Test Before You Invest: Clinical Needs. Physical Constraints. Real Components.
Chapters:
00:00 Welcome and Speaker Introduction
02:00 Moving From Concept to Prototype With Standard Components
03:45 Framework for Turning Clinical Needs Into Component Decisions
08:15 Neurovascular Catheter Shaft Case Study
13:55 Why Early Mechanical Lessons Cost Less
18:00 How Tolerance Stack-Up Creates Assembly Risk
25:00 Core Components That Shape Early Prototype Performance
32:15 Design Tips: Heat Shrink, Fittings, Needles, and Mesh
48:10 Live Q&A with Mark Maffett on Tolerance Stack-Up and Custom Features
57:50 Closing Remarks
00:00 Welcome and Speaker Introduction
Steve Maxson
Hello everyone, and welcome to the Chamfr webinar series. Today’s session is Test Before You Invest: Clinical Needs, Physical Constraints, and Real Components. I’m Steve Maxson, and we’re excited to have you with us today.
A couple quick notes before we begin. This session is being recorded. The replay will be sent to everyone who registered. You’re all muted, and the chat is disabled. Please drop any questions in the Q&A box, and we’ll answer as many as we can.
Our webinar is headlined by Kristin Livesay, VP of Sales and Marketing at Component Supply. With over ten years of experience in the medical device industry, Kristin helps developers, doctors, researchers, and R&D engineers get the high-quality components and technical support they need to move their projects faster. She specializes in same-day delivery on standard parts and quick fabricated solutions for early prototyping and development.
We’re also proud of our promotional sponsor, Workplace Modular Systems. Workplace designs and manufactures fully custom, US-built workstations specifically for MedTech and R&D environments. Their modular systems support precision assembly, testing, and manufacturing, engineered to your exact requirements and built to scale for your process from early development all the way to production.
What really sets them apart is their rapid quoting, detailed engineering drawings, and some of the fastest lead times in the industry. Huge thank you to Workplace for making this webinar possible. Check out the QR code here on the bottom. You can scan it to learn more.
With that, let’s hand it over to Kristin and get started.
02:00 Moving From Concept to Prototype With Standard Components
Steve Maxson
I’m real excited today to have Kristin Livesay on from Component Supply.
Kristin Livesay
Thank you. Happy to be here.
Steve Maxson
Absolutely. We’re going to talk about Test Before You Invest, and this is going to be a real exciting conversation. What was really exciting for me was coming over here east of Nashville from Hickory, North Carolina, where I live, driving through the rolling hills.
Kristin Livesay
Oh, yeah.
Steve Maxson
A beautiful day, and when you said, “Let’s do a webinar, and we’ll go for a hike and get barbecue after,” sign me up.
Kristin Livesay
Yep. That’s right.
Steve Maxson
It’s going to be a fun time and a fun day.
Kristin Livesay
Yes. We’re so excited to talk to everybody about how to test before you invest, how to get concepts locked in before you invest in complexity, which often means expense, right?
Steve Maxson
Yeah. Let’s get into it. I want to talk about, from an agenda standpoint, the different phases of a project. Concept phase, which could be a napkin sketch from a doctor or a surgeon or somebody with an interesting idea, to the building blocks to enable somebody to iterate, to build a component, the manufacturing aids, the mandrel, heat shrink, all these components that you do so well at supplying quickly with our partnership with Chamfr as well.
Kristin Livesay
Yes.
Steve Maxson
The prototype phase, iterating, going through different iterations, trying different things out that enable this concept design for manufacturability, long-term thinking ahead so that you can validate these things. And then we’ll do some Q&A at the end as well.
Kristin Livesay
Sounds good.
Steve Maxson
All right.
03:45 Framework for Turning Clinical Needs Into Component Decisions
Kristin Livesay
Well, let’s get started. So we’ll start with the concept phase, right? Clinical needs define concepts, so every concept begins with some clinical need, a problem that you’re trying to solve. But it’s really the components that define whether or not that becomes a working, valuable prototype.
I want to use some examples of high-level clinical needs going over physical constraints that they create that impact your component selection early on in the performance of your device as you’re moving from concept to early prototypes. So here, we’re not optimizing. We’re not trying to get the best components or the exact components. We’re really trying to understand trade-offs when we’re developing a medical device.
Every device can be broken into three layers: what you need to achieve, what limits you, and what problems you choose to build with. On this slide you’ll see three columns. You’ll see clinical need, physical constraint, and component impacts or the component decisions that you’re going to make.
We’re going to walk through them one at a time, and as we do, be listening for where decisions are going to need to be made and where trade-offs will occur. I’m going to use catheter-style examples because they’re easier to visualize, but the same framework will apply whether you’re using drug delivery or robotics or other device types. A similar framework can be used.
First, let’s talk about a clinical need for tortuous anatomy. Here the need might be to navigate a complex pathway. That’s going to create physical constraints, your OD limitations, your wall thicknesses, and trade-offs related to pushability and flexibility.
Here, you’re going to be making component decisions that are in a few different categories. They might be structural geometry, reinforcement strategy, how you are going to support the structure, and surface interaction, so how the device is going to interact with its environment.
Then the anatomy fixes your outside diameter. Everything that you’re deciding, all the trade-offs, all the decisions are in that geometric envelope, right? You have tortuous anatomy, you have a fixed OD, and you can only do so much within that space. So your component decisions are all going to be made within that geometric envelope.
Then you have precise placement. The need here would be accurate delivery. You’re going to be evaluating accurate delivery and positional control. You’re going to be considering torque transmission efficiency or stiffness, transitions, and distal responsiveness.
Here, your decisions are about material and structural selection, torque transmission strategy, and transition design. What carries load? What transmits force? How do inputs translate to output? How does the proximal end affect the distal end? Then, how within the same geometry are you balancing responsiveness with control or flexibility? There’s always a trade-off in the component decision based on that clinical need.
