Medical Wire Coating Q & A Video: PTFE Guidewires

Precision Coating Answers Your PTFE Guidewire Coating Questions

Dave DiBiasio, Precision Coating’s (PCCI) Vice President of Sales and Marketing, and Dick Buxton, PCCI’s Director of Process and Application Engineering answer more of your questions—today, they address coating guidewire. Precision Coating is recognized as the expert, worldwide, in coating guidewires. We’ve literally coated hundreds of millions of wires over the past 40 years. PCCI coats for all major CMOs and OEMs throughout the world, coating various platforms in eventual, minimally invasive platforms, wire products used in various markets and sectors, and other core surgical applications.

Today we’re exploring some common questions customers ask us about coating guidewires and the substrates. We hope this information helps you to choose the right coating and expedite your platform to production as soon as possible.

Question: One of the most common questions that we receive from our customers is: when you’re coating discreet length wire, what is the maximum length and the minimum length that you can coat?

Answer: The real issue for us isn’t the wire length, but what is the maximum length coated area you’d like to have coated. We can coat a longer wire length than the actual coated length.  The coated length maximum is 320 centimeters, or about 10 feet. The remainder of the wire would be masked or suspended somehow on the fixture. Obviously, it would have to be somehow handled in a different way.

Question: That takes us to our next question, which is: how much holding area do you need to be able to coat the wire?

Answer: That goes hand-in-hand with some of the questions of masking.

How much of a masking tolerance will I get? In some cases, if I have a tight masking tolerance, it’s preferred to use a tape method; the masking tolerance in that case is plus or minus 60,000th, or one and a half millimeters. In that case, I prefer to have at least 50 millimeters, if I could (about two inches). I can live with less, but it also is dependent upon wire diameter and length.

If I go into the mechanical fixturing, it’s not such of a discrete length or cut; let’s say sharp. It’s more of a fade out of coating. The fade out could be as much as 200 thousands. Usually it’s a little less, about five millimeters. In that mechanical fixturing, I can hold a minimum of 200 thousands, but prefer a half an inch if I could have it.

Question: You mentioned masking, and are a lot of questions associated with that. You talked about fixtures and tape—sounds like there’s multiple ways to mask the product.

Answer: There are many ways. There are also ways we can add areas in the midsection of the wire that would be uncoated as well.

In either case, being taped or mechanical fixturing, we have ways of doing that both. And we have ways that we can coat wires with two different colors, and put micro bands, if you’d like. There’s a lot of flexibility in that regard.

Question: Do you have to buy specific fixturing to mask, or can you use existing fixturing and maybe a cap on tape?

Answer: Depending on your drawing requirements, we prefer almost always to use our standard fixturing methods. Volume might have more to do with a repeat customer producing a large monthly quantity, we might ask for an NRE charge where we would buy fixturing, or you would buy fixturing, so the racks are ready to go and readily usable.

Question: For our listeners, Precision Coating coats, about 89% of our product via automated application. What are the benefits of automated application?

Answer: One of the things we did is we replicated as much as we could, what the sprayer [person] did. I can’t imagine me being an old man, trying to keep up with that robot all day long—keeping the same arm speed, same distance. And just doing that every minute. Every day, the same method. I think it’d make anybody tired, holding tight tolerances, to boot. The benefit of automation, as well as the fact that as we’ve grown and learned more and more about the attributes of coating, is we can dial in and hold a better coating thickness, masking tolerances, and overall a better performing wire because of the automation process.

Question: Regarding fixturing, you prefer to use the existing fixturing, it tailors itself well to a lot of different applications that we have, but there are times where you may need specific fixturing that the customer may need to purchase?

Answer: True. And again, it’s based mainly on the drawing, application, wire diameter. There’s a lot that goes into it, and really, to have a drawing upfront to understand the customer’s requirement is always beneficial.

Question: You just mentioned wire diameter. One of the other questions we almost always seem to receive is: what’s the smallest diameter wire you can coat? Customers are using this in torturous vessels with a lot of turns and small diameter. What’s the smallest we can go?

Answer: We go down as small as five thousands in diameter. We have done some four thousands, but they’re more of a ground distal end on a larger diameter.

So, if my set up is an O 14 and then be ground as a fine distal down to a three and a half or a four; when we’re down around the 5,000, we’re probably at a length of anywhere from, let’s say four to 10 inches. The issue with the small diameter is it becomes more of a, let’s say, a bird’s nest when we start to handle large volumes of wires—it wants to intertangle. So it’s very important how we receive it, how the packaging is, what packaging is used, and how it’s set.

Question: There are various substrates that you can coat. What type of substrates do you work with?

Answer: All the substrates. We work with all the stainless-steel alloys, such as MP35N; we do nitinol, tungsten, and platinum, as well. We handle just about all.

We hope we’ve answered question you may have in choosing the right coating for your medical guidewires.

This is a snippet of what we offer to you both on our website and on various social media platforms. If you have any additional questions or other thoughts, please look around our website, www.precisioncoating.com.

Check out our blogs and other video clips for more details of how we can help you with your next coating project.

Precision Coating for Your Medical Device Applications

Precision Coating provides high-tolerance coating and specialized metal-finishing services to the medtech industry for applications including vascular, endosurgical, and orthopedic instruments and devices.

The GlideLine™ family of medical device coating finishes is the broadest offering of applied fluoropolymer (PTFE) coatings in the industry, customized to optimize the design, quality, and performance characteristics of high-quality medical products.

InfiNiTiCoat™ is Precision Coating’s proprietary low-temp cure process, optimized for coating performance on nitinol devices; specifically optimized to preserve the desired characteristics of nitinol in wire, strip, and tube forms. PCCI has unique process control over challenging nitinol handling, coating, and curing.

The MICRALOX® portfolio of chemistries offers superior patented aluminum oxide coatings with a microcrystalline barrier that revolutionizes aluminum anodizing with exceptional barrier properties and corrosion resistance over industry leading product life cycles.

Contact us at the earliest stages of your device innovation so we can create a comprehensive solution for you—from concept to commercialization. Contact us now to get the conversation started.

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