Force over a given length

[Erb]

I have Worked out the force needed to punch one hole in 6061 aluminum 3mm thick. Now I need to know what force is required to punch 11 holes spaced 300mm apart in a single length of the same product at once with a single rail holding the 11 hole punches?? I am not a student it is not homework!! I'm sure that over distance and the number of holes, would increase the force required, but by how much I am unsure. The hole punch required is a 4.7 ton hydraulic hole punch. Would three spaced out evenly over a distance of 3.7m give me enough force to punch the 11 hole simultaneously. Anyone got any ideas or tip on how to work it out let me know please. Thanks

[Externet]

If I understand your question properly, the 11 holes could be punched in one downstroke by the same 4.7 ton press if the punch dies are sequentially staggered in depth.

I do not know what the 3.7 m have to do here.

 

It would take each punch die to be ~4 mm longer than the other; when punch 1 exits trough the material, the next one starts punching.

 

If that is not what you were after, sorry, will count only as "an idea on how to work it out."

 

- - - - - - - - - - - <---- 11 punch dies assembly going down

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- - - - - -

- - - - -

- - - -

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- -

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============ <---- 6061 sheet

 

The leftmost and longest punch die will go trough first, then the next and next while the whole die assembly comes down...

[DrRocket]

I have Worked out the force needed to punch one hole in 6061 aluminum 3mm thick. Now I need to know what force is required to punch 11 holes spaced 300mm apart in a single length of the same product at once with a single rail holding the 11 hole punches?? I am not a student it is not homework!! I'm sure that over distance and the number of holes, would increase the force required, but by how much I am unsure. The hole punch required is a 4.7 ton hydraulic hole punch. Would three spaced out evenly over a distance of 3.7m give me enough force to punch the 11 hole simultaneously. Anyone got any ideas or tip on how to work it out let me know please. Thanks

 

 

There is something called St. Venant's Principle that roughly states that stresses at points significantly distant from one another are essentially independent.

 

To punch a hole requires application of a load that results in the local shear stress exceeding the material allowable. So to punch 11 holes (simultaneously) in your saituation you will need to apply 11 times the force necessaer to punch one hole. If you stagger the punches as suggested earlier the necessary force will be the same, but the required travel will increase by a factor of 11, plus some tolerance slop.

Edited October 25, 2011 by DrRocket

[Erb]

Thanks for the feedback guys! It has helped. I think I might use three 15 ton hydraulic rams to force the 11 punch dies through the material at once. The 3.7m is the length of the armature the 11 punch dies are attached too. If I spread the load evenly across the armature I think I should be able to punch the holes in one downward motion. Thanks heaps!!