🧪 PEEK
PEEK Machining and Supply in Bath, ME — Unfilled, Glass-Filled, and Carbon-Filled Grades
Polyether ether ketone — PEEK — occupies a performance tier in engineering plastics that nothing else in the polymer family matches: continuous service temperature to 480 degrees Fahrenheit, chemical resistance that survives virtually every solvent and hydraulic fluid used in shipboard systems, and mechanical properties that rival aluminum in specific stiffness. For Bath, Maine's defense and naval manufacturing community, PEEK is not an exotic substitute material — it is the go-to choice when metal wear, corrosion, electrical conductivity, or weight drives a redesign into high-performance polymer territory.
AS9100ISO 9001ITAR
PEEK Grade Selection for Naval and Defense Applications
Three PEEK grades cover the meaningful performance range for Bath-area defense procurement. Unfilled PEEK — also called neat PEEK — is the base grade with no reinforcing filler, providing the highest chemical resistance, best electrical insulation properties, and FDA/USP Class VI biocompatibility in the PEEK family. Tensile strength is 14,500 psi and continuous service temperature is 480 degrees Fahrenheit. Unfilled PEEK is specified for electrical standoffs and insulators, chemical-resistant bushings in corrosive fluid systems, and any component where the purity and inertness of the polymer must be maintained — environments where glass or carbon filler particles would contaminate the fluid or the contact surface.
Glass-filled PEEK (typically 30 percent short glass fiber by weight) boosts tensile strength to 24,000 psi and stiffness from 550,000 psi to 1,400,000 psi, at a modest reduction in chemical resistance and a significant increase in abrasion resistance at the workpiece interface. For structural brackets, high-load bearing pads, and stiff electrical housings where dimensional stability under mechanical load is as important as chemical resistance, 30 percent glass-filled PEEK delivers more consistent performance than unfilled. The glass fibers also dramatically reduce the coefficient of thermal expansion — from 26 micrometers per meter per degree Celsius for unfilled PEEK to 14 micrometers per meter per degree Celsius for 30 percent glass-filled — a critical advantage for precision fits in mixed-material assemblies that cycle through temperature ranges.
Carbon-filled PEEK (30 percent short carbon fiber by weight) takes stiffness to 2,100,000 psi — approaching the modulus of cast aluminum — and adds electrical conductivity (surface resistivity drops from greater than 10 to the 16th ohm-cm for unfilled to approximately 10 to the 3rd ohm-cm for carbon-filled), which is essential in applications where static charge buildup would damage electronic assemblies or create ignition risk. Carbon-filled PEEK is also the lowest-friction PEEK grade in sliding contact, with a PV limit (pressure times velocity) nearly twice that of glass-filled PEEK, making it the default choice for shipboard bushing and bearing applications.
Machining PEEK: Tolerances and Process Control in Bath-Area Shops
PEEK machines cleanly with standard carbide tooling, producing tight tolerances and excellent surface finishes when cutting parameters are appropriate. Surface speeds of 500 to 800 SFM for turning and 300 to 500 SFM for milling are the working range, with feeds of 0.004 to 0.008 inch per revolution for turning and 0.002 to 0.004 inch per tooth for milling. The critical parameter difference from metal machining is heat management: PEEK's glass transition temperature is 300 degrees Fahrenheit, and localized heat buildup from dwelling or rubbing at low feed rates can cause surface glazing or, in extreme cases, thermal deformation of thin features. Consistent chip load — ensuring the cutter is always removing material rather than rubbing — is the primary thermal control mechanism.
Tolerance capability on PEEK in a qualified CNC shop is excellent: plus or minus 0.001 inch on bores and plus or minus 0.002 inch on position are routine for unfilled PEEK at ambient temperature. The key thermal stability consideration is conditioning: PEEK rod and plate stock retains residual stresses from the extrusion or compression molding process, and cutting into that stress field can cause the part to spring or distort. Best practice for tight-tolerance PEEK components is rough machining to leave 0.020 to 0.030 inch stock, stress relieving at 300 degrees Fahrenheit for 1 to 2 hours, then finish machining to final dimension. This two-step process adds cycle time but dramatically improves dimensional consistency on final inspection.
Filled grades introduce additional considerations. Glass-filled PEEK is highly abrasive — carbide tool life is 30 to 50 percent of what unfilled PEEK delivers, and insert edges must be inspected and replaced on a more aggressive schedule to prevent the radius growth that degrades bore size control. Carbon-filled PEEK conducts electricity; in an ESD-sensitive machining environment, grounding fixtures and tooling eliminates static buildup risk. Bath-area shops experienced in precision defense polymer machining already manage these parameters as routine process controls.
