Help! Problems with spindle/spindle driver on an old VMC100.
Hi!
As the title says... Need advice here,,, My Emco just started acting crazy..
Started it up 2 hours ago. It homed to reference point just fine. Changed tool fine, and the spindle ran fine for the first run over the working piece(I was in manual mode when this happened). Then all of a sudden the spindle motor started stalling. At first it made a couple of hiccups, and 2 secs later it went into stall, and it's been there since.. I tried restarting the machine without any change. Now it stalls and make noise when pushing the auxillary button. It stutters and shakes until the spindle driver seem to shut off. This takes approx. 15-20 secs. Steppers and drivers still works and I can home the machine without problems, and move around the table while in manual mode. The problem seem to be isolated to the spindle and it's driver. My TM02 controller emits a high frequency noise when 'Aux on' is activated. I now know that it's the spindle driver doing this noise. It has always done this, and I've run several hundred hours on this machine. I don't know if this is a common thing with these controllers in conjuction with a mill. I got an Emcoturn 120 with TM02 controller aswell, and it does not emit this high pitched noise. I'm perplexed, I checked all 4 brushes on the spindle motor and they seem to be almost new. The manual says that they are 16mm in length when new, and should be replaced if shorter than 6mm. The brushes are at least 12-13mm long, and the spring got good tension. At this point I'm stuck. But to be honest I'm quite tired of this controller. Im about to upload a video showing the behavior of the machine on Vimeo. It'll be available in 40 minutes. I'll link it later, right now I just want some opinions.
What do you guys think? Is the machine trying to tell me that it wants a retrofit? :) Has anyone come across this problem before? Any advice, hint or thought is appreciated, I'm clueless..
Thanks in advance!
//Johan
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Johan,
My VMC100 is operating correctly at the moment... hopefully I don't get your problem!
After looking at the video, my best guess is possibly a toasted bridge rectifier in the spindle drive... It seems to have a 60hz buzz as if you are sending AC to your DC spindle motor...? I'm no electrical expert, but that is what it looks like to me.
You mentioned the high frequency noise when it is running normally, mine does this as well; Does your spindle ever turn freely when the spindle is in the "off" condition (M05)... On industrial machines I've used, the spindle will spin freely by hand after spindle stop command. I usually chuck up a test indicator to pick up the center on my workpiece, squaring up the vise etc... but the VMC100 spindle drive stays engaged and will not permit the spindle to spin by hand. I find this to be a pain when doing set-ups.
Cheers,
Dan
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Ummm , I think your VMC100 problem is contagious...!
Yesterday mine was working fine, but tonight after my last post I went to finish the job I started yesterday - and now mine is doing the same thing....!!
Now, I'm thinking it isn't the bridge rectifier, as mine will revolve around stutter then continue revolving (if the rectifier failed, I think it would just stop dead) ... maybe it is a position feedback error...?
Please update if you make any progress in diagnosing the problem.
Dan
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Dan!
Thanks for you reply!
I seldom use the M05 command, since I think the machine is a pain to program I usually just run it through the EXEC menu. But I can't remember ever being able to turn the spindle while the auxillary button is active. My spindle is as rigid as the torque of the spindle motor allows it to be, and I think they're made that way.. :) I haven't investigated the faults on my machine any further yet. I wanted some opinions or thoughts first before I start the venture into the guts of the machine.. Your thoughts about a faulty rectifier is a bit interesting, I'll have to investigate that.. Thanks for the input! When I turn the spindle with aux off I can feel the resistance from the motor and the mechanics, and from that I make a qualified guess that there's nothing wrong with the collet or it's mechanics. To be honest I'm already leaning towards a straight through retrofit. The machine is old, and my feeling is that it has lived past its electronics by several years already. And I would love to be able to use CAM and a proper postprocessor to make programs. You mention that your machine is acting the same way now? Exactly the same, or similiar? :) What year is your machine? I think mine is 1993. What version of software does it have? Anyways, good luck with your troubleshooting. I'll let you know if I come across a solution.
//J
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Btw. Dan, my spindle behaves the same way. From time to time, perhaps for half a second, it seem to find it's way back, albeit not running smoothly, and spins a couple of revolutions before going back to stuttering. Oh well.. Just wanted to let you know. I guess a good start is to measure if there is DC or AC going to the spindle.
//J
EDIT: spelling...
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Johan,
The spindle on my machine seems to be behaving EXACTLY as you described yours. It started as a slight hiccup, but after shutting down and restarting the next day, it is just buzzing similar to your video. I don't think it can be the rectifier at this point as I don't believe they would fail intermittently, I think it would be all or nothing. Plus it will usually blow a fuse on the drive when it fails, I've also seen the PCB traces burn out when the rectifier blew on drives from other machines.