Then you have minimal trauma. The goal here is protecting fragile anatomy. This is very critical. Your constraints become surface hardness limits, edge conditions, friction, and how the device interacts with tissue. You’re going to be focusing more on your distal material selection. You’re going to be considering transition design. There’s a higher risk in your device anytime you switch materials or switch diameters, and then you have surface conditions to be strategizing with: coatings, finishes, friction control, things like that.
You might be dealing with a fluid and drug delivery system, in which case you’re dealing with effective and reliable flow. Your constraints are going to be balancing your ID needs with your wall strength. Here, you’re going to be considering burst pressure and chemical compatibility. Your component impact then is your lumen sizing. How much space do you have to work with? What materials are you able to work with? How are you approaching the construction of your device? And then the connection interface, which becomes really important. We’ll talk about that more later.
Here, the pattern is consistent. The clinical need is what’s driving and defining the objective, and physical constraints are what are defining the limit. Component decisions impact the trade-offs at this level. We’re not selecting components yet. We haven’t even gotten that far yet. We’re just identifying decision points that will shape the design and testing the physics based on your clinical need before you invest in complexity of these parts.
Steve Maxson
Excellent. That was a great and very comprehensive overview. I think to bring that to real life a little bit, we can go through a case study, right?
Kristin Livesay
Yeah.
Steve Maxson
A neurovascular case study.
08:15 Neurovascular Catheter Shaft Case Study
Kristin Livesay
Right. This is that general framework applied a little bit more specifically. Again, you have that clinical need, that tortuous anatomy. Here we’re dealing with a distal tortuous cerebral vessel because you’re dealing with a neurovascular catheter shaft.
Here, your vessel diameter is what’s going to fix your maximum OD. You have an anatomical constraint, and that’s going to define your total wall budget, right? This is all you have to work with because you’re working in a very confined space.
Within that constraint, your early decision is really selecting some kind of hypotube OD/ID structure that lets you evaluate what you have left for strength and reinforcement. There’s always a trade-off. When you’re dealing with wall thicknesses, you want the flexibility, but you want the strength. How much trade-off are you giving for each one?
Then you have precise placement. You’re going to be introducing constraints around your torque transmission efficiency, column strength, rotational lag, and stiffness gradients along the shaft. An early validation, even sometimes using something as simple as a hypotube, can help you. Not because it’s the final answer, but because you can characterize pushability and torsional response, see how something at one end affects something at the other end. What you’re really measuring is how that proximal input impacts your distal motion. You have to accept some kind of lag to attain flexibility. How much is okay?
Then you have minimal trauma. Again, really important. You don’t want to damage any vessels in a procedure like this. Here, the constraint shifts to your distal flexibility and strain concentration at transitions. This is where a lot of people have struggles that they have to overcome, the transitions.
When you’re putting a proximal input into distal motion here with final architecture, just testing at the component impact level, it’s really interesting to see what R&D engineers can do when they layer different polymer jackets or heat shrink just over a catalog tubing to see how those transitions between materials work. Learning how these interact together, even if it’s not your finished component, can be a really valuable tool early on.
These things let you see where strain concentrates and how the device behaves under flex. You don’t have to commit right away to complex laser structures, laser cutting, or a complicated braid. You’re probably going to move to that at some point, but you can test some of that fit, form, and function early on with off-the-shelf materials in a way that’s meaningful, even for something as complex as a neurovascular catheter shaft.
The framework I hope you can see is consistent. You have a clinical need that’s defining performance targets. You have these physical constraints, and then the anatomy and the physics define your geometric and mechanical constraints. With that, when you’re selecting components, you’re able to isolate and test constraints before final architecture is locked.
Again, we’re not in the final design phase. That’s what I love about R&D. That’s what I love about the concept-to-early-prototype phase. You have a lot of flexibility to test affordably if you know what your goals are. That’s why this framework is so helpful. You have your clinical need. Because of that clinical need, we have these constraints, and now we know the types of components that we need to think about to determine impact on the device.
Steve Maxson
This was a great example, Kristin, for complex tortuosity, neurovascular. You touched on the balance or the trade-offs between stiffness and flexibility, torque response, and in the complex neurovasculature, it’s almost like you need a wet noodle.
Kristin Livesay
Yeah.
Steve Maxson
So soft, even the polymer materials, the extrusions are super low durometer. The metallic components have extreme flexibility, whether it’s a cut pattern that gives you that or the material. It’s a great example of a case where you need ultimate flexibility, but you still need torque response and pushability.
13:55 Why Early Mechanical Lessons Cost Less
Kristin Livesay
It’s a hard balance because anytime you say yes to something, you’re going to say no to something else. But in the concept phase, you get to determine those mechanical boundaries. You get to determine, does the concept physically make sense? Is my concept going to work?
Even if it doesn’t, the universal lesson is that it’s really not a clinical failure, which is so great. You’re not at this point where expense is high and stress is high. You’re early on. You’re napkin drawing. You’re building early prototypes. If your concept doesn’t make sense here, it’s not a failure. It’s a lesson. These mechanical lessons are so much more affordable at this stage in the game rather than waiting for custom tooling or custom components or long-lead materials.
The same framework really does apply to drug delivery, structural heart, robotics. We’ve seen it early on that proof-of-concept prototypes really don’t need final parts. They need components that are chosen deliberately so that you can determine what really matters. You can test geometry, you can test stiffness, you can test transitions even with substitute materials, and find structural gaps before there’s a whole redesign cycle that costs a lot of money and a lot of time.
Steve Maxson
You can do it on the bench.
Kristin Livesay
That’s right. Do it on the bench.
Steve Maxson
Excellent. Let’s move on to the component feasibility aspect before you even build a first prototype.
