Shear strength n mm 2.
Psi required to punch through a sheet of aluminum.
How to obtain tonnage required for punching round holes.
Multiply x 1 25 stainless steel.
With a small twist bit 1 16 in.
Multiply x 52 high carbon steel.
For round holes in steel this is diameter pi 30.
To calculate the force to punch holes in metal you determine the cross section in shear and multiply it by the shear strength of the metal.
The shear strength is 350 mn m 2.
To calculate the tons needed for other metals just multiply number times the tons required for punching mild steel.
3 1416 x 2 000 x 250 x 25 39 26 tons.
Multiply x 70 copper 1 2 hard.
As this happens you gain a small amount of total length in your part.
Punching force calculation formula.
Tonnage required for punching round holes.
Likewise when you are trying to develop a flat pattern you will have to make a deduction from your desired part size to get the correct flat size.
Recommended die clearance in of thickness low carbon hr steel rb 70 50 000 345 1 00 20 low carbon c r.
If you punch round holes or square holes or some other forms of holes through a given thickness of metal you just want to know the force required to punch a hole in steel.
Sheet rb 40 000 276 80 25 astm a 36 bhn 119 159 58 80 000 1 20 20 25 45 50 carbon hr sheet bhn 200 80 000 552 1 60 25.
To 3 16 in you can drill through most metals at 3 000 rpm.
Multiply x 36 brass 1 4 hard.
Tons 2000 lbs required to punch round holes in mild carbon steel having a shear strength of 60 000 psi subject to the multiplier from table above of 75 to 1 3 according to the state of the metal whether annealed or work hardened.
When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched.
You can calculate the punching tonnage been required with the help of the following punching force calculation formula blanking force formula.
Tonnage in mild steel 3 1416 x diameter of hole x material thickness x 25 example.
The formula is perimeter times thickness times shear.
Problem 115 what force is required to punch a 20 mm diameter hole in a plate that is 25 mm thick.
Required tonnage for punching mild steel with tensile strength of 50 000 psi how to calculate required tonnage for punching mild steel with tensile strength of 65 000 psi how to calculate the diagonal dimension of a punch.
Thirty tons being the approximate shear strength of mild steel plus an allowance for friction.
Hard metals like steel and larger drill bits require even slower speeds.
