TECHNOLOGY GUIDE

Fine Blanking Die Clearance & Tolerance Guide

How cutting-edge clearance, V-ring geometry and tool steel selection combine to control shear-face quality, burr height and tolerance in fine blanking dies.

What Is Cutting-Edge Clearance?

Cutting-edge clearance is the gap between the punch and die cutting edges. In fine blanking this clearance is far tighter than in conventional stamping — typically a very small percentage of material thickness — to help maintain a compressive cutting condition rather than a tearing one.

The Role of the V-Ring

The V-ring (impingement ring) is a raised, angled rib on the stripper or die plate that presses into the material just outside the cut line before and during the blanking stroke. It locks the material against lateral flow, which is what allows the shear face to stay smooth instead of fracturing.

Burr Height & Edge Quality Targets

Even with optimal die clearance and V-ring geometry, a small residual burr typically remains on the die-side edge. Target burr height is usually specified as a percentage of material thickness and is achieved through a combination of correct tooling geometry, tool steel selection/coating, and — where required — secondary deburring. See our deburring equipment page for finishing options.

Tool Steel & Coating Selection

Cutting punches and dies are typically made from high-alloy tool steels (such as powder-metallurgy or high-Cr grades), sometimes with PVD coatings, selected against expected production volume and material abrasiveness.

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