Sheet Metal Blanking
Compute blanking force F = π d t τ and punch face compressive stress σ_c.
Inputs
Formula
F = π d t τ; σc = F/(π d t) = τ
Fundamentals
Blanking punches the workpiece out of sheet with a punch — the basic separation operation in stamping.
Blank force $F\approx L t \tau$, $L$ cut perimeter, $t$ thickness, $\tau$ shear strength. Punch-die clearance affects edge quality and tool life.
History
Stamping rose with mass car production (Ford 1913); blanking is the basic cutting operation.
Engineering applications
Used for high-volume blanking of motor stators, terminals and housings.
Glossary
| Blank force $F$ | Max force to separate the sheet. |
| Bridge | Material kept between parts for feed rigidity. |
| Clearance | One-side gap between punch and die. |
How to use
- Fill in Blank dia. d, Thickness t, Shear strength τ in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Blanking force F, Punch stress σc in the results area.
Formula notesBlanking force P = L·t·τ (L perimeter, t thickness, τ shear strength); stripper force ≈ 5–10% P.
Formula · Worked Example · Knowledge
Formula
Blanking force $F=\pi d t\tau$, punch face stress $\sigma_c=F/(\pi d t)=\tau$.
Worked Example
d=40, t=2, τ=350 MPa → F≈87.96 kN, σc=350 MPa.
Key Points
- Blanked edge has rollover, burnish and fracture zones.
- Proper clearance extends die life.
- Stripping and ejection forces are extra.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Blank dia. d (mm) | d | mm | 40 |
| Thickness t (mm) | t | mm | 2 |
| Shear strength τ (MPa) | tau | MPa | 350 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Blanking force F | F | N |
| Punch stress σc | sigc | MPa |
Applications
- Cutting parameters and speed
- Gear measurement (3-wire/base tangent)
- Blanking and deep-drawing process
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: F = π d t τ; σc = F/(π d t) = τ
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Cutting parameters and speed