Press Tonnage Calculation Formula
If you need to punch round, square, or any other type of holes through a given thickness of metal, you want to determine the pressing force required to make a hole in steel. The punching tonnage required can be calculated using the following press tonnage calculation formula, which can also be used for blanking force calculation.
Press Tonnage (KN) = Perimeter (mm) * Plate Thickness (mm) * Shear Strength (kn / mm2)
Converted into metric tons: dividing the result of KN by 9.81
- Perimeter: The total length of the continuous line forming the boundary of a closed geometric figure.
- Thickness: The thickness that will be penetrated by the punching mold.
- Shear Strength: The physical properties of the plate, which are determined by the material of the sheet, can be found in the material manual.
Common materials’ shear strength are as follows: unit: KN/mm2
| Aluminum | Brass | Low Carbon Steel | Stainless Steel |
| 0.1724 | 0.2413 | 0.3447 | 0.5171 |
For various shear strength table, you can check out the following post:
e.g: If punching one square hole in the 3mm thickness low-carbon steel plate, side length 20mm, you will get:
- Perimeter = 20×4 = 80mm
- Thickness = 3mm
- Shear Strength = 0.3447kn/mm2
Punch Force (KN) = 80 x 3 x 0.3447 = 82.728 KN Convert into tonnage: 82.728 KN ÷ 9.81 = 8.43 Ton
For further information about shearing strength, including how to calculate it, you can refer to the Wikipedia article. The formula mentioned can also be applied as the cutting force formula in press tooling or as the formula for determining the force required to punch a hole.
Press Tonnage Calculator
How to calculate the force (tonnage) of a punch press machine?
I believe the following press tonnage calculator can be used to calculate the required punch force for your workpiece.
P.S: If you want to calculate hydraulic press tonnage, you can use our hydraulic press tonnage calculator.
Punch and Die Clearance
The clearance between punch and dies is represented by the total difference, which is one of the critical factors in the punching process.
For example, when using ø12 upper die and ø 12.25 lower die, the optimal clearance is 0.25mm.
Improper clearance can reduce the die service life, cause burrs, and result in secondary cutting. The irregular opening will increase the demounting force, etc.
Besides, the die clearance is dependent on the material and thickness, with a recommended value of 12-18% of the thickness for carbon steel plates.
See also:
If there are no special requirements for the CNC punch, you can refer to the following table for selecting the die clearance.
Punch Press Die Clearance Table
| Plate Thickness | Material | ||
|---|---|---|---|
| Mild Steel | Aluminum | Stainless Steel | |
| 0.8-1.6 | 0.15-0.2 | 0.15-0.2 | 0.15-0.3 |
| 1.6-2.3 | 0.2-0.3 | 0.2-0.3 | 0.3-0.4 |
| 2.3-3.2 | 0.3-0.4 | 0.3-0.4 | 0.4-0.6 |
| 3.2-4.5 | 0.4-0.6 | 0.4-0.5 | 0.6-1.0 |
| 4.5-6.0 | 0.6-0.9 | 0.5-0.7 |
I might purchase punching machine to perform riveting operation. for that I needs to calculate the force require to rivet of mild steel material having following specifications,
diameter of mild steel material is 5mm
for further details isn’t able to share here make contact us on below Email
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Definitely no problem, our sales team will contact you asap.
I will found hydraulic power press Machine for washer menufecturing,so guide me to shuttable for us.
Our sales team will contact you asap.
Hi,
How to calculate tonnage reqrd for CSK operations?
Kindly suggest.
HOW TO CALCULATE THE FORMING TONNAGE PRESS FORMULA FOR EASY.
Do you mean the bending force calculation? If yes, you can use the calculator online here: https://www.machinemfg.com/press-brake-tonnage-calculator/
I would like to punch 24k gold and silver discs from extruded bars. The thickness is 2.8mm and a 30mm dia. I do not need it to be automated, We can perform foot pedal control as we are punching 50 a day.
Do you mean you need the punch press machine?
Press fit a .500″ dia. pin into a .499″ dia. hole?
how to find fatigue failure ??
Is it possible to punch 1 mm brass sheet with a 5 mm square punch?(Tmax=320N/mm²) (E=210Gpa)?
Dear Sir
We need punching m/c for spring steel hole dia18 mm Max Thikness 18 mm .So we want know how much ton pres required for this operation much
Omdutt Sharma
Jamna Auto industress
Our sales team will contact you.