controle system for a cycling hydraulic press.

[basher]

Up until now I have used an analog spool valve to run my press. I have however been very impressed by some of the cycling hydraulic presses I have seen, that run like a power hammer using a microswitch for top of up stroke and  a microswitch for bottom bottom of down or a pressure switch whichever kicks in first.

 I love my press for punching but found it limiting for drawing out work, the limitation being my reaction time at top and bottom of stroke, which sucked into heat time and at the bottom of the stroke cooled the metal too quick.

 My thoughts were that with tooling set close and a cycling control system the press would really become the tool it always wanted to be. There was some impressive footage of a German press set up like this.

 I had this idea about 3 years ago and bought a solenoid valve block  and some relays and a pressure switch and micro switches and a foot pedal.....anyhow life took over and 3 years passed..... I am back on this idea.

 At the time I had someone draw me up a circuit diagram. I think it makes sense again.

 what I want is :-

 Foot on pedal ram moves down, foot off of pedal ram lifts up until it hits top micro switch then stops.

 If I keep the pedal down  ram moves down until it hits bottom micro switch or reaches pressure , it then cycles up until it hits top switch and then down again and the cycle repeats until the pedal is depressed.

 

here is what I have :-

any critique , ideas or suggestions would be most welcome.

[Richard Furrer]

Make sure the electric solenoids are controlling valves that can pass the volume of oil...the larger GPM valves cost quite a bit more.

If you move a lot of fluid then you may run into a "hammering" effect in the line with rapid flow changes. This can increase the PSI load greatly.

That said I have seen several 8gpm presses with very fast action and I ran an 11 gpm with foot switch an auto return (spring detent to reverse flow) without the upper microswitch that worked well for many many years till I sold the whole press.

 

Ric

[phabib]

You also need some diodes on the solenoids or the switches and relays will fry in short order.  Basic rule of thumb is they should be rated for at leas 4x the operating voltage.