Kristin Livesay
Yeah. Testing feasibility before that first prototype. We see this a lot. I’m sure you’ve seen this in the whole of your career and at Chamfr, that components are sometimes thought of as afterthoughts. We’ve developed a device, we’ve designed it, it looks perfect on paper, it looks perfect in SolidWorks, but the components that you’ve chosen for your build aren’t easily, readily available or are very expensive.
So that’s one of our real engineering tips for you, to work with suppliers early on. A good supplier wants to hear a phrase like, “We’re just thinking about this.” That is not scary to a good supplier. They want to be in on the ground level because that’s going to save expensive corrections later.
Feasibility asks a question like, could this work now? Versus down the road, how do we make this work? Yes, we’ve selected something that’s not really what we should have selected, but we’re already this far into the process, now we have to make it work. Asking, could we make this work now, versus how can we make this work later, is really valuable because what we see is when it is ignored early, when components are treated as afterthoughts, we see it fall into really two categories.
Either unrealistic components are selected, so those that are not really commercially readily available, or they’ve created a plan, a concept that requires very tight tolerances, tolerances that are just not realistic. Particularly, we have the whole DFM conversation. It’s one thing to make one part. It’s another thing to make a hundred, a thousand, ten thousand. Knowing in advance how you’re going to scale and then constructing with tolerances that are reasonable. Otherwise, you’ll find specified ID/OD combinations that do not exist. They’re not commercially available immediately. You have cost immediately. You have lead times. You’re dealing with wall thicknesses that are below structural limits. Everyone wants the thinnest wall possible, but that wall still has work to do, and we want to be mindful of that.
Then you have, I think, a conversation we’re having a lot, and I know you’re having a lot too, is tolerance stack conversation. That is across devices. It’s not just catheters. It’s not just ablation. It’s not just fluid delivery systems. There are tolerance stacks that are happening because you’re never working with one component. Component Supply might be dealing with one component, one piece of the puzzle. You might be buying one component from Chamfr, but it’s going into a finished device. That component has a tolerance and the whole device has a tolerance. How are we dealing with that? So I want to zoom in on the tolerance stack.
Steve Maxson
Before we do that, I want to bring up something that you mentioned. It’s very important, this idea of collaboration. You talked about presenting a concept or an idea to somebody and said, how do you want to do this? What are your end goals? How can we work together to achieve that? Versus a supplier that says, give me a print and I’ll give you what you want. That’s not really what you’re looking for. You’re looking to iterate.
Kristin Livesay
Right.
Steve Maxson
And collaborate.
Kristin Livesay
Yeah, and I think it’s important. There are times, sometimes they’re working with a supplier because they need a second-tier or tertiary supplier. They already have their design locked and there’s nothing really we can advise them on. But if you get the opportunity to look at a napkin drawing, to look at it before it hits rev one even, and start having those conversations, there is so much value there. I think it’s a little more time on the front end, but the payoff is huge when you’re dealing with the finished device, when you’re dealing with scaling. It is a little extra effort to have those conversations early, both from the engineering side or the sourcing teams and the supplier, but I think it’s so worth it. If we take the time early on, it’s a better output down the road.
Steve Maxson
Down the road, not only scaling, but validation, all these other things. Excellent. I love that you brought that up.
18:00 How Tolerance Stack-Up Creates Assembly Risk
Kristin Livesay
Yeah. So to zoom in on the tolerance stack, and again, having the early conversations, this is what we’re trying to avoid. Let’s give an example of another catheter shaft. Again, this is not just because this is a catheter webinar, but because these are easier to visualize, these layers and how these work together.
Steve Maxson
A composite catheter shaft.
Kristin Livesay
Exactly. You have some kind of hypotube OD. Let’s say your hypotube tolerance is three tenths, right? This is very standard when you’re dealing with any kind of mandrel, whether it’s a hypotube, mandrel, stainless steel, depending on your diameter. Just best practices, the bigger your diameters, the wider your tolerance should be. That’s just a DFM basic. But three tenths, not the end of the world. No one’s crying about that.
Then you’re going to add a polymer liner. Let’s say that has a similar tolerance, maybe a little bit looser. Then you’re going to add some kind of braid thickness variation. That’s another set of tolerances that you have. Then an additional polymer variation, that nylon tubing, and then you’re going to have a heat shrink variation. All of those on their own, if you’re looking at them individually, it’s not a problem. No one’s looking at any of these tolerances thinking, oh, this is a bad idea.
But when you put them together, they can create a problem. You can eliminate clearance in your device. You can create excessive friction. You can impact your flexibility. If it’s too tight, it can prevent proper bonding because nominal does not define production. Production does not operate well when you’re only working toward nominal tolerances. It operates across a full tolerance range, and that tolerance range has to be considered for every component that’s going into the device.
It doesn’t really matter that it’s a catheter. We’ll take another example, which would be fluid delivery systems or drug delivery systems. We see this a lot too because of the amount of fittings that we have and that we’re working with. These questions come into play. You have a drug delivery system where you’re dealing with tubing IDs, you’re dealing with fitting specs, and you’re dealing with transitions between your materials.
Again, we’ll say this over and over. Anytime you have a transition between material, between diameter, those are always major risks for a failure down the road. It’s not one of those components that’s out of sight. It could be, but generally it’s the stack-up that creates the failed connection. That creates the leak, for example, with a fluid delivery system. So IDs might affect consistency. Transitions between materials can cause alignment issues, and validating those stacks early can really prevent leaks. It can prevent the misalignment and ultimately cost. It all comes down to that because you want your device to be accessible, and accessibility means affordability.
All devices have these same struggles. If your device only works when your dimensions are perfect, when every nominal tolerance is hit, it’s not going to scale. It just can’t. That’s why validating early with realistic components is so important, so you can test how those tolerances interact with each other at the earliest phases.
