PEEK Machined Components for Aerospace and Offshore Applications in New Bedford, MA

Unfilled PEEK in natural (tan/beige) color is the baseline specification when chemical purity, FDA compliance for food-contact or implant-adjacent applications, or MRI compatibility are requirements. Tensile strength runs 14,500 psi, flexural modulus approximately 600,000 psi, and elongation 30 to 50 percent — relatively flexible for an engineering plastic. Unfilled PEEK machines with less tool wear than filled grades, holds tight tolerances well because thermal expansion is moderate (2.6 x 10 to the -5 per degree Fahrenheit), and produces a cleanable surface that does not harbor contaminants in medical and semiconductor applications. The primary limitation is wear: in sliding contact applications, unfilled PEEK wears relatively quickly. Glass-filled PEEK (typically 30 percent short glass fiber by weight) increases flexural modulus to approximately 1,400,000 psi — more than double unfilled — and improves creep resistance under sustained load at elevated temperature. The glass filler reduces elongation to about 2 percent, making the material stiffer and more brittle in thin sections. Glass-filled PEEK is the default for structural brackets, bearing cages, and stiffened housings where dimensional stability under load and temperature is the primary requirement. The trade-off is accelerated tool wear: glass fiber is abrasive to cutting edges, and polycrystalline diamond (PCD) tooling or frequent carbide insert changes are required to maintain surface quality on production quantities. Carbon-filled PEEK (30 percent short carbon fiber) brings flexural modulus above 2,100,000 psi, adds electrical conductivity (resistivity drops to roughly 10 to the 2 ohm-cm, compared with 10 to the 15 for unfilled), and significantly improves dry-running tribological performance. Carbon fiber in the matrix acts as a solid lubricant in sliding applications, reducing the coefficient of friction from 0.35 (unfilled on steel) to approximately 0.15. For bearing surfaces, thrust washers, and seal rings in offshore pumps or aerospace actuators, carbon-filled PEEK extends service intervals substantially versus unfilled or glass-filled grades. The black color and electrical conductivity also address ESD concerns in semiconductor and defense electronics environments.

PEEK machines on standard CNC lathes and machining centers without coolant — dry or with compressed air blast is preferred because water-based coolants can absorb into unfilled PEEK over time and cause dimensional instability in tight-tolerance parts. Sharp, uncoated carbide tooling at positive rake angles (15 to 20 degrees) is the standard starting point; PCD tooling extends tool life dramatically on glass-filled and carbon-filled grades, which justify the tooling cost on production quantities of 10 or more parts. Recommended cutting speeds for unfilled PEEK turning run 600 to 800 surface feet per minute with feeds of 0.005 to 0.010 inch per revolution for roughing and lighter for finishing. Glass-filled and carbon-filled grades run 300 to 500 SFM to protect tool edges from abrasive fiber damage. Milling PEEK with high-helix carbide end mills at 400 to 600 SFM and full flood air blast achieves surface finishes of 32 Ra or better; stepping down to a 0.010 inch radial depth of cut on finish passes pushes below 16 Ra if the drawing requires it. Tight-tolerance PEEK work — connector housings with +/-0.001 inch bore tolerances, precision spacers with parallel face requirements — requires stress-relief annealing of the stock rod before machining. PEEK rod extruded from rod mills carries residual stress from the extrusion process; annealing at 300 degrees Fahrenheit for 1 to 4 hours (depending on diameter) releases this stress before machining so that the part does not spring after roughing. Shops in New Bedford running defense or aerospace PEEK programs that skip this step report warped finish-machined parts, especially on asymmetric cross-sections.

PEEK purchased for defense or aerospace programs requires material traceability documentation: lot number, resin manufacturer (Victrex, Solvay, or equivalent), and a certificate of conformance to the applicable material specification. For unfilled PEEK in medical-adjacent or semiconductor applications, extractables testing data from the resin manufacturer confirms ionic contamination limits. Colored PEEK (black unfilled, for instance) requires additive documentation because some colorants affect chemical resistance or purity. Dimensional inspection for PEEK parts follows the same CMM protocols as metal: a climate-controlled 68-degree Fahrenheit environment with parts allowed to thermally stabilize for a minimum of 4 hours before measurement. PEEK's thermal expansion coefficient is roughly 10 times that of steel, so a PEEK spacer measured at 85 degrees shop-floor temperature can read 0.003 inch oversize on a 4-inch length compared with a 68-degree CMM room reading. New Bedford shops running AS9100 programs for aerospace customers document measurement uncertainty and temperature compensation in their inspection plans.