It is definitely not a mechanical problem; maybe it could be bad wiring or a failed encoder...? I'd rather keep the machine running under the original control for now, the integration of the tool changer and synchronized tapping functions are very important to me. I always run in full Auto Mode no matter how simple the program.
I have no idea the age of my machine, the only software "VERSION" I've seen displayed on the monitor is: AC07.10/DC07.22/IC07.00.... what is yours?
Dan
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Re: Help! Problems with spindle/spindle driver on an old VMC100.
Good news… I think found the problem!!
It turns out the problem is purely mechanical; I pulled the encoder off the top of the spindle motor and found the Polyurethane insert in the flexible coupling between the encoder and the spindle motor had crumbled into pieces, and the spindle was just beating itself back and forth against the encoder trying to stay in position….
I’m assuming that once the flexible insert is replaced, the problem will be gone… I hope!
Attachment 277328
Attachment 277330
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Dan!
Nice to see that you've made progress. :) I'll take a look at my machine when I get home. Have you found any part number for the insert? Is it listed in the manual? I hope this solves the issue with your spindle, and I hope my problem is caused by the same thing. I think a retrofit is right around the corner anyway, but it would be nice to be able to use the machine until a new controller arrives. Do you have any personal thoughts about a retrofit?
Btw... I think my machine has 6.0-something loaded. I think it's the first version which got the ram expanded. But I'm not sure about that.
//Johan
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Johan,
I can say conclusively now that my problem is due to the failure of this flexible coupling. I used a few drops of crazy glue to re-assemble the original polyurethane insert. After it was dry, I popped it into position together with an O-ring to keep it together in case it let go again. I reassembled the encoder in the spindle motor, and voila! it powered up normally and the spindle now responds normally forwards and reverse.
Please be careful when you remove the encoder, I scribed a line on the body of the encoder and the spindle mount to be sure it is clocked in he same orientation when it is reinstalled. the encoder is held on by the three cap-screws on the underside of the spindle mount - I would not recommend removing the screws on the top cover. Also, the button head screws holding the perforated cover were a PITA to remove - I stripped the Hex and had to use a chistle to free them up. I think they must have been secured with Loctite.
The Flexible coupling is NOT listed or pictured in the parts diagram. I could read the insert had the name "ROTEX" ; what found when I searched for this is that this is likely a Rotex GS series coupler and the size seems to be a #9 (GS9)... the broken flexible piece is referred to as the "spider" and it can be replaced as a separate item.
I should also give some of the credit for my success to a member of another CNC forum who was very helpful in guiding me towards the faulty item.... Thanks WRENCH !!!:banana:
At this time if I were to consider a retrofit I would try to utilize as much of the existing components as possible. I'm not sure if I would use Mach3; I'm leaning more towards the Dynomotion Kflop.
I found a few videos of a guy who did a really nice conversion to Mach3 using all of the original motors, it seems all the functions are working (its not clear what drives he used, he said in one of the videos they were "Berger Lahr" to match the motors...) I have no association with this individual....I just like the way he did the retrofit.
- https://www.youtube.com/watch?v=QldE8tRRR7E (Part 1 - I guess this is the before shot...?)
- https://www.youtube.com/watch?v=EqpDUYT6Yuk (Part 2)
- https://www.youtube.com/watch?v=6-GK3EKs6ZM (Part 3)
- https://www.youtube.com/watch?v=ebzOxl6z3TE (Part 4)
- https://www.youtube.com/watch?v=lRab4ic2hjQ (Part 5)
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Dan!
Called KTRs office in Oslo today. They had the spider in stock. One unit costs 26 Norwegian kroner, that's about $3 a piece. They had a purchase fee of approx. $25 if you ordered for less than 50$, so I ordered 16 units. I guess I won't run out of spiders in the near future. :) Apparently GS-series comes with different rigidity and the color of the spider tells what rigidity you want. #9 is l, as you said, the size of the spider. The lady I talked to said it's quite common that the spider fails. But I guess she referred to industrial level applications when she said that.
