Eric Sugalski, President and CEO of Smithwise (Newton, MA), isn’t a 3D printing denier by any stretch of the imagination. His company, which offers product design, engineering and manufacturing services to technology startups and OEMs, uses 3D printers extensively for prototyping. But during a recent conversation with PlasticsToday, he brought up a few caveats about the suitability of additive manufacturing for the production of medical devices, a sector that accounts for approximately 75% of his business.
|Rapid prototype builds from Smithwise.|
“When we get closer to production,” explained Sugalski, “we typically rely on other methods to fabricate prototypes in the true materials that are likely to be used in the finished part. We use CNC machining, even injection molding, which has gotten to a price point where it competes with some of the rapid prototyping processes in relative low volumes.” He opts to use alternative methods, he says, because of the limitations of 3D printing, notably in terms of materials and resolution.
Some 3D-printing materials will degrade over time in the presence of UV, says Sugalski. “Also, in many cases, the production components being designed require glass or mineral fills that are only available in pelletized plastics used in injection molding, so that can be very restrictive.”
In many medical applications, meeting biocompatibility is a requirement. “Some 3D printing materials have a USP Class VI designation, but most do not,” he explains. For a Class I or Class II device, you probably don’t want to take on extensive biocompatibility studies, which are time consuming and costly. “That’s a strong reason to use an existing USP Class VI material,” explains Sugalski, many of which are not available for 3D printers. “That cuts back on some of the regulatory pressures that new device companies wrestle with,” he adds.
Sugalski also notes that resolution can be a challenge in additive manufacturing techniques. “We might be looking at a fused deposition modeling process, because it has the strength characteristics we need, but it may not have the resolution. It’s building in layers of 1/1000th of an inch, so the step sizes are too large to print small features or provide smooth aesthetic properties.”
That said, the pace of innovation in 3D printing is surpassing even what engineers were expecting, adds Sugalski, so he is keeping an open mind. “New materials such as carbon fiber and metallic-infused resins are being developed, printer speeds are accelerating and the cost is coming down. Are we able to mass manufacture right now as a replacement for injection molding? In most cases, the answer is no. But it could become viable in the not-too-distant future,” says Sugalski. And in some specific applications, the use of additive manufacturing techniques to fabricate a finished product is viable today and presents some unique advantages over other processes.
“We do a lot of work in pediatric applications, and 3D printing presents some real benefits in low-volume products or where custom elements related to a specific child need to be included,” explains Sugalski. “You don’t have to invest in tooling and you can make that product or device unique to that patient.”
That is also true in some orthopedic applications, where implants can be manufactured to suit specific patient anatomies.
There’s no denying that 3D printing has tremendous potential in medical applications, but, Sugalski stresses, it’s not the only, or the best, technology in all cases. That verity is sometimes lost amid the hype.