Steve Maxson
This is a great conversation about tolerance stack-up. I hear it all the time, especially about this particular application, a composite catheter shaft. We have a mandrel liner reinforcement, outer jacket materials, and some kind of reflow, FEP heat shrink. You’re right, the tolerances because of capabilities are different on each one of those. The hypotube, the base, super tight tolerance. You talked about the liner, maybe plus or minus a thou, maybe even tighter. But the outer jacket extrusion, it might be plus or minus two, one and a half. It’s a thicker wall, like you said, a bit larger diameter, or it could be.
The other aspect for this application with this connector is process capability. On all these dimensions that we’re talking about, how tight, not only the tolerances, but how capable they are. From a Cpk/Ppk standpoint, industry standard 1.33, in some cases going up to 1.66, even more stringent. But there are trade-offs, just like we talked about trade-offs in the application, flexibility and stiffness. There are trade-offs in those tolerances, process capability, manufacturability, and being able to validate doing things repeatedly.
Kristin Livesay
Exactly.
Steve Maxson
You have to leave some wiggle room there to validate your process. I do want to bring that up. This example that you talked about, when you’re adding a connector or a hub over a catheter or an extrusion, if the interference is too loose, functionally you’re going to have a problem with product leakage. You’re going to have a problem with a secondary operation of adding that connector, whether it’s overmolded, solvent bonded. You’re going to have a problem. If it’s too tight of an interference, you’re going to have a process capability validation issue, and you’ll have pinching and other problems. So it’s always like we talked about, this balance and trade-off.
Kristin Livesay
There’s a balance. It’s hard because there are so many great manufacturers out there, they can hold really tight tolerances, and so you feel in the clear. But it’s how all the tolerances engage with each other once you put all these components together that’s really causing the issue. It’s something that oftentimes you don’t think about. We’ve talked with engineers before that say, we didn’t think about it because it worked on my drawing. Then it’s very frustrating to realize that how it is in the program, once you get it on the bench top, it’s not working out. We didn’t consider all the variables with the tolerances.
So that’s really it for the tolerance stack. With the fluid delivery systems in general, there’s a lot of impact with pressure. Every component that’s going in your fluid delivery system can affect how your fitting performs. It’s not just about the fitting’s pressure rating. It’s the whole assembly together, and again, that’s where the stacking tolerance issue comes into play.
Steve Maxson
Okay. Excellent. Let’s go over some of the core building blocks, right? That composite catheter shaft was a great example. What are some of the manufacturing aids that assist in achieving such a high overall tolerance level?
25:00 Core Components That Shape Early Prototype Performance
Kristin Livesay
Yeah. We’ve seen some of these common mistakes and examples. You still have to use some kind of core components. When you’re looking, this is very high level, right? I’m certainly oversimplifying it, but really there are these basic building blocks of medical devices, whether it’s wires, polymer tubing, hypotubes, heat shrink, fittings, needles, mesh. All of these are used in medical devices throughout the industry, a vast industry, so they’re used in lots of different ways. There’s no way that we could give an exact application for application on how these are used.
But I want to mention just briefly for each one where you’ll see these, just in case there’s crossover. We love medical device, and we work with it primarily, but we have some cross-industry applications where someone will see a device or see a use in a different industry and say, oh, I wonder if we can pull that to medical. So that’s one of the reasons I want to bring some of these things up, because we have a lot of creatives making our medical devices, and hopefully they’ll find some inspiration here.
Steve Maxson
Excellent.
Kristin Livesay
This is going to help you consider components first, not as afterthoughts, and how you’ll select them with intention. Starting with wires, everyone is using a wire, whether it’s stainless, whether it has a coating, whether it’s Nitinol. Everyone is using them. They’re used for torque, flexibility, kink resistance. They are used in devices like catheters. They’re your mandrels and your guidewires.
I want to provide for each of these an engineering tip. This is strictly based on what we’ve seen in our experience. Again, some of these might be an oversimplification, but because we’ve been exposed to it, we want to share what we’ve learned and what the engineers we’ve worked with have learned.
The engineering tip for wires would be to prototype early with material extremes. Just because Nitinol is trendy, right? Everyone loves to talk about Nitinol, and it’s a great product. It has a lot of great characteristics, but not every application is going to use those characteristics. So we encourage defining your performance window with two different materials. Something like superelastic Nitinol is going to allow deflection without deformation, versus stainless steel on the other side of the spectrum. It’s going to set an opposite boundary because it’s a stiffer material. What you need is probably going to fall somewhere in the middle.
Just because you can use Nitinol doesn’t mean you should. That could be costly later. It might be too flexible depending on what your device is. The bonus tip here is to define your base material early, because more than likely you’re going to have a coating or a feature on it. You have to know what base wire material is going to work for your application, and then move into features after that. Otherwise, if you’ve already made all these features or you’ve added coating, that’s adding costs. Then to find out your base material didn’t work appropriately, that’s an obstacle you would like to avoid.
Steve Maxson
That’s a good point. We talked early on about having DFM in mind, but COGS, right? The cost of your goods in a catheter build is a huge component, so good point.
Kristin Livesay
Right. What are the reasons that you get a no quote, or what are the reasons you don’t get a job from either side? It’s either cost or capability. You either don’t have the capability to do this, or you don’t have the ability to do it affordably. That’s why jobs are lost or awarded, at the oversimplification.
Steve Maxson
Or even further, Kristin, is there a payment code for this new device?
Kristin Livesay
Oh, fair. Yeah.
Steve Maxson
And within that payment code, there’s a certain price range. Are you within that price range, even to get money for the device from a CMS standpoint?
Kristin Livesay
No, that’s so true.
Steve Maxson
So COGS are huge.
