PEEK Machining Janesville WI — All Grades

Karl Gillihan

🧪 PEEK

PEEK Components and CNC Machining in Janesville, WI: Unfilled, Glass-Filled, and Carbon-Filled Grades

PEEK (polyether ether ketone) sits at the top of the engineering thermoplastics hierarchy, and its presence in Janesville's manufacturing supply chain is a direct reflection of the city's industrial ambitions beyond legacy automotive production. Where nylon, acetal, or UHMW polyethylene would fail — whether from heat, chemical exposure, radiation, or sustained mechanical loading — unfilled or reinforced PEEK holds its dimensions and properties. Machinists in Janesville's precision job shops are familiar with the material's demands: consistent cutting speeds, sharp tooling, and careful management of thermal stress during machining to preserve the crystalline structure that gives PEEK its performance advantage.

ISO 9001ISO 13485AS9100

Unfilled PEEK (polyether ether ketone, homopolymer) in its natural semi-crystalline form delivers a continuous service temperature of 250 degrees Celsius, tensile strength of approximately 100 MPa, and flexural modulus around 3.6 GPa. Its inherent chemical resistance — it is unaffected by virtually all organic solvents, fuels, and hydraulic fluids at temperatures below 200 degrees Celsius — makes it the material of choice for seals, bushings, and valve components in the aggressive chemical environments found in automotive under-hood and heavy industrial applications. For SHINE Technologies and the medical device supply chain extending through southern Wisconsin into the Madison and Milwaukee corridors, unfilled PEEK's gamma radiation resistance is critical. Unlike most polymers that degrade rapidly under ionizing radiation, PEEK retains most of its mechanical properties up to absorbed doses of 1,000 to 10,000 kGy depending on the irradiation conditions — a property that makes it suitable for sterilizable surgical instrument components, imaging equipment housings, and radiation-transparent structural elements. FDA-compliant and USP Class VI grades are available from primary resin suppliers (Victrex, Solvay Ketaspire, Evonik Vestakeep) and are the required specification for any medical or food-contact application. CNC machining of unfilled PEEK in Janesville shops follows a defined protocol: sharp uncoated or TiN-coated carbide or HSS tooling, cutting speeds of 100 to 200 m/min for turning, dry cutting or light air blast to evacuate chips without causing thermal buildup. PEEK is hygroscopic — it absorbs moisture from ambient air — and parts machined from improperly conditioned stock or stored in humid conditions before machining may exhibit dimensional drift. Parts requiring tight tolerances (plus or minus 0.025 mm or tighter) should be machined from stock that has been dried at 150 degrees Celsius for 3 to 4 hours and allowed to equilibrate at room temperature before final finishing.

Glass-Filled PEEK: Stiffness and Dimensional Stability for Structural Applications

Glass-filled PEEK (typically 30 percent short-glass-fiber reinforcement by weight, designated GF30) increases flexural modulus from 3.6 GPa to approximately 10 GPa while raising tensile strength to 160 to 170 MPa. The fiber reinforcement dramatically reduces the coefficient of thermal expansion — from about 47 ppm/degrees C for unfilled PEEK to roughly 20 ppm/degrees C for GF30 — which is the primary reason engineers specify glass-filled grades for precision structural components that must maintain dimensional stability across temperature cycles. For Janesville's automotive supply chain, GF30 PEEK finds application in throttle body components, sensor housings, electrical connector bodies, and fuel system parts where dimensional precision at elevated temperatures (up to 200 degrees Celsius continuous) is required. The glass reinforcement that improves structural performance also increases abrasiveness during machining — glass fibers erode carbide cutting edges at roughly three to five times the rate seen with unfilled PEEK, making TiAlN-coated carbide or PCD (polycrystalline diamond) tooling the preferred choice for production machining of glass-filled grades. Expected carbide tool life drops significantly compared to unfilled PEEK, and shops should plan cutting speed and feed parameters accordingly. For heavy-equipment structural inserts, guide rails, and wear-resistant liners, GF30 PEEK competes with glass-filled nylon (PA66 GF30) and glass-filled acetal. PEEK's advantage is thermal and chemical performance; its disadvantage is material cost, which runs 15 to 30 times higher than glass-filled nylon. When operating temperatures remain below 120 degrees Celsius and chemical exposure is limited to oils and mild solvents, glass-filled nylon or acetal is the more economical choice. Above 150 degrees Celsius or in aggressive chemical environments, GF30 PEEK's premium is justified.

