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Power Drawbar dropping the Tool Holder when the computer is turned off on a Journeyman 325 Tree

Chrome Dome

Jan 15, 2009
Lake Oswego, Oregon
Hey guys I am a bit of a novice and apologize ahead of time for any incorrect lingo. I have an old Journeyman 325 Tree. I recently replaced the solenoid air valve that releases the tool holder, because it would not pull the holder in when you flipped the switch to clamp. Even though the exact solenoid air valve was not available the one I got looks almost exactly the same with the same diagram on it and same specs. When I installed it and fired the machine up it worked better than it ever had. I put a tool holder in and out multiple times. But then when I turned the computer off it dropped the tool holder out of the spindle. Oh, I also replaced the wiring up to the tool holder release switch prior to swapping the valve because the insulation was all melted together near the spindle/switch end and I was thinking something may have shorted. After replacing that wire (3 conductors) nothing changed. Any help or thoughts would be greatly appreciated. Thank you.

One other thing I just noticed is the clamp/unclamp switch is backwards. I don't remember if it has always been like this or if this is new feature since replacing the wiring and solenoid air valve.
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There are three-position air valves available that require a voltage to be applied to effect the change in state. If your solenoid is two_position with a spring return, then it's gonna drop the tool when you remove the power. I installed a three-position switch on the collet closer of my Hardinge CHNC. It can be operated either manually or within a program, but requires either pushing an "off" or "on" button or two outputs from the cnc I/O.
I never got into the wiring of my tree 325 tool release solenoid, but the mechanism has a spring that retains the tool when no air pressure is present at the release cylinder. It sounds like you somehow flipped the logic of the air valve and/or electrical switch for it to work as you describe.

To verify the tool unclamp mechanism works as it should, remove the air supply with the control powered on, then switching off the control. The tool should not drop, but be ready to catch the tool in case it does.

The electrical switch maintains power to the solenoid when in the release state and drops power to the solenoid when you tap the switch the to clamp state. I suspect the direction change you noted happened when you replaced the wiring. I also suspect the air logic swap is due to using different ports on the air valve than originally set up, if you are positive the air valve has the same configuration at the original.

let me know how it goes, good luck!