ULTEM (PEI) (UNS PEI-1000) is a moderate-to-machine material that we run regularly for export customers. It has a density of 1.27 g/cm3, a tensile strength of 105 MPa and a typical hardness of M 109 (Rockwell). Those numbers make it the right choice for aircraft interiors and medical trays, and a poor choice when cost or corrosion resistance matters more than mechanical performance.
On our machines we hold +/-0.02 mm on turned and milled features and reach Ra 0.8 um where the drawing calls for it. Standard lead time for ULTEM (PEI) parts is 3-7 working days, including material procurement, machining and any finishing operation you specify.
ULTEM (PEI): key properties
| Property | Value |
|---|---|
| UNS / designation | PEI-1000 |
| Density | 1.27 g/cm3 |
| Tensile strength | 105 MPa |
| Hardness | M 109 (Rockwell) |
| Machinability | Moderate |
| Suggested cutting speed (carbide) | 150-300 m/min |
| Relative material cost | 5 of 5 |
Machining ULTEM (PEI): what to plan for
- Not for long UV exposure
- Stress cracking with solvents
- High cost
Cutting speed for ULTEM (PEI) with carbide tooling sits around 150-300 m/min. Going faster burns the edge; going much slower causes rubbing and a poor surface. Air blast or flood coolant both work, but chip evacuation must be positive. If your part has thin walls or a lot of stock to remove, say so in the RFQ — we plan roughing, stress relief and finishing as separate operations when the geometry demands it.
Parts we machine in ULTEM (PEI)
- Aircraft interiors
- Medical trays
- Sterilisable parts
- Electrical housings
Most ULTEM (PEI) work arrives as 2D drawings with a mix of critical and non-critical features. Loosening tolerance on the non-critical ones is the fastest way to cut cost, and we will tell you which features those are before we quote.
Tolerances, finish and lead time
| Item | Capability |
|---|---|
| General tolerance | +/-0.02 mm |
| Achievable surface finish | Ra 0.8 um |
| Minimum wall thickness | 0.8 mm (aluminium) / 1.0 mm (steel and stainless) |
| Typical lead time | 3-7 working days |
| Prototype quantity | 1 piece |
| Production quantity | 10 to 50,000 pieces |
Frequently asked questions
What is the lead time for ULTEM (PEI) parts?
Standard is 3-7 working days from drawing release, assuming the material is in stock. Exotic grades and cast forms can add 5 to 10 days. Finishing such as anodizing or plating adds 3 to 5 days.
What tolerance can you hold in ULTEM (PEI)?
+/-0.02 mm is routine on turned and milled features. Tighter than that is possible on specific features by grinding or lapping, but it is quoted separately because it changes the process.
Do you keep ULTEM (PEI) in stock?
We hold common sizes of ULTEM (PEI) and buy mill-certified stock for everything else. Material certificates are supplied with the parts on request.
Can you supply ULTEM (PEI) parts with a certificate of conformity?
Yes. We issue a dimensional report, a material certificate and a certificate of conformity as standard for production orders, and full PPAP or AS9102 paperwork when the programme requires it.
Related pages
- Materials — the full index for this section.
- PMMA Acrylic CNC Machining: Clear Optical Parts
- 6061 Aluminum CNC Machining: Specs, Tolerances, Cost
- PPS CNC Machining for High-Temperature Parts
- 7075 Aluminum CNC Machining: Aerospace-Grade Parts
- Instant CNC quote
- Tolerance quick reference
- Frequently asked questions
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