Fine Blanking for Electronics Connectors

Connector Terminal Geometry: 0.1-0.3 mm Features at 0.5 mm Pitch

Modern electronic connectors push the boundaries of stamping technology. A typical USB-C connector terminal has contact beams 0.2 mm wide, spaced at 0.5 mm pitch, with a beam length of 3.5 mm and a contact radius of 0.15 mm at the beam tip. The terminal material — C5191 phosphor bronze at 0.2-0.3 mm thickness — must be blanked with 0.002 mm die clearance to maintain the beam geometry without distortion, and the 100% shear zone on the beam sidewall is essential for proper contact spring function.

Conventional progressive-die stamping of these terminals leaves a burr on the beam sidewall that varies from 0.01 to 0.03 mm across the die life, creating inconsistent insertion forces and contact resistance. Fine blanking eliminates this variability: the carbide punch with wire-EDM ground beam cavities produces identical beam geometry for the full die life, with 100% shear zone on all beam surfaces. The V-ring — miniature geometry at 0.1 mm depth and 0.2 mm distance from the beam profile — compresses the thin phosphor bronze material into the beam cavity, preventing the lateral flow that would distort the beam width.

The HF-320 with 3200 kN total force, programmable blanking speed of 5-45 mm/s, and ±0.1 mm feed pitch accuracy is the production standard for connector terminal manufacturing. The programmable speed is critical for phosphor bronze — too fast and the material work-hardens excessively at the shear zone, reducing beam flexibility; too slow and production rate drops below the economic threshold.

EMI Shielding Cans: Depth-to-Width Ratio and Spring-Back Control

EMI shielding cans are stamped metal enclosures that sit over sensitive electronic components on the PCB, creating a Faraday cage that blocks electromagnetic interference. The typical shield is a drawn or formed box, 10-40 mm on each side, 3-8 mm deep, blanked from SUS304 stainless steel at 0.2-0.4 mm thickness. The critical fine blanking requirement is on the shield's base flange — the flat perimeter that solders to the PCB — which must be burr-free to ensure continuous shielding contact with the ground plane.

A gap in the shield perimeter — caused by a burr that prevents the flange from seating flatly on the PCB — creates an antenna aperture that radiates electromagnetic energy at the gap frequency. Fine blanking eliminates this risk by producing a 100% shear zone on the flange perimeter with zero burr. The counter-pressure pad holds the thin stainless flat during blanking, preventing the spring-back that distorts the flange flatness in conventional stamping, where the unsupported strip warps as the profile is cut.

For SUS304 at 0.2-0.4 mm thickness, the HF-200 provides sufficient force for shield production, but the press must be configured with reduced V-ring depth (0.1-0.15 mm vs. 0.3-0.4 mm for thicker materials) to avoid V-ring penetration through the thin material. The coil-fed progressive die configuration, combined with the automatic feeding and leveling system, delivers 80-120 SPM production rates for shield manufacturing.

Deburring and Cleaning for Contact Surfaces

While fine blanking produces burr-free edges, the micro-deburring requirement for electronics is even more stringent than for other applications. A 0.005 mm edge radius on a connector terminal beam can affect insertion force by 15-20%, and surface contamination from stamping lubricant can degrade contact resistance. HS-FINEB provides ultrasonic cleaning and precision deburring equipment matched to the electronics production line.

The combined fine blanking + ultrasonic cleaning cell delivers terminals ready for plating — no secondary deburring, no surface contamination, no edge inspection sorting. For contact pin arrays, the cleaning process also removes the micro-burr that can form at the coining interface, ensuring 100% pin geometry compliance before the insertion-cycle validation test. Learn about our deburring and polishing equipment →