Kristin Livesay
Yep. Next, hypotubes. Component Supply loves hypodermic tubing. We have a lot of capabilities for it, and we see it all the time in lots of different devices, lots of different applications. This is your shaft support when you’re dealing with catheters or just pushability. We see it in biopsy needles as well. There are other applications: pharmaceuticals, surgical procedures, things like that.
This one is a really interesting engineering tip, and it’s something that people, I think, don’t think of. ID/OD ratios have a nonlinear effect on column strength. Just because you make a minor adjustment with your wall thickness, it doesn’t mean that there’s not a significant impact on the strength of that tube. So you always want to test that.
A bonus feature here, a bonus tip: if you have an ID that works and you truly believe that you maybe could have a slightly smaller wall, you can do OD grinding. Lots of grinding houses are doing this. You don’t have to go to a mill to get a custom-drawn material. Hypodermic tubing, we talked about this on our tour, the process for that is expensive. It’s interesting. It’s fascinating, but it’s not always needed. If you can find an ID that works for you, but maybe the wall that you’re looking at for the off-the-shelf component is a little too thick, that can usually be ground off in a way that’s very beneficial and more cost effective.
Steve Maxson
Good point. It’s also thinning the wall. You talked about the ratio and column strength. The impact on kink resistance is another variable.
Kristin Livesay
Oh, yeah, exactly. You sacrifice strength, and the result is often kinking if you go too thin. The desire is always the thinner wall, of course, which you can’t get away from. We try to get as close as we can to the desired point while being honest that you can do this, it is fine, it might work for two, but as you scale, I cannot guarantee for you that this won’t cause some kind of breakdown or kinking.
Steve Maxson
That’s exactly it. Profile is king.
Kristin Livesay
Yes, that’s right.
So polymer tubing, these are your FEPs, your PTFEs. These are your liners, your bonding components, chemical thermal properties that you’re using, whether it’s catheters or infusion or robotics, electronics. These are such versatile components, and they come in lots of different ways. You have an extruded tube that goes off the spool that’s used more in the electrical insulation side of things versus an FEP/PTFE liner more on the catheter side of things.
Steve Maxson
The etched liners.
Kristin Livesay
Yep. Here, this one’s always interesting. Everyone wants the more flexible durometer. Well, not everyone, I shouldn’t say that, but that’s always, what’s the lowest durometer? But keep in mind, sometimes changing a durometer in your design is a more complex design change. Sometimes if you can slightly adjust your ID/OD spec, that can also affect flexibility.
So don’t just rely on a durometer callout. That’s a great place to start, but test it. Get it in your hands and test what the stiffness really is of that material. Know that usually geometric changes are less costly than a full material change.
Steve Maxson
Yes, absolutely.
32:15 Design Tips: Heat Shrink, Fittings, Needles, and Mesh
Kristin Livesay
Okay. We’ve got heat shrink. Man, do you remember, Steve, in 2020 when no one could find heat shrink?
Steve Maxson
Yes.
Kristin Livesay
And we hoarded it like toilet paper during the pandemic, right?
Steve Maxson
There was probably security all around the building.
Kristin Livesay
Yes, exactly. We had to work so far ahead to maintain it, and people have really stepped up to the plate to provide a lot of different options for heat shrink. If you’re having trouble finding a heat shrink that works for you, we could probably help you with our powers combined.
There are so many options. It’s used everywhere: strain relief, transitions, catheters, ablation, robotics. Such a versatile material. The tip here is to validate shrink transitions. Again, I can’t say it enough: that’s where a device fails the most, in a transition. Being able to repeat it early on with off-the-shelf components to see how it works, to see if your strain relief is gradual, if you’re using it as a liner, to ensure that you don’t have an abrupt mechanical step, which can cause a breakdown.
You can test these things early with off-the-shelf components. There are so many options now thanks to so many people who have picked up the capability to do this. So it’s an exciting time to be in the heat shrink world.
Steve Maxson
And further, between Component Supply and Chamfr, there’s probably no source that has the wide selection of heat shrink tubing from PTFE, FEP, PET, polyolefin, Pebax.
Kristin Livesay
The sky’s the limit. Yeah. I think everyone working in our organizations really does have a desire to help you find the right fit. So the sky’s the limit there, I think.
Fittings. Another component where the sky’s the limit as far as materials go, whether it’s nylon, polypropylene, polycarbonate, stainless, acrylic. We’ve got these radiation-stable fittings that are coming into play where you want to test the sterilization of your entire assembly early with small quantities that are available to you. You don’t have to wait until you’re in a clinical setting to sterilize your components.
These are what are securing your connections. These are your fluid and drug delivery components that are so critical: pharmaceuticals, drug delivery systems, catheters. We mentioned this before, we touched on it, so I want to touch on it again. Don’t blindly trust your catalog ratings for fittings. Pressure test fully assembled parts as early as possible. Get that full prototype, that early proof of concept, even if it’s not exact, and test that as early as possible because it’s the tolerance stack. It’s how those components are working together that determine the leak. Usually it’s not the fitting itself that’s out of spec. Just an encouragement there to test early.
Needles. These are your access points, precise placements, dispensing. These can come with various hub options, whether that’s your standard polypropylene fitting. These are generally more used for a single use, or being welded into a stainless hub, which is something that has more reusability, more expensive upfront, but you’re getting more uses out of it. These are your drug delivery systems. We see them a lot in biopsies.
This is really important, I think, for an engineering tip. Most needles have some kind of tip. You’re trying to dispense something precisely. You’re trying to puncture a septum. There’s a certain angle that’s required. Once you put that cannula, just the metal tube part, and you incorporate it into a hub, it becomes exponentially more expensive. It doesn’t matter if it’s polypropylene or a stainless hub, you’re adding cost. So if you can confirm your grind angles early, how the configuration works, just that one feature, before it goes into the assembled hub. Now, to test leaks and things like that, you need the full hub. But if you’re just trying to test, can this pierce, can this puncture, then you want to test that early from that point.