PEEK Procurement and Stocking in the Southern Wisconsin Market

PEEK raw material for machining — rod from 6 mm to 150 mm diameter, plate from 6 mm to 100 mm thick — is stocked by plastics distributors serving the Janesville market from Milwaukee, Madison, and Chicago. Standard unfilled natural (off-white) and black PEEK rod and plate in common sizes are typically three-to-five-business-day items; glass-filled and carbon-filled grades are one-to-two-week items for standard sizes. FDA-compliant and USP Class VI certified PEEK commands a slight premium and requires documentation of resin lot traceability — Victrex 450G, Solvay KT-820, and Evonik Vestakeep 2000G are commonly referenced FDA-compliant grades. For production programs consuming significant PEEK volumes, blanket orders against annual forecasts provide the most economical procurement path. PEEK sheet and rod have a long shelf life when stored in clean, dry conditions away from UV exposure; multi-month inventory positions are practical for shops with established demand. Some distributors offer custom semi-finished forms — near-net discs, sleeves, and tube stock — that reduce machining time compared to starting from rod. ISO 13485 certification at the machining shop level is required for PEEK components entering the medical device supply chain. This standard adds document control, design history file requirements, and traceability obligations beyond ISO 9001 — specifically, each machined PEEK component must be traceable to the resin lot from which it was produced, enabling field recall capability if a resin quality issue emerges. Janesville shops pursuing medical device work should confirm their quality management system addresses these requirements before quoting PEEK medical components.

Carbon-Filled PEEK: The Tribology Grade for Demanding Bearing and Seal Applications

Carbon-filled PEEK (CF30, 30 percent carbon fiber by weight, or grades containing both carbon fiber and PTFE/graphite for lubrication) is the tribology-optimized variant specified when wear rate and dynamic friction coefficient are the governing design parameters. Carbon fiber reinforcement raises tensile strength to approximately 200 MPa and dramatically increases compressive stiffness, while the graphite or PTFE additions (often combined in three-component grades: 10 percent carbon fiber, 10 percent graphite, 10 percent PTFE) reduce the coefficient of friction from around 0.35 for unfilled PEEK against steel to 0.05 to 0.15, enabling dry running in bearing applications. In Janesville's automotive and industrial machinery sectors, carbon-filled PEEK bushings and thrust washers replace bronze bearings in applications where grease contamination of sensitive systems is unacceptable, where high PV (pressure-velocity) values exceed what acetal or nylon can handle, or where the operating temperature exceeds the service limits of standard bearing plastics. Carbon-filled PEEK bearing grades can handle PV values up to 0.30 MPa-m/s continuously and short-term PV spikes of 0.50 MPa-m/s — performance that approaches oil-impregnated bronze bushings without requiring external lubrication. Machining CF30 PEEK requires the same precautions as glass-filled grades — aggressive carbide or PCD tooling — but with additional attention to workholding. Carbon fiber reinforcement makes the material more prone to delamination at cutting edges if tools are dull or feed rates are too high. Flood coolant is acceptable for CF30 PEEK (unlike some filled polymers where coolant causes issues), and it is often beneficial for heat dissipation in production runs. Surface finishes of Ra 0.4 to 0.8 micrometers are achievable for bearing bore surfaces, which is within the range required for most bushing applications against hardened steel shafts.

Frequently Asked Questions

SHINE Technologies produces medical isotopes using accelerator-driven neutron flux, which creates an environment with significant gamma radiation exposure. Most engineering polymers — acetal, nylon, polycarbonate, even many specialty plastics — degrade rapidly under gamma radiation, losing tensile strength, elongation, and dimensional stability at doses above 50 to 100 kGy. PEEK retains most of its mechanical properties up to doses of 1,000 kGy and acceptable performance up to 10,000 kGy under some irradiation conditions, making it uniquely suitable for structural and semi-structural components in radiation zones. Combined with its chemical resistance to the acids and solvents used in isotope processing and its ability to be steam sterilized at 134 degrees Celsius without degradation, PEEK fills a role that no other polymer material can match in this application. Custom CNC-machined PEEK components for shielding apertures, collimators, and fluid handling parts are procured by facilities like SHINE from qualified ISO 13485 or AS9100-certified machine shops in the region.

