--- title: "PEEK CNC Machining | High-Temp Engineering Plastic Parts | OpenSpindle" description: "Get quotes for custom PEEK parts from independent machine shops. Unfilled, GF30, and CF30 grades machined for high-temperature, chemical, and wear service. Upload a drawing." canonical: https://openspindle.com/materials/peek --- # Custom PEEK parts from independent machine shops PEEK is the high-performance thermoplastic engineers reach for when a part must survive heat, chemicals, and load that would soften common plastics. Upload a drawing and hear back from shops that machine unfilled, glass-filled, and carbon-filled PEEK to tight tolerances. ## PEEK shops on OpenSpindle Real shops that machine PEEK and other high-performance plastics. See their equipment and talk to the person making your part. [Browse all PEEK shops](https://openspindle.com/manufacturers?material=PEEK) ## PEEK grades shops run most The filler sets stiffness, wear behavior, and cost. Unfilled is the general-purpose choice; filled grades trade toughness for strength and stability. If yours is not here, ask when you request a quote. ### Unfilled PEEK Natural tan (or black) general-purpose grade with the best toughness and elongation of the family. Machines cleanly and takes the tightest detail. The default unless you need added stiffness or wear resistance. **Best for:** Seals, insulators, general high-temp and chemical parts ### PEEK-GF30 30% glass-fiber reinforced for higher stiffness, better dimensional stability, and improved creep resistance at temperature. Less abrasive on tooling than carbon-filled, but more brittle than unfilled. **Best for:** Structural parts, fittings, dimensionally stable brackets ### PEEK-CF30 30% carbon-fiber reinforced for the highest strength and stiffness in the family, with improved wear and higher thermal conductivity. ESD-safe variants exist for electronics handling. **Best for:** High-load structural, wear, and static-dissipative parts ### PEEK-HPV / bearing grade Blended with PTFE, graphite, and carbon fiber for low friction and long wear life in dry running or lightly lubricated service. Trades some strength for a slick, self-lubricating surface. **Best for:** Bushings, bearings, wear pads, valve seats ### Medical-grade PEEK Implantable and biocompatible grades (for example PEEK-OPTIMA) supplied with documentation for surgical and long-term contact use. Sourced and traced separately from industrial stock, so call it out early. **Best for:** Surgical instruments, spinal and orthopedic implants ## Material Properties Representative values for unfilled PEEK. Filled grades raise stiffness and wear resistance while lowering elongation. | Property | Value | | --- | --- | | Density | ~1.32 g/cm³ (0.048 lb/in³) | | Tensile strength (unfilled) | ~14 ksi (100 MPa) | | Max continuous service temp | ~250 °C (480 °F) | | Glass transition / melt | ~143 °C Tg, ~343 °C melt | | Coefficient of friction / wear | Low friction, excellent wear (better in bearing grades) | | Chemical resistance | Outstanding; attacked mainly by concentrated sulfuric acid | | Moisture absorption | Very low, ~0.1 to 0.5% | | Machinability | Good, but stress-relieve (anneal) for tight tolerances | PEEK is one of the most expensive machinable thermoplastics, so most parts are cut from solid rather than molded in low volume. Internal stresses in the stock can cause parts to move as material is removed, which is why annealing before and between machining steps matters on toleranced features. ## Stock Forms - **Plate & block** -- Milled housings, insulators, and prismatic parts from solid. - **Round bar** -- Turned seals, bushings, spacers, and fittings. - **Sheet** -- Thinner insulators, gaskets, and flat machined parts. ## Processes That Run This Material - [CNC Machining](https://openspindle.com/capabilities/cnc-machining.md) -- Milled insulators, manifolds, and prismatic parts from plate and block. - [CNC Turning](https://openspindle.com/capabilities/cnc-turning.md) -- Turned seals, bushings, and valve seats from round bar. - [Swiss Machining](https://openspindle.com/manufacturers?capability=Swiss%20machining) -- Small, high-precision PEEK components in volume. - [5-Axis Machining](https://openspindle.com/manufacturers?capability=5-axis%20milling) -- Complex PEEK geometry in a single setup with fewer re-fixtures. - [Waterjet Cutting](https://openspindle.com/manufacturers?capability=Waterjet%20cutting) -- Cold cutting of thick PEEK plate with no heat-affected edge. - [3D Printing](https://openspindle.com/manufacturers?capability=3D%20printing) -- High-temp filament printing where geometry beats machined strength. ## Finishes PEEK almost always ships as-machined; it needs no coating to resist heat, chemicals, or wear. The real decisions are stock color and annealing. - **As-machined** -- The standard. PEEK is chemically and thermally stable on its own, so most parts need no surface treatment. Ships fastest. - **Annealing / stress relief** -- The key process step for tolerance-critical PEEK. A controlled heat cycle relieves internal stresses so parts hold size and flatness after material is removed. Done before and between machining passes on tight features. - **Natural (tan) vs black stock** -- Unfilled PEEK is natural tan; filled and pigmented grades are black. Color is a stock and grade choice, not a coating, so specify it with your grade. - **Bead blast** -- An optional