Press Tonnage Calculation: Avoid Under or Over-Sizing Your Press

Selecting the correct press tonnage is critical for efficient metal stamping operations. Too little tonnage causes incomplete forming and press damage. Too much tonnage wastes capital and operating costs.

Basic Tonnage Calculation Formula

For blanking and punching operations:

Tonnage = Perimeter × Thickness × Material Shear Strength

Where:

• Perimeter = Total cut edge length (mm or inches)
• Thickness = Material thickness (mm or inches)
• Shear Strength = Material property (varies by material type)

Material Shear Strength Reference

• Mild Steel (Q235): 350-450 MPa
• Stainless Steel (304): 550-650 MPa
• Aluminum (6061): 200-250 MPa
• Copper: 250-300 MPa
• Brass: 300-350 MPa

Example Calculation

Blanking a 100mm diameter circle from 3mm mild steel:

• Perimeter = π × 100 = 314mm
• Thickness = 3mm
• Shear Strength = 400 MPa (mild steel)
• Tonnage = 314 × 3 × 400 = 376,800 N = 38.4 tons
• Add 20% safety margin = 46 tons
• Recommended press: 60 ton (next standard size)

Additional Considerations

Beyond basic blanking, consider:

• Forming and drawing operations require additional tonnage
• Multiple stations in progressive dies add cumulative force
• Stripper force typically 10-20% of cutting force
• Material work hardening increases required tonnage

Why Choose LAIFU Press Machines

LAIFU press machines feature rigid C frame construction, precision crankshaft design, and reliable clutch-brake systems. Our engineering team provides free tonnage calculation services for all customers.

Contact Us

Send us your part drawings and material specifications for accurate press selection recommendations.