Unfilled PEEK machines well with standard CNC turning and milling parameters, but a few key rules determine whether parts come out dimensionally accurate and stress-free. Use sharp tooling — either high-speed steel or uncoated carbide — and replace inserts before the edge shows visible wear, as dull tools generate heat that can anneal the crystalline structure and cause dimensional instability. Recommended turning parameters for unfilled PEEK: surface speed 100 to 200 m/min, feed 0.1 to 0.25 mm/rev, depth of cut 0.5 to 3.0 mm. For milling: surface speed 150 to 300 m/min, chip load 0.05 to 0.15 mm per flute. Coolant is optional for unfilled PEEK — many shops use dry cutting or compressed air. For tight-tolerance parts, rough machine to within 0.5 mm of final dimensions, allow the part to rest at room temperature for 30 minutes to relieve any machining stress, then take finishing passes to final dimension. Semi-crystalline PEEK has essentially no creep at room temperature, so stress relief is about temperature equilibration rather than long-term relaxation.

Both GF30 PEEK and GF33 nylon 66 offer significantly improved stiffness and dimensional stability compared to their unfilled counterparts, but they occupy different performance tiers. GF33 nylon 66 delivers flexural modulus around 9 GPa and continuous service temperature of 120 to 130 degrees Celsius (lower when wet, since nylon absorbs moisture). GF30 PEEK delivers 10 GPa flexural modulus and continuous service temperature of 250 degrees Celsius. For most under-hood automotive applications below 130 degrees Celsius in dry or lightly humid environments, GF33 nylon 66 is the economical choice — it costs roughly 4 to 8 dollars per kilogram compared to 100 to 150 dollars per kilogram for GF30 PEEK. For applications near exhaust systems, turbochargers, or direct injection fuel systems where temperatures regularly exceed 150 degrees Celsius, or where contact with aggressive fluids (E85 fuel, brake fluid, DEF) is expected, GF30 PEEK justifies its premium. Janesville automotive engineers typically make this decision at the design stage during DFMEA, mapping expected operating conditions against each material's property data sheet.

Minimum order quantities for CNC-machined PEEK parts at Janesville precision job shops vary by shop and part complexity, but most shops will quote prototype quantities of 1 to 5 pieces for initial evaluation, with per-piece pricing that reflects setup amortization over a small run. For a moderately complex part — say a bushing with multiple turned diameters and a keyway — prototype per-piece cost in unfilled PEEK typically runs 150 to 400 dollars depending on tolerances and material size. Production quantities of 50 to 500 pieces bring per-piece costs down to 25 to 80 dollars as setup is amortized. For high-volume programs (1,000-plus pieces per year), dedicated fixturing and automated loading reduce unit costs further. Shops with 5-axis CNC capability can often produce complex PEEK components in a single setup, which is particularly valuable for medical device components requiring tight true position tolerances (plus or minus 0.05 mm or tighter). Always confirm whether the quoted price includes material certification documentation if ISO 13485 or AS9100 traceability is required.

Carbon-filled PEEK bearing grades (CF10-GF10-PTFE10 or similar three-component grades) are viable replacements for oil-impregnated bronze bushings in many heavy-equipment applications, particularly where relubrication is difficult, contamination risk from grease is a concern, or the operating environment includes chemicals that would corrode bronze. The key comparison parameters are PV rating, coefficient of friction, and wear rate. Bronze bushings with oil impregnation handle PV values up to 0.10 to 0.20 MPa-m/s with a coefficient of friction of 0.05 to 0.10 against a hardened steel shaft. Carbon-filled PEEK tribology grades match or exceed this PV rating (up to 0.30 MPa-m/s continuous) with similar friction coefficients. The advantage of PEEK over bronze in corrosive environments — hydraulic fluid contaminated with water, agricultural chemicals, fertilizer contact — is significant because PEEK is inert to these media while bronze corrodes and seizes. The disadvantage is cost: a PEEK bushing machined from CF30 rod costs 3 to 8 times more than an equivalent bronze bushing. For equipment with high relubrication labor costs or inaccessible pivot points, the lifecycle cost comparison often favors PEEK.

Last updated: July 2026

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