Common Pitfalls of Reused Old Threading Molds in Secondary Processing

From years of on-site machine debugging and after-sales communication with packaging manufacturers, we've noticed a widespread industry habit: many factories choose to regrind and reuse aging threading molds to cut production costs. It seems like a practical small cost-saving move, but most operators ignore the hidden long-term quality troubles behind reused molds.

After thousands of hours of continuous stamping for aluminum threaded caps and anti-theft metal caps, molds will develop invisible internal metal fatigue, alongside roughly 15-20% drop in surface hardness, these internal damages cannot be fixed simply by surface polishing, even after careful secondary grinding, the mold's core structural performance can never return to its original state.

In our daily production tests, we found refurbished molds tend to make uneven thread shapes during mass runs, the thread flaw rate is around 3% to 5% for reused molds, much higher than the 0.6% rate of intact new molds. What's more, these refurbished molds wear nearly 40% quicker, leading to frequent machine stops for minor adjustments that disrupt continuous production schedules.

Based on our real workshop operation data, we've set a practical mold replacement rule for reference, we suggest phasing out threading molds after they finish 500,000 finished products, this standard comes purely from our long-term machine running records, not empty theoretical data.

We don't mean reused molds cannot work at all, they can handle small-batch, low-standard orders temporarily, but for stable bulk production of standard aluminum caps and metal packaging parts, sticking to reasonable mold replacement cycles helps factories avoid unexpected batch quality issues and unnecessary production delays.