# Ultem and PEI in Manufacturing
Ultem is a trade name for polyetherimide, and 1000 unfilled and 2300 glass-filled are different materials with different stiffness and machining behaviour. Coolant choice matters more than tooling because the polymer stress cracks.

# Ultem and PEI in Manufacturing

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Ultem is a trade name for polyetherimide, and 1000 unfilled and 2300 glass-filled are different materials with different stiffness and machining behaviour. Coolant choice matters more than tooling because the polymer stress cracks.

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This is the engineering plastic where the machining failure is chemical rather than mechanical, which catches shops treating it as a stiff nylon. The programme argument is in [manufacturing SEO](/manufacturing-seo).

## The grades a drawing calls

**Polyetherimide is the polymer and Ultem is the trade name**, and a drawing may carry either. Naming both on a page matches both strings.

**Ultem 1000 is the unfilled grade**, transparent amber, used where dielectric properties and dimensional stability matter. **Ultem 2300 carries 30% glass fill**, stiffer and more stable at temperature and considerably more abrasive to tooling.

**A flame rating is why this material is specified** in aerospace interiors and electrical enclosures, and the rating belongs to the grade rather than to the polymer family.

## What drives the quote

**Stress cracking is the failure mode that ruins parts after machining rather than during it.** Polyetherimide is susceptible to attack from some cutting fluids and solvents, and a part that looks correct at inspection can craze days later.

That makes coolant selection a real capability rather than a shop preference. **A shop that has run polyetherimide knows which fluids are compatible**, and one extrapolating from aluminium practice discovers the problem in the field.

**Annealing relieves machining stress** and is specified where the part must hold dimension or resist cracking in service.

Glass fill raises tool wear in the same way it does in PEEK, so the filled grade quotes differently from the unfilled one on tooling rather than on time.

## What a capability page should state

**A capability page must state process, materials, tolerances, capacity, certifications, and industries served**, and polyetherimide belongs there by grade with the trade name alongside.

State whether the shop anneals, which coolants it runs for polymer work, and whether it segregates polymer machining from metal. Where parts serve electrical assemblies, the requirements at [industrial automation and robotics](/industries/industrial-automation) apply alongside.

The structure is at [capability page structure](/content/capability-page-structure) and the cluster reasoning at [materials](/materials).

## Common questions

**Is Ultem the same as PEI?**

Ultem is a brand of polyetherimide. Naming both is the safest form since drawings use either.

**Why does coolant matter so much?**

The polymer stress cracks in contact with some fluids, and the damage appears after the part leaves. It is the failure that reaches a shop as a return.

**Which grade for electrical work?**

Usually 1000 for dielectric properties, and 2300 where stiffness and thermal stability matter more.

**Does it need annealing?**

Where dimension or crack resistance matters in service. It is a specified step rather than a default.
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Source: https://manufacturingseo.ai/materials/ultem-pei/
Last reviewed: 2026-08-11
Author: ManufacturingSEO.ai