Ironworker/punch/calculations/springs
Jump to navigation
Jump to search
==Problem Statement:== Specify springs for a Piranha style punch Knowns:
- Max punching force: 90T
- Max stripping force: 25% of punching force, or .25*90T=22.5T
Unknowns:
- Necessary compressive force for spring
- Spring Length, solid and stretched
- Spring constant
- Spring Diameter
Calculations
Max Compressive force
=Force/# of springs
- 22.5T/2 = 11.5T, at 1", or any other application which requires 90T of force.
Spring Specs
Thoughts
- Since the machine can theoretically do a cut which uses 90T of force in infinitely thin material (the diameter of the hole would need to be really big!) we should use springs which will have close to the 11.5T of force with very little distance moved. Also, this would not need to change too much as the machine progresses towards making 90T punches at the 1" thickness.
- What this tells me is that we should use a spring with spring constant (k) relatively low with relation to it's diameter, and compress it to install. This way, we won't be needing to overcome more force than necessary.
- IE if we need 11.5T for 1/4" steel, we have two options use the low constant or the high one.
- If we use the low one, precompressed, the force will be relatively close to that, maybe a max of 15T or 20T, if we are punching thru 1" thick.
- If we use a high constant, the force would quadruple over that distance, making it 46tons. If you don't understand this, take a physics class.
- IE if we need 11.5T for 1/4" steel, we have two options use the low constant or the high one.
- What this tells me is that we should use a spring with spring constant (k) relatively low with relation to it's diameter, and compress it to install. This way, we won't be needing to overcome more force than necessary.
- Research on how Piranha does it:
- Perhaps the easiest solution is to buy a set of piranha urethane strippers, as they are relatively cheap ($76 here).
- Problem with this is that it requires same length of bit and attachment as piranha, which we don't have access to... we could guess from videos and get close, but this is not preferable.
- Another option is to buy the polyurethane die strippers from McMaster. It appears they don't have anything which offers enough resistance... but perhaps it is something which can be tested.