S136 Medical-Grade Mold for Portable Diagnostic Device

Challenge

A UK medical device startup developing a portable blood analyzer needed an injection mold for the device enclosure. The part required S136 stainless mold steel for ISO 13485 compliance, a medical-grade surface texture, and full process documentation for their FDA 510(k) submission. UK mold makers quoted £22,000-28,000 with 10-12 week lead times, stretching the startup's timeline and budget.

What We Did

• Material compatibility: The enclosure is molded from PC/ABS with a biocompatible additive package. S136 was the correct steel — its corrosion resistance prevents mold rust even with humid manufacturing environments, and the 48-52 HRC hardness supports the 200K-shot production target.
• DFM for medical: Our DFM review identified three issues: insufficient draft angle on the snap-fit features (would have caused ejection marks), a wall thickness transition that risked sink marks on the visible surface, and gate location that would have left a visible witness line on the mating face. All corrected before steel was cut.
• ISO 13485 documentation package: We provided the full traceability package required for FDA submission: incoming steel spectrometer report, in-process inspection records at each machining stage, T0 sample CMM dimensional report, material certificates for all mold components, and a comprehensive mold validation report.
• Surface finish: The enclosure required a specific medical-grade matte texture (MT-11020 equivalent) that hides fingerprints and provides a professional feel. Our factory partner matched the texture from a reference sample the customer provided.

Results

Customer Feedback

"The documentation package Peifeng provided was exactly what our FDA reviewer needed. No follow-up questions on manufacturing. The mold has been running for 18 months with zero quality issues. As a startup, saving 35% on tooling meant we could allocate budget to clinical trials."