Weld Failure in the Medical Device Industry
Recently, EB Industries hosted a problem solving session with a team of ten engineers from one of the largest medical device manufacturers in the US. This particular manufacturer requested our help because they were experiencing significant failures in the field of laser welded components. The engineers were justly concerned: The devices were implanted or used in surgery and failure could mean physical harm or even death to a patient as well as huge financial risk to the health care provider right on back to the manufacturer itself. However, the parts that were failing were laser welded by various third party shops not specializing in laser welding. There was not a single instance of an EB Industries welded part failing in the field, which is why they came to us, to find out what we were doing differently. After some careful data gathering and analysis, an interesting narrative was developed.
A Problematic History
About 35 years ago, an entry level laser welding system cost over $300,000 and was exceptionally difficult to operate and maintain. The technology involved flash lamps, water cooling systems, large power supplies, gold plated cavities, and fixed optics laser heads. Additionally, the control systems were minimally computerized and required a highly trained operator, and the whole system needed trained maintenance personnel. This meant that only those companies that could invest in both the equipment and, more importantly, the manpower to operate the systems, could laser weld.
Today, an entry level 200 watt laser welding workstation can be had for around $15,000. Laser technology has advanced significantly and systems often come with easy-to-use fiber optic beam delivery. The result is a very low cost of entry for a system that is easy to operate. So, many companies these days get into laser welding with a minimal investment in equipment and almost no investment in training. Indeed, the concept of laser welding seems so straightforward that it’s hard to disagree with this notion. What could be more simple than pointing a laser at something and melting it?
The reality is that it is nowhere near that simple. Having a laser welding workstation doesn’t make someone an experienced laser welder anymore than buying a TIG welder from Home Depot makes someone a TIG welder that actually knows how to weld. Would a company doing commercial work in the aerospace or medical devices industry hire a non-certified TIG or MIG welder? Probably not. But many shops doing critical work have basically untrained personnel performing laser welding, sometimes utilizing traditional stick welders or even machinists as laser welders, and often that laser welding is done by hand, with minimal to no automation, resulting in an uncomfortably wide continuum of weld quality.
A Lack of Standards
In the United States, laser welding training exists but is not nearly as widespread as training in other welding methods. A few certificate programs exist and cover topics such as laser welding technology, beam delivery, weld geometry, shield gases, power density, inspection techniques and such. However, these classes are often book based and do not involve hands-on practice. There are very few schools or programs offering hands-on laser welding training. If a company chooses to send employees to one of these classes the benefit can be tremendous, but often this simply isn’t done.
Because there is very little training to standards, there is very little adherence to standards in the workplace. It is hard to put into practice that which you do not know, and that which is not promulgated on the shop floor. It’s rare to see an engineering drawing calling out any requirement for laser welding other than “LBW” (the American Welding Society symbol for laser beam welding). The American Welding Society does have several specifications, but they are typically not referenced. The aerospace industry is a bit ahead of most other industries in terms of standards. For example, the AWS D17.1 specification is a comprehensive document designed for fusion welding, and includes laser welding for aerospace applications, but sadly, many other high tech industries lag far behind. In fact, one of the biggest findings from the problem solving meeting was that the medical device industry does not have any specifications for general laser welding. A few large medical device OEMs have proprietary specifications, but they’re neither widely adopted nor called out. For critical pieces, such as a heart pump, for example, medical device manufacturers usually rely on part specific procedures and operators that are locked in when the part goes through the FDA approval process but, as a whole, there is a basic lack of regulating and best practices within an industry that is a large consumer of laser welding services.
Why EBI is Different
And this leads to why EB Industries had such an astonishingly low weld failure rate. The visiting engineering team determined the difference between EB Industries and other laser welding vendors came down to adherence to best practices and standards, differences in operator training, use of automation, and quality control procedures. In short, our zero percent weld failure rate is a by-product of our long standing engineering culture.
EB Industries was founded in 1965 and started out doing precision electron beam welding for the aerospace industry. Our early work was on commercial and military aircraft parts, on satellites, and on the Apollo moon project, and all of that work was to exacting mil-spec and proprietary standards. Our entire system of doing business was essentially set-up around meeting high standards, and as we evolved and expanded into other end user industries, such as medical and energy, and added technologies, such as laser welding and hermetic sealing, we brought along a rigorous in-house training system, an equipment maintenance program, and a quality management system that is beyond industry standard.
Early on, EB Industries adopted computer control of virtually all facets of electron beam welding, and that philosophy has been extended to our laser welding and hermetic laser sealing services. We never hand weld anything when we can instead create proper fixturing and automate the welding process such that it is reliable and repeatable. We use glove boxes whenever possible to increase weld purity, such as when welding titanium. We have the test equipment available and the knowledge of its use to thoroughly check and test what we assemble and weld. We have a highly experienced engineering staff to consult with customers and design joint configurations that take into account everything, from metallurgy to environmental conditions, and all of this is basically done to the same standards used for spacecraft, aircraft, or critical military equipment.
Our quality processes, and our plant culture in general, are also unique in that we rely on positive verification that our welds are applied as required for every job, every lot, and when required, every part. We have an onsite materials lab that specializes in cutting and potting welded parts to analyze depth of penetration, width of weld bead, porosity, and a number of other factors that verify a quality weld. When a customer can’t spare a production part to sacrifice, we create separate test pieces of similar material and configuration to confirm our operators and equipment are performing as required. We also employ a number of non-destructive test methods, such as liquid penetrant, x-ray, and CT scan, when weld quality must be assured for every part.
We’ve always known that EB Industries is different from most of our competitors, and we’ve always been confident in the efficacy of the quality driven engineering culture at EB Industries. At the end of the problem solving round table with the ten engineers, it was affirming to have proof that what is central to our business truly makes a difference to our customers.