//Johan
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Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Johan,
Its seems like the "Best Before Date" had expired on our machines...! :)
I don't know what the shelf-life is on these spiders, but I found a couple "new old stock" on eBay; I paid too much for them, but not that much. I guess you have about 100 years worth of spares... :D
I find the machine to be fairly rigid for its size, I had more flex on my old manual round column mill than the Emco. However, It takes up a lot of floor space for such a small work volume... I'd like to do the retrofit to be able to get rid of the control cabinet (or be able to re-locate it underneath the machine base). I just wonder if there is any easier way to interface a modern computer to control the drives through the existing backpane in the cabinet; I noticed when I had the operators panel open to troubleshoot the spindle problem, there is what looks like a standard IDE ribbon cable connector on the backpane PCB... maybe it could be connected directly to the bus of a computer somehow? The electrical manual shows that the original Emco stepper drives use step/dir inputs, if you were to trace back the connections it may be possible to create a new connection to replace the current machine interface and use Mach3 or similar software.
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Dan!
Sorry for late reply, been busy working...
I hope the spiders you've acquired is in good condition. Let me know otherwise, and I'll send you one or two. :)
I'm not sure about interfacing a pc directly into the drivers, but I totally agree with you that most of the original electronics should be re-used again as long as they function properly. I've read on different forums all over the internet about people blowing their stepper drivers. But I've never experienced it myself(knock on wood). The only downsides with the vmc100 are, as you mention, the poor travel, especially the Y-axis. And the controller itself, which is fairly outdated. Personally I would choose an old Emco mill versus one of those China machines any day.
I totally agree that it would be a nice thing to get rid of the control cabinet and do it as TanTan did it. That is a really nice installation. Same goes for the trusty old emcoturn 120. I even got a crazy idea when they're fully retrofitted to put them in the back of the cargo hold of a truck along with a conventional mill and a small lathe and make a mobile workshop. :) I travel a lot between Norway and Sweden and it would be nice to take a workshop with you.
Anyways, I hope this spider thing is the culprit in my machine. Time will tell. :)
//J
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Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Johan,
I received my replacement spider the other day and installed it; the machine is functioning 100% correctly now. (The temporary fix came unglued after only a few minutes of test runs, but it was enough to confirm it was the culprit).
I've given the retrofit idea some more thought and came to the realization the conversion could (possibly) be done even easier than most have done in the past. Considering a few factors such as the overall condition of my machine and controller are very good with very little use over its lifetime; the drives and motors on my machine are in 100% usable condition. I started to wonder how I could utilize the existing backplane of the control box, and discovered it appears the backplane itself may be an actual "standard bus" configuration, and not EMCO specific...? Well after a bit of googling, I found that it appears to be made to "VMEbus" 6u standards (also called Eurocard). To make things even more interesting, I found on eBay, there are used FANUC singleboard computers complete with hard drive and Windows XP Pro CofA available (cheapish from $100 to $250 usd) that will plug directly into the VMEbus slots of the control cabinet.... hmmmm (G.E. still makes new VMEbus singleboard computers even with i7 cpu's... but I'm sure the new ones would be ridiculously expensive)
Now to figure out how to complete the interface..! I wonder if the Fanuc card might be able to communicate with the existing "Axiscontroller" module directly through the backplane...? (This is my hope). I would think it is possible as the Emco modules appear to communicate through the backplane.
Even if you are not interested in trying to figure out a VMEbus computer for the controller, the backplane could still be used as a ready-made giant breakout-board to interface the original drives with an external computer. For example, see attached photo; I traced the pin-outs of the backplane from the "Axiscontroller" board which generates Step & Dir signals to the drives (only X-axis traces are highlighted, but Y & Z are similar). There is a spot in the backplane if you follow the PCB traces (position - X6a) where a connector could be soldered to existing solder pads for external supply of step/dir signals. (note: if you dont have a copy of the Electrical manual, there is one available on Yahoo Groups - you'll need it to find all the pin-outs)
I have not found any examples where anyone has attempted the retrofit in this manner, I’m just trying to think outside the box…., I think it is well worth exploring, but we'd be in uncharted territory.
Cheers,
Dan
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Dan!
This is quite interesting news. I've thought about wiring up newer hardware to the existing controller before, but quickly dropped the thought due to it's complexity. But as you say it's well worth a shot. We'll have to look into this. :) For me it's natural to start with the emcoturn 120 since it's a more simple machine.
//Johan
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Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi all, I realise this is a very old thread but just wanted to check if this went anywhere? i am the proud owner of a Emco VMC 200 and am looking into using a more modern way of controlling it than the Emcotronic TM 02 system. Thanks, Martin
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi Martin,
For now the machine is still chugging along under the original TM02 control, I have not had any time to do any further investigating on an upgrade.
Cheers,
Dan
Re: Help! Problems with spindle/spindle driver on an old VMC100.
Hi. I have an Emco vmc100 that the spider stops working on. it wound up and then the fuse went. it burned a 250 volt 10a fuse. changed fuse but it did not help. Do you still have the pictures of what you mistaken for yours?
Best regards
Magnus
