VF2SS shutting down

[Fantail]

I purchased a used 2005 (aprox 9 months old) VF2SS 1 year ago and have been machining the same part since then.
My problem is that during a tool change the machine goes into alarm and stops.
The alarm messages are

102 Servos off
123 Spindle drive fault
105 Z servo error to large.

I've had the local Haas techs out to try to fix it many times. They have added 2 more fans under the controller cards as well as replacing the card itself. The Z drive bearings have also been replaced. After all this the problem is still there.
In the hot weather it shuts down more than in the cold weather. I've had it go down 11 times in a 14 hr day. On average it's 3-4 times per day which is a LOT of down time!! and that is with the electrical cabinet door open and a big fan blowing lots of air inside the cabinet (as per the tech's suggestion). During the winter I can go for days and sometimes weeks without any alarms.
The local tech told me that the program I'm running had too many tool changes for the cycle time. 10 tool changes in aprox 8 minutes.
I have checked with another company locally that has a VF2SS and from what I understood they are running a similar cycle and number of tool changes.
The last time the tech was over I was told they can't do anything more for me. Pretty sad really.

So my question is ....has anyone else experienced this issue on a VF2SS or am I the only lucky one.

FYI the times between tool changes and RPM's are

Tool 1 19 sec 10,000 rpm
Tool 2 125 sec 10,000 rpm
Tool 3 18 sec 10,000 rpm
Tool 4 37 sec 10,500 rpm
Tool 5 42 sec 9,500 rpm
Tool 6 146 sec 10,000 rpm
Tool 7 50 sec 10,000 rpm
Tool 8 10 sec 5,500 rpm
Tool 9 10 sec 700 rpm
Tool 10 11 sec 5,500 rpm

Any comments would be greatly appreciated.

[trubleshtr]

Hi, I've never worked on a Hass, but I have plenty experience repairing other cnc's so here is a list of things to consider..

"Z servo error too large" sounds like a following error to me.

So What came first the drive fault (spindle faulting) or Z axis not in the right position during a tool change...

1. due to z axis brake failure if your machine has a brake on Z??
2. Backlash on Z axis ball screw/assembly
3. spindle drive faulting ? too much amps, drive hot, loose wiring
4. spindle not orientating to correct position to accept a tool change,not sure what type of tool holder you use?

The drive for the spindle might want to see the spindle ramp down to a certain speed before allowing a tool change to occur? try and slow the machine down as a test to see if your problem lessen's (spel?)
maybe in the G-code before the tool change is called out, call out a wait,or dwell for a certain amount of time and then do a tool change, play with the time value and see if it helps.
Record the Z axis position during a fault and compare it with where it should be during a tool change, moniter the amps on both the spindle drive and z axis when running good and try to capture it when it faults to see if you are drawing too much amps, that might indicate a tight spindle or a damaged ball screw/assembly....I could go on, but it's hard to be an arm chair mechanic.
If the Haas guys have given up, I'd look at your g-code and see if maybe you need to tweek it a little, as your machine gets older, the optimized time you once had might be slipping away due to wear and tear.just like an old car needs a little more TLC??

My 2 cents

hope it helps.

[Fantail]

Hi trubleshtr, thanks for the reply. I'll take a look at some of your suggestions and go from there.

[Geof]

It sounds like it is an overheating problem. Here are some possible ways to combat it.

Reduce the spindle acceleration maximum load. The factory setting is 195% for Parameter 196 Sp ACCEL LIMIT LOAD. Change the 195 to something like 120, the accelerationg time does not change noticeably.

Separate the rapid return to Z zero for the tool change from the spindle stopping and orienting. On the Haas the normal tool change command is just Tn M06 and the controller homes Z, stops and orients the spindle all at the same time. Put G53 G49 G00 Z0.0 on the line ahead of the Tn M06 and the Z axis will home before the spindle orients which puts less demand on the DC power supply.

