Medical Manufacturing Supplement: Software, a Productivity Pill
Medical manufacturers make money by marshalling the resources in their software
By James R. Koelsch
People might be constructed in the same basic way, but they come in all sorts of sizes and shapes. Consequently, shops like Alphatec Spine Inc. (Carlsbad, CA) that are in the business of making parts for people must produce a wide selection of sizes for each of their products. The dozens of versions of every bone prosthesis, clamp, and other implants that they make demand that they choose between running small lots or carrying inventories—both of which add cost and pose their own headaches.
To complicate the task, the products must be perfect. Mistakes in this business can have dire consequences for patients, the end users. The federal Food and Drug Administration (FDA) requires many of these medical manufacturers to take pains to demonstrate that they are making quality products and conforming to governmental regulations.
Yet manufacturers of surgical instruments and medical devices are not immune to market pressures. Like other manufacturers, they need to make their products faster, better, and cheaper. They are always looking for ways to streamline their design and manufacturing processes. Many have been successful at generating efficiencies through a variety of software packages that can automate redundant tasks.
In Alphatec's case, one of these packages is CAMWorks programming software from TekSoft Inc. (Scottsdale, AZ). It's what developers call parametric and associative—that is, all of the parameters in a program are variables. Users, therefore, can change the value of each variable to adjust for size at any time after they write the program. "In most instances, it automatically updates the toolpath, changing it to accommodate the change in geometry," says Mike Coleman, TekSoft President. "It recognizes the changes and asks you if you want to update the toolpath."
This parametric associativity is a productivity enhancement for developing different sizes of vertebrae. Alphatec's programmers don't have to develop the toolpath for each size from scratch, reports Gil Chavez, director of manufacturing. They simply adjust the toolpath of another size within the same family of parts.
Modularity is another trend that is gaining traction among developers of programming software, and is showing potential among manufacturers of medical devices. A growing number of software developers are integrating modules from other specialty houses called independent software vendors (ISVs). The goal is to build a superior product around your field of expertise, adding modules that offer the best-of-class performance for those other tasks.
The strategy allows vendors like TekSoft to tap into the research and development departments of several other companies. "I'd need around 400 people if I were to match all of the R&D engineers that I leverage into my products through these ISV and third-party associations around the world," estimates Coleman. He, in turn, sells some of his company's modules to other computer-aided manufacturing (CAM) software developers.
"In the past, the strategy was to develop everything yourself," he adds. "The downside of doing that is you can't offer the best of class in everything. You typically have a technology that you excel at, and are mediocre at everything else. So the customer might get the best threeaxis milling package available, but get a lousy lathe or EDM package with no sheetmetal capability. That kind of a solution no longer fits today's market expectations."
This is especially true in the medical industry. Most machine shops producing implants, surgical instruments, and other medical devices need the capacity to perform a variety of operations well. "They typically do three-axis milling, turning, mill-turning, and EDM," says Coleman. "Some even do some mold making and make sheetmetal housings. So they typically need a pretty complete package."
He notes that more manufacturers are asking for highspeed machining (HSM). "Rather than pretending that a couple of guys in the back room can come up with everything that we need, we buy our HSM algorithms from a third party that devotes 10–15 programmers to developing just the HSM modules," he says. This third party can afford to invest more in the module than most other developers because selling it to companies allows it to amortize the cost over a larger user base.
A solid modeler from SolidWorks Corp. (Concord, MA) is one of the modules in CAMWorks that is of particular importance to NCAD Products Inc. (Oviedo, FL). As a contract manufacturer specializing in producing, painting, and packaging small lots of aesthetically pleasing parts and assemblies, its typical orders range between 30 and 100 units a quarter. One of those jobs involves the outer panels for the laser units used in the outpatient surgery that clinics use to correct vision.
The solid modeler and its parametric associativity helped NCAD to work with the customer through several iterations of the complex, swept surfaces to ensure that they were correct and economical. "Our products are in the limelight," explains Neil Porter, president and owner of NCAD. "Because we're in the boutique item business, they have to be perfect—smooth with no blemishes." But that doesn't mean that cost is irrelevant. The customer must be happy with the price tag, as well as the engineering advice that Porter's people give and the quality of the products that they ship.
Getting that perfect mix begins with importing data. The engineering staff at NCAD relies on the SolidWorks solid modeler for importing complex surfaces and accommodating design changes. "We import the initial design into SolidWorks, either as a native SolidWorks file or as an IGES file," says Porter. His staff then works with the customer's designers to suggest any adjustments that might make the initial design easier to produce.
The designers will take those suggestions under advisement for revisions. Meanwhile, the NCAD staff begins programming the two sets of toolpaths for the machine tools supporting the vacuum-forming process that will produce the short run of plastic parts much more economically than injection molding would. One set is for the machining centers that will cut the composite molds, and the other is for the five-axis high-speed routers that will trim the parts afterward.
"If we make a change to the part, CAMworks notices and asks whether you want to change all of the G-code that goes with it," says Porter. "If you say yes, it revamps all of the toolpaths for you automatically."
He finds that the parametric associativity and the internal automation come in handy for expediting the programming of the finishing operation. "At the end, maximum scallop heights are one to five tenths," explains Porter. "The stepover is so small that you don't even know it's cutting, other than that there is dust." Once the program is converted to G-codes, it can exceed 400,000 lines and take the machine 50 hr or so to run.
This means, of course, that the computer may take 45 min to regenerate the program after the programmer makes any changes. To keep the regeneration time to less than a minute, the programmers refine the finishing path, rapid traverses, and clearances with a coarse stepover, perhaps a half-inch. "Then all we have to do is to reduce the scallop height or stepover," says Porter.
