Nitinol: Medtech’s Biggest Innovation... And Biggest Roadblock

Nitinol is becoming a critical material for next-generation medical devices because its shape-memory and superelastic behavior enable stents, orthopedic fixation devices, guidewires, and neurovascular tools to flex, compress, deploy, and recover shape inside the body. But those same properties make nitinol difficult to machine, creating demand for non-contact, non-thermal processes like PECM that reduce burrs, recast, tool pressure, and surface-integrity risks.

The shape-memory alloy Nitinol has arguably become the most important material in medical device manufacturing. It has enabled incredible new medical devices with increased flexibility, compressibility, deployability, and fatigue strength: all while being able to move through constrained areas before returning to a controlled shape. 

The FDA has helped integrate the gradual transition of medical devices towards nitinol in the past decades, describing nitinol’s extensive use in cardiovascular devices such as stents, heart valves, guidewires, and vena cava filters, with growing use in new areas, especially in minimally invasive procedures (U.S. Food and Drug Administration).  

Nitinol’s increased usage and applicability has been well-received by patients, medical practitioners and design engineers alike— but many manufacturers have not shared that positive sentiment. Nitinol certainly helps unlock better device functionality, but it also introduces considerable machining and finishing challenges that conventional methods sometimes struggle to work around. As nitinol medical devices become smaller, more intricate, and more performance-sensitive, the manufacturing method becomes part of the device-design strategy. In this article, we’ll explain the cause of nitinol’s rise across medtech, why conventional methods are struggling to keep up, and how Voxel’s PECM methodology offers a new solution at scale.  

---

Key Takeaways 

• Nitinol is increasingly important in medtech because it supports shape recovery, superelasticity, kink resistance, and fatigue-loaded device designs.  

• Its strongest use cases include stents, heart-valve frames, guidewires, orthopedic fixation devices, and newer neurovascular tools.  

• Nitinol is difficult to machine because it is tough, elastic, strain-hardening, heat-sensitive, and highly dependent on finished surface condition.  

• Conventional machining, laser cutting, EDM, and downstream finishing each have useful roles, but each also introduces tradeoffs. 

• PECM offers a non-contact electrochemical route for conductive nitinol features where burrs, thermal damage, recast, tool pressure, or edge consistency create risk. 

  
  

---

Why nitinol keeps showing up in next-generation devices 

Nitinol fixation device machined via PECM.

Nitinol is an extremely unique material: it is a nickel-titanium alloy that is almost entirely “equiatomic”, meaning it has nearly equal amounts of nickel and titanium. While the presence of those materials do not make Nitinol inherently special, two key material behaviours of nitinol do set it apart:  

• Shape memory allows a nitinol component to recover a pre-determined geometry under the right thermal conditions. In other words, manufacturers could shape nitinol wire into a complex geometry, heat treat it while in that shape, and the component will “remember” that geometry even if it is bent into another geometry by simply heating it at a certain temperature.   
  

• Superelasticity allows substantial deformation of a nitinol component, and it will still be capable of returning to its “pre-programmed” geometry.  
  

Consider how in medical environments, these devices undergo geometric transformations for a wide number of reasons: it may need to be constrained during delivery and then expand/flex/grip/support, or perhaps return to its “pre-programmed” shape after delivery. Unlike other materials that may be chosen due to their strength or corrosion resistance, Nitinol completely transforms how a component can be shaped and delivered into the patient.  

Let’s review a few examples of Nitinol in action: 

Stents are an excellent example. A vascular stent must perform three core functions perfectly, in order:  

• Collapse into a small delivery-friendly geometry  
  

• Be inserted and travel safely through the patient vasculature and then, most importantly,  
  

• Expand with a controlled radial force into their “pre-programmed” geometry  

  
  
  
  

  

  Illustration of stent device within a vascular system. Credit: Wikimedia Commons

Another key area Nitinol is utilized is in the orthopedic world. Many orthopedic devices use nitinol’s shape-memory and superelastic behavior to create active compression across bone. Staples, plates, clips, and fixation devices can be designed so the implant applies a sustained compressive force after placement: extremely in procedures where bone segments need to be held together during healing, including osteotomies, arthrodesis, and fracture fixation. Nitinol’s elasticity is especially useful in anatomical areas that undergo constant movement such as in the feet (as opposed to a tibia bone, for instance).  

