Help choosing a spindle drive motor/driver

[Vancbiker]

I have some early AC drive documentation in my shop. I'll have a look through next time I'm down there. IME it was pretty rare (maybe never) that I saw a builder use the 12 bit digital speed control when using an AC drive. I will have to look at what it might take to get your control to output the S command as an analog signal.

Post the board number of your orientation card and I can check to see if it is compatible with an AC drive.

 

[J.Caraher]

I have some early AC drive documentation in my shop. I'll have a look through next time I'm down there. IME it was pretty rare (maybe never) that I saw a builder use the 12 bit digital speed control when using an AC drive. I will have to look at what it might take to get your control to output the S command as an analog signal.

Post the board number of your orientation card and I can check to see if it is compatible with an AC drive.

Already gone for the day. Hit the canal across the street, got caught/released a bluegill, chichlid and about a peacock, all within 30min on a BlueFox spinner, though.

Probably should throw the Kitamura machine parts list manual in the laptop bag for work so it's with me. :/

Thanks so much for all your help everyone. Hopefully I can return the favor some day.

EDIT: When you say 12bit control, would that be eliminated when the spindle drive was changed? OR - is that the I/O signal you are referring to? It seems the I/O and MoBo would be sending similar signals to the actual "spindle box" since the DC to AC change happened mid-Sytem 6 production?

For instance when I was working on GM cars many years ago and they went from a distributor and HEI to wasted spark. Well, it tunrs out that if you added the crank reluctor to the ignition control module of the DIS, added the triple coil packs, then the ECU output would still control wasted spark since it's just a 05-v signal from the ECU. In other words, builders will typically retro-fit when a big change is made mid-ship vs redesigning everything. Would be wonderful if FANUC was as lazy as GM in this regard, and the I/O signals to the DC and AC spindle driver boxes are the same.

 

[CarbideBob]

......
A little off topic, but would an AC spindle drive have the same I/O signals as the DC stuff? In other words could an AC spindle drive and motor plug and play into this machine? (or at least retro-fitted?). Only ask because the old 6m AC drives and boards are more abundant, and less cost than the DC stuff.

But you have a DC motor, is changing that cheap also? Who and where is the spindle orient signal for tool change and does the machine do rigid tap?
When the DC drive on my Chiron (contraves) went to poop the first thought was AC motor for more top end. Pricing and re-fitting even with E-yuck stuff changed my mine quickly.
Signals and such control not a problem to change or move as the machine has my own control in it and all the Fanuc stuff went to the dumpster. Yet changing that spindle motor got a big no.
Commissioning a drive as a refit depends. Some will have +/-10 volt go speed, 0-to x and direction, some digital wires, some 422 or even fiber optic and that is just the speed control section.
So many options and methods over the years.

But it is not that hard to do.
Define the functions you want and speed/power vs original. Not much that can not be hacked to works to cut parts but not like new or neat things like tool change or tap or speed or power in the the cut.
I most certainly understand money spent as the issue and when $500 on a long bet is crazy time.
Bob

 

[J.Caraher]

Define "long shot".

If the FANUC 6m came with a DC motor when my machine was built in Dec 1981, and the same machine (and I mean builder, and NC: Kitamura/FANUC 6m) had the same exact machine available in Jan 1985 with the same System 6m, but the latter has AC spindle drive(er) and motor - MIGHT - lead one to believe that the AC drive accepts and sends the same signals as the DC drive, in this one particular case.

A local friend and mentor has a MyCenter1 with FANUC O, wishing he had an earlier machine with 6M that voltage and signals could be compared.

CarbideBob, what controller did you go with? Completely custom firmware, or off the shelf? In my mind, the machine is solid and true, so slowly converting the 5,000lb of electronics, and 250k miles of wiring to an Audrino would be a welcome change - after all the 19kb bubble memory unit alone is the size of a large magnetic 1tb HDD. The servos/axis drivers, tool change and encoders are super accurate and functional. When changing to manual mode and moving the dial a tenth, it's spot on all over the machine, and all axis on the indicator.

 

[Vancbiker]

..... and does the machine do rigid tap?......

C'mon man it's a Fanuc 6M. Roots from the late 70s. About 10 years before a Fanuc did rigid tapping. Also right at the end of the DC spindle era.

 

[J.Caraher]

I have rigid tapped thousands of holes on this very machine when the PO was mentoring me. It's been a while since I fat-fingered a program, but want to say it's m29, and only need a spring loaded tap holder.

 

[Vancbiker]

...... so slowly converting the 5,000lb of electronics, and 250k miles of wiring to an Audrino would be a welcome change - ......

