Non-thermal precision cutting
Why cold cutting matters: material integrity from prototype to production
In medical devices, the material you specify must behave exactly as specified, in the lab, in validation, and inside the patient. How you cut it decides whether it does.
The problem
What heat does to medical-grade alloys
Thermal cutting doesn’t just leave a surface defect. It creates a regulatory problem, a biocompatibility risk, and a potential failure point inside a human body.
Laser cutting · heat-affected zone
HAZ degrades fatigue life
Titanium’s thermal conductivity is roughly one-seventh that of aluminum, so heat can’t dissipate. It concentrates at the cut surface and permanently alters the microstructure. On laser-cut Ti-6Al-4V ELI, fatigue cracks initiate at that layer, and mechanical post-processing is required just to restore acceptable fatigue life.
EDM · recast layer
Recast layers seed micro-cracks
EDM’s plasma channel reaches 8,000 to 12,000°C, melting and re-solidifying a thin surface layer that is harder and more brittle than the base material. Fatigue cracks originate from micro-cracks, pores and inclusions inside that recast layer, and in nitinol or titanium, those defects are exactly where fatigue failure begins.
Thermal · residual stress
Residual stress & lost function
As the cut surface cools faster than the subsurface, differential contraction locks in tensile stress, distorting thin walls, shifting tolerances, and cutting corrosion resistance. For nitinol, thermal damage can shift transformation temperatures and degrade the superelastic behaviour the alloy was chosen for.
The regulatory dimension
It’s not only engineering. It’s compliance.
If your cutting process changes the material, you carry the burden of proving those changes are acceptable, every batch, every lot, every audit.
ISO 13485
Identify & control process risk
Cutting included. HAZ or micro-cracks demand documented evidence they fall within limits: validated testing, statistical process control, corrective action for every deviation.
FDA 21 CFR 820 · QMSR 2026
Conform to safety & effectiveness
Manufacturers must show surface features from cutting don’t compromise biocompatibility or mechanical performance. Final implant surface cleanliness is a critical safety property.
ASTM F86
Surface preparation of implants
Manufacturing methods must not introduce contaminants or unacceptable defects on metallic surgical implant surfaces.
ASTM F2063 · F1537
Composition & property limits
Nitinol and cobalt-chrome specifications set mechanical and compositional requirements that thermal degradation can violate.
Cold cutting removes the defect, and the documentation burden that comes with proving it’s acceptable.
The solution · micro-abrasive waterjet
A cold cutting process
Material is removed by erosion: a fine stream of water and abrasive garnet at ultra-high pressure, with no thermal energy transferred to the workpiece.
No heat-affected zone
The microstructure at the cut edge is identical to the bulk material. No altered phases, no recast layer, no thermal gradient.
No micro-cracks
Without thermal shock or rapid re-solidification, the crack-initiation mechanisms of laser and EDM cutting simply don’t exist.
No residual stress
No differential thermal contraction means parts come off the machine dimensionally stable.
Preserved properties
Nitinol keeps its superelasticity. Titanium keeps its fatigue life. Cobalt-chrome keeps its corrosion resistance. The material you specified is the material you get.
Cutting accuracy
Held across the full range of medical device materials. Clean, burr-free edges that meet biocompatibility requirements without secondary thermal post-processing.
Materials cut on the Finecut micro-abrasive waterjet
From proof of concept to production
Same process, same results
Switch cutting methods between prototype and production and you revalidate: new parameters, new surface characterisation, new risk assessment, new documentation.
Prototyping
First cuts on real material & geometry.
Design verification
Same machine, same response.
Validation · IQ/OQ/PQ
Same validated parameters.
Production
Identical results at scale.
No process-transfer surprises.
Start with proof, not projections
Start with a proof of concept on your material.
If you’re cutting titanium, nitinol, cobalt-chrome or any medical-grade material, and dealing with HAZ, micro-cracks, or post-processing that adds cost and risk, a proof of concept will show what cold cutting does for your specific geometry and material.
Same precision. No thermal compromise. From first cut to full production.
References
- Sharma, A., et al. (2022). A comprehensive review on metallic implant biomaterials and their subtractive manufacturing. Int. J. Advanced Manufacturing Technology. PMC 8865884. link
- Mzopogiannis, A., et al. (2019). Fatigue behavior of non-optimized laser-cut medical-grade Ti-6Al-4V-ELI sheets. Metals, 9(8), 843. link
- Li, Z., et al. (2025). Recast layer-induced fatigue degradation in high-speed EDM microholes. PMC 12072793. link
- Zhao, X., et al. (2024). Study on forming mechanism of the recast layer during micro EDM. PMC 10933879. link
- ASTM F2063, Wrought nickel-titanium shape memory alloys for medical devices & surgical implants.
- ASTM F86, Surface preparation & marking of metallic surgical implants.
- ASTM F1537, Wrought cobalt-28chromium-6molybdenum alloys for surgical implants.
- FDA Quality Management System Regulation (QMSR), 21 CFR Part 820. link
Note: FDA 21 CFR Part 820 / QMSR is United States federal regulation, applying to manufacturers placing medical devices on the US market, not an international standard. Its requirements are substantively aligned with ISO 13485:2016; manufacturers certified to one are generally well-positioned to meet the other.