Consider how different this acts from a titanium or stainless fixation device that holds geometry because it is mechanically rigid. A nitinol implant can be designed to recover toward a programmed shape, helping maintain compression even as bone surfaces settle, small gaps close, or local loading changes.  

Nitinol's presence in stents and orthopedic fixture devices is fairly well-known, but it is also moving into smaller, more specialized device categories: 

• Guidewires and delivery systems: Nitinol’s flexibility and kink resistance help devices navigate challenging anatomy while maintaining what is called “pushability” and shape recovery  
  

• Neurovascular devices: Stent retrievers and clot-retrieval tools also rely on fine nitinol structures that can collapse for delivery through extremely small vessels, then expand to engage thrombus in the brain’s vasculature. Literature on neurovascular stent retrievers describes these devices as “nitinol structures designed to remove clots from blood vessels in the brain, with microfabricated surface features being explored to improve thrombectomy performance”. (NCBI)  
  

• Dental and orthodontic devices: Orthodontic archwires are a key nitinol application as they can apply relatively consistent corrective force over a useful range of deflection (setting teeth into certain shapes over prolonged periods).  

Application Area	Why Nitinol Matters	Manufacturing Pressure
Cardiovascular stents	Self-expansion, radial force, fatigue resistance	Thin struts, clean edges, consistent geometry
Heart-valve frames	Collapsible delivery and shape recovery	Complex frames, fatigue-loaded features
Orthopedic fixation	Shape recovery and sustained compression	Controlled edges, repeatable implant geometry
Guidewires and delivery systems	Flexibility, kink resistance, pushability	Long, slender, small-diameter features
Neurovascular devices	Delivery through tortuous anatomy and expansion at target site	Microfeatures, thin structures, high surface sensitivity
Dental and orthodontic devices	Consistent corrective force over a useful deflection range	Fine wire geometry, predictable spring behaviour

This increased range of nitinol usage across medical devices is, however, creating new challenges for manufacturers. But why is nitinol challenging to machine?  

Why nitinol is difficult to machine 

Machining micro-features like these in Nitinol can be challenging for conventional processes-- PECM is uniquely suited for them.

The “double-edged sword” allegory we utilize often—of extremely corrosion and heat-resistant materials like inconel being the precise reasons it is hard to machine—also applies to Nitinol, but for different reasons. Nitinol’s unique properties (being elastic, tough, heat-sensitive, and prone to strain-hardening) makes it fundamentally different on the workbench than other medical metals like stainless steel, Ti64, or cobalt-chrome. 

Research on electrochemical microslot machining states it is difficult to machine conventionally because of high strength, toughness, strain hardening, and heat generation. (MDPI) Those machining difficulties show up in several ways:  

First, consider mechanical cutting methods such as milling, drilling, and grinding. These methods are accustomed to applying force into a material that does not elastically recover. With Nitinol’s superelasticity, that creates unique problems with dimensional control, burr formation, surface roughness, and tool stability. For instance, nitinol resists predictable chip formation during machining. Instead of shearing cleanly, nitinol can deflect, recover, smear, or work-harden near the cutting zone, making it harder to maintain a stable tool-workpiece interaction-- notably on small features, thin sections, or flexible geometries. The result? Inconsistent surface roughness, faster degradation of cutting performance, and a higher risk that the machining process itself introduces the surface defects the device designer is trying to avoid are but a few consequences.  

Thermal processes like laser or EDM have their own tradeoffs. Laser cutting is widely used for the smaller nitinol devices including stent-like structures. In fact, a recent review of laser cutting of NiTi shape-memory alloys describes laser cutting as the most widespread cutting technology micro-nitinol devices (ScienceDirect). Laser cutting, EDM, and wire EDM avoid the cutting-force challenges of mechanical machining, but they remove material through highly localized heat. Nitinol’s very performance depends on maintaining uniform microstructure, transformation capabilities, and surface quality. Yet, surface irregularities commonly introduced from thermal machining (HAZ, recast, microcracks) can alter fatigue behaviour, or interfere with downstream finishing. For a material whose value comes from predictable recovery and repeated deformation, thermal damage near the finished edge can become a functional manufacturing concern. 