Just as well scrap the machine then. I've never seen a really good retrofit. Always buggy, sometimes dangerous, and never well documented. The person that did the retro is usually the only person effective at keeping it going. Because of that the resale value drops to zero.

I had a quick look at the early analog AC drive info. It is plug compatible on CN1 with your DC drive. The DAC was an option but I'm pretty sure that just means the DAC chip was installed and a jumper set. The DAC used is the same as the DC drive. You would need new power and speed feedback (CN2) cables between the new drive and new motor. I need to look a bit more at CN3 (alarm signals) to see how that lines up.

 

[Vancbiker]

I have rigid tapped thousands of holes on this very machine when the PO was mentoring me. It's been a while since I fat-fingered a program, but want to say it's m29, and only need a spring loaded tap holder.

It will tap, but it is not rigid tapping. If you need proof, put a tap in a collet and run a tap cycle. It will either break the tap, pull the tap partially out of the collet, or pull the threads out of the part, or a mix of these. The use of a spring loaded tap holder is to accommodate that it is not rigid tapping.

 

[J.Caraher]

It will tap, but it is not rigid tapping. If you need proof, put a tap in a collet and run a tap cycle. It will either break the tap, pull the tap partially out of the collet, or pull the threads out of the part, or a mix of these. The use of a spring loaded tap holder is to accommodate that it is not rigid tapping.

Thanks for the correction. It taps, 100%, and it's not like the older machine the mentor had - it required the reversing tapping head with a long handle. This machine uses m29 and just a spring loaded tapping head. Mentor called it "rigid tapping".

 

[J.Caraher]

Just as well scrap the machine then. I've never seen a really good retrofit. Always buggy, sometimes dangerous, and never well documented. The person that did the retro is usually the only person effective at keeping it going. Because of that the resale value drops to zero.

I had a quick look at the early analog AC drive info. It is plug compatible on CN1 with your DC drive. The DAC was an option but I'm pretty sure that just means the DAC chip was installed and a jumper set. The DAC used is the same as the DC drive. You would need new power and speed feedback (CN2) cables between the new drive and new motor. I need to look a bit more at CN3 (alarm signals) to see how that lines up.

Scrapping isn't an option. There is an underlying issue of sentimental value. My mentor was eaten up by colon cancer, the machine was taken over by his partner, and sat, used 2x a year for spray nozzle parts, then came to me. When I was working for the gentleman, we would hold .0001 across thousands of parts, and they were all tiny low friction machining - basically a slotting mill in a rotating collet chuck to put an X pattern on the end of drops from a Brown a& Sharp screw machine. If any of you are familiar with Kitamura, they used rectangular key ways vs dove-tail, and this mill is super square.

thanks for the info about the AC drive. Looking at the block diagrams, it seems there's not a whole lot of interface from the actual big spindle driver (takes 208v 3ph in, three big transformers turn that into 90, 100, 200v DC out). The 6m AC spindle drive connectors look a little different than the Honda connectors Kitamura used, but if it's a 1:1 transfer on the actual data (TX/RX), great.

 

[J.Caraher]

At the same time? Should have voltage on SFR when M3 is commanded and ~0 on SRV. The opposite should happen when M4 is commanded. If both are high at the same time then the spindle will not run.

Out of curiosity, removed SRV wire from the CN1 and left the rest plugged in. When testing the voltage on the SRV and SFW, both are still at 20.8 (testing SFW SRV at the spindle side of the disconnected wire).

With NC turned off (testing on the I/O side of disconnected wire), but servo side of the machine turned on, there's 1.9vAC, 2.8vAC with NC turned on, and that drops to 0v with m4 command. Similar when isolating the SFW signal from the I/O board.

Note this was testing between the 0v (earth) and SFW and SRV. When testing between any of the power leads (15v, -15v, 24v etc), it appears the SFW/SRV legs are going to ground with m3 and m4 inputs.

 

[Vancbiker]

Out of curiosity, removed SRV wire from the CN1 and left the rest plugged in. When testing the voltage on the SRV and SFW, both are still at 20.8 (testing SFW SRV at the spindle side of the disconnected wire).

With NC turned off (testing on the I/O side of disconnected wire), but servo side of the machine turned on, there's 1.9vAC, 2.8vAC with NC turned on, and that drops to 0v with m4 command. Similar when isolating the SFW signal from the I/O board.

Note this was testing between the 0v (earth) and SFW and SRV. When testing between any of the power leads (15v, -15v, 24v etc), it appears the SFW/SRV legs are going to ground with m3 and m4 inputs.

That seems like the I/O is fine then. The DAC stuck high is still making me wonder about a bad chip. I think that the DAC is not the whole problem though. If the DAC is stuck at ~10VDC and all other things are good, the spindle should run at max speed with an M3 or M4 command. Have you tried that with the MRDY signal jumpered?

