Retention mechanism woes :(

Solar71 · Mar 19, 2012

Sticky Mechanism on our Hitachi 6M cnc mill.

I put it into jog or rapid mode and i can manually unclamp my tools.
But sometimes when i put the tool back in and try to clamp it, the mechanism will not clamp.
The unclamped Light stays and the tool does not get held in.

But sometimes it works fine. Its sort of a hit and miss.
Also its coldish today.

Any tricks or tips to getting this thing working ?

Thanks

Boris · Mar 19, 2012

If its a air piston on top to drive the drawbar bar up and down, check the thing is actually going full stroke and not leaking from its seals,
Then check the action of the drawbar, sometimes they fill with gunk and a good blast of WD40 will clean it out.. maybe
Then check your switches on the drawbar mechanism for drawbar down and drawbar up, sometimes these will stick and give a false clamped/unclamped signal

After that...... dunno really :confused:

Boris

WILLEO6709 · Mar 19, 2012

I have had to disassemble the whole tool clamp works, clean and reassemble before. sometimes a good air blast from the front,,,, sometimes you have to replace a collet or the belleville springs. sometimes its a bolt loose, depends on the machine.

Solar71 · Mar 20, 2012

Thanks you guys.

Well this morning i tried shooting some penetrating oil up in the spindle area. Straight up paste the taper.
So far no joy.
If this doesnt work we will start looking at the air leaking theory.

John_B · Mar 20, 2012

You may need to pull it apart. I've had the belleville washers break up into multiple pieces and cause erratic operation before - apparently the pieces were moving around and intermitently holding the drawbar closed, then open, then midstroke.... The thing you don't want to do is use the machine with low draw bar force!

Solar71 · Mar 20, 2012

I don't know how to take apart the draw tube assembly. Unfortunately.

But I can ask my boss to call one of our repair guys.
Thanks for your help.

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Retention mechanism woes :(

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