Need Help!- Tool Unclamping too early/Spindle Vibration!

[99bluemoon]

We have a 1999 VF4 mill that has gradually got worse with terrible vibration when cutting. It is nothing to do with speeds/feeds/tool wear because they work fine doing same job on our other VF4. As from yesterday I shut it down and told maintenance to get it sorted.
As I work nights, I returned to find that they had attempted to investigate what was causing this when really not having any experience.
However, it appears they removed a few covers and basically looked to see if anything seemed wrong. They tightened the drive belt to the spindle then put everthing back together.
The day shift guy did a toolchange but it crashed due to the orientation being incorrect.This was put right following a phone call before I went to bed.
The machine is out of use , but I was told this morning that the the spindle is releasing the tool too early when entering the drum during a change. It completes the change ok but it needs to be adjusted. What area/parameter needs changing?
If you rotated the spindle by hand there appears to be a slight knocking from within. Before I left this morning, I told the other guy to put a face mill in and see if the vibration has gone.

Are the Tool Clamping problems/ Vibration connected in any way?

The annoying thing is that I only get to know the full facts on machine problems when I am on the way out in the morning. When I arrive at night there is no change over and any issues may not arise until later. I can usually tell straight away if anything is wrong but it can be very frustrating in attempting to correct things given the limited time available.

[Haas__man]

Sounds like you have too seperate problems.

Spindle releases too early during tool change:
So you are saying that when you command a tool change, the head moves to the correct position, then as the tool changer moves over, the tool is released before the tool changer reaches the spindle and the tool falls out?
If thats correct the the limit switch to the right of the tool changer is probably bad. It is a plunger/roller limit switch and is usually blue.

alternatively your drawbar could be very weak.
This could account for both problems. It would give you a bad finish/vibration, and could allow the tool to drop from the spindle during tool change.
You could try to remove and check out yourdrawbar yourselves, or get your HFO to check it out. They should have a 'Drawbar testing tool' that is inserted into the spindle and shows actual clamping force.

Hope this helps

[99bluemoon]

Thanks for the reply

The Tool is being released just as it enters the tool changer.This stops it falling out completely, but I believe it is too early.
It is noticibly worse since our guys had a look at things and enough for the day shift setter to pick up on it.

The problems may be linked, but the vibration was getting worse on a daily basis so I shut it down. The tool change release seemed to be working fine though.

As previously stated, if you rotated the spindle by hand you could feel a knocking from within. Also, when you get a period of relative calm during breaktimes you can hear strange noises from the spindle area.

We want to try and locate the problems then fix if possible before calling in outside repair people. I will pass on your ideas when I go in again Monday evening.

Thanks

[SORCHEROR]

i think your spindle bearings are going bad,as for the early release,like haas said,bad limit switch,you really need to have the haas guy check the draw bar tension and spindle bearings,other wise your just wasting time,which costs money

[rlabonte18]

when the tool changer begins its motion there is a precharge valve that opens which brings the release piston down to the drawbar then another set of valves open when the tool changer hits the limit switch releasing the tool. possibly weak drawbar causing the precharge too release the tool. or the regulator may be bad the regulator is just behind the spindle motor you can unplug the valve to rule it out.

[99bluemoon]

The spindle does require new bearings and is presently having a operation to insert new ones. We expect it back at the end of this week.

The early tool release problem will be sorted then.

Thanks for the replies.


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