Companies developing medical devices — whether for diagnostics, prosthetics, monitoring, or surgery and treatment — face tough challenges that most other manufacturers are blissfully un-aware of. The Food and Drug Administration (FDA), for example, rightfully demands that medical companies comprehensively document development and that many medical products undergo actual patient trials. And the FDA gets final approval on whether or not a device goes to market. This stringent regulatory environment not only leads to longer, more costly development cycles and riskier investments, but also compels many medical manufacturers to be more conservative when it comes to new products.
So although innovation is the life blood of most manufacturing enterprises, medical companies — especially the small and medium-sized firms — usually opt for safe, proven development routes rather than cutting-edge approaches. But these proven routes are more expensive, and require more people, training, and infrastructure.
Fortunately, new design methods and high-tech tools let medical manufacturers innovate and manage risk.
SMOOTH SHAPES AND SHORT CYCLES
Software advances have streamlined product development, shortening the time needed to go from concept to design to defined parts and assemblies. For example, it once took specialized tools and manual techniques to generate smoothly flowing curves and complex geometries. Companies had to invest in surfacing software, hand-drawn illustrations, and sculpted models, and design iterations were many and costly.
Today, however, 3D CAD packages include surfacing, model definition, and tools tailored for complicated shapes and geometries. And to save time, medical companies standardize files and formats, which fosters collaboration between designers and engineers. In addition, there are also services such as 3D ContentCentral (3dcontentcentral.com) that make it easy to use economical, off-the-shelf components. Such sites let engineers download and use models of common components and subassemblies instead of designing them from scratch.
At Siemens Medical Systems Inc., Danvers, Mass., engineers re-lied on SolidWorks software that combines solids and surfaces to design the Infinity Patient Monitoring System for hospital-based monitoring. The software helped Siemens cut design time by 25%.
"We needed software that could handle solids and surfaces, and let us see the design as it evolved," explains Per O. Hoel, senior mechanical engineer at Siemens. "And because the software made it so easy to model organic shapes, we came up with something much more elegant than our initial concept."
At Southmedic Inc. in Barrie, Ontario, the design team used the same software to create the OxyArm oxygen delivery system, the only device of its kind that delivers oxygen through a headset instead of through a mask or nasal cannula.
"We wanted a CAD system that would help us take a the way through to and tooling design," says Engineering
Manager Maurice Lavimodiere.“The design cycle for the OxyArm was about three months. And product development was 30 to 40% shorter with the integrated software.”
CLOSE LINKS TO ANALYSIS
Many modern CAD include close links gives designers a chance performance and fix problems before a device goes into clinical trials. Besides holding down costs and risks, early FEA improves the likelihood of a quick and painless certification. It also frees engineers to be more innovative.
For example, engineers at Tensys Medical Inc., in San Diego, attribute their 50% reduction in development time for their T-Line Tensymeter to the close coupling between CosmosWorks' analysis and SolidWorks Office Premium development packages.
The Tensymeter is the first continuous, noninvasive arterial blood-pressure monitor. "The design uses an actuator that moves a pressure sensor over the patient's wrist to find the best position for picking up a continuous heartbeat," explains Russ Hempstead, senior engineer. "The sensor floats in a rigid frame attached to a flexible serpentine arm. When we investigated designs for the arm, we realized we needed analysis because geometries were too complex for hand calculations and we wanted to avoid iterative prototypes."
The analysis software let Tensys engineers identify high-stress areas in initial designs for the olefin-based serpentine arm and modify them. "With analysis inside CAD, we could quickly determine if the arm would break under specified loads, change the design based on the analysis, and make the arm more reliable," Hempstead says. "Our original design had so many stress risers that flexing would shorten the part's life span. We virtually eliminated those stresses based on analyses' results. Now the arm can flex almost indefinitely."
"Analysis software saved us prototype costs and development time," says Hempstead. "And if we had used prototypes, we would probably still be working on the design."
