admin
Seat frames are stamped from HSS/UHSS 590-980 MPa.
## Motion Profile
- Approach: 400mm/s
- Pre-contact: 80mm/s at 20mm above material
- Forming: 50-100mm/s
- Dwell at BDC: 50-100ms (reduces springback variation 80%)
- Return: 500mm/s
## Blank Holder Force
- HSS 590MPa: 15-20% of forming force
- HSS 780MPa: 20-25%
- UHSS 980MPa: 25-30%
Increase if wrinkling. Decrease if splitting at punch radius.
## Lubrication
EP draw compound at 2-4 g/m2 both sides. Never dry stamp UHSS.
## Tonnage Limits
- High: 110% nominal (die crash, double blank)
- Low: 85% nominal (missing blank, broken punch)