Case Study: Improving Punch Life at 280 SPM Through Edge Radius Control

At high stamping speeds, punch failure is rarely caused by dimension error alone.

In this case study, we share how controlled edge radius — not tighter tolerance — improved punch life significantly in a 280 SPM progressive stamping application.

Background

A progressive die toolmaker producing automotive connector terminals was running at:

The issue was not dimensional deviation.

The issue was premature edge chipping on the punch after a short production cycle.

Average tool life: unstable and inconsistent.

Initial Analysis

The original punch met drawing tolerance:

However, microscopic inspection revealed:

At high SPM, impact force multiplies.

When edge geometry is uncontrolled, force distribution becomes uneven.

The result: micro-chipping initiates early and propagates quickly.

The Core Problem

At 280 SPM:

A theoretically “perfect sharp edge” becomes unstable under dynamic load.

Dimensional accuracy alone does not guarantee performance.

Edge geometry control becomes critical.

Solution: Controlled Edge Radius via Profile Grinding

Instead of tightening dimensional tolerance further, we adjusted:

Manufacturing process:

Tolerance maintained at ±0.002 mm.

Results

After implementation:

The key improvement was not material change.

Technical Insight

At high-speed stamping above 200 SPM:

For progressive die applications, edge design should be evaluated under dynamic load, not only static measurement.

When This Matters

This approach is particularly relevant for:

Conclusion

If your punch operates above 200 SPM and experiences:

The issue may not be tolerance.

It may be edge control.

Profile grinding allows controlled machining — not just accurate machining.

Technical Consultation

If you are experiencing similar tool life instability in high-speed stamping applications, send us your drawing for a technical review.

We can evaluate:

We act as an extension of your toolroom — not just a machining supplier.