Material
PEEK Parts
For the jobs that melt, dissolve, or outgas everything else.
PEEK is the plastic specced when every other plastic disqualifies itself: continuous service near 480 °F, repeated steam sterilization, resistance to nearly every chemical on the shelf, and strength at the top of the thermoplastic range. It costs what it costs, and when the requirement is real, there’s rarely a cheaper material that survives. Send a STEP and print through the quote form for a quote in 24-48 hours.
Updated June 2026
PEEK
The high-performance plastic: shrugs off heat and chemicals that stop other plastics. Expensive stock; spec it deliberately.
Typical parts
- Seal & valve seats
- High-temp insulators
- Semiconductor fixtures
- Chemical-exposed parts
What PEEK survives
The short list reads like a torture test. Continuous service around 480 °F, where acetal and nylon are long gone. Steam and autoclave cycles, repeated for years, which craze polycarbonate and warp most engineering plastics. Chemical exposure across nearly the whole shelf: solvents, fuels, acids, and bases barely touch it, with concentrated sulfuric acid the famous exception. Add very low outgassing for vacuum work, inherent flame resistance, and good wear behavior, and it’s clear why medical, lab, and semiconductor work keeps it on the approved list.
Where it shows up
Medical and lab instrument components lead the list: parts that go through the autoclave every day, fluidic fittings and manifold internals, and biocompatible-grade hardware. Semiconductor and vacuum work follows, where low outgassing and freedom from metal ions matter. The rest is industrial: seal rings and back-up rings in hot assemblies, insulators that hold strength at temperature, and bushings in hot zones where acetal would slump.
Why it costs what it costs
PEEK stock is among the most expensive plastic sold, running tens of times the price of acetal by the pound, so a blank of it is costly before any cutting starts. Tight-tolerance PEEK work often adds stress-relieving steps to keep finished dimensions stable, which adds time. A modest PEEK part can quote like a metal part, and that’s the material, not padding.
The flip side: when the spec genuinely requires it, PEEK is routinely the cheapest thing that survives the job, because the alternative is exotic metal or scheduled replacement.
When Delrin is the better buy
Most of the time, honestly. If the part lives below about 180 °F, sees water or mild chemicals rather than steam and solvents, and never visits an autoclave, acetal delivers the slippery, stable, accurate-plastic behavior at a small fraction of the price. PEEK is bought by requirements, not prestige. Describe the environment in the quote notes, and if acetal covers it, the quote will say so.
Questions
Before you send a job.
01 Why is PEEK so expensive?
The resin itself: PEEK is difficult to polymerize and sells for tens of times the price of commodity engineering plastics, so most of a PEEK part’s price is the blank it starts as. Careful machining and stress-relief for tight tolerances add the rest. There’s no version of the job where that cost disappears, which is why the first question is always whether the part truly needs PEEK.
02 Is PEEK biocompatible or medical-grade?
Grades are the whole story. Industrial PEEK is the standard stock; USP Class VI and ISO 10993 certified grades exist for medical instrument work, and implantable grades are a separate, tightly controlled category. The certificate belongs to the specific lot of material, so name the requirement in the quote notes and the quote is built on stock that carries the right paperwork.
03 Can PEEK really be autoclaved over and over?
Yes; tolerance of repeated steam sterilization is one of the main reasons instrument parts get specced in it. PEEK shrugs off the cycles of heat, pressure, and moisture that gradually craze, cloud, or warp most other plastics. For parts with very tight fits, note the sterilization regime on the print so dimensions are checked with that service life in mind.
04 Should I spec filled or unfilled PEEK?
Unfilled is the default: the toughest version, and fine for most hardware. Glass-filled adds stiffness and dimensional stability at temperature, carbon-filled adds more stiffness plus better wear, and bearing grades blend in lubricants for sliding service. Fillers change cost and behavior, so spec them for a reason and note it on the print.
05 When is PEEK overkill?
Whenever no number on the spec demands it, which is most parts. Below about 180 °F in air or water, acetal does the slippery, stable plastic job at a small fraction of the cost, and if stiffness is the driver, aluminum is often cheaper than PEEK too. The honest test: name the requirement PEEK satisfies. If there isn’t one, the budget will thank you.
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