STAVAX ESR Cores for Corrosion-Free Syringe Barrel Molding
Formaldehyde released by POM resin was corroding SKH51 cores on a medical syringe barrel mold, forcing three cleanroom shutdowns a year β mirror-polished STAVAX ESR cores ended the corrosion entirely.
PROJECT OVERVIEW
"A medical device OEM molding POM syringe barrels ran hardened SKH51 core pins for the barrel bore. POM releases formaldehyde at molding temperature, and the aggressive gas attacked the core surface over time. Corrosion pitting transferred onto the bore, producing surface defects that failed the fit and cosmetic spec. Each failure meant a cleanroom teardown, core replacement and full requalification β three times a year on a program running in an ISO 14644 Class 7 cleanroom."
PAIN POINTS
- Formaldehyde outgassing from POM corroded SKH51 cores, causing pitting on the barrel bore
- Corrosion incidents three times per year, each requiring cleanroom entry, teardown and requalification
- Pitted bores failed the surface and fit spec, raising scrap on a program with documented quality requirements
OUR SOLUTION
- Replaced SKH51 cores with STAVAX ESR (electro-slag remelted) stainless cores, hardened and tempered to 52 HRC with full corrosion resistance to formaldehyde attack
- Mirror-polished bores to Ra < 0.1 ΞΌm in-house, with the bore diameter held to Β±0.005 mm
- Full material certificates and processing records supplied for cleanroom compliance, verified against ISO 14644 Class 7 requirements
MEASURED RESULTS
| Core life | 300,000 β 2,000,000+ shots (6.6x improvement) |
| Corrosion incidents | 3 per year β 0 |
| Bore surface finish | Ra < 0.1 ΞΌm mirror finish, defect-free across the full run |
| Cleanroom compliance | ISO 14644 Class 7 maintained β no requalification stops |
YOUR APPLICATION MAY DIFFER
"If your medical program runs aggressive resins in a cleanroom, ask us for a steel and finish recommendation matched to your resin chemistry β DFM review is free within 24 hours."