Core Pin Life & Consistency in a 64-Cavity Packaging Closure Mold
A 64-cavity HDPE closure mold running over 5 million shots a year was losing core pins unevenly across cavities, forcing unscheduled line stops and dimensional scatter on the tamper-evident ring.
PROJECT OVERVIEW
"A packaging manufacturer ran a 64-cavity mold producing HDPE beverage closures, with the tamper-evident ring feature formed on one-step core pins. At 5M+ shots a year the pins wore unevenly across the 64 cavities; first failures forced unscheduled line stops, and cavity-to-cavity scatter on the ring feature exceeded the closure spec."
PAIN POINTS
- Uneven core pin wear across the 64 cavities, with the first failures around 300,000 shots
- Cavity-to-cavity dimensional scatter on the tamper-evident ring feature
- Unscheduled line stops for pin replacement on a 24/7 packaging schedule
OUR SOLUTION
- SKH51 (M2) one-step core pins hardened to HRC 62, TiN-coated for consistent wear
- All 64 pins ground to ±0.002 mm with matched diameters, CMM-verified before delivery
- 24-hour DFM review to confirm pin grade, venting and interchangeability for the closure design
Taperless one-step core pins — straight-bore friendly, 64-position repeatability
JIS standard one-step core pins — matched diameters across all 64 cavities
MEASURED RESULTS
| Core pin life | ~300,000 shots (uncoated) → 900,000+ shots (SKH51 + TiN), 3x improvement |
| Cavity-to-cavity consistency | ±0.002 mm on pin diameter across all 64 positions |
| Line stops for pin replacement | From roughly monthly to once per quarter |
| Replacement scheduling | Scheduled swaps at a common interval instead of odd-interval failures |
YOUR APPLICATION MAY DIFFER
"For multi-cavity closure, cap and thin-wall molds, send us the part drawing — we will quote the pin grade, coating and maintenance schedule for your resin and shot count."