must work in a smaller environment. Therefore, today's tolerances are much tighter," noted Bob Walden, manager of new business development for Staunton, Va.-based IncisionTech. While IncisionTech used to routinely see tolerance requirements of .003 inch to .005 inch, today customers typically expect tolerances from .001 inch to as tight as .0005 inch.

Customers also expect their instruments to be able to perform more cuts within a single procedure. "In a minimally invasive environment, surgeons concentrate on doing more in a smaller space within a shorter amount of time so the patient can heal faster, with less trauma," Walden explained. "More and more in the last year or two, we've seen a device that previously would have been used to make one or two cuts in a more invasive procedure now required to make substantially more cuts in a new minimally invasive procedure."

For instance, hysterectomies used to be performed as an open procedure with a minimal number of cuts. Today, more women undergo a less invasive surgery that makes a .075-inch or smaller incision. Because the pieces of tissue being removed must fit within the narrow-diameter trocar inserted into this smaller incision site, more cuts must be made so that the tissue will be small enough to remove. (Previously, larger pieces of tissue would be removed through a larger incision site.)

"Durability in the blade edge is now an increasing concern, and it drives much of what we do," Walden said. "We're now working with materials that will produce a more durable product." Before, many cutting instruments were fashioned from 300 series stainless steel. Now, more instruments use harder materials such as 400 series stainless steel for the blades, and some are using coatings such as titanium nitride for increased durability. As a result, IncisionTech maintains a much wider breadth of materials in its inventory and has altered processes to accommodate the use of new materials in revamped product lines.

Laserage Technology Corp., located in Waukegan, IL, also has seen a dramatic change in customer requirements due to the increasing popularity of minimally invasive surgery. Ten years ago, customers would ask the company to cut stents with strut widths of .010 inch and greater, with acceptable struts falling within a range of  .001 inch to .0015 inch. Today, finished struts of .004 inch with .0005-inch tolerances are typical.

"Smaller struts mean they can be introduced into a smaller catheter and go more places in the body. Don't get me wrong. We still cut the big ones, but smaller struts and much tighter tolerance variances are becoming a bigger part of the business," said Dan Capp, vice president of sales development for Laserage.

The skyrocketing popularity of minimally invasive surgery and record-breaking gains in the venture capital funding of medical device firms also are fueling strong growth in medical device machining and laser processing. Several companies reported 2007 sales growth in the 35% to 40% range, and even companies with high single-digit growth expect sales in 2008 to reach double digits.

"Here on the West Coast, the explosive growth in minimally invasive surgical device development is fueling phenomenal growth in our business as well," said Patrick Pickerell, president of Peridot Corp. in Pleasanton, CA. "Spinal in particular is doing well. This particular market is so heavily invested in miniaturization, which is physically impossible to produce with conventional machines."

VentureOne found that as of the end of the third quarter of 2007 (the latest quarter from which data were available at press time), investors had poured $2.82 billion into medical device companies, already besting the record $2.69 billion invested in all of 2006.

Established OEMs are tackling their own growth goals, which also affect their outsourcing partners. "More customers have a mandate to produce X percentage of new products each year. Some must increase new sales by 15%, some by 20%," Walden said.

Such increases in new product development, as well as jumps in product volume as more markets worldwide demand the latest in medical advances, are showing up not only in more outsourcing of manufacturing, but also in an uptick in orders of equipment and who comprises machine builders' customer bases. "The trend is for larger OEMs to outsource more manufacturing to first- and second-tier contract manufacturers, and so our business has reflected an increase in the amount of equipment sold to these companies in the past few years," noted Tom Travia, director of operations for Everite Machine Products Co. in Philadelphia, PA.

"We're up a little over 11% this year. Our largest growth is in components for ventricular assist devices [VADs] and laparoscopic surgical components," said Al LaVezzi, president of LaVezzi Precision Inc. in Glendale Heights, IL. "We are fortunate to make major components for five of the eight recognized manufacturers of VADs, which are mechanical pumps used to aid or replace the pumping action of a weakened heart. With an aging population and only so many donor hearts, these devices will save many lives, and as they pass FDA requirements, production demand will grow exponentially.

"Also, minimally invasive surgical procedures are the way of the future; thus, the demand for miniature surgical instrumentation is growing," LaVezzi continued. "In both of these fields, the component tolerances are getting very tight, with related quality documentation a standard requirement."

