Sheet Metal Drawing
Compute drawing ratio m and first-draw punch force F = π d t σ_s·C₁.
Inputs
Formula
m = d/D; F = π d t σs·C1
Fundamentals
Deep drawing forms an open shell from a blank by pressing it into a die — a stamping forming operation.
The punch radius is in tension, the flange in circumferential compression; draw ratio $m=d/D$ smaller = harder, needing multi-stage drawing or a blank-holder to avoid wrinkling.
History
Deep drawing grew from tinplate and canning (19th c.); auto body panels pushed it to large size.
Engineering applications
Used for plastic forming of containers, shells and automotive body panels.
Glossary
| Draw ratio $m$ | Part dia / blank dia; smaller = harder. |
| Blank holder | Clamps the flange to prevent wrinkling. |
| Punch radius | Stress-concentration / fracture risk zone. |
How to use
- Fill in Punch dia. d, Blank dia. D, Thickness t, Yield σs, Coeff. C1 in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Drawing ratio m, Drawing force F in the results area.
Formula notesDrawing force P ≈ π·d·t·σ_b·k (d part dia, t thickness, σ_b tensile strength, k factor).
Formula · Worked Example · Knowledge
Formula
Drawing ratio $m=d/D$; first-draw force $F=\pi d t\sigma_s C_1$ (d punch, D blank).
Worked Example
d=50, D=100, t=1, σs=300, C1=1 → m=0.5, F≈47.1 kN.
Key Points
- Very small m (<0.5) wrinkles; use multi-stage draws.
- Punch/die radius and blank-holder force affect quality.
- Annealing improves ductility.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Punch dia. d (mm) | d | mm | 50 |
| Blank dia. D (mm) | D | mm | 100 |
| Thickness t (mm) | t | mm | 1 |
| Yield σs (MPa) | sigmas | MPa | 300 |
| Coeff. C1 | C1 | 1 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Drawing ratio m | m | |
| Drawing force F | F | N |
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: m = d/D; F = π d t σs·C1
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