uniform matte texture where a non-glossy machined surface is preferred. Purely cosmetic on PEEK. PEEK is not plated or anodized. If tolerances are tight, note them clearly so the shop can plan annealing into the process. ## Applications - Aerospace - Medical & surgical implants - Semiconductor & wafer handling - Oil & gas / downhole - High-temp electrical insulators - Pump & valve seats - Bearings & bushings - Analytical & lab equipment PEEK earns its cost wherever a plastic has to hold up to heat, chemicals, or wear that would destroy commodity grades. ## How It Compares How PEEK stacks up against the other machinable plastics and metals shops quote most. ### [Delrin (acetal)](https://openspindle.com/materials/delrin.md) - PEEK survives far higher temperatures (~250 °C vs ~90 °C continuous) and much harsher chemicals - Delrin machines faster, holds tight tolerances easily, and costs a fraction of PEEK - Both have low friction and good wear, but PEEK keeps its properties under heat and load **Verdict:** Choose Delrin for everyday precision parts at low cost. Choose PEEK when the part sees high temperature, aggressive chemicals, or sustained load. ### [Nylon](https://openspindle.com/materials/nylon.md) - PEEK is far more thermally and chemically stable and absorbs almost no moisture - Nylon is tougher in impact, cheaper, and easier to source, but swells as it takes on moisture - Nylon dimensions drift with humidity; PEEK holds size in wet or hot service **Verdict:** Choose nylon for tough, low-cost parts in mild environments. Choose PEEK when dimensional stability, heat, or chemical exposure rule nylon out. ### [Aluminum](https://openspindle.com/materials/aluminum.md) - PEEK is lighter, an electrical insulator, and does not corrode in chemical service - Aluminum is far stiffer and stronger, conducts heat, and costs much less to machine - PEEK replaces metal to cut weight, isolate electrically, or remove galvanic and corrosion problems **Verdict:** Choose aluminum for stiffness, strength, and cost. Choose PEEK to lightweight, insulate, or eliminate corrosion where a metal part struggles. ## Frequently Asked Questions ### What is the difference between unfilled, glass-filled, and carbon-filled PEEK? Unfilled PEEK has the best toughness and elongation and machines to the finest detail, so it is the general-purpose choice. PEEK-GF30 adds 30% glass fiber for higher stiffness and dimensional stability with less tool wear than carbon. PEEK-CF30 adds 30% carbon fiber for the highest strength and stiffness plus better wear and thermal conductivity, with ESD-safe variants available. ### What temperature can PEEK handle? Unfilled PEEK has a continuous service temperature around 250 °C (480 °F), far above common engineering plastics. Its glass transition is near 143 °C and it melts around 343 °C. Filled grades hold stiffness even better at elevated temperature, which is why PEEK is used in aerospace, downhole, and semiconductor applications. ### Why does PEEK need to be annealed before or after machining? PEEK stock carries internal stresses from how it is produced, and removing material lets those stresses relax, so parts can bow or shift after machining. A controlled annealing (stress-relief) heat cycle before and between machining passes lets the part settle so it holds size and flatness. This matters most on thin, asymmetric, or tightly toleranced features. ### Is PEEK chemically resistant? Yes. PEEK resists nearly all industrial chemicals, solvents, hydrocarbons, and hot water or steam, and it barely absorbs moisture (roughly 0.1 to 0.5%). The main exception is concentrated sulfuric acid, which attacks it. This broad resistance is a large part of why it is chosen for oil and gas, semiconductor, and lab equipment. ### Can PEEK be used for medical or implantable parts? Yes. Biocompatible and implant-grade PEEK (such as PEEK-OPTIMA) is used for surgical instruments and long-term implants like spinal cages. These grades are sourced and traced separately from industrial stock and come with documentation, so identify medical use up front so the shop can quote the correct material and handling. ### Why is PEEK so expensive compared to other plastics? PEEK is one of the most costly machinable thermoplastics because the raw polymer is expensive to produce and the stock is priced accordingly. Machining adds cost too, since tight-tolerance parts often need annealing steps and careful cutting. It pays off when cheaper plastics cannot survive the temperature, chemicals, or load, or when it replaces a heavier metal part. ### What file formats should I send for a PEEK part? STEP, IGES, X_T, DWG, DXF, or a dimensioned PDF. Include the grade (for example unfilled PEEK, PEEK-GF30, or PEEK-CF30), critical dimensions and their tolerances, quantity, and any special requirements such as ESD grade, medical documentation, or annealing for tight features. ## Related Materials - [Delrin](https://openspindle.com/materials/delrin.md) - [Nylon](https://openspindle.com/materials/nylon.md) - [Aluminum](https://openspindle.com/materials/aluminum.md) - [Titanium](https://openspindle.com/materials/titanium.md) - [Stainless Steel](https://openspindle.com/materials/stainless-steel.md) - [Brass](https://openspindle.com/materials/brass.md) ## Get PEEK part quotes Upload a drawing once and compare quotes from independent shops that machine unfilled, glass-filled, and carbon-filled PEEK.