PEEK in Shipboard and Marine Defense Systems
Bath Iron Works' Arleigh Burke destroyers represent arguably the most demanding civilian-adjacent service environment in manufacturing: salt water immersion and spray, wide temperature cycling from Arctic to tropical deployment, exposure to jet fuels, hydraulic fluids, cleaning solvents, and weapons system propellants, combined with the continuous vibration of gas turbine propulsion at 75,000 shaft horsepower. PEEK's chemical resistance profile — it resists virtually all solvents, acids, and bases at shipboard operating concentrations, with the notable exception of 98 percent sulfuric acid and halogens at elevated temperature — makes it one of a small number of polymer candidates for fluid system components in this environment.
Specific applications in naval destroyer programs where PEEK appears include: thrust bearing pads and wear rings in propulsion line shaft arrangements (carbon-filled PEEK for low friction at high PV); electrical standoffs and terminal blocks in weapons systems electronics enclosures (unfilled PEEK for electrical insulation and solvent resistance); cable penetration fittings and gland seals at hull penetrations (unfilled PEEK for pressure resistance and chemical inertness); valve seats and plug components in hydraulic and fuel systems (glass-filled PEEK for high compressive load capacity at temperature); and structural insulators in cathodic protection systems (unfilled PEEK for electrical isolation in seawater environment).
For defense buyers sourcing PEEK components for shipboard programs, material lot traceability matters as much as for metals. Specifying that PEEK stock must be accompanied by manufacturer's certification documenting grade, lot number, and conformance to Victrex 450G or equivalent specification — with the certification tied to the shipment lot number — establishes the traceability chain required for naval quality systems.
Procurement and Lead Times for PEEK in New England
PEEK rod, plate, and tube stock in standard sizes is maintained by plastics distributors in Maine and throughout New England. Rod diameters from 0.250 inch to 4 inches and plate thicknesses from 0.250 inch to 4 inches in unfilled and 30 percent glass-filled grades are typically available from stock with 3 to 5 business day lead times for cut-to-length blanks. Carbon-filled PEEK in standard sizes is also typically stocked, though in fewer size options. Custom profiles, large-diameter rod above 6 inches, and specialty compositions are available on 4 to 8 week lead times from the major PEEK producers.
For machined PEEK components, Bath-area precision CNC shops with polymer machining experience typically quote 2 to 4 week lead times on prototype and low-volume work. Production quantities — runs of 100 or more parts — often benefit from injection molding evaluation: injection-molded PEEK in high volumes reaches material costs of 30 to 50 percent lower than machined-from-rod, but tooling investment of $15,000 to $50,000 per cavity must be justified by part volume and unit cost targets. For defense programs with quantities below 500 pieces per year, machined PEEK is almost always more economical than injection molding.
ManufacturingBase allows Bath-area buyers to filter PEEK suppliers by grade capability (unfilled, glass-filled, carbon-filled), certification status (AS9100, ITAR), and program type (defense, marine, aerospace) to focus RFQ activity on shops with demonstrated experience in the specific application context.
Frequently Asked Questions
Unfilled PEEK has a continuous service temperature of 480 degrees Fahrenheit (248 degrees Celsius), which is the highest of any unfilled semicrystalline thermoplastic. This means PEEK components remain dimensionally and mechanically stable in shipboard mechanical spaces where peak ambient temperatures can reach 200 degrees Fahrenheit without any degradation. The glass transition temperature of PEEK is 300 degrees Fahrenheit (143 degrees Celsius), but because PEEK is a semicrystalline polymer, its mechanical properties are governed by the crystalline melting point at 644 degrees Fahrenheit (340 degrees Celsius) rather than the glass transition — meaning it remains strong and stiff well above 300 degrees Fahrenheit in crystalline regions. For comparison, Nylon 66 loses significant strength above 250 degrees Fahrenheit and Delrin above 220 degrees Fahrenheit, putting both materials out of contention for the same service environments where PEEK performs reliably. At cryogenic temperatures, PEEK retains impact strength and ductility far better than acetal or nylon alternatives, making it suitable for Arctic-deployment shipboard systems where temperature cycling from minus 40 degrees to operating temperatures imposes significant thermal stress on polymer components.
