How is press force calculated for blanking?

Press force F = L × t × τ, where L is the cut perimeter in mm, t is material thickness in mm, and τ is the shear strength in N/mm² (MPa).

What is shear strength vs tensile strength?

Shear strength is typically 60–80% of ultimate tensile strength for most metals. For mild steel (UTS ~400 MPa), shear strength is approximately 250–320 MPa.

How do I account for die clearance?

Die clearance does not change the blanking force formula but affects edge quality. Typical clearance is 5–10% of material thickness per side.

What safety factor should I use for press selection?

A 20–30% safety factor above calculated force is recommended. Also consider stripping force (5–10% of cutting force) that the press must overcome.

Can I reduce the required press force?

Yes. Shear angle on the punch or die reduces peak force by spreading the cut over time. A 1–2× material thickness shear angle can reduce force by 30–50%.

Free Engineering Tool #209

Press Force Calculator

Calculate required press force for blanking and punching. Enter cut perimeter, material thickness, and shear strength.

F = L × t × τBlanking / PunchingTonnage

Blank Shape

Cut Perimeter (mm)

Material Thickness (mm)

Shear Strength (τ) (MPa)

Quick presets

Results

Required Press Force

—

Force in kN

—

Cut Perimeter

—

With 25% Safety Factor

—

Blanking / Punching Force

F — required force (N)
L — cut perimeter (mm)
t — material thickness (mm)
τ — shear strength (MPa = N/mm²)

Shear Strength Reference

Material	UTS (MPa)	Shear τ (MPa)
Mild Steel	370–450	250–320
Stainless 304	515–750	350–500
Aluminium 6061	240–310	150–200
Copper	210–370	140–250
Brass	310–450	200–300

Example — Ø50 blank from 2mm mild steel

L = π × 50 = 157.08 mm

F = 157.08 × 2 × 300 = 94,248 N = 94.2 kN ≈ 9.6 tonnes

Press Force Calculator | Blanking & Punching | F = L × t × τ

Published by Nikolai Shelkovenko on February 15, 2026 February 15, 2026

Results

Blanking / Punching Force

Shear Strength Reference