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Fine blanking produces parts with smooth shear faces and tight tolerances in a single press stroke. Servo presses are the preferred platform due to precise force and position control.
## Fine Blanking Fundamentals
Unlike conventional blanking, fine blanking uses three forces simultaneously:
1. **Blanking force** (punch)
2. **Counter force** (counter punch from below)
3. **V-ring force** (stinger ring that clamps material)
The V-ring prevents material flow, creating hydrostatic compression that produces a clean, crack-free shear face.
## Why Servo Press for Fine Blanking
Servo presses allow independent programming of blanking speed (5-15 mm/s), V-ring engagement force, and counter punch pressure throughout the stroke.
## Achieving ±0.01mm Tolerance
**Press requirements:** Slide parallelism <0.005mm, position repeatability ±0.005mm, thermal compensation active.
**Die requirements:** Clearance 0.5% of material thickness, hardened to 60-62 HRC, ground to Ra 0.4μm on cutting faces.
**Process parameters for 3mm steel:**
- Blanking speed: 8 mm/s
- V-ring force: 15-20% of blanking force
- Counter force: 5-10% of blanking force
- Lubrication: EP oil, 50-80 ml/min flood
## Quality Control
Measure rollover depth (<10% of thickness), burnish zone height (>80% of thickness), burr height (<0.05mm). CMM measurement every 500 parts.
## Applications
Fine blanked servo press parts: automotive seat adjusters, transmission components, hydraulic valve bodies, watch components, medical device parts.