The difference between working with an experienced Nitinol supplier and one that treats it like any other material is dramatic and could determine success.
For the right medical device application, Nitinol can offer physical properties and performance that no other metal can provide. However, due to those same favorable advantages, it can be a challenging material to manipulate. As such, selecting the right supplier to assist in the fabrication of a Nitinol-based device or component can directly lead to the success or failure of a development project.
Given the unique processing technologies required to successfully work the metal, a supplier must have a proven track record for handling Nitinol specifically. A machine shop that works with titanium, stainless steel, and other more common metals may not have a grasp of the novel properties associated with this material. Therefore, the selection process of a suitable supply partner can be a critical element before development even begins.
To help further explain the intricacies associated with selecting the right supply partner for a project involving Nitinol, Eric Veit, Vice President of Business Development at Resonetics, responded to questions about this topic. After explaining the types of applications for which Nitinol is ideally suited, he also provides specific insights on what makes the material challenging to process and what the right supply partner looks like.
Q&A with Eric Veit
Sean Fenske: What makes Nitinol a desirable metal for medical device manufacturers, and for what types of applications is it used?
Eric Veit: For the first part of your question, I suggest you take a look at the Medtech Makers Q&As with my colleagues Rich LaFond (Addressing Concerns with the Nitinol Supply Chain) and Scott Robertson (Nitinol’s Role in Medical Device Manufacturing). They both discussed some of Nitinol’s highly desirable and unique properties, particularly its superelasticity, shape memory properties, and elastic deformation behavior similar to structural materials in the human body. Today, let’s concentrate on where these well-documented characteristics are used.
Think of Nitinol as the “superhero metal” of the medical device world. Like a superhero with shape-shifting powers, it has an uncanny ability to remember its shape—even when twisted, stretched, or put through the wringer. Imagine a tiny wire that can be bent, wound, or compressed, yet always returns to its original form. This remarkable trait is one reason Nitinol is ideal for high-stake medical applications.
For this discussion, let’s define three primary market use areas with increasing levels of criticality and complexity and explain how Resonetics offers tubing, wire, and components that fit those different levels so you don’t waste time or money.
Precision Delivery Components: This category encompasses non-implantable components and disposable devices used for general delivery, positioning, and navigation. Products include guidewires, catheters, needles, dental devices, snares, and sheaths, where precision grinding is heavily used, but high-stress demands, laser cutting, or advanced shape setting are not typically required. These are often used in procedures requiring fine control and flexibility but do not endure high mechanical stress or fatigue over time. In our superhero analogy, let’s take guidewires, for example. They need flexibility to wind through the body’s twists and turns, but they also need to “snap back” and provide stability. Nitinol handles this balance of flexibility and rigidity like a pro.
Stable Implant and Support Devices: This group includes semi-critical implantable devices and delivery aides for temporary or permanent use, particularly in orthopedic and some cardiovascular applications. These products, such as delivery system components, peripheral stents, and orthopedic implants, require reliable material performance with moderate demands on fatigue resistance and geometric consistency. Consistency in material behavior is essential, but extreme mechanical durability and precision are not as crucial as in higher-criticality implants. Back to our superhero analogy, take stents, for example. They need to navigate through blood vessels, expand once in place, and stay put—all without harming the delicate walls of the artery. Nitinol’s superelasticity and ability to adapt like a contortionist make it the perfect candidate for such demanding tasks.
High-Durability Precision Implants: This top-tier category includes devices that must withstand high-stress environments, demanding both exceptional dimensional precision and fatigue resistance. Products include structural heart devices (e.g., heart valves, left atrial appendage closures), neurovascular stents, and carotid artery stent systems. These devices are used in life-sustaining and high-stakes applications, demanding tubing and materials sourced from specialized suppliers. The high durability superhero? Let’s not forget its impressive endurance. Nitinol can undergo millions of stress cycles, which is essential for devices designed to last in the body, like a heart valve.
It’s no wonder we’re seeing it in everything from orthopedic implants that need to withstand constant movement to tiny, shape-shifting surgical tools that can sneak through minuscule incisions. Just like a superhero with a perfect blend of strength, flexibility, and resilience, Nitinol is ready to tackle the challenges of the medical world, one device at a time.
Fenske: What makes this material challenging to work with? Why is identifying the right supplier important?
