Conventional punch press dies!! Fastening Them

[meps11]

Hi just like to know when installing dies into punch press all dies have to be bolted in and not clamped correct!!! thx

 

[racookpe1978]

???

Each punch design can be different. Show a photograph of the problem, I cannot interpret your question from your words. The dies are usually set into the holder, not bolted at all. What do you mean by "clamped" ?

 

[berkshire]

Custom Die sets can sometimes use Dog Clamps to hold them.
B.E.


You are judged not by what you know, but by what you can do.

 

[ornerynorsk]

Perhaps you should define the difference between what you mean as "bolted" and "clamped". Typical clamps as used in presses and molding machines of all types are referred to by many different names - setup clamps, strap clamps, toe clamps, etc, etc and use bolts or studs for the tightening mechanism.

Now if you mean "clamp" as in a manually tightened threaded screw C-clamp or welders clamp . . . Never use these.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[meps11]

Yes that what I mean is manually tightened screw C-clamps . I myself are not running the machines .They are also putting washers between the C-clamp and bed under the tightening bold. Pictures soon.

 

[ornerynorsk]

Thanks for the feedback meps11. The danger of that lies in that you cannot tighten that sort of clamp to get proper preload on the threads, and the vibration and movement inherent in a punch press will eventually cause the clamp to completely loosen. Once the clamp(s) is off there are several scenarios which can play out, none of which are good.

Also, those kinds of clamps may not have the tensile strength to adequately resist stripping forces on the upstroke in cases a fixed stripper is employed.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[meps11]

Thx for the feed back ornerynorsk. These are being used in 30 to 40 ton punch presses stamping 14g steel .I told them that wouldn't pass a grade 9 machine shop set up.And that those machine are a good accident ready to happen .Put in a work refusal and let ministry get involved .Needless to say they have not put me on either machine yet. Like I said ill take a pic. Considering even a foreman asked what kind of set up that was . ???? and then said it is only 14g .

 

[meps11]

Ornerynorsk .Here are some pics.You will see Clams are level . and other wrong things. Sry about pic fussiness.

 

[meps11]

pic 2

 

[meps11]

Pic 3

 

[meps11]

Pic4

 

[BrianPetersen]

To answer your original question, as a general principle the standard for operation of power presses in Canada (and elsewhere) does allow the use of hydraulic die clamping but there are requirements for how it is supposed to work included in the standard, because of the obvious safety consequences of what happens if the tooling detaches from the machine while it is running. Hydraulic die clamping is standard practice in the automotive industry in large power presses for quickly changing out the tooling between, let's say, left front fenders and right front fenders and left front door panels and right front door panels, all in the same machine. (The whole tooling set for each piece to be made is on a die cart, unclamp the outgoing one, wheel the whole set out of the way, wheel the next one in, clamp it up, carry on)

But as for the tooling in your photos ... yep, that's scary.

 

[chicopee]

The pictures do not show a punch press as they are showing a press brake. So are you using a press brake as a punch press?

 

[berkshire]

What you are referring to a C clamps are in fact UniPunch self contained punch and die sets , properly mounted on a unipunch bed plate.
B.E.

You are judged not by what you know, but by what you can do.

 

[meps11]

NO its an old cut off sheer with a massive flywheel . In the picture the center clamp is totally horizontal and not even touching the make shift die. I would have taken a pic of the other press but they didn't set it up yet. That one has welded holders.

 

[berkshire]

Meps11,
I have looked through your pictures again, Unless you are showing something I cannot see , I do not even see a C clamp in the picture .
What I see are three UniPunches " Blue" bolted to a setup plate that appears to be about 1/2" thick. I see two gauge stops and one end stop "Red " and the restraining dog clamps , natural metal color. The UniPunch is a self contained punch and die set that has its own return spring and material ejection chute. The setup plate appears to be properly dogged down with Dog clamps ( setup clamps) The stroke of the press , or converted machine would be adjusted so as to bottom out at the point where the material just punched through to avoid excessive wear on the punch and die set Look at the tools in the link I have put here.

http://www.toolsetinc.com/our_products.html

You will see your Blue " C clamps ", which appear to be LP series punches.
B.E.

You are judged not by what you know, but by what you can do.

 

[ornerynorsk]

Hmmm, I'm not seeing it either. This is a typical uni-punch set-up that does appear to be properly bolted down.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[meps11]

I Always was shown to have toe down and heel up on the use on restraining dog clamps or any clap. I thought is was it was strange that they would put 1.5 inch square tubing over the threaded rod and then the restraint and then the washer and bolt. Cause when you go to tighten the bolt down once you bottom out your bolt to the 1.5 square tube there would be no pressure on your plate??

 

[berkshire]

meps11 (Materials),
I agree that the dog clamps are a bit marginal, clamping down on that square tubing, there is not a lot of leverage. I would rather see the tubing ,or a solid block, or a proper pair of Vee toothed step blocks, placed behind the hold down bolt to give more leverage, but it does not look like the setup man has a lot of room there.
But this was not what you appeared to be complaining about , you were referring to C clamps Per your quote " what I mean is manually tightened screw C-clamps." which the hold down dogs are definitely not. However if the setup plate is sufficiently ridgid and does not move on the press it should be ok to run.
B.E.

You are judged not by what you know, but by what you can do.