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was pretty much ubiquitous in the industry, used in tubing, in shunts, drains, and all kinds of devices,” Kvalo remembered. But, as has been widely reported in recent years, PVC has toxicity concerns—not only for patients but also to the envi- ronment at large. “When it is incinerated—and incineration is a preferred way for hospitals to dispose of medical waste— PVC emits chlorine gas.” Chlorine gas—the scourge of the battlefields of Europe in WWI.


“Ecomass was originally marketed to the military ... It’s starting to catch on now in the medical field. The material is more expensive than lead, but the medical industry seems willing to bear that cost increase— the benefits are worth it.”


“PVC is probably one of the cheapest thermoplastics available today—still is. But because of these concerns, we’ve been trying to steer customers [in all industries] away from it. If a customer comes to us requesting to have some- thing made from PVC, we’ll want to talk to them about it,” Kvalo said. “There might be some better materials that cost a little bit more but that won’t lead to the problems that can come with PVC use.” The ‘End-of-Life’ Discussion


Mike Kvalo understands what some in the industry are still coming to grips with, namely that in medical, as in other industries, sustainability concerns are not going away. “In our initial quality planning meetings with a customer,


long before we cut any steel for a new mold, we talk about ‘end-of-life’ considerations for the product,” Kvalo said. “We ask, ‘How are you going to recycle this? How are you going to dispose of it?’ Questions like that, just to get the conversa- tion going. Of course, our customers are concerned about the environment, and they’re concerned about safety, too. So we have these questions on our checklist and make sure these issues are raised up front.”


Finding the right substitute for PVC depends on how the


product is used. “This is where we’ve really got to apply intel- ligence,” Kvalo said. “What does this thing have to do? What kind of temperature range will it see? What kind of chemicals


will it be exposed to? Does it need to be clear or is it light- opaque? What’s the expected life? Is it a single-use dispos- able device?


“When someone comes to me and says they want to make a single-use medical device, probably the first question I’m going to ask is, ‘Is it going to be sterilized?’ If the answer is ‘yes,’ then my next question would be, ‘Can you use poly- ethylene?’ Polyethylene is cheap, readily available, nontoxic, and easily recyclable—it’s the same stuff that milk jugs are made out of now. And polyethylene is naturally resistant to gamma radiation, so it’s not going to get brittle and yellow when you radiation-sterilize it. I’ll try to get the customer to look at it as a material choice. “If they have a reason that polyethylene can’t be used for


the product, then we start going down the list of materials with similar desirable properties— ‘How about polypropyl- ene,’ I might ask. It’s a harder material, more temperature resistant. We know that part cost is important—that’s just a given today—so we try to recommend materials and manufacturing methods that are going to be cost-effective for the client.


“Another question we’ll ask is ‘What do you think your annual volume is going to be on this part? What is it going to start at and what do you think it will mature at?’ The answers will help us decide on what kind of tooling and automation will have to go along with this program too.”


Mold Flow Analysis


With advances in materials come advances in the manufacturing process. An example of a process that EVCO Plastics uses now that the company didn’t—at least not regularly—in past years is “a full mold flow analysis for every new mold we build,” Kvalo said. “We look at whether a part is going to warp, a particular problem with larger parts. “The current state of the art in mold flow analysis and


predicting warp is that we—the industry, the science—can’t predict it quantitatively very accurately yet. But we can pre- dict it qualitatively; we know which direction it’s going to go. And once we know that, we can suggest design modifica- tions to try and mitigate it, to minimize the amount of warp, or maybe get it to go in a different direction, one that’s not going to cause problems for the OEM. “That’s something relatively new that we do 100% of the time now. We have the software in-house—we use the Autodesk Moldflow program,” Kvalo said. “We’ve used it for a number of years. We’re just routinely doing more of it now.”


53 — Medical Manufacturing 2015


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