Haas VF2/Tool change pop

I've noticed the 2005 Haas VF2 we have making a horrible sound lately. It only happens first thing in the morning and only once, I always leave the spindle without a tool when we power down and go home for the night. When we start the machine in the morning it will load the first tool into the spindle and when it changes to the next tool it pops real loud like the tool is stuck in the spindle! It happens with all types of tooling, drills end mills etc.... I also tried a bunch of different holders as well. It will only do it on the very first tool change and that's it until the next morning. The spindle is clean and the pull studs are fine, I even tried it with a brand new tool holder and pull stud and it still does it on the first tool change. Any thoughts on this?

My machine will often not release the tool at all on the 1st cycle, or pop loudly. I have gotten in the habit of manually cycling the tool release once or twice without a tool before running and that "fixed" it. Perhaps the release piston and draw-bar could use some attention. Or in my case I think it is in the solenoid sticking at first use, if you listen and watch the click of the solenoid sounds delayed at first use, I swear the Z axis starts to move before the valve has opened, but only that first time.

I would try to get some air tool oil into the line for the tool change piston. May be dry and sticking on the first one where it has to work hard. If that doesn't work try some oil on the shaft for the stack washers.

Just a thought.

Mike

This may be hard to do, but next time see if you can tell if the sound comes from the tool releasing from the spindle or if the sound comes from the top of the spindle.

My thoughts are that possibly the pre charge solenoid is sticking which causes the tool release piston to slam onto the top of the drawbar.

Thanks for the replies guys, I appreciate that. I'll look into it later in the week when I get a spare minute.