Haas VF-1 tool change issue - Watch Video

[jpmf1001]

We have a 2003 Haas VF-1 and are having a problem during tool change.
Below is the link to a slow motion video I made. You can clearly see the tool holder lowering down a slight bit before it enters the umbrella carousel. Then the "fork" is not lining up with the groove in the tool holder. The fork is actually grabbing right above the groove. Sometimes it ends up correctly in the groove on the holder, but it is definately always lowering that slight bit out of the spindle before entering the carousel.

What could be the matter?

Video link:


Thanks in advance for the help,
Walter

[behindpropeller]

We have a 2003 Haas VF-1 and are having a problem during tool change.
Below is the link to a slow motion video I made. You can clearly see the tool holder lowering down a slight bit before it enters the umbrella carousel. Then the "fork" is not lining up with the groove in the tool holder. The fork is actually grabbing right above the groove. Sometimes it ends up correctly in the groove on the holder, but it is definately always lowering that slight bit out of the spindle before entering the carousel.

What could be the matter?

Video link:


Thanks in advance for the help,
Walter

Has it been crashed recently?

The problem can be fixed by changing the parameter that drives the tool change height. I don't know what parameter it is though.

Before you go changing parameters you really need to figure out what the original cause was.

[Machineit]

It is not the tool change height problem. The tool is beginning to release way before the carousel moves in. It should not begin to release until the changer is in place and trips the switch indicating so.

I have seen the switch that indicates that the carousel is in place stick and tools get dropped straight out of the spindle, but never seen one only partially release.

One thing is that the video is slowed way down, so it is possible that the carousel is almost there before this happens, which means that a switch may be sticking.

There are two switches that trip when the carousel is in the "IN" and "OUT" positions. I would start by cleaning each one. Spray something like WD-40 on them and cycle them by hand many many times to free them up. They often get sticky and move but not that last .02" or so they need to trip. Often they just stick for a fraction of a second and appear to be working fine.

Anyway, sorry for the poor explanation, but this is not a tool change height setting problem. The carousel should be in place before the tool is even starting to be released. Not saying that the change height may not be off, but it does not cause this problem.

Mike

[Haas__man]

I am nearly certain that your drawbar needs to be replaced.
When a tool change is commanded :
the machine orientates the spindle,
then precharge is commanded - precharge is very low pressure and is intended to put the bottom of the TRP in contact with the top of the drawbar prior to full unclamp so as not to damage either face.
the toolchanger then moves toward the spindle with the tool still clamped.
when the toolchanger is in position, the tool is then fully unclamped
and the head lifts.

your problem is that the very low precharge pressure is enough to unclamp the spindle and therefore the drawbar is weak and needs to be replaced.

hope this helps

[jpmf1001]

I am nearly certain that your drawbar needs to be replaced.
When a tool change is commanded :
the machine orientates the spindle,
then precharge is commanded - precharge is very low pressure and is intended to put the bottom of the TRP in contact with the top of the drawbar prior to full unclamp so as not to damage either face.
the toolchanger then moves toward the spindle with the tool still clamped.
when the toolchanger is in position, the tool is then fully unclamped
and the head lifts.

your problem is that the very low precharge pressure is enough to unclamp the spindle and therefore the drawbar is weak and needs to be replaced.

hope this helps

We have taken the hood off and are able to see the precharge in action. When the TRP comes down and makes contact with the drawbar we see that it pushes the drawbar down a little bit and then fully depressed when it is in the carousel.
Could there be an issue with too much air pressure that is causing it to go down this little bit? Or is it just a weak drawbar causing it?

How hard would it be to replace a drawbar?

thanks for the help
Walter

[Machineit]

I am nearly certain that your drawbar needs to be replaced.
When a tool change is commanded :
the machine orientates the spindle,
then precharge is commanded - precharge is very low pressure and is intended to put the bottom of the TRP in contact with the top of the drawbar prior to full unclamp so as not to damage either face.
the toolchanger then moves toward the spindle with the tool still clamped.
when the toolchanger is in position, the tool is then fully unclamped
and the head lifts.

your problem is that the very low precharge pressure is enough to unclamp the spindle and therefore the drawbar is weak and needs to be replaced.

hope this helps

While you very well might be right about the weak drawbar, the precharge goes to the opposite side of the cylinder. I don't see how it would release the tool, as the pressure would be in the opposite direction.

Maybe dirty sticking solenoids and the precharge is somehow going to the wrong side?

Nice mystery!!!!!

Mike

[rlabonte18]

probably bad regulator on your precharge valve. the precharge brings the tool release cylinder down until it it makes contact with the drawbar to reduce the popping sound of the tool change, the precharge valve engages the second the carousel goes into motion is why your tool is slowly starting to push out the main valve does open until the carousel is in position. easiest way to set precharge pressure is unplug your main valve and hold the manual tool release button and adjust the pressure on the valve behind the spindle motor so that it is just enough pressure to move the cylinder down to the drawbar. or like others have said maybe your drawbar is bad but that would likely show in the quality of the finish on your parts.

[Geof]

"Drawbar" has been mentioned in a few posts. To be picky I think it is not the drawbar but the Belleville springs that need replacing.

Have you tried just prying the tool down with the large screwdriver between the flange and spindle nose. The drawbar tension from the springs should be somewhere around 2500lbs so it takes a fair bit of force to pry the flange down. You can do a rough estimate of your drawbar tension by figuring out your lever ratio and the amount of force you have to apply.

[gizmo_454]

...Have you tried just prying the tool down with the large screwdriver between the flange and spindle nose. The drawbar tension from the springs should be somewhere around 2500lbs so it takes a fair bit of force to pry the flange down...

I was told to try this when we were having issues with chatter on one machine, and not on another with the exact same program, and a similar tool change issue. I'll tell you, it was difficult to move the tool at all. The service tech came from the HFO and, after checking with a force gage, told us we had 0 lbs. of force on our draw bar. Haas does not replace just the washers, they replace the whole draw bar. After the new one was installed, we had 1750 lbs. of force on our VF2SS.

I would first find someone with a draw bar force gage and check the tension. I think that is a good place to start.

Good luck!

Mike

[haastec]

I am unable to watch the video where I am currently, so I will comment based on what I have read.

To much air pressure in the precharge line CAN cause the tool to drop lower that it should be. It can also cause the tool to drop out all together, though I have never actually heard of this happening to someone.

First, check the precharge air pressure. It should be about 5 PSI.
Next, download the service manual from the Haas website if you don't already have it. Look up setting tool push out and tool clamp/unclamp switch adjustment and follow the steps.

After all of that, then go ahead and check your drawbar for cracked springs if needed.

As a side note for anyone with an umbrella style tool changer, before changing any tool change height parameters, spot check several different pockets around the tool carousel to see if the plate is bent first.

Good luck!

[iamhaastech]

jpmf

this is what you need to do _
first you need to see if your umbrella (the main aluminum part is bend) if it is you have to split the difference or replace, part no 93-0089

if its not bend you need to change your parameter 64 tool change height


1st setting 7 turn off
2nd par 64 , keep this number in case you mess up you can alway go back , start by adding of sub 5000 to this number
3rd zero rtn
4th do a tool change make observation and mod. par 64 til forks line up!
after changing par 64 alway do a z rtn :0 if not it wont change.
rem to set 7 when your done

[iamhaastech]

i just watched it again i see the tool is starting to come out while the tc is comeing to pick up the tool, i would say you need to set you tool release switch on top of the tool release piston, check the limit switch and spray it with wd-40, see of that helps if not you might need a haas tech to set the switch kinda tricky