[omy005]

We have a VF2SS of similar vintage and very similar tool cycle times. Our factory varies from about 5°C in winter to 37°C in summer. We had the Z axis servo amp replaced about 12mths ago. Other than that it runs 16hr shifts every Monday to Friday and has done over 630,000 tool changes with out a stop. The HFO we deal with are very prompt and if they can't solve it they call the factory and have an answer back the next day.

Andrew.

[serviceman]

what voltage are you bringing to the machine is it 208 240 or 480 is it a delta or wye wired configuration? the z axis fault is a by product of the 123 alarm the 123 alarm is a spindle drive fault when this happens the z axis overload because the spindle is not turning anymore. are youi able to reset the 123 alarm or do you have to power down the machine?

[serviceman]

are the regens smoking hot when you run the job?
there was a vintage of vector drives that had 123 alarms because they sensed ground faults in the power line usually this only happens on ungrounded systems like delta which is usually 240 volts with no ground reference. the haas machines are not meant to be run on ungrounded supplies and i do not think there are many companies out there that will ground a delta system. sometimes the vector drive interprets a phase imbalance as a ground fault and it may be. there may be a machine in your shop that throws what looks to be a ground fault on a delta circuit since the voltage does not have a ground reference the stray voltage just bounces around the 3 phase circuit. if you are able to reset the alarm right away and continue then this may be your problem if not and you are just running the machine too hard you can put a couple of dwells in the program to see if that helps or you can slow the accel decels on the spindle down to ease up on the vector drive or regen assemblies.

[HAILINHAAS]

check to see you have the right regen. There should be 4 elements in the regen box on top of the control cabinet. You could have a bad regen. Have the tech check the ohm's on the regen, it should be 5.6 ohm.

[JROM]

If all else fails try a cold air gun. You will have to mount it outside the box because they drip water from condensation. Just pop a hole thru the box and point the gun thru the hole. you could set it up with a timer to turn it on and off thruout the day. A cold air gun will turn regular shop air into 38 deg air.
I have used them before to cool controls

[HaasTech83]

When does it fault out during the tool change? When its removing the tool or placing the tool into the spindle?

thanks

[trubleshtr]

Serviceman has a good point.... Check the regen circuit, the poor machine might not be able to dissapait (sp?) excessive power in the system when you ask it to quickley stop....Deffinetly check the Ohms values on the regen circuit....

[Fantail]

Hi all, thanks for the responses. I'm gonna try and answer them as best I can.

Geof...I've always thought it was an over heating problem too so when I get a chance I'll try your suggestion.

omy005 (Andrew)..Glad to hear that someone has a machine that doesn't have this problem. Your temps are a bit higher than what we experience during the day so I wonder whats different with your machine???.

Serviceman...Voltage to the machine is 208. I don't know if it's delta or wye wired config. Sorry but electrical is not one of my strengths.
You said ......."the z axis fault is a by product of the 123 alarm the 123 alarm is a spindle drive fault when this happens the z axis overload because the spindle is not turning anymore".
Well when the machine goes into alarm, the spindle is still rotating so I have to wait until it comes to a complete stop (aprox 6 mins) then clear the alarms. When I clear the 102 alarm there is a "clunk" and the spindle is locked .Next I have to do a recover in order to start running the machine again.
No I don't have to power down the machine and the regens are not "smoking hot" when the machine is running. The top 2 elements are hotter than the bottom 2. I've even put a fan in front of them to help with cooling it didn't help. Another thing the vector drive has already been replaced and yep it did nothing.
The only other machine in my shop is a compresor.

HAILINHAAS.....thanks for your suggestion I'll get a tech to check the ohms, and as mentioned above its a 4 element regen.

JROM....will leave that as a last resort. If others aren't having the same issue then there is something wrong with this machine.

HaasTech83..... The machine faults with a tool in the spindle the next tool facing down in the side mount tool changer. The tool changer arm is in it's 'home' position ready to turn and grab both tools to do the change.

Hope someone can make sense of all this. Thanks again for everyones input. Greatly appreciated.
Fantail