Complying with government regulations for documentation has historically led to significant overhead cost for medical companies. But adding product-data management (PDM) to a CAD system, such as PDMWorks included with SolidWorks Office Premium, can simplify documentation. This includes design changes at the part and assembly level, which should decrease overhead.
Zoll Medical Corp., in Burlington, Mass., for example, makes devices used in patient therapy, so documentation of its design processes must meet rigid FDA standards. And the number of parts and assemblies in Zoll's devices often total more than a thousand.
"Most of our documentation is under strict control. Parts have a record of all changes to show they were all tested," explains Fred Faller, principal mechanical engineer. "But whenever you have four or five people working on different components of the same project, such as the recorder, display, and control panel of a defibrillator, how do you ensure everyone is working on the most up-to-date version of a particular part? You need to control both the version people are looking at and which people have access to the design and drawings."
SHARING LEADS TO INNOVATION
Modern CAD software lets medical companies minimize risks by letting design teams and management see and share design data with all those who will be involved with a particular device. Having models in 3D also lets companies validate designs, such as using collision detection to pinpoint interference problems in assemblies.
Giving physicians and health-care professionals an early look at designs lets companies gather important feedback before finalizing the design. Doctors may have difficulty visualizing 3D concepts from 2D drawings, so design tools such as eDrawings let engineers e-mail 3D designs created in Solid-Works in compact, self-executing files. Users can rotate 3D color models, look inside assemblies, and even mark up models with notes and comments. Other software packages, such as Animator, create AVI files, which include audio and video. Such multimedia presentations have become important for quickly conveying design concepts to the less technically inclined. Sharing design data with partners, suppliers, and vendors without model conversions or often error-prone file translations leaves more time and money for innovation.
Berchtold Corp. , Charleston, S.C., for example, relies heavily on communication and animation software for visual representations of the surgical suites it designs and builds. All its suites are custom built based on a hospital's operating room, equipment needs, and the types of surgeries it performs. So the company uses its CAD software, Visual Basic, and an application programming interface (API) to create a system that lets users put together a surgical package and get a price quote on it.
"The system also lets us generate designs for about 70% of each suite using already-designed assemblies," says Ted Atchley, CAD project designer. "This has increased profit margins and reduced order errors because it gives us a consistent way of getting data and generating designs using design tables and past designs."
Berchtold also uses files associated with part numbers to clarify communications with vendors and field technicians.
Advances in CAD packages have also spurred productivity growth in prototyping, manufacturing, and machining. For example, most 3D CAD packages work with CAM software and support rapid prototyping for making sample parts. Some 3D design packages address specific manufacturing techniques, such as sheet-metal fabrication and moldmaking.
The Oklahoma City-based Modular Services Co. relies on its Solid-Works CAD package for all product development. While designing its Pumpstar portable pump cart for intensive-care units and operating rooms, for example, the company let manufacturing and fabrication engineers use the CAD software and its 3D data to generate tool-paths in its CAM software. The CAM software later drove CNC lathe and mill. Engineers also use the 2D design data for CNC sheet-metal lasers and a sheet-metal brake in other devices.
"The complexity and number of different parts we make means sheet-metal capabilities are important for improving manufacturing quality and throughput," says Marcus Brown, a project development engineer.
Engineers at BioProcessors Corp., Woburn, Mass., use Solid-Works mold design and draft analysis with mold-filling simulation software to trim time and costs from injected-molded parts. "Before using this software, we could not simulate filling a mold," says Sean LeBlanc, associate director of manufacturing. "Instead, we paid vendors to do fill simulations. And resolving mold issues with vendors often stretched out the development cycles. With our new software, if a corner does not fill properly or if we change a feature and want to know if it will fill, we can handle these issues before going to the mold-maker. This helps reduce costs, cut time, and preserve the accuracy of our designs."
With the availability of affordable design software, innovation no longer has to take a backseat to medical regulations. The key is to use software that operates on and manipulates the same design data from concept through manufacturing.