VMC ATC Glitch?

We have 5 different models of Bridgeport VMC's, but this issue is only with 2 that I have heard about so far.

These 2 Bridgeport VMC's are loading/defaulting to a non-existent "tool zero" sporadically. One is a TC4g(Torq Cut CIB) which has had the same issue several times this week and another Torc Cut 30 DX32(non-cib) that did the same thing once yesterday. Makes me wonder if it is a glitch in the posted program or dirty power since it is so rare. Both got a brain fart mid run, so it wouldn't appear to be an operator issue.

I wondered if the tool is getting stuck in the spindle and was getting pulled out of the carousel.....but..... both times, the tool(1) ended up on top of the carousel. Although, when the tool changer comes in to put tool(2) away, I think it has already lost its pocket home position and bumps tool(1) out of its pocket gripper fingers. Strange, very strange.....maybe questionable memory on the tool changer board, failing carousel encoders, hmmm?

After resetting the ATC and reloading the tools, all runs as expected......until the next time which could be hours, days or weeks away.

As we all know, it is of little use troubleshooting what we cannot duplicate. I was hoping, maybe, just maybe, someone has already tracked down this little gremlin! LOL!

DC

PLC's can be reaallyt stupid things. If you have dropped a tool because of some mechanical issue, it my result in unusual things. I would check the tool finger adjustment retention knob etc. On my [unrelated] machine, tool zero means just that, it thinks there is no tool there, which sometimes means a loose retention knob allows the fingers to retract too far

Nope, Tool 2 is still in the spindle. Somewhere along the run, the machine periodically forgets about the existing tool in the spindle and is trying to put that tool into the tool 1 pocket on the carousel that already has a tool 1 in it. The result seems to end (by the time I see it at least) in an alarm condition of reload carousel, incorrect tool, re-home tool changer. The tool changer is smacked against the tool in the spindle, trapping the tool 1 above the carousel.

Some of the alarm conditions may be a result of the start of a component failure, be that in the spindle retention sensor, carousel sensor or tool change I/O itself. Possibly it may have never "technically" completed the previous tool change cycle, but doesn't catch it in error handling. There is no PLC per say. The machine controls are somewhat different as far as the tool changer driven via hardware on one and software on the other, so that makes it even tougher to nail down to a common fault.

DC

The TC30 is not a CIB machine. Each time you change a tool, it gets written to the LCTLAUF. I have heard that this chip may get flaky. Also these are PC based controls. When was the last time you did a scan disk or defrag? It is possible the logic power supply filtering capacitors are leaking (electrolytic). This is an electrical term meaning they are not working as well. Possible the hard drive is misreading. Possible you have a loose connection. When was the last time you changed the air filter? The entire machine needs to work in unison.
How about spindle drift? It would make the tool change fail just when the head comes up after releasing the tool.
I have to remember what is inside a VMC with a CIB. I just worked on one too, two weeks ago. Shorted encoder. Also had to adjust the drift on the spindle drive. All the above applies but I cannot remember if the current tool is written to a chip on a board or written to the CFGPRMS.SYS file. Interesting that 2 machines have done this. Could also be heat related.

George

Have you actually seen it not return to the tool 2 pocket and go directly to the next tool?

Thanks for the tips George.

The TC4G is the CIB machine and it has no LCTLAUF board. We do not store programs on the machines. I suspected noise, but now that you mention the hard drive writing errors could be suspect. I'll try the scandisk approach and see how that checks out. My guess is that this happens when the program has finished and is in process of going back to tool 1 for the next part run.

As far as spindle drift, is that in terms of orientation or Z axis? I have seen no indication of that on either machine.

I have learned that the LCTLAUF board is handed control on the non-CIB machine in a canned cycle seperate from the BMDC. As I understand it, the CIB tool change is handled by discrete I/O relay boards with the MB CPU as the controller via a software macro. Somewhere along the sequence there must be communication to hold the current tool number and the M6 tool change parameter active and pending. Whether that information gets dumped due to another issue that does not allow the canned cycle to complete is what I am suspecting. The offending step contributing in the sequence is what I was going to focus on......if I could catch it in the act or duplicate the fault.

The air filters are changed once every 3-4 months as part of our normal PM schedule. EMI sure is proud of those things!

I would not expect it to be heat related at this point. The ambient temp in the building is fairly consistant around 70deg.

I have yet to witness the fault occur on either machine. By the time I am informed that there is a problem, all I can do is reset the tool changer issues, check out the tool change sequence and then tell the operator to go back to production.

I am worried that the tool changer transport gearbox will become a victim if this continues.

DC

Do a S0M3 on each machine and tell me how many RPM each is doing.
Actually the CIB machine may have a disk on a chip, a disk on a module or a hard drive.

George

I finally had some time to check the spindle drift. It could be around 1/2 RPM, but it does drift. Seems like I have done some reseting for this some time ago, but cannot recall the procedure and have not had the time to look through my notes.

That may have been for a Siemens simodrive or some such thingy on a VMC1000 as I recall. Too many other hot projects in the works, I gather.

DC

The TC machines cannot drift 2 RPM or greater or they will fault. That is adjusted at the Yaskawa. The VMC are more tolerant and cannot drift more than 4RPM. That is parameter 15.1 on the Siemens spindle drive.
Of course 1/2 is excellent.
Check connections, do a scan disk and defrag, etc.
Has it happened again since your original post? Or was it just a fluke?

George

It has not happened again as far as I know. No one else has complained about it or has had to reset it, but then I have been out all this week on vacation.

We'll see what next week brings.

DC