KEVOS® MAKEOS · Fabrication
Deep Drawing Plan (Blank, Draws, Forces and Press)
What blank does this drawn cup need, how many draws will it take, and what punch and blank-holder forces must the press supply?
Plan for drawing a cylindrical shell: blank diameter from the shell diameter, height, corner radius and any flange (as the shell blank tool), the diameter after each draw from your first and later drawing ratios (as the draw reductions tool), the drawing force for each draw by the handbook-style formula F = π d t UTS (D ÷ d − 0.7) (as the deep draw force tool), the blank-holder force on the flange annulus at your holding pressure, and the press check for the heaviest draw.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Shell diameter (mean) | mm | Mean diameter of the finished shell. |
| Shell height | mm | Height of the finished shell. |
| Bottom corner radius | mm | Corner radius at the bottom of the shell. |
| Flange diameter (0 = none) | mm | Outside diameter of a flange left on the shell (0 for no flange). |
| Sheet thickness | mm | Sheet thickness. |
| Tensile strength | MPa | Tensile strength of the sheet. |
| First drawing ratio (d₁ ÷ D) | Largest reduction in the first draw as a ratio of cup to blank diameter (your value for the material; lower is more severe). | |
| Redrawing ratio (dₙ ÷ dₙ₋₁) | Ratio for each redraw (your value for the material and annealing). | |
| Blank-holder pressure | MPa | Pressure on the flange from the blank holder (your value; roughly 1–3 MPa for steel, less for aluminium). |
| Die entry radius | mm | Radius of the die entry, which sets the inner edge of the flange under the holder. |
| Press capacity | kN | Rated capacity of the press. |
Method and formulas
- Blank D = √(d_f² + 4 d h − 0.5 r d), with d_f the flange diameter or d (as the shell blank tool).
- Draw diameters: d₁ = max(m₁ D, d), then dₙ = max(m₂ dₙ₋₁, d) until the shell diameter is reached.
- Drawing force Fₙ = π dₙ t UTS (dₙ₋₁ ÷ dₙ − 0.7) with d₀ = D (as the deep draw force tool).
- Blank-holder force = p_BH × π ÷ 4 × [dₙ₋₁² − (dₙ + 2r_d)²] where positive; press load = drawing + holder force.
- Example: a 60 × 50 mm shell needs a 124.42 mm blank and 2 draws; the first draw takes 101.83 kN with the holder.
Limitations
- Thin-wall cups without ironing; ironing and tapered shells need other formulas.
- Drawing ratios are material- and lubricant-dependent: use your proven values.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Plan the draws and tooling for a drawn shell
- Choose a press for a deep-drawn part
- See how the drawing ratios change the number of draws
Who it is for
- Press tool designers
- Sheet-metal engineers
- Manufacturing engineers
What you get
- Blank diameter and first drawing ratio
- Diameter and force for each draw
- Blank-holder force and press check
Interpreting the result
- If the first draw is close to the press capacity, a lower blank-holder pressure or a larger first ratio helps.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1353–1361. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Deep Drawing Plan (Blank, Draws, Forces and Press) calculator
