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BRIDGEPORT VMC1000/30 Tools ROTATING ARM TOOL-CHANGER PROBLEM

sputnikprecision

Aluminum
Joined
Mar 21, 2007
Location
Malta- Europe
This machine started to give up this problem. When machine changes the tool, the tool arm will stop half way with the error TOOL NOT UNCLAMPED. air keeps blowing.. then if you press CE and start button, it would proceed with the tool change and proceed with the program. This would happen with every toolchange..
Action;-
Dismantled/inspected and assembled the belleville springs, cleaned everything.
Checked both limit switches on the Drawbar piston.
everything looks ok.

However by accident, when testing with the meter the lower microswitch during toolchange, if the meter is left connected, the tool change would proceed without a problem.

Then I bridged the lower microswitch with a Zener Diode, the machine would work, tool change works but it will skip blowing air in the spindle taper to clean and will not do spindle orientation.

I put M19 before each tool change and got round the problem this way. Machine seems to work ok but something is not right.
Somebody encountered anything like this? I do not want to leave it like this definitely.

I am suspecting something may be a problem with the swinging arm 30 POS tool-changer. Anybody has a schematic of how this works?
Thanks in advance.
 
Sure sounds like that switch is bad or mis adjusted.
'shorting' the switch makes it proceed but must stop the other processes when it is closed at the wrong time. PLCs are kinda dumb. My Auto saw does freaky things when a limit switch gets stuck closed
 
……PLCs are kinda dumb……
It’s not the PLC that’s dumb, it’s the program running in it that’s dumb. It’s tough to write logic that foresees all potential hardware or operation failures. I’ve seen lots of ladders that overlooked even the most simple of failure modes like mutually exclusive conditions. That’s a complete fail on the part of the machine builder’s group responsible for control integration.
 
It’s not the PLC that’s dumb, it’s the program running in it that’s dumb. It’s tough to write logic that foresees all potential hardware or operation failures. I’ve seen lots of ladders that overlooked even the most simple of failure modes like mutually exclusive conditions. That’s a complete fail on the part of the machine builder’s group responsible for control integration.
Is there a way to access the PLC????
 
No one knows since you failed to include what control you have.
It`s a TNC407 control.
I have noticed that the LED`s and Relays on the Type D relay board are not giving the correct signals. The Relays 9CR (tool Down) and 10CR (tool up) are not functioning. I have taken a similar pCB from another machine and it confirmed that the board on the machine is not defective. Even the two switches which sense the Tool down and Tool up mounted on the Drawbar piston are functioning well.
We have changed all the Belleville washers and rehauled the pullstids mechanism because initially we thought it might be the culprit.
 
Well, for those who wrote a possible solution, I will explain. After taking apart and renew the Springs in the Pull stud mechanism, taking off the Plunger piston and renewing the seals and another valve which operates the piston, changed the card, renewed the switches.. nothing was solved. I connected a push switch in parallel to the down plunger position and operated it by hand when the piston comes down and the problem disappeared.
What was happening was that the piston plunger was moving down slowly and was not hitting the tool unclamp switch fast enough. There is a diaghram valve on the side of the piston and it had the diaphram cracked and losing air. Fixed it and problem sorted. many thanks for your help.
 








 
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