Medical device CNC machining sits at the intersection of tight geometry and clean, documented process. A surgical instrument, an implant component, or a fluid-path fitting has to be dimensionally correct, made from the right biocompatible alloy, finished without contamination, and backed by records. This guide covers the materials, finishes, cleanliness expectations, validation, and cost drivers for precision medical CNC parts.
Materials for Medical Device Machining
Material selection drives biocompatibility, corrosion resistance, and how the part behaves in service. Common grades in medical CNC machining:
- 316L and 316LVM stainless: instruments, fasteners, and fluid-path parts
- 17-4 PH stainless: load-bearing instrument components
- Titanium Ti-6Al-4V and CP titanium Grade 2: implantable and structural parts
- PEEK and Ultem: polymer components where imaging transparency or weight matters
- Cobalt chrome: high-wear articulating components
Each lot ships with a certificate of conformance and mill test report so the alloy and heat lot are documented. We machine to DFARS-compliant material with made-in-USA stock.
Tolerances and Surface Finish
Medical parts frequently combine fine features with tight fits. Typical production ranges:
- General features: +/-.002 in to +/-.005 in
- Sealing and bearing diameters: +/-.0005 in to +/-.001 in
- Fine instrument features: +/-.0002 in to +/-.0005 in
Surface finish matters for cleaning, sealing, and tissue contact. Common callouts run Ra 32 uin for general surfaces, Ra 16 uin for sealing faces, and Ra 8 uin or better for polished contact surfaces. Reaching a fine finish on 316L or titanium adds finishing passes and, in some cases, secondary electropolish or passivation.
Small and Slender Parts
Bone screws, cannulas, pins, and connectors are often long and thin. Parts under roughly 1.25 in diameter with high length to diameter ratios are a natural fit for Swiss machining, where guide-bushing support holds tolerance on features that would deflect on a conventional lathe. For larger turned parts, CNC turning handles housings, spacers, and fittings, while CNC milling handles complex instrument bodies.
Cleanliness and Handling
Medical machining is as much about what does not end up on the part as what does. Practical cleanliness controls include:
- Segregated coolant and tooling for reactive alloys like titanium to avoid cross contamination
- Passivation of stainless per ASTM A967 to restore corrosion resistance after machining
- Deburring and edge control so there are no loose particles or sharp transitions
- Controlled handling and packaging to protect finished surfaces
We are ISO 9001-aligned in our process controls, which keeps documentation, calibration, and revision control consistent from job to job.
Validation and Inspection
Medical buyers expect proof, not assurances. Our inspection flow supports that:
- First article inspection with a ballooned drawing and a numbered report for every characteristic
- In-process checks at defined frequencies to catch drift before it becomes scrap
- Final CMM inspection on our Brown & Sharpe coordinate measuring machine for critical dimensions and GD&T
- Documentation package with material certs, inspection reports, and certificate of conformance
For device makers who need process capability data, we can report measured characteristics across a sample to support your own validation work. See our inspection and quality capabilities for detail.
Medical Device CNC Machining Cost Drivers
The table below shows typical illustrative estimates for a mid-complexity 316L instrument component in a lot of 50 to 250 pieces. These are planning ranges, not binding quotes.
| Cost Driver | What It Covers | Typical Range |
|---|---|---|
| Setup | Programming, fixturing, first-piece proveout | $250 to $1,000 per setup |
| Material | Certified 316L or titanium bar stock | $4 to $45 per part |
| Machine time | Cycle time at shop rate | $6 to $30 per part |
| Finishing | Passivation, electropolish, deburr | $3 to $20 per part |
| Inspection | FAI plus sampling CMM reports | $150 to $500 per lot |
Titanium and cobalt chrome push machine time and tooling up because of slower speeds and higher tool wear. Fine polished finishes and electropolish add finishing cost, and full documentation packages add inspection cost. Higher volumes lower the per-part setup share.
Lead Times
Proven medical parts typically ship in 3 to 5 weeks, with first articles adding 1 to 2 weeks for the layout and documentation. Stocked 316L parts without secondary finishing can move faster.
Machining Medical Parts in Canastota, New York
Wexmar runs turning, milling, and Swiss with in-house CMM inspection in Canastota, NY. We machine biocompatible alloys with certified material, ship nationwide, and are SAM.gov and CAGE registered. Start with our instant quote and attach your drawing, material, and finish callouts.