Gearing Up for Greater Requirements

Certainly, machine builders and laser processing firms are focusing on refining quality control systems and documentation procedures to ensure their customers' needs are met in this area. In addition, shrinking lead times coupled with tighter tolerances are pushing these companies' technology offerings and capabilities to ever-higher levels.

For instance, Potomac Photonics in Lanham, Md., recently added micro-welding capabilities to its portfolio so that it can make full devices, further simplifying its customers' supply chains. The company also recently installed four lasers, each with 100 watts of power.

"Lasers in the past had one-quarter the amount of power they have today," said Mike Adelstein, senior vice president and chief operating officer for Potomac Photonics. "We can split the beam coming out of the laser, so rather than working on just one part at a time, we can do two or three. While new lasers have increased the power level to a point that is significantly greater than what was available in the past, the price hasn't changed, and in some cases, it has been lowered. Therefore, we now can do multiple parts for the same price as a few years ago."

Shown above are needle and cannula products by Popper and Sons, which was acquired by IncisionTech in 2007 for its laser welding capability. More machine builders and laser processing firms are adding or acquiring new technologies to better serve the medical device market. Photo courtesy of IncisionTech.

Lasers also are allowing customers to add more features to their products. "We're able to help biotechnology applications increase the number of holes on a testing device by orders of magnitude," said Lori Beer, Potomac Photonics' president. For instance, instead of placing DNA or other elements into just 400 holes on a device, today's lasers can place 2,500 or more holes within the same area, allowing OEMs to conduct many more experiments on a single device than could have been performed in the past and saving them a great deal of money in testing.

Another big change in laser processing is the new ability to cut fine details in hypodermic tubing using a rotary axis attachment on the laser, Pickerell said. The axis allows the laser to cut radially and in lattice-work designs.

"Before, you had to rely on flat sheet cutting. Now the tubing spins and is cut three-dimensionally down to as small as .010 inch, or twice the size of a human hair. Some of these cuts previously were done on wire EDM, but the throughput on a laser is substantially better-conservatively, I'd say it is two to three times as fast. Therefore, we've converted some jobs from EDM to laser," Pickerell said.

One of the biggest changes in machining is in redesigning equipment to allow for manufacturing parts completely in one operation, reported Trish Mowry, vice president of Metal Craft Machine and Engineering in Elk River, MN. "We've seen growth in complex products that require multiple-axis machines and very tight tolerances," she noted. "To accommodate this trend, we've added the latest high-tech computer technology to our machines, allowing for multiple complex operations to occur simultaneously, saving our customers time while also improving product quality."

Mowry pointed out that while Metal Craft now may spend three days programming a machine to perform six operations, it spends less time doing machine setups and runs. "Start to finish may take two weeks, compared with the old method, which may have allowed you to get product on the machine quicker but could take four weeks to finish, depending on the part," she said. "Multi-axis machining also lends itself to better quality controls to ensure parts fit together optimally. Before, you would run a product through a machine on one side, flip it over then run it through again. Now the product rotates on multiple axes so you can guarantee five or more sides are held within tolerance of one another."

Saving time and reducing the potential for human error were among the reasons Everite Machine has revamped its product line. "Our electrochemical grinding [ECG] machines are now easier to use and to change over from one job to another, which requires less training," Travia said. "The older machines had more moving parts and mechanical adjustments. We replaced the hydraulics and pneumatics, which required more maintenance, with electronics that are faster, quieter and more reliable. Now, rather than dismantling hardware to change out a job, the operator simply pushes a button on the computer screen.

"It's also designed to be as unattended as possible," Travia continued. "The operator can load 10 to 20 feet of tubing, do the first cut [and] then walk away; the machine adjusts automatically as the wheel gets smaller. The operator no longer has to adjust the machine manually as the wheel gets smaller, so he's free to work on something else."

Travia added that ECG is not as well known a process outside of niche markets, but its ability to produce incredibly sharp cutting edges and needle pointing, with little need for deburring, can prove a good alternative to laser or EDM cutting techniques. "EDM, laser and ECG each have specific areas they perform optimally, but some little-thought-of functions are also suited for ECG, which can perform the same function up to 10 times faster than EDM or laser," Travia said. Tubing processes, form grinding and needle pointing all are areas ripe for ECG consideration, he added.

