PEEK Screws in Medical Devices - Autoclave Sterilization, Biocompatibility | FASTKING Case
Case Background
A domestic endoscope manufacturer assembled its main unit housing with ABS+PC alloy and SUS304 stainless steel screws. Two issues emerged in hospital use: thermal expansion mismatch between metal and plastic under alternating low-temperature plasma and 134°C steam sterilization caused thread hole enlargement and assembly loosening; metal screws produced artifacts during MRI examination, affecting physician imaging.
Solution
FASTKING recommended peek (polyetheretherketone) natural medical-grade screws. peek passes ISO 10993-5/-10 cytotoxicity, intracutaneous reactivity, and sensitization biocompatibility tests; its CTE (23×10⁻⁶/°C) closely matches ABS+PC, eliminating thermal-cycle stress; PEEK withstands 500+ autoclave cycles at 134°C without cracking or leachables.
Specifications
- Material: PEEK 450G (Victrex equivalent), natural beige, biocompatible grade
- Sizes: M2.5×6 / M3×8 / M4×10 Phillips countersunk + M3/M4 hex socket nut
- Performance: tensile 95 MPa, CTE 23×10⁻⁶/°C, continuous 260°C
- Certifications: ISO 10993-5/-10, RoHS, REACH, USP Class VI
Results
Over 10 months, FASTKING delivered 280,000 PEEK medical screws to this customer:
- Thread hole mismatch issue fully resolved; zero after-sales repairs (vs 3.2% previously).
- Unit now MRI-compatible (PEEK has zero magnetization in 3T field), upgrading the endoscope from diagnostic to surgical navigation.
- Withstands 500 autoclave cycles at 134°C/18min (tested 800+ with no cracking).
- Resists IPA, glutaraldehyde, and quaternary ammonium disinfectants for 10 years without swelling.
- Adopted on all three of the customer's endoscope generations.
Contact the FASTKING engineering team for medical-grade fastener selection (PEEK / PI / PPS / PSU) or biocompatibility documentation.