Veit: If you don’t understand the material properties from start to finish, you can easily get variability in your part performance. Nitinol is notoriously challenging to work with due to its sensitivity to processing parameters and its complex phase transformation behavior. Achieving precise control over mechanical properties like transformation temperature requires exacting and consistent manufacturing and finishing techniques. Finding a supplier like Resonetics with expertise in material properties and handling Nitinol is crucial because improper processing can alter its transformative properties and compromise device performance. An experienced supplier not only ensures the material’s quality but also provides confidence in meeting the strict tolerances necessary for medical applications. This is probably the main reason there are far fewer Nitinol component manufacturers than other material processors.
Fenske: Why is the right supplier often a vertically integrated company that handles the material from melt to market?
Veit: A vertically integrated supplier such as Resonetics offers distinct advantages in consistency, quality control, and efficiency, but above all, in material understanding. The feedback loop is essential. By managing every stage—from the Nitinol melt through processing—a single supplier can provide immediate and long-term feedback to the supply chain. They can enforce rigorous quality standards at each step, reducing variability and defects. This integrated approach is particularly important for Nitinol, where the slightest deviation in processing can affect performance. Vertical integration also shortens lead times and streamlines development, which is essential for manufacturers seeking reliable and timely delivery to meet regulatory requirements and market demands.
Fenske: What other attributes should a medical device company seek in a Nitinol supplier?
Veit: A world-class supplier will be heavily involved in the industry from a technical perspective, know where it is headed, and be an active member of the community. This is critical to the evolution of the Nitinol community and to the advancement of the material science behind the material. Beyond technical expertise, a medical device company should look for a supplier with a proven track record in quality assurance, regulatory compliance, and innovation. The supplier’s familiarity with medical device standards and ability to adhere to FDA and ISO requirements is vital. Ideally, they are active partners in research with the FDA. Additionally, a commitment to R&D shows a forward-thinking approach and positions the supplier to adapt to industry shifts or develop custom solutions. Finally, transparency in the Nitinol community and customer support are critical; working with a supplier that offers collaborative design input and responsive service can streamline development and reduce costs.
Fenske: What capabilities are important beyond what may be considered the first level of service (i.e., laser, heat treatment, and electropolishing processing)?
Veit: Beyond fundamental processing capabilities, Resonetics offers many processing options that smaller shops just can’t provide, such as wire EDM, waterjet cutting, braiding, micro ablation, wire forming, and a vast profile of grinding capabilities. In addition, we offer advanced capabilities like surface coating, custom alloy formulation, and fatigue testing, which are sometimes essential for higher-performing Nitinol components. Surface modifications can improve biocompatibility or enhance wear resistance, while alloy customization allows for tailored transformation temperatures and mechanical properties. Fatigue testing is particularly relevant in vascular applications where components must withstand millions of cycles without failure. A supplier such as Resonetics has deep technical talent from the industry equipped to handle these additional capabilities and provides a medical device company with greater control over product quality and a competitive edge in device performance.
Fenske: What aspects of working with a Nitinol supplier are overlooked or not always considered that are still important?
Veit: One often overlooked aspect is the supplier’s understanding of Nitinol’s unique properties and their ability to maintain consistency batch after batch. Many suppliers can work with metals, but the technical nuances of Nitinol require specialized knowledge. Another important factor is the supplier’s capacity for prototyping and scale-up; early-stage development and rapid prototyping can be challenging with Nitinol, so a supplier who offers these services can accelerate time to market. Resonetics has what we call “Lightspeed” teams with dedicated engineers and equipment that can turn around a quote in one day and get your parts in hand in a week or two. Better yet, we offer a Lightspeed Lab Day, where engineers come on-site and can turn multiple iterations out in a single day. Although not the sexy side of things, having robust documentation and traceability in place is also invaluable for regulatory submissions.
Don’t forget equipment and scalability, as well. Nitinol processing equipment, like automated salt bath ovens or electropolishing stations, are not off the shelf. Not everyone can automate this, which, as noted earlier, can wildly impact part performance. You should seek a company that has the experience and capability to build their own equipment, ensuring speed and control as you ramp for production. Resonetics has its own Automation Group, which builds our equipment and helps us scale.
Fenske: Do you have any additional comments you’d like to share based on any of the topics we discussed or something you’d like to tell medical device manufacturers?
Veit: Nitinol’s role in medical devices continues to expand, driven by both technological advancements and an increasing demand for minimally invasive solutions. Collaborating with a Nitinol supplier who not only understands the material but also stays ahead of industry trends can be transformative. At Resonetics, we recognize the need for precision and are committed to delivering the highest quality standards in Nitinol tubing and components. We’re constantly refining our processes to meet the unique demands of our clients, and we’re excited to support innovation in healthcare.
(Originally featured in Medical Product Outsourcing on April 17, 2024.)
Learn more about nitinol by downloading our Introduction to Nitinol whitepaper.