The bonus tip here is to always quantify standard grind or standard bevel. We do get requests, I’m sure a lot of people get requests for, can you put a standard bevel on this? And we don’t use standard bevel. We want you to provide an actual specification, provide an angle, because depending on what application you’re in or what segment you are in, medical device standard might mean different things to different people. Various tips can be called standard depending on who you are. So we just want everyone to call out a specific angle.
Steve Maxson
Okay. I was going to ask, what’s a standard bevel?
Kristin Livesay
There’s not one, at least in our mind, but we get asked enough that I think it might be there. There might be something out there, so someone can ask that in the Q&A later or give us that tip. But for the most part, we don’t. Also, there is a tolerance on your angle. That could be different. Some people can deal with a very large tolerance and others can’t handle it. It just depends on what the application is.
I think our last one is mesh. Maybe people don’t think of mesh as much unless you’re dealing with wound care or some kind of filter, but it’s really important for filtration and flow control. There are so many different versions. When you’re out in the shop, we showed you a seven-micron. It’s so fine, it’s like silk.
Steve Maxson
Yeah. It was amazing. And Mark going over how the process of the loom, how that’s made, I’d love to see that. Just like I love the tour that you gave me, which is awesome, by the way. If anybody wants to, I’m going to invite people.
Kristin Livesay
Go for it.
Steve Maxson
You’re going to have people lining up at your door here in Sparta. It was a great tour of all the different capabilities, and I loved it. Especially that mesh was really amazing.
Kristin Livesay
There’s just a lot that goes into these. I think we sometimes work with these materials every day, you’re ordering them every day, and you forget what goes into it. You forget that hypodermic tube starts as a strip that’s welded and drawn. You forget that mesh is woven. Everything is so intricate. There are people behind those parts that are making them, designing them. We have operators with magical hands that can do all these things, and it really is amazing.
Steve Maxson
AI can’t really help you with that at this point.
Kristin Livesay
Yes, there are lots of good things that AI can do and so many processes it can simplify, but it’s hard to replace the heart behind the people that are doing the work.
For inline fluid and drug delivery filters or blood filters, filter bags, biopsy bags, wound care, those are your mesh products. That’s why there’s such a range of sizes. Something that looks as thin as silk, that mesh opening is as small as fabric, versus something that looks like the screen on your back porch. You’re like, this isn’t important, this is so big. But it really does matter.
The tip here, and this is a little history behind mesh, is that not every component is determined by the need in the medical device industry. Screen printing actually determines the vast majority of the manufacturing processes of mesh. Those configurations are based on that need. So you have a vast array of sizes and configurations to pick from, to test in your application.
But not everything is available in a medical grade. A lot of it is, and for most applications, those small differences in micron mesh opening size probably don’t matter. You can test everything with off-the-shelf industrial mesh, as close as you can get. But as you are doing that, make sure that you are checking to make sure it is available in a medical grade. It’s usually just several additional washes, and it has the pedigree for medical grade. You get some extra paperwork with that than you would get buying industrial-grade materials.
Steve Maxson
Little extra cost.
Kristin Livesay
Little extra cost. Yes. I think that’s all the components I have to talk about.
Steve Maxson
Excellent. This whole concept, Test Before You Invest, is very interesting. I love the tolerance stack-up conversation as well. So important. That could be a webinar or a podcast in and of itself, right? That could be one where you have a lot of guests just going after it on tolerance stacking, because at these MPP events, that’s often the topic. Someone will bring up tight tolerances, and it always ends up saying, okay, we’re talking about a component level. Now let’s look at the stack-up. People don’t think about that enough.
Kristin Livesay
That’s right. Because you’re thinking about the one element that you’re working on in the moment, and rightly so. Everything deserves attention. But it’s interesting. Talk about the tolerance stack-up. I’m over here arguing for standard parts. We know so many things are going to go to custom. At least some part of that device is going to be custom. So does it sound crazy that I’m saying start with standard?
Steve Maxson
No.
Kristin Livesay
Well, surely not from Chamfr because that’s what you guys do, provide everyone with the opportunity to buy standard. It is so important to have access to that.
Steve Maxson
That’s the key point. You think about just five, maybe 10 years ago, if you wanted access to have these components on your desk within a couple days to build a composite catheter shaft, like this example, all these different components, you’re reaching out to multiple suppliers, different lead times, two to four weeks, six to eight weeks. FEP heat shrink back during the tough times.
Kristin Livesay
Seventy-two weeks, I think, was the longest one I got.
Steve Maxson
Right. So now the ability to put a kit together of standard components to iterate and then go to more customization, it’s critical.
Kristin Livesay
Yeah. What we’ve seen a lot of times is that there is a reason to test with standard. It’s not a waste of time. You talked about earlier, sometimes it’s not about getting the finished design or the finished components. It’s about what you will learn from what you’ve selected. How does this interact with this? If I add this, what will this do? Evaluating as you go, sourcing components as you’re building your design out.
Standard components really do allow you to test and evaluate impacts really early. Using standard hypotubes to evaluate fit, form, function, OD/ID specs. You don’t have to start with a laser-cut tube. You might go into that, but if your ID/OD isn’t accurate, what’s the point of moving to that custom, more expensive capability, even if it’s what you’re eventually going to go to?
Standard reduces variables and helps you to isolate issues. If everything is custom, how do you know what’s wrong? If you start on the basis of what is standard with what you can live with, and then you can add a custom component and that fails, then you know that’s what it was. We can go back. It gives you a very good baseline, helps you build a foundation on repeatability and reliability because these are the components that are always available, and so I can try to make adjustments with these that are maybe a little bit trickier, something that’s not as readily available.
