As far as I know, it used to work. The machine hasn't been run for a couple of months and the ATC a bit longer than that.

It's hard to tell what's happening because it happens too fast, but the swing arm will drop tools either removing them from the spindle or the pot. The arm looks to be aligned, but hard to tell since I don't know how to jog it.

It seems like the arm isn't grabbing the tool. Is there a mechanical gripper? Operated by air? If so, is there a solenoid controlling that buried somewhere deep inside the machine? The manuals I have are useless. Just a page on the arm and it mentions using buttons that don't exist on my machine.

It's a 1990 MV-40B with Fanuc 0M and 20 tool ATC.

Any clues would be helpful since I can't afford weeks of downtime while I search for the problem. Right now I'm limited to manual tool changes. No fun.

Thanks in advance.

-Steve

The claws that grip the tools on the ATC arm have a plunger that holds the tool to the claw. If any of that is damaged, tools will fly. Also, the claws themselves can be bent and not fully gripping the tools.

Thanks I'm guessing that the plunger isn't activating. Nothing looks bent or damaged at all. Any idea how to manually cycle the plunger to check to see if it's working? Or even better ... any schematic of the plunger mechanism so I can trace the fault?

the plunger on the mv40 that I used to work on used to come out of position every so often and wouldn't push down properly to open the grippers , we had a maintenance guy who dealt with the problem so unfortunately i can't help you with that but i do remember that it was a fairly simple fix

Without digging too deep, I can't see where that plunger lives. There was an air leak from somewhere within the ATC a few months ago that disappeared. My partner was running the machine and wasn't using the ATC but never mentioned why.

Is it possible that the plunger was stuck open (air leak) and now is stuck closed (no more leak - dropping tools)?

If anyone can tell me how deep to dig and where that plunger is, I'd appreciate it. Don't want to end up taking apart half the machine if I don't have to.

It sounds like the gripper is sticking from non use. WD 40 that little catch on the gripper to make sure it is moving. Also on these older machines I can remember we had to fill the upper cavity with lube oil every couple years for the Tool changer or it would not work properly. I think you can operate the tool changer in manual mode. Where the coolent on button and other buttons will cycle the changer. But you have to put the machine in the manual state to do this. There should be 2 buttons under a cover on the right side of the Control for this purpose. Does your manual show a manual mode for the tool changer?

The gripper moves freely. I went through a bunch of tool changes from the spindle and from the ATC and it drops them regardless. I thought that would free things up, but no dice.

I tried to follow the instructions in the manual for manual operation but my controller doesn't have the buttons it's telling me to press. The side of the controller only has a magazine start button that jogs the magazine and an emergency release button. No MAN ATC button as in the manual. BTW, I tried both and neither put it in manual mode.

Any ideas on where to start digging would be greatly appreciated.

Don't know if you have solved the problem or not but..
ATC manual is on the Aux page.
reasons for tool throwing..

Stuck plungers or stuck plunger lock (under the atc arm )
Z axis crash, ATC height is off.
ATC arm out of rotation ( usually caused by above )
Bent ATC claw (or two )
Unclamp cylinder needs to be bled. (air in the oil system)

A real Mori tech could have you running in an hour if no parts are needed. Might be worth it.

Take out the 4 cap screws holding the round cap under the arm in the middle, it is spring loaded. Remove the the spring and rod and clean them up.
Now you can check the plunger operation on the grippers.
If it throws tools out of both grippers, it will be the rod in the middle of the tool change arm shaft, if it's only one gripper problem it will be the plunger for that gripper.