200 Ton Hydraulic Press

Easier part is the mechanical design. You have simple mechanical loading assume the worst condition scenario .

I never meant it is simple. Sorry if you felt that way. The point I made is (though we do not manufacture press, we are in other machinery, we only buy them as we need) our design concept is as above, so my comment was on those aspects.

In fact now I am struggling to put one of my machines up, where the controls have not taken the worst case scenerio in account.

Problem is simple in a center lathe, the Z axis has a habit of hitting the end stop and as expected sooner or later the lead screw gives way (after a few failures of the encoder area threads now the shaft itself has failed, clearly fatigue failure)

Unfortunate: the operator does not come out clearly about the way he was handling it: manual mode on program, so on my part function as maintenance left with guess.

Aalysis shown the feedback system has a habit of occasional failure. The operating system however surprisingly do not handle the absence of feed-back signal, so in absence of feed-back, it goes in rapid mode and hits the end stop. (BTW we now want to check the other few machines whether they have the same habit- their feedback is working, but if it fails whether they too are going to behave this way or not).

This is a clear signal, that the controls safety features have missed out a potential failure mode.

_{Anyway we are scrapping the machine, it is a small one (500mm swingx1mt long) and may not be worth the effort and expense to recondition and system change.}

I do not know where your lathe comes from but it is common practice to supervise the signal coming from the position sensor and build in a redundancy as Red Fred suggested in order to avoid a mechanical failure in case of feed-back fall out for which ever reason (for instance a cable is interrupted).

In your case the designer was not at the right level it is an aspect you could contest by the manufacturer.

It is an old one, and anyway we are scrapping it as mentioned. Part of modernisation and capacity augmentation. We are trying to keep it running till the replacements (new machines) come.

There is a hard stop (hitting that repeatedly the shaft fails on fatigue). The limits are a bit before that but still the momentum (on rapid) carries the cross slide.

Lead into gold is not done by pressure but by a proton particle accelerator. It's been done. It makes the most expensive gold in the world.

Alright, diamonds then. Gary