The goal truly is to test the physics before you invest in complexity. R&D can get expensive fast if you’re not using off-the-shelf components. We encourage you to start very standard and add custom gradually. It’ll make your tests more meaningful, it’ll make your failure sources easier to find, and your next iteration, whatever comes next, is going to be grounded in data from parts that are real, that are available to you at all times. It gives you a really strong foundation to iterate on.
Steve Maxson
Especially for a startup, with limited capital. Your burn rate, you just go through cash quickly. Resources, materials. The longer you’re waiting for components just to do a first phase iteration, it’s not feasible. So many startups go out of business because of that burn rate issue. It’s been a major issue and it’s been a major saving grace for a lot of startups to be able to have quick access to these components at a standard level so that you can iterate to the next gen. You can do little fabrication pieces as you go.
Kristin Livesay
There are certain contract manufacturers that we work with that are building out devices and they have customers that are just a doctor working in his garage trying to figure it out. He doesn’t have much of a budget versus a big OEM that does. Being able to pivot, providing similar componentry for different organizations, different napkin drawings, and to be able to pivot from that small budget to the large budget and know how to satisfy both well, I think is a real value for sure.
Steve Maxson
Just to bring that to a real human level. That example of a surgeon, because I’m involved in a startup called Anchor Balloon. It started by Dr. Byel, a practicing interventional cardiologist. That burn or that money, that’s a family and friends situation. You’re thinking about developing this device and you sold this concept to your family and friends and they invested in it. You need those parts quick, right? It’s not only you, your life, but your family and friends invested in this.
Kristin Livesay
That’s the pulling of the heartstrings. I like to talk about sometimes, because I’ll never forget the first time someone called Component Supply, this was 10 years ago, and said the cutoff time was over. We ship, if we get your order at 2:00 PM, whether it’s Chamfr or direct, we will ship that part if it’s an off-the-shelf component. This was not off the shelf, this was cut. This was before we had machines. We were doing it manually, and they wanted some amount. I was like, we passed the shipping deadline, but also this is going to be at least a three-day lead time. This is a custom part.
He said, if I could just pull on your heartstrings, I’m working on an Alzheimer’s device, it’s going to trial, I need these components. I walked out to the shop and was like, listen guys, I heard the story. I think that’s some of the humanizing that can happen in the medical device industry. You need a component, tell us the story. It really helps. We’re cutting tubing. We’re pick, pack, ship all day long. It is a huge encouragement to know someone was investing, your friends and family believed in your device and wanted to invest. I love that so much. Thank you for sharing that.
So just some practical prototype principles. Very basic, very high level. Use your off-the-shelf wire, tubing, hypotubes to test fit, form, function. These are your geometric shapes. You can utilize quick-turn, small runs of fabricated components. Lots of manufacturers are doing this. You might find a sample, something that works, but validating a specific feature before it’s incorporated in a finished device.
Consider your real-world constraints. Go back to that three-column structure and think about that clinical need. You are constrained by real-world, real-life situations. You can only make it so big, so don’t lose that when it’s blown up on your screen, on your drawing. Remember the real-world constraint at the end of the day.
Remember that the goal is to learn, not just produce. Yes, the end goal and where it’s meaningful is when it hits the patient, but there’s a lot of learning that happens in that process. I recently read, I wish I could remember his name, but he had just received his patent on something and he said, this is not what’s going to get into the device, but it’s what I learned from it that is so valuable. I loved that so much, to celebrate the learning that you’ll take with you later.
Then don’t ignore trade-offs. We talked about this a million times. You cannot have it all. I think about even your visit today, of all the things I wanted to show you. I take you on a hike, I take you barbecue, and I threatened line dancing. At some point, we can’t do it all. Neither can you with your device. Every time you say yes to something, you’re going to say no to something else. You have to determine what is important, and you have to realize what is actually the trade-off. You made this decision; the impact is here. Keeping that in mind as you’re making these decisions and as you’re sourcing components, all those things are incredibly important.
Steve Maxson
Absolutely. Excellent. Wow. This has been a great conversation.
Kristin Livesay
Thanks, Steve, for having me on. I hope it’s been beneficial just to see, really at a high level, how big of an impact components can have in your concept-to-prototype phase.
Steve Maxson
Absolutely. So important discussion, and thank you for the tour. I’m looking forward to some hiking and barbecue next.
Kristin Livesay
That’s right.
48:10 Live Q&A with Mark on Tolerance Stack-Up and Custom Features
Steve Maxson
Hey, folks. Hope you enjoyed the webinar, and we’re going to move on to some Q&A now, if that’s okay. We have Mark with us.
Mark Maffett
Hello.
Steve Maxson
Hey, Mark. Let’s go to the first question. It’s a great one, actually. It’s if you don’t account for the tolerance stack-up on the front end, what’s the next step to try and rein it back in in your overall tolerances if your overall tolerances aren’t working? How do you regroup if you didn’t consider that upfront?
Mark Maffett
This is one of those things where I guess you just hopefully don’t say, “Oh no, the sky has fallen.”
Steve Maxson
Fail fast.
Mark Maffett
Yeah. I think most of this was not just about catheter construction or design, but it was based around that. We’ll talk about that. You really have to start. You have to pick one place, right? At some point, you have to put a line in the sand and say, okay, what isn’t really working? Obviously, this gets back to applications that may or may not all be the same.
I would say pick an OD or you pick the ID and say, okay, that’s where I’ve got to work from a place. If I start working with everything, then I’m not really basing it off a foundation. In this situation, if somebody were to come to us and say, hey, look, here’s the problem, we would suggest saying, hey, let’s start with what’s important for you. Let’s pick one, ID or OD. Once you pick that, then you can say, okay, if I’m going to start with the ID, what’s the next component?
