Delrin, PEEK, UHMW, polycarbonate, and PTFE — milled, turned, and finished to the same tolerance class as our metal work.
Engineering plastics are not just a cheaper substitute for metal — they earn a place on a print when chemical compatibility, electrical isolation, low friction, biocompatibility, or weight reduction are the requirement. Engineering thermoplastics run across the same milling, turning, and Swiss-type platforms in the production network that handle metal work, with a few important changes to how the job is set up. Plastics expand and contract several times faster than steel under cutting heat, so finish passes are planned to land the part at temperature, not while it is still warm from roughing. Work-holding is gentler — soft jaws, vacuum fixtures, and supportive nests prevent the deformation that ruins a critical dimension on a thin-walled bushing. Tool geometries are sharper, with polished flutes to keep chips moving instead of welding to the cutter. Coolant choice matters: water-soluble cutting fluids work for most plastics, but PTFE, polycarbonate, and a handful of others run dry or with air blast to avoid stress-cracking. The result is a finished plastic part that holds dimensions and surface quality on par with metal work — not the rough, oversized blanks that show up when a metal shop bids a plastic job without changing its process.
The default engineering plastic for precision-machined parts. High stiffness, low friction, dimensional stability, good chemical resistance. Specified on gears, bushings, manifolds, instrument bodies, and any part that needs to slide or rotate against another component. Machines almost like an easy-cutting metal — clean chips, good finish, predictable dimensions.
The high-performance engineering thermoplastic. Withstands continuous service to 250°C, near-immune to chemical attack, biocompatible in implant grades, and inherently flame-resistant. Specified on aerospace insulators, semiconductor wafer-handling, medical instrument components, and any high-temperature or harsh-chemistry application. Premium material cost; predictable machining.
Ultra-high molecular weight polyethylene — the wear-and-slide plastic. Extremely low coefficient of friction, excellent abrasion resistance, FDA-compliant grades available. Specified on chain guides, conveyor wear strips, food-handling components, and any sliding contact that has to run dry. Machines fine but watches tolerance — high thermal expansion coefficient means warm parts are dimensionally different from cold ones.
Polycarbonate (PC) brings optical clarity and impact resistance — specified on viewports, light pipes, and protective covers. PTFE (Teflon) brings the lowest friction coefficient and broadest chemical resistance of any common plastic — specified on seals, valve seats, and chemical-process hardware. Both require careful work-holding and sharp tooling to come off the spindle at print.
Other engineering plastics — Nylon 6/6 and Nylon MDS, PEI (Ultem), PPS, polysulfone, glass- and carbon-filled grades, and conductive-fill plastics — are available against the drawing.
Machined plastic parts ship into instrumentation, medical, semiconductor, and general industrial work where a metal part would be wrong: electrical isolators in PEEK, fluid-contact components in PTFE, low-friction wear strips in UHMW, transparent guards and viewports in polycarbonate, and Delrin used liberally on instrument internals where dimensional stability and clean machining are the requirement.
Routine machined tolerances on rigid engineering plastics (Delrin, PEEK, polycarbonate) ship at ±.0005" or better on most features — tighter than the metal class only when ambient temperature is controlled, since plastic dimensions shift several thousandths across normal shop-floor temperature swings. Surface finish straight off the cutter runs 32 to 63 Ra. Tumbling, deburring, and bead blasting are available within the network for edge break and uniform matte finishes. Bonding, ultrasonic welding, and any printing or pad-marking secondary operations are coordinated with qualified partner suppliers on the program's schedule.
C360 brass and C110 copper for fittings and conductive parts.
6061 and 7075 when metal is the right answer.
Hub page covering every alloy family we machine.
22 CNC platforms across our production network — 5-axis milling, Swiss-type turning.
