Stamping Copper 2

[RustyH]

Good Evening,

I am looking to design and make a machining that can stamp out a 5mm hole in 3mm think copper.
I was wondering how I would go about calculating the force needed to do this.

Also, does anyone think that this would be possible pneumatically with an air piston running off an air compressor?

Many thanks
Rusty

 

[dvd]

Please provide a sketch of the hoop

what quantities do you intend to produce?

 

[RustyH]

Sorry, that was a Typo, was meant to say "5mm Hole", so it's just a simple 5mm diameter hole to be punched out.

I would say around 2000 holes per week.

 

[MintJulep]

This is the second of 27 million hits from Google.

https://www.machinemfg.com/punching-tonnage-calculation/

 

[RustyH]

Thanks for the link

So using that, I need less than a tonne.
Is that something that can be achieved pneumatically?

 

[ctopher]

I don't know the details of the machine, but we have a pneumatic press for stamping beryllium copper (a little harder than copper).
Copper is soft, doesn't take much force.

Chris, CSWP
SolidWorks
ctophers home

 

[RustyH]

Hi Chris,

Appreciate the reply. If you get chance to see the make and model of the machine please let me know

 

[dvd]

It would be possible to punch these by hand with a Whitney punch

You could also use a Unipunch setup in a press brake, or with a custom pneumatic arrangement. There is discussion of this on the Unipunch website.

 

[RustyH]

Thanks DVD

I would certainly like a press brake setup, but I don't have the facility to place such a large machine unfortunately, and I only have access to 240v

I would be punching in the region of 2000 holes per week

 

[SnTMan]

If I have done my F = P * A right, 100 psi shop air and a 5" cylinder would get you a ton (2000 lb).

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[EdStainless]

small holes in thick material (especially when it is soft) are a job for 'fine blanking'.
If you look it up there will be a lot of info.
There is considerable clamping force applied and then the punch is driven quickly.
It results in very clean holes.
We had special toolset made for an electrical solenoid driven press.
We were putting coffin shaped holes about 3x5mm into 5mm thick high purity Cu.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[SnTMan]

Can they be drilled?

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Artisi]

any sheet metal shop with a small press could handle this without even thinking about it.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[EdStainless]

They cannot be drilled because of the very soft Cu.
It would be very difficult to get clean holes.
Stamping these is a lot harder than you think, holes that are as deep (or deeper) than the diameter pose very special problems.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[mfgenggear]

I agree with Ed
I would suggest testing

 

[SnTMan]

Well, TBH, we have no idea what the OP is doing, really.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[dvd]

Mat'l thickness 3mm
Hole dia. 5mm

(see attached Dayton Rogers Redbook for more info)

from -

https://alloys.copper.org/alloy/C10100

 

[tygerdawg]

Most textbooks in Manufacturing Processes will give the equation provided in the link above.
If you don't have Shear Stress values, an alternative formula is F = (0.7)*T*L*(UTS) where UTS is Ultimate Tensile Strength (T = thickness, L = perimeter length of shear line). Mind your units in the calculations.

The critical issue for quality holes is clearance values between the punch and die. In none of your descriptions did I see any mention of the process quality requirements.

A websearch using the terms arbor press, ironworker, stamping press, hydraulic press, air-over-oil press, etc. should lead you to various types of equipment that could do this. 5mm hole punch and die sets are readily available on the market. Knowing that there will be substantial support structure design requirements, I wouldn't waste my time designing anything. I'd just purchase a suitable unit from somewhere.

2000 holes per week:
For a 40-hour week and 100% efficiency, that will be a continuous production rate of 72 seconds per hole at one hole per stroke. At a more realistic 70% efficiency, it will be ~102 seconds/hole. It is unlikely you will be able to maintain that rate for 40 hours.

TygerDawg
Blue Technik LLC
Manufacturing Engineering Consulting

http://www.bluetechnik.com

 

[SnTMan]

One hole in 2000 pieces of metal? 2000 holes in one piece of metal? Something in between? Who knows?

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[RustyH]

Thank you for all the replies, much appreciated.

It will be approx 2000 HOLES per week

I do drill them at the moment, but drilling leaves a large burr on the drill out side, which them involves a separate process to deburr.

In terms of quality, pretty low quality in all honesty, a shear burr from punching out would be ok, as it would form flat with a fastener anyway (The burr from drilling is pretty excessive, but I dont have coolant setup so that may play a part)

I think you right in finding a compact machine that is capable of doing this with out designing and making one. Every time I search, it either throws up the huge 55 tone presses or the manual pump hydraulic type ones. Some new terms thrown out in the thread though that I will google now