VF-3 tool change problem

Monday I'll be close to Buffalo trying to solve a problem that has plagued this mill for at least a few weeks. It is considered a "test" for me to secure a job.

I don't have much info (very little in fact) but any helpful tips would be greatly appreciated. Here goes.

This is an intermittent problem. It happens a few times a day to a week. From what I've been told over the phone, the spindle orients correctly every time. The tool goes in and arm retracts.
Then, somehow, the spindle turns slightly before the drawbar has a chance to fully secure the tool and the result is a tool that is .100"-.200" or so too low but will come down and scrap a part, vise or whatever.
No alarm.
They have added an M01 to "catch" it when it does this and manually reseat the tool.

That's all I got, literally (I know, )

Oh, and no manuals when I get there and I got a feeling the local Haas dealer won't be much help other than a phone call or two, but I think I can get by with that.

I know a few possibilities to check first.
Loose set screw on encoder pulley.
Verify that it does indeed orient correctly.
Verify tool arm height and alignment.
Check for chips, crashes, etc.
AND, the guy running the shop said he had similar problem with another machine (Haas, I'm pretty sure), that he fixed by replacing the solenoid on top of the spindle.
The local Haas guy here in NC explained the function of that particular solenoid and it does seem likely.
My worry is that I will spend a day or so checking everything out, probably replace that solenoid and seemingly fix the machine only to get a call halfway home saying, "It's doing it again!"

Welcome to my nightmare scenario.

From what I've described, is there anything else, anybody run across this before, any extra diagnostic tips you could pass along?

Thanks to all in advance.

I would think that the tool would have to be clamped before the arm let go. I think it is a tool clamp problem. A solenoid would be suspect as well as the collet. Of course, if the tool isn't oriented correctly, it may not allow the tool to go in all the way.

Many years ago we had a Haas that would pickup the wrong tool from time to time killing the part, tool, and holder. Haas replaced all sorts of stuff and after a year or so, they replaced a board in the control panel and fixed it.

Good luck. I just bought my first Haas for my own shop and hope I don't have any of these troubles. I have two Mazak VTC's in here already, so the Haas has a lot to prove.

David Willingham
Advanced Motorsports Engineering

I hear ya. I used to install and service MAZAK's in FL.
Good machine, but I just never took to mazatrol. The best thing about them is the large number of alarms. It allows you too narrow down malfunctions pretty well.

On the Haas, though, they did away with the old shot pin system on tool orient and now it brakes and holds electronically with the spindle.
So I'm wondering if the "brake" is releasing early due to board problem, bad cable, etc.
That would be something I would need to have more technical info than is available to me, not to mention the 2 days I have. No telling what other surprises await.......
I just don't want to chase the wrong problem or be fooled by the "intermittent" nature of this.

Yep. Intermittent=PITA.

Could you give me a bit more info....Inline spindle or gear box machine?
Roller or prox switch?

The arm will not retract unless the draw bar switch fires.....Check in Diagnostics for correct operation. Though there are many variables chances are that is the the cause.

Long Shot

Tool clamp Dwell Time parameter? If you are that lucky.

If the spindle is spining, look at arm aliginment and spindle height.
Remember arm is aligned to the tool holder pocket in the carosel and then the tool changer assembly is aligned to the spindle.

Thanks for the replies and suggestions.
I did visually check the spindle height and alignment, looked ok.
I didn't have much time or access to Haas info on parameters, etc.
Just got back yesterday after spending a day stranded in WV during snowstorm. (Great OT story, maybe later)
Timing was the issue, I think and my suggestion of turning up air pressure to solenoid has seemed to work to date.
It didn't screw up at least the whole week I was there. Unfortunately, I had lots of other stuff to fix, like a problem Citizen lathe that has stumped at least 3 or 4 techs so far. LOL
Thanks again.