For shipboard bushing and bearing applications in Bath-area defense programs, PEEK, Delrin, and nylon represent three distinct performance tiers. Nylon (PA66 or PA6) is the lowest-cost option with decent wear resistance in dry or lightly lubricated sliding contact, but its moisture absorption of 8 to 10 percent by weight in seawater immersion causes dimensional swell of 0.002 to 0.006 inch per inch that ruins tight clearance fits in precision applications. Delrin (acetal homopolymer) solves the moisture absorption problem — acetal absorbs less than 0.2 percent moisture — and delivers excellent dry-running wear resistance and dimensional stability, making it superior to nylon for most shipboard bushing applications. However, Delrin's continuous service temperature limit of 220 degrees Fahrenheit and its susceptibility to degradation by strong acids and some hydraulic fluids make it unsuitable for hot mechanical spaces or chemically aggressive fluid system environments. PEEK eliminates both of those limitations: it absorbs essentially no moisture, resists virtually all shipboard chemicals, and operates continuously to 480 degrees Fahrenheit. Carbon-filled PEEK specifically is the first choice for high-PV shipboard bushings where thermal stability and low friction under load are the governing requirements. The cost difference is real — PEEK raw material is 10 to 20 times the cost of Delrin — but for components that must survive a destroyer's 35-year service life in demanding service locations, the total cost of ownership argument strongly favors PEEK.
Unfilled PEEK is an excellent electrical insulator with a dielectric strength of 480 volts per mil — sufficient for most shipboard electronics standoff and isolation applications — and a volume resistivity greater than 10 to the 16th ohm-cm. It meets the requirements of MIL-I-24768 Type GEE (glass-fabric-reinforced epoxy is a different material; PEEK's qualification is tested against the electrical property requirements) for high-temperature insulation applications. Unfilled PEEK's tracking resistance is superior to most other engineering thermoplastics, meaning it does not form conductive carbon tracks on the surface when exposed to high-voltage arcing — an important safety characteristic in naval power distribution systems. For applications where ESD protection rather than insulation is needed — electronics assembly trays, machining fixtures for ESD-sensitive components — carbon-filled PEEK provides controlled conductivity with surface resistivity in the 10 to the 3rd to 10 to the 5th ohm-cm range, within the ESD-protective category defined by ANSI/ESD S541. The transition from insulating unfilled PEEK to ESD-protective carbon-filled PEEK requires attention to part geometry: any carbon-filled PEEK component in contact with signal conductors must be confirmed to have a resistivity that does not create a leakage path at the operating voltage.
PEEK's chemical resistance is one of its defining advantages for shipboard service. It is resistant to: seawater and salt spray at all concentrations; diesel fuel, JP-8, and aviation turbine fuels; hydraulic fluids including Skydrol, MIL-PRF-5606, and MIL-PRF-83282; lubricating oils, greases, and gear oils; most acids at concentrations below 50 percent at room temperature; strong bases including sodium hydroxide and potassium hydroxide; and common cleaning solvents including MEK, acetone, IPA, and toluene (MEK and acetone cause surface softening with extended immersion above 140 degrees Fahrenheit but do not degrade PEEK at room temperature for brief contact). PEEK is attacked by: concentrated sulfuric acid above 95 percent concentration; chlorosulfonic acid; fluorine gas; and prolonged contact with some halogenated solvents at elevated temperatures. In practical Bath-area shipboard service, none of the attack conditions are routinely encountered; the chemical resistance profile is essentially comprehensive for the maintenance and operational chemical exposures of a US Navy destroyer. Buyers specifying PEEK for novel chemical environments not listed in standard chemical resistance tables should request soak testing data from the material supplier or perform a 30-day immersion test at the service temperature before finalizing the material specification.
For custom-machined PEEK components from Bath-area and New England precision CNC shops, typical lead times for prototype and low-volume work run 2 to 4 weeks from approved drawing release. This timeline includes material procurement from local plastics distributors (3 to 5 business days for standard stock) plus machining and inspection time. For tight-tolerance components requiring the stress-relief cycle described above — rough machine, 300-degree bake, finish machine — add 2 to 3 business days to the schedule. Rush services at 1 to 2 week lead times are available from shops with in-stock PEEK material but typically carry a 25 to 50 percent premium on machining cost. Minimum order quantities for machined PEEK components are generally 1 piece — PEEK machining is set up per-job with no meaningful economy-of-scale in the setup, only in per-piece run time. For quantities above 50 pieces, asking the supplier about blanchard-grinding a batch of blanks before final machining can reduce per-piece cost by 15 to 25 percent by leveraging grinding efficiency on the roughing operation. For quantities above 500 pieces per year, requesting a compression molding or injection molding feasibility assessment alongside the machining quote is worthwhile — PEEK injection molding tooling is expensive but pays back in material cost reduction above certain annual volumes.
Last updated: July 2026
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