NCAD applied these and other lessons that it learned from using the software to program some prototypes of internal aluminum parts that it produced for the next generation of the laser units. These pieces are in the customer's research and development labs. They're undergoing the function tests necessary to refine the design before the company can present it to the FDA for approval.
Getting rapid turnarounds with conventional software is possible, too. You don't necessarily need parametric associativity to be creative and productive. Just ask Viasys Orthopedics (Wilmington, MA), a contract manufacturer supplying orthopedic implants, cardiovascular products, and components for imaging devices. The company gets extremely rapid turnarounds that compete with rapid prototyping technologies by using conventional Unigraphics programming software from UGS PLM Solutions (Plano, TX) in unconventional ways.
Registered with the FDA, the company does more than just make trauma products and joint replacements from cobalt chromium, titanium, zirconium, and stainless steel. It also supports its customers' product launches. "Our customers want superior results in first-article development and clinical market assessment," says Giulio Perillo, group president. And they want those results fast.
One element of his strategy for delivering the necessary support services is to standardize on one machine tool builder. "The main issue was cost," he explains. "A variety of equipment manufacturers affects costs in a number of areas: setups, programming, changeover, training, spare parts, and service." So he simplified the process by equipping the shop with 15 Nexus VCN-410A VMCs and a Super Mold Maker 2500 VMC from Mazak Corp. (Florence, KY).
Another element of his strategy was to create a rapidresponse development laboratory called the LaunchQuick Process Development Center. The lab's main job is to produce prototypes and develop manufacturing processes, in addition to accommodating rush orders. A programmer dedicated to the lab generates and optimizes the toolpaths for three Mazak machines: an Integrex multitasking machine equipped with a bar feeder, a Variaxis 500-5X fiveaxis VMC, and a Nexus VCN-410A VMC.
The lab has proven itself to be very fast time and again. A case in point is the high-speed machining process that it developed for a customer producing titanium spinal implants. "We were able to show how our Integrex could feed the bar stock, do all the milling and grooves, tap holes on the back, cut off the part, hand it to the subspindle, and finish profiling the part," says Robert Lynch, senior director, R&D and product development. "What used to take the customer hours, we had down to 45 min, all on one machine." And that was before the staff began optimizing the toolpaths.
An unusual programming technique lets the lab capitalize on the ability to produce completed parts in one setup. Upon receiving a model of an implant under development, the programmer breaks the process into segments, and generates the program for each separately.
For example, he might have the machine turn the raw stock into a near-net shape before going into milling mode to generate a surface profile on the first side. Rather than waiting until the entire program is completed, he sends the turning portion of the program to the machine as soon as it completes it. So, the machine is working while he creates the surface and toolpath for the next milling segment.
Programming and machining simultaneously can save a tremendous amount of time. "It may not be the optimum way to make it out on the process floor, but it is certainly the fastest if our customer wants to see it right away in metal," says Lynch. "We might get a complex model of a hip stem on a Monday morning and ship it on Tuesday afternoon."
Lynch points out that the turnaround is almost as fast as stereolithography and other rapid prototyping technologies. Parts produced in his lab, however, have the added advantage that they are real, metal versions that can go into a patient, if no further iterations are necessary. If there are small changes, the lab's technicians blend the surfaces together and post from Unigraphics directly into the machine. "It takes only a few minutes to a few hours, depending on how big the change is," says Lynch.
After machining, some implants go to one of two processes that give select surfaces a texture that enhances an implant's bone-fixation qualities. In some cases, the implants go to an outside service to receive a porous coating. In others, they receive 3-D texture from Viasys' own patented Tecotex photochemical etching process. Engineers develop the texture patterns using the company's proprietary computer-aided design (CAD) software. The Tecotex process then replicates these patterns to microscopic dimensions.
Once the development phase of a project ends, the new implant can go straight from the lab to the shop with no headaches because both places have similar machine tools. "Fixturing, tooling, programming, they're all the same," Lynch says. "And if the product launch is a success and we get a panic call for 300 pieces, it's no problem." For this reason, orthopedics has grown from about 49% of the company's total business to more than 66% since implementing the strategy. Creative use of software, indeed, has been a painless pill that drives productivity ever higher.
Software Can Track Your Process
Validation and traceability are two big problems that software can solve for medical manufacturers. Such software works at two levels, the device and the network levels. This kind of software operating at the device level typically archives data for retrieval by either a person working at the device or software operating at network level.
An example at the device level is the software developed by Metronics Inc. (Bedford, NH) to enhance its Quadra-Chek 300 digital readouts. Because proprietary technology combines several video-measurement functions into one display unit, some inspection equipment builders are fitting their vision systems with the readout. On the Galileo EZ manual vision system from L.S. Starrett Co. (Athol, MA), for example, the readout's software gives the device a video display and automated edge detection.
The software's image archiving capability allows users to document and store measurements, including test data and descriptive text, as JPEG (JPG) images for documentation and quality inspection. Users can print these images for regulatory and quality-control audits and studies.
At the system level, various kinds of manufacturing execution software reach across a manufacturer's computer network into the computerized machinery and other devices in its shop. "Machines usually come with an HMI package that have an historian that will give the manufacturer all the process information that it requires to pass an audit," says Yves Dufort from Wonderware (Lake Forest, CA), a unit of Invensys Systems Inc. (Foxboro, MA) that develops this kind of execution software. "As the machine is manufacturing the pieces, say bone screws or implants, the controller is collecting data."
This article was first published in the September 2007 edition of Manufacturing Engineering magazine.