PEEK Machining Services
PEEK MACHINING SERVICES
CNC PEEK Machining for Metal-Class Tolerances
PEEK is the only polymer we machine that holds metal-class tolerance, and it will only do it under conditions most shops do not talk about. ±0.0002" on a critical dimension is genuinely achievable from annealed stock, in a temperature-controlled environment, with the part allowed to equilibrate before it is inspected. Skip any of those and you are quoting a number you cannot hold.
Steelcrest machines unfilled, glass filled and carbon filled PEEK for medical, aerospace and semiconductor customers, with annealing performed in-house and UDI laser marking available on the same site.
PEEK Grades We Run
| Grade | Tooling | Character |
|---|---|---|
| Unfilled PEEK | C-2 carbide minimum | Best machinability of the three and the best surface finish, at Ra 0.8–1.6 µm. Thermal expansion two to four times steel. |
| 30% glass-filled PEEK | PCD recommended, required for production | Stiffer and more dimensionally stable, but tool life runs 50 to 70 percent shorter than unfilled. |
| 30% carbon-filled PEEK | PCD mandatory | The most abrasive. Best achievable finish is Ra 1.6–3.2 µm because of fibre pull-out but thermal expansion drops to around 5 µm/m·°C, which makes it MORE dimensionally stable than aluminium. |
Tolerances We Hold On PEEK
| Tolerance band | When it applies | What it requires |
|---|---|---|
| ±0.005" | Non-critical features | Standard practice |
| ±0.001" | Standard machined features | Stress-relieved or annealed stock |
| ±0.0002" | Critical dimensions | Annealed stock, a shop held at 20°C ±2°C, and four hours or more of thermal equilibration before final inspection |
NOTE*: On any PEEK drawing tighter than ±0.002", the inspection temperature belongs on the drawing. Without it the tolerance is not measurable in a way both parties can agree on.
Annealing Is Mandatory, Not Optional
This is the part most suppliers leave out. PEEK stock carries extrusion stress, and machining adds thermal stress on top of it. A part machined from unannealed stock will move sometimes on the machine, more often days later.
Our annealing protocol: pre-dry at 150°C for a minimum of three hours, ramp at 10°C per hour to 200–250°C, soak for three to four hours at four hours per inch of wall thickness, cool at 10°C per hour to below 140°C, then allow natural cooling. On parts with heavy material removal we anneal again after roughing, before finishing, which prevents the warping that otherwise shows up during the finish pass.
We perform PEEK annealing in-house within our furnace capability. Confirm the specific ramp rate requirement with us at RFQ on parts with heavy wall sections.
How We Machine PEEK
Swiss turning covers small medical instruments and components details up to Ø1.5" bar. Conventional and precision turning covers larger round work, with live-tool and Y-axis platforms for cross-features. Milling runs across our vertical, horizontal and 5-axis centers, and INTEGREX multi-tasking handles one-hit mill-turn parts.
Tooling is grade-dependent: C-2 carbide minimum on unfilled, PCD recommended on glass-filled and mandatory on carbon filled. Positive rake between 6 and 12 degrees with 5 degrees of relief, kept sharp. Unfilled PEEK runs at 300 to 800 surface feet per minute at 0.004" to 0.025" per revolution; reinforced grades drop to 120 to 180 SFM at 0.004" to 0.012".
Coolant is an application decision. Flood coolant extends tool life meaningfully, but medical and implant work is often machined dry with cold air to avoid coolant residue and the validated-cleaning burden it creates. Tell us which regime your part requires.
Finishing and Post-Processing
Machining, marking, and inspection stay in-house, and we manage PEEK-specific services like sterilization validation and cleanroom packaging through qualified outside partners.
In-house at Steelcrest
- Annealing and stress relief of stock and semi-finished parts
- Laser etching for UDI marking, lot codes and traceability
- Deburring, CMM and FARO Arm inspection
Managed through qualified partners
- Steam, gamma and EtO sterilisation validation for medical components
- Cleanroom packaging where the application requires it
Industries We Machine PEEK For
Steelcrest Precision machines unfilled, glass-filled, and carbon-filled PEEK for aerospace and defense and medical and pharmaceutical applications, where the material replaces metal at a fraction of the weight.
We also machine PEEK for chemical processing and semiconductor customers, where its chemical resistance and in the carbon-filled grades its exceptional dimensional stability are the reasons it is specified.
Talk To Us About Your PEEK Parts.
Send the drawing and the quantity. We will come back with a real number, a real lead time, and if there is a better material or condition for what the part has to do we will tell you that too.
Frequently Asked Questions
How tight a tolerance can you hold on PEEK?
±0.0002" on critical dimensions, which is genuinely metal-class and unusual for a polymer. It requires annealed stock, a temperature-controlled environment at 20°C ±2°C, and four or more hours of thermal equilibration before final inspection. ±0.001" is the standard band without those controls.
Do you anneal PEEK?
Yes, in-house. Pre-dry at 150°C, slow ramp to 200–250°C, soak at four hours per inch of wall, then slow cool. On parts with heavy material removal we anneal again between roughing and finishing.
Which PEEK grade should I specify?
Unfilled for the best surface finish and easiest machining. 30 percent glass-filled for stiffness and dimensional stability. 30 percent carbon-filled where dimensional stability is critical its thermal expansion is around 5 µm/m·°C, better than aluminium accepting a rougher achievable finish from fibre pull-out and significantly higher tooling cost.
Can you machine PEEK dry for medical parts?
Yes. Dry machining with cold air avoids coolant residue and the validated-cleaning burden that comes with it, which is why it is common on implant and instrument work. Tell us at RFQ which regime your part requires.
Can you laser mark PEEK for UDI?
Yes, in-house on our Tykma Vereo fiber laser marker with rotary attachment.