We stick with the mandrel. If it’s the OD, now you’ve got, okay, what are my calls on the Pebax or whatever? You know what the first component to go after is once you choose the ID or OD. That would be my suggestion on that. I would not suggest saying, oh, the sky’s falling. We need to start over. Let’s just pick one and start systematically working through that.
Steve Maxson
Okay. Another good question. For testing purposes, an off-the-shelf heat shrink size is sometimes close enough, but what happens when I need something more specific for the final design?
Mark Maffett
Heat shrink is, there are a lot of really good companies that specialize in heat shrink tubing. That is definitely one where it is good to start off with something standard. But obviously as you go through, it gets more complicated. All of a sudden, you’re trying to recover to a particular shaft diameter OD. You’ve put whatever that is, whatever mandrel, you’ve got your braid or your structural side of that, and now you’re dealing with wall thicknesses, durometers, recovery.
You’ve got this OD that recovers. The minimum or the shrink diameter, the recovery diameter, is theoretically smaller than the targeted OD. What is that ratio? There are some software tools out there that can help you determine that. But the reality is, even with those software tools that exist, talking to someone in that industry who makes those products and knows that side of the business well is really the answer.
We keep pushing this over and over again, right, Steve? You talk to people and we push, go have the conversation. Have a conversation with someone. We would rather you have a conversation with us in the beginning, even if the standard stuff is not the right stuff, so that no one’s surprised later. So that you’re not designing products or various components from different suppliers and then need a custom shrink tubing that is not going to produce the desired result.
Again, even in the testing phase, it’s worth having a conversation so that we can say, hey, let’s loop someone in who knows about heat shrink, who can talk to you about what you’ll need in the future so this is scalable.
Steve Maxson
On that end, I guess both on the stack-up question and going from a standard part to something a little bit different, I remember when I was out in the back, you showed me some of the grinding capabilities. Related to a mandrel, if you’ve got something that’s off the shelf and you know you just need a little bit more room there, or I want to add a distal feature, you can do some of that customization fairly quickly to a standard component?
Mark Maffett
Yes. We’re in a position to be able to do that really quickly. We’ve got a lot of different sizes on the shelf, whether that’s wire or even hypodermic tubing for some of the larger mandrels that are out there that need either some profile, or they just need the OD a couple of thou or a thou and a half off from what they’re targeting. We have the capability, if the inventory is available to us and the capabilities to do that, to make those adjustments really quickly.
Steve Maxson
Okay. One other question related to features. You said somebody said there’s no standard bevels, and if you need a different feature like a lancet tip, what specific angle specs would you need from a customer to start prototyping?
Mark Maffett
We see this with lancets, or I’m also going to throw out trocars. That’s a little bit easier. But there are options out there. When somebody just says, hey, we need a standard lancet or standard bevel, the bevel doesn’t really solve the problem, right? You’re using that to go through something. Some septum, some tissue, something. There’s something you’re trying to penetrate, and not everything penetrates the same.
So we generally say, hey, tell me what it is. Is it a piece of rubber? What does it feel like? Is it super soft? What are you trying to accomplish? If they truly don’t know what to choose, we’ll make some suggestions based off of what we’ve seen. But ultimately, for the bevel, we’re looking for an angle, and we’re going to call that out, not just standard. We’re going to call out some angle for that bevel.
For the lancet, we’re going to call out a primary angle, primary grind or bevel, a secondary grind, and what axial rotation it takes to produce that lancet tip, those three facets, the two grinds. Then even in the trocar, in general there’s an angle, and then you grind three sides. They’re 120 degrees, so everything’s nice and even. But that’s not true. Some people want something a little off or something different, so they’ll call it a double bevel or something like that. Again, there you’re talking about grind angles and a rotation, an axial rotation for the part itself.
Steve Maxson
Is a bevel similar to a chamfer?
Mark Maffett
Yeah. A bevel is similar to a chamfer. I guess you would say that the bevel probably goes all the way to one end, where the chamfer doesn’t go all the way down.
Steve Maxson
Okay. I’m glad when Katie and Julie came up with the name of Chamfr for our company that they didn’t use bevel. I thought I’d throw that in.
All right, cool. There are a few other questions, and we’ll answer those separately and wrap it up. Thanks, Mark. I appreciate it.
57:50 Closing Remarks
Before we wrap up, I want to share a few valuable resources from Chamfr that can help you move faster in R&D. First, we launched our Resource Hub, your go-to place for practical tips, new technologies, and the latest sourcing trends to accelerate your projects. You can scan the QR code here on the screen to explore more.
We also have a full suite of tools designed to help you source faster. Everything from request a quote, project lists, share cart. Share cart, if you’re working on a program and you identify the components that you need for a particular catheter build, you can share that cart with a colleague or someone in procurement or another engineer.
And net terms. A lot of engineers use P-cards, credit cards to place orders, but we do have net terms available. For a particular project, you can use a blanket PO, so we can accept purchase orders. Then download a quote. All these are built to save you time and make the experience as frictionless as possible.
On a thought leadership side, as you know, I host the MPP, Medical Processing Panels. A couple of months ago, actually in April, we had MPP West in the Bay Area. It was hugely successful and has a lot of momentum going into the next event, MPP East, June 24th in Quincy, Mass at Granite Links Golf Course. Beautiful venue, and the content will be stellar. Then we have MPP Ireland in Galway the day before MTI, the Medical Technology Ireland show. Finally, MPP Minnesota, Maple Grove, Rush Creek Golf Club, our favorite golf club, the day before MD&M Minnesota.
We also have webinars like today each month for thought leadership.
I want to thank you for joining and thank our co-host, Kristin Livesay, and Mark for joining. Component Supply has over 3,000 SKUs in a partnership with Chamfr. Thank you to our promotional sponsor, Workplace. Before we leave, check out Chamfr. You can see the QR codes here. You can subscribe to emails and follow us on LinkedIn. Thank you so much for joining.