Finishing and postprocessing methods, while able to fix many of the aforementioned problems, come with their own challenges. Whether it's electropolishing, chemical finishing, blasting, tumbling, or abrasive methods, postprocessing may improve burrs or surface roughness but may also change critical dimensions, round edges, alter small features, or introduce variation across complex geometry. On a large part with a simple geometry, that might be manageable—but on a thin nitinol device like a mesh or a neurovascular device in the brain, the finishing process is absolutely essential.  

Why PECM fits the nitinol manufacturing problem 

Capability Area	PECM Relevance for Nitinol
Material fit	Electrically conductive nitinol and other advanced medical alloys require application-specific evaluation.
Best-fit geometries	Slots, grooves, mesh-like openings, thin-wall features, microfeatures, and difficult-access edges.
Process mechanism	Non-contact electrochemical material removal.
Thermal impact	No EDM-style recast layer from the PECM step.
Edge condition	Strong fit where burr reduction and edge consistency are central requirements.
Tooling behaviour	Cathode tooling with minimal tool wear compared with conventional cutting tools.
Scale-up relevance	Parallel feature processing for repeated patterns, arrays, and fine openings.
Production model	Process development, tooling, machine logic, and manufacturing pathway developed together.
Medical-device relevance	Useful where the finished feature affects deployment, fatigue performance, cleaning, or inspection strategy.

PECM, or pulsed electrochemical machining, approaches the problem differently. Instead of cutting nitinol with a mechanical edge or melting it with a thermal process, PECM removes conductive material through a controlled electrochemical reaction. 

That distinction may seem superfluous but genuinely matters: Nitinol machining problems often center on force, heat, burrs, tool pressure, recast, and surface integrity, but PECM reduces many of those mechanisms at the source, as the process does not rely on physical cutting contact between a tool edge and the workpiece. 

Nitinol fixture device machined via PECM

For conductive nitinol components, PECM is especially relevant when the geometry includes small slots, grooves, mesh-like openings, thin-wall features, internal features, or edges that cannot tolerate uncontrolled burrs. PECM also fits applications where laser or EDM processes create too much downstream burden because the customer must remove recast, manage thermal effects, or protect fine geometry during post-processing. 

As nitinol use expands across medtech, the manufacturing challenge is not limited to making one difficult feature once; OEMs increasingly need a credible path from prototype geometry to repeatable production. PECM is well suited to that scale-up problem because the process can machine multiple features in parallel rather than treating every slot, groove, or microfeature as a separate toolpath event. It also uses cathode tooling with minimal tool wear, supporting more stable feature replication across production runs than many conventional cutting processes. For nitinol components with repeated patterns, fine openings, or arrays of small features, that combination of parallel processing and reduced tooling degradation can shift PECM from a specialty development method into a scalable production strategy. 

The manufacturing takeaway 

Nitinol is gaining ground because medtech devices increasingly need to flex, recover, collapse, expand, and survive repeated loading. That is true in established categories such as cardiovascular stents and heart-valve frames. It is also true in newer or smaller applications such as neurovascular devices, steerable systems, microfeatured delivery tools, and advanced orthopedic fixation. 

But nitinol’s value depends on preserving the material behaviour that makes it useful. A poorly controlled manufacturing process can create burrs, recast, heat-affected surfaces, dimensional drift, or surface integrity problems that undermine the design intent. 

That is why nitinol should not be treated as just another difficult alloy. It is a functional material, and functional materials need manufacturing methods that protect function. 

For the right conductive nitinol application, PECM gives engineers another route: a non-contact, electrochemical process for producing difficult features without the same cutting-force and thermal-damage mechanisms found in many conventional workflows. As nitinol devices become smaller and more complex, that difference becomes more than a process detail. It becomes a design-enabling manufacturing strategy.