Premium performance. Or cost-effective precision. 15× price difference.

Yes. Delrin machining-grade billet: $10–15/kg. PEEK unfilled billet: $120–180/kg. PEEK-OPTIMA medical grade: $300–400+/kg. For equivalent small precision part, PEEK version typically 8–15× cost of Delrin. This cost difference is the single biggest factor in material selection between these two plastics. Only specify PEEK when Delrin genuinely cannot meet requirements.

Technically yes — PEEK's mechanical properties exceed Delrin in every category. Practically no — the cost difference makes over-specification wasteful. Rule of thumb: if Delrin datasheet shows the application works, use Delrin. If Delrin fails (temperature too high, chemicals too aggressive, implantable medical), upgrade to PEEK.

Delrin is the easiest-machining engineering plastic — cuts cleanly at high speeds (300+ m/min), single-pass surface finish Ra 0.8 µm, minimal tool wear. PEEK machines well but 30-40% slower feeds, slightly more tool wear, Ra 1.6 µm single-pass. For equivalent part, PEEK machining time 1.3-1.5× Delrin. Combined with material cost, PEEK finished parts are typically 10-15× cost of Delrin.

Yes. Delrin against 316L or hardened steel: PV (pressure × velocity) up to 2,500. Delrin AF (PTFE-filled): PV to 5,000. PEEK unfilled: PV to 5,000 (similar to Delrin AF). PEEK-bearing grades (carbon + PTFE filled): PV to 10,000+. For moderate bearing applications, Delrin is adequate and much cheaper. For high-PV or elevated temperature bearings, PEEK wins.

PEEK sterilization: autoclave (121°C), gamma radiation, ETO. Retains full mechanical properties through 1000+ autoclave cycles. Delrin sterilization: limited autoclave compatibility (some grades deform), gamma radiation (some grades embrittle). For reusable autoclavable medical instruments, PEEK is dramatically better. For single-use or non-sterilized medical devices, Delrin may suffice.

Yes — laser, ultrasonic, and hot-plate welding all work on PEEK. Weld strengths 60-80% of parent material. Less common than bonding or mechanical assembly for PEEK parts. Delrin also welds via ultrasonic and spin welding. For PEEK assemblies, mechanical fastening with heat-set brass inserts is more common than welding.