 

[J.Caraher]

That seems like the I/O is fine then. The DAC stuck high is still making me wonder about a bad chip. I think that the DAC is not the whole problem though. If the DAC is stuck at ~10VDC and all other things are good, the spindle should run at max speed with an M3 or M4 command. Have you tried that with the MRDY signal jumpered?

Tried, no dice.

After checking those signals, wasn't surprised, really. I have a spare working I/O board that was changed early on at the suggestion of the FANUC phone tech. The spindle high current drive box under it is actually new as of 2016. The main MoBo was changed mid-17, but only because of scoring a really nice clean one for short money.

This isn't the first time the spindle drive PCB has given issues, and apparently is the death of these old DC machines (we had to hire an electronics specialist who found a bad IC chip in situ, he since passed away). Hence having a spare board, and another for parts.

One cannot find a used spindle drive board for a reasonable price, and even most repair/exchange companies don't stock them, so I would have to send one in and hope for the best ($$$), and not guaranteeing it's the issue. A few hundred isn't a hard pill to swallow on a crap-shoot, but $2.5-3k is.

Thanks again for taking the time to reply.

 

[J.Caraher]

The new DAC chip came in today. SRV and SRV are dropping the appropriate signals, each switches from 20.8v constant to 0v on m3/m4. CH7 remains at ~12vDC in all conditions.

Also tested the field and armature when the relay is manually depressed, the armature is going straight to 200vDC, the field is 9vDC at rest and drops to 0 when the armature starts rotating. Very short test as to not burn the brushes or damage the commutator.

 

[CarbideBob]

CarbideBob, what controller did you go with?

Control Techniques Quantum III on the Chiron and Mentor series on the grinder which has FANUC DC spindle motor.
Both bought as NOS on E-yuck for a touch over $1000 each.
These drives are just plain great.
Will talk to just about anything, have all the nice stuff like field weakening, field shut off so the motor does not get warm when setting idle, tons of protection, nice on motor brushes, detailed diagnostics on a connected laptop, and will run all by themselves with no connection to the cnc control if desired.
Expensive but worth every penny.
Super configurable and once you commission one of these you'll never want to deal with the lower cost stuff again.
In the past I've built my own from super high power servo amps, done my own field and interlock and added logic as needed. A good learning but wasted a lot of time.
Bob

 

[J.Caraher]

Control Techniques Quantum III on the Chiron and Mentor series on the grinder which has FANUC DC spindle motor.
Both bought as NOS on E-yuck for a touch over $1000 each.
These drives are just plain great.
Will talk to just about anything, have all the nice stuff like field weakening, field shut off so the motor does not get warm when setting idle, tons of protection, nice on motor brushes, detailed diagnostics on a connected laptop, and will run all by themselves with no connection to the cnc control if desired.
Expensive but worth every penny.
Super configurable and once you commission one of these you'll never want to deal with the lower cost stuff again.
In the past I've built my own from super high power servo amps, done my own field and interlock and added logic as needed. A good learning but wasted a lot of time.
Bob

Thank you Bob. You are giving me a sanity check, as is Vancbiker.

This machine was designed in 1979 and built in 1981. Logic control, switching, memory and even simple AC/DC equipment has been exponentially advanced, and am having an internal battle about repairing in situ again, or upgrading. The internal BUBBLE memory is 19kB, it's a bit cumbersome to drip feed, or DNC etc. Modern PC's don't use printer parallel ports, or even rs232 for decades, so even that nuisance becomes non-existent. Often use rs232/USB cables and in my racing side of the industry, can't tell you how many times those converters fail - at the worst times ..... EVER. FTDI clone chips and firmware was a nightmare not long ago.

Anyone have any experience with Emerson drives? Looks to be very similar for interface as you describe, Bob. This motor is 6hp, and needs 32amp max, 200vdc, which is over many 5hp drives. Must bump up to 7.5 units and the prices jump significant when going over "5hp" and/or 25amp.

$1000 and a weekend of installing/interfacing is a mighty strong candidate for this repair.

Right now, the options are: used/working complete 6M DC spindle drive, with top board included, for $3k, another used board at $1200-2000, reman my board that has loose guesstimates at $2200, or go ahead and use newer equipment (?$?$). Years ago, took a weekend and de/re-soldered all the resistors/rectifiers/regulators/capacitors, tested/replaced all of them for the spindle drive, then one of the "RVxx" FANUC-proprietary Ic's went out a couple years after.

 

[J.Caraher]

Control Techniques Quantum III on the Chiron and Mentor series on the grinder which has FANUC DC spindle motor.
Bob

Maybe in the future, but for now, manually X-ing my 1956 Delta Toolmaker for surfaces.