Compare PEEK, PAI and PEI using the same application description and evidence for the actual grade and supplied form. A useful selection relates load, temperature, environment, function and acceptance. Ranking three polymer names by a catalogue temperature or reputation leaves open whether the data applies to the component.
Prepare an application record before choosing a winner
PEEK is polyetheretherketone, PAI polyamide-imide and PEI polyetherimide. They are different families, each containing different formulations. The family name does not define reinforcement, wear modification, supply form or the scope of a compliance record.
Manufacturer examples make this clear: Victrex separates unreinforced 450G from tribological 450FC30 PEEK; Syensqo distinguishes PAI references such as 4203L and 4301; SABIC differentiates PEI ULTEM 1000 and 2300. These are documentation examples, not PomDepot inventory or automatic project recommendations. The actual offer must confirm identity, form and applicable evidence.
Ask the same questions of each candidate
| Requirement | Common input | Evidence to retain |
|---|---|---|
| Load and time | Stress type, duration, cycles and permissible deformation | Grade data under relevant conditions; distinguish short tests from sustained service |
| Temperature | Operating conditions, peaks, duration and environment | Meaning of each reported value and its test method |
| Contact and wear | Counterface, finish, motion, lubrication and contamination | Test conditions and wear or friction criterion |
| Chemicals and moisture | Medium, concentration, exposure and material state | Grade/condition-specific evidence, without borrowing another specimen’s result |
| Electrical function | Required property and design-defined conditions | Applicable method and documentation for grade, variant and geometry |
For an empty field, identify who can supply the missing information. Do not fill an unknown with a favourable assumption. This record also reveals incomparable offers: one may document resin, another a stock shape and another a tested component.
Use each family to frame a specific question
PEEK: establish whether the candidate is unreinforced, reinforced or modified for sliding contact. For moving contact, request relevant counterface and test data; a strength value is not a contact-life prediction. References: 450G and 450FC30.
PAI: ask about the actual product’s supply, moisture and processing condition. Syensqo’s information explains why these aspects matter. Do not transfer a procedure or result from another product without checking applicability.
PEI: identify grade and required property, particularly where electrical or fire-behaviour requirements apply. Read ULTEM 1000 and 2300 data within their conditions and limitations, not as universal component acceptance.
Two applications need different records
A sliding guide needs a contact, motion and permissible-change description. An electrical spacer needs its function and the requirements the technical authority must verify. Temperature being relevant to both parts does not make their acceptance criteria equivalent or justify choosing the same material by habit.
A comparison may properly end with an unanswered question instead of an immediate selection. That is preferable to a conclusive-looking table mixing methods, forms or conditions. Where functional or compatibility testing is needed, define it separately from purchasing material.
Information for a PEEK, PAI or PEI enquiry
- Component function and a drawing or sufficient description.
- Material family, reference grade and permitted alternatives.
- Purchase form, dimensions, quantity and required records.
- Known operating conditions and unresolved inputs.
- Acceptance criteria and the person responsible for validation.
Review PEEK, PEI and the family catalogue, or send a material enquiry for PAI or another reference. Confirm availability and documents for the actual offer. This article promises no prices, inventory, component manufacture, certification or approved substitution.
Frequently asked questions
Which is best: PEEK, PAI or PEI?
The family alone cannot answer. Compare actual grades against the same requirements, methods and application conditions, keeping missing verification explicit.
Are the example grades available from PomDepot?
Availability is not confirmed here. These are manufacturer documentation examples. A quotation must identify the actual grade, form and documents offered.
Can I request a substitution using only a material name?
You can start an enquiry, but approval needs component information and criteria defined by your technical authority. A commercial response is not design validation.