GlossaryKind of term: Manufacturing termPEEK
What is PEEK?
PEEK (polyetheretherketone) is a high-performance engineering plastic that keeps its strength at high temperature and resists many chemicals and steam.
PEEK is semi-crystalline; its stiffness also holds up well under heat, and it withstands radiation as well. It comes unfilled, glass filled or carbon filled, as plate, rod and tube. Filled grades are stiffer and more stable but wear tools faster. Implant work uses separate grades with their own documentation, and there are antistatic grades for semiconductor equipment. Applications include medical instruments, semiconductor and vacuum parts, pumps, valves and insulators.
How does PEEK behave in the shop?
The price per kilo is far higher than for POM or nylon, so allowance, clamping margin and saw loss weigh heavily; how heavily depends on blank size, quantity and machining time. For tight tolerances, annealing before finishing is common practice, which adds a step and lead time to the route. Filled grades call for carbide or, with carbon fibre, often diamond tooling. Heat from the cut can cause stress and dimensional error, so sharp tools and limited heat input matter. Medical work comes with a certificate or batch documentation, traceable to the stock.
What is PEEK often confused with?
PEEK is not PEI or PPS: those are high-temperature plastics too, but with different temperature limits, chemical resistance and price. Unfilled and carbon-filled PEEK also differ: the fibre makes it stiffer and stronger but also more abrasive, and its properties can differ with direction.
Frequently asked questions
Why is PEEK so expensive?
The raw material and its production cost far more than POM or nylon. On a PEEK part the material can therefore cost more than the machining, and every millimetre of allowance counts.
How do you machine PEEK to tight tolerances?
Rough it, anneal to relieve stress, then finish to size with sharp tools and little heat. Use carbide or diamond for filled grades. Put the annealing step and the extra setup into the route and the schedule.