IncisionTech acquired Popper and Sons, a specialty needle manufacturer, in 2007. With that acquisition, IncisionTech gained additional capabilities, including laser welding. It also has expanded its laboratory facility where engineers examine blade edges at both the micro and macro levels to determine durability and sharpness. "We use diagnostic equipment to examine the current product-or its competitors-and then we determine the current level of performance and how different changes in manufacturing would affect that performance," Walden explained. He estimated that about 20% to 30% of customers use the lab to test existing products, and a little more than half call on its specialized services when developing new innovations.

Beyond Machining and Laser Processing

Just as US cable companies have expanded their offerings in recent years to include high-speed Internet, wireless home networking, digital phones, digital video recording and Web TV, contract manufacturers and machine builders are expanding their capabilities and service offerings to meet medical device firms' expanding list of requirements.

Recently, Peridot added a clean room and final assembly and packaging capabilities. By spring, the company expects to add another 10,000 square feet in manufacturing space, with an additional clean room and assembly, testing and laser services.

Before the Fall season, Metal Craft plans to move into a new building that will more than double its current manufacturing space to 60,000 square feet.

IncisionTech is looking at adding light assembly and custom packaging this year.

Companies also are adding computer programmers as electronics become an increasingly common component of medical devices. "We have recently added a process engineer and are adding a wireless data collection for real-time analysis of critical facets," LaVezzi said.

Indeed, real-time analysis of manufacturing functions and the use of other project management methods and tools are becoming more commonplace. Laserage recently made some significant adjustments, including restructuring its organization into new product groups and instituting the Hoshin Kanri planning tool.

"We used to be split into the Medical Device Group and the Metals/Plastics/Glass Finishing Group," Capp recalled. "We realized that metals and plastics work in medical, too, so we reassigned our engineers into two new groups: the Precision Cutting and Welding Group and the Precision Tube and Finish Group. We then moved from a more typical strategic planning model to one based on Hoshin Kanri planning, which is a resource allocation process wherein you visualize and focus on a plan by project. It links and aligns the total organization with near real-time monitoring of the progress toward the stated goal."

Maximizing Product Manufacturability

Customers' stated goals for their products may not always match with what can be achieved in the real world, experts noted.

"Overtolerancing is the biggest challenge," Mowry said. "A computer program may say one thing, but in the real world, variations with materials, machines and tools will mean a specification simply won't work. The best design engineers are those who have worked in a manufacturing environment and truly understand the limitations that can arise."

Design adjustments can be crucial to ensuring a part can be manufactured, agreed Capp. He said in laser processing, two details often are left out or overlooked: While computer programs can easily design a straight line on a piece of paper, in real life, a laser removes a width of material from the part, so the resulting design is no longer in a straight line. Second, engineers may design two lines meeting in a small corner; however, a laser needs to move into and out of the corner, which creates a radius. By not accounting for a laser's dimensions or cutting capabilities, product designers may find their specifications simply are not possible.

Another common challenge is that customers don't consider the vast variety of materials that could be used for an application, Walden said.

"So many designers pick nitinol right away, but is it the most cost-effective solution for many devices? Definitely not," Pickerell noted. "Yes, nitinol is a super-elastic material, but it is very pricey. We challenge them to evaluate other materials we suggest that will be much less expensive and perform adequately."

A final challenge is lead time, particularly for products that use nonstandard materials, which may require a mill run. "Tubing can be the real culprit," Walden said. "Unless it is a standard-size tube, we may have to go to a mill for a special run, and that can take up to 19 or 20 weeks in some cases. Even flat-stock steels with a nonstandard thickness can require a mill run, adding much more lead time. Or, you could grind current stock down to the proper thickness, but then you add more cost."

In the End

Pricing pressures, shrinking lead times, tighter tolerances, increasingly miniaturized products-it's enough to stress out even the hardiest of souls. However, just as aspirin can reduce a pounding headache to a distant memory, advances in machine and laser technology-and the addition of new services and capabilities by their suppliers and contract manufacturers-are sure to help mitigate the pressures OEMs encounter as they continue developing innovations that will better life for all.

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

Related Manufacturing Processes: