Fine Blanking Guide

Short answer: fine blanking is a precision stamping process that uses a triple-action press with a V-ring impingement ring to produce parts with a fully sheared, smooth edge (100% shear zone) and positional accuracy of plusmn0.01-0.02 mm. Unlike conventional stamping, fine blanking suppresses the fracture zone, producing near-burr-free functional edges ideal for gears, ratchets, levers, and parts that cannot tolerate secondary deburring.

This guide is for design engineers, sourcing teams, and quality engineers evaluating whether fine blanking is the right process. Fine blanking costs more per stroke than conventional stamping but eliminates secondary operations such as shaving, reaming, grinding, or deburring.

Send your part drawing, material, thickness, and edge quality requirements through the RFQ form. For related precision processes, see 高精度金属プレス加工 and metal stamping tolerances guide.

How fine blanking is different

Before the punch moves, a V-ring on the die presses into the material around the part contour, creating a compressive state that suppresses fracture. The punch then moves through under counterpunch back pressure.

Material suitability

• Low-carbon steel (DC01, SPCC): excellent, 0.5-6.0 mm
• Stainless steel (304, 316): good, requires higher V-ring pressure, max ~4.0 mm
• Aluminum (5000, 6000 series): good, lower tooling pressure
• Copper and brass: excellent, mirror-like edges
• High-carbon steel: limited, typically below 3.0 mm

Design rules for fine blanking

• Minimum hole diameter: 60-70% of material thickness
• Minimum web width: 70-80% of material thickness
• Minimum corner radius: 0.2-0.5 mm for most materials
• Maximum material thickness: 6 mm for steel, 4 mm for stainless
• V-ring clearance from part edge: 2-3 mm

When fine blanking is worth the higher tooling cost

Fine blanking is not automatically better for every flat stamped part. It becomes attractive when the edge is a working surface, when the print calls out tight perpendicularity or hole position, or when conventional blanking would need a second operation to remove fracture, taper, or burr. Buyers usually compare fine blanking against conventional stamping plus shaving, grinding, reaming, or deburring.

• Choose fine blanking: gears, ratchets, lock plates, brake hardware, latch parts, contact carriers, precision levers, and parts where the cut edge carries load or locates another component.
• Use conventional stamping: covers, brackets, washers, and spacers where the cut edge is not functional and a small burr is acceptable.
• Review the annual volume: the die is more expensive, so the cost advantage usually appears when secondary machining can be removed or annual volume is high enough to absorb tooling.
• Confirm the inspection method: ask how edge shear, rollover, burr height, flatness, and hole position will be measured during first article inspection.

RFQ data that improves a fine blanking quote

A useful quote needs more than the outside profile. Send the 2D drawing with datums, the 3D model if available, material grade and hardness, thickness, required shear percentage, burr direction, finish, and expected annual usage. If the part currently runs by machining or conventional stamping, include the problem you are trying to solve, such as burr, edge cracking, flatness, or positional drift.

For related decisions, compare this page with the metal stamping burr control guide, material selection guide、および first article inspection checklist. If the part may be produced by a multi-station die instead, review the progressive die design checklist.

FAQ

Submit your fine blanking inquiry

If your part requires 100% sheared edges, send your 2D drawing or 3D model through the RFQ form with material grade, thickness, annual volume, and edge quality requirements.