[Deano7/11]

hi guys

looking at an old nakamura lathe (TMC3) with a 6t controller on it. all working great and in pretty good nick.

i don't come from a cnc lathe background and as this is an old machine (1986 mod) i am unsure if i am buying a headache or a solid well built machine.

what can you tell me about the controller? can someone that has only cnc mill and manual lathe experience pick it up easy enough,
are parts still available for this controller. it comes with a few bits like spare screen and boards and fuses.

the previous owner had it DNC connected but sold the dnc gear off with one of the other machines. what is involved with setting up DNC?.

most of my mill work i program on mastercam so assume i can use this on the 6T as well with the correct post of corse.

[Deano7/11]

hey guys.
looking to purchase a nak tmc3 lathe. going by the pics looks pretty good for an 86mod.

from what i have read the nakamura lathe seems to be a great thing. has swarf conveyor, 12 tool turret, programable tailstock, 8inch chuck with heaps of soft jaws and a disassembled parts catcher.

is still under power and the price is pretty good. has contoller spares like screen. fuses. boards etc.

the current owner cant say enough good things about it. he has had some pretty new fancy lathes and vmc's but seems to have a soft spot for this old lathe.

what are your thoughts guys. are they a good thing ? could i do worse?
would i still get parts surport on the controller or lathe?

TIA

[fordav11]

there's a bit more brain work required in setting it up and the machine will not be as user friendly as latest machines but a 6T is like most controllers except there's no workshifts or geometry offsets so you need to use G50 for tool setting unless it's a very late model 6T with workshifts and geometry offsets (very unlikely). parts are still available for System 6.
For MC any common Fanuc POST will do. you won't need DNC unless you don't have enough memory for your program but there are other options like installing a new memory card available from one of our CNCZone regulars (memoryman) that will do the job much better than DNC.

[Al_The_Man]

One issue is if it has not been maintained well this machine can cost a $$ in a short while, costly areas of preventative maintenance overlooked are DC servo's and DC spindle, these machines are of an age where either the brushes should already have been changed or need it shortly, due to quite the number of years in use since new.
Al.

[yours_prabhat]

you will get a rigid and perfect machine ( Old is Gold ) still in germany , Europe , USA , India , Thefailure rating of 6 T control are less than others ...

[Deano7/11]

That's good news to hear about the momery. From what he tells me I get the opinion it quite well maintained and the same cnc tech looked after it for years so I can always ring him and ask what has been replaced.

The owner was talking about adjusting g50 for tool offset ?? So sounds like it is the earlier 6t

Do you guys have a clue on what this machine would weigh?

I am a home shop machinest so need to move it to my garage. I have a double garage roller door to get it through so assume the machinery movers would skate it in?

Good news about the mc post. Assume a fanuc post will be easy to come across

[tc429]

home shop- do you have three phase? the dc servo drives(if tthey are 6047 yellw cap motors) can be rigged for single phase, but the spindle needs 3 phase and might not like a phase converter...

we had a small shop for a couple years, did a few rebuilds, found out the old dc spindle drives needed true three phase, had to rent a big generator for testing before we shipped it. I did run some ac spindles on our phase converter just fine, but the old dc one just wouldnt accept it... just wanted to mention.

personally, I loved the 6TB-2 control, we bought probably 200 of them from 1984~maybe '90 before we switched to the zeroes reluctantly... the 6 was easy to repair(if you have board level prints) they were ultra reliable, really only weak spot was the reed relay outputs on the i/o card(s)- they get sticky...the old 6 was like a old ford pickup, nothin fancy, but very dependable. Last one I 're-retrofitted' was back in 1998, remember distinctly because i did the wire wrap 'connection unit' to keep me busy in the waiting room while my 9 day old son was having his first open heart surgery...that machine was just pulled offline a month ago, and this summer we are going to rebuild it again, likely will keep the 6 on it too- its the last one of the 6s in our shop, but weve still got a bunch of controls upstairs...I keep trying to talk my boss into letting us resurrect more 6s, as we are running low on zeroes,this might be the year...they are dinosaurs, but run great. I'd like to keep at least one of those 1984 controls up 'just because'... the geometry issue is a issue- but I think you can just buy new firmware- call fanuc. if its not a 'B2' version, the control is pretty crippled...we had two of the '6-A' as some referred to it, one didnt even have a crt, but the old led/cursor crap off a 5T...didnt like that control at all. the 'B2' versions have a 'ROM' card, the 6-A had all the firmware chips across the top/left side of the mother board...like 2 rows of 8~10 sockets... that control was far inferior to the 'B2' versions.



dc servos kinda suck- the 6045 or older SCR style drives with the 'black cap' motors are really bad, I didnt like those at all, we were always having issues with them... hopefully youve got at least the yellow cap 'M' series servo motors and 6047 drives- they were kinda ok, easy to fix...but the magnets in the yellow cap motors come unglued if they get hot.
theres a lot of 6050/red cap stuff out there that can be retrofitted easily... my garage bridgeport has 6047 yellow caps, but running at reduced output (running it off a single 120 volt 15A plug) the little motors really cant heat up... we went thru tons(literally) of 10m/20m yellow caps over the years, always because magnets came off, damaged the armature...eventually replaced ALL of them with redcaps by the early 90's

in my opinion a 6_B-2 with 6050 drives, or a Zero-A with 6050 drives would be my first choices in controls. easy to maintain/fix, only bad thing, parts are becoming 'old', that alone causes issues...

dozin at the keyboard- bedtime
Tim

[Deano7/11]

good info there. will ask the owner what servos are on it when i talk to him next.

he is getting the serial number for me. and i am curious about the floor space needed so i can try and work out where it might fit. shop filling fast.

i spoke to the maintanence guy that looked after the machine for the last 20 years. he couldn't fault it. he through they would have replaced the brushes about 15 years ago when they gave the machine a overhaul but in the same sentence he thought it may even have AC servos on it but was not sure. he didn't have a bad thing to say about the machine.

i have contacted the nak agent and they requested the serial number to give me all the detail on the machine from when it was new.

i only have single phase at this stage but the sparky was here today to start the ball rolling on 3 phase. all 3 phases are in the pit out the front of my house so they suspect i can get it to the shop for between 2-3k.

my manual lathe and converted bp clone mill have been converted to single phase but if i want a proper vmc as well then i really need 3 phase. not only the spindle but the hyd pump, chip conveyor and coolant pump i would suspect run on 3 phase and with an invertor costing a few hundred and all the stuffing around to do it i think 3 phase is the better option. after convverting my mill i said i wouldn't do a cnc and single phase conversion again cause i takes $$$ and time. for me the money i not the problem the time is. it is also about the destination not the journey, i want to make parts not make the machine to make the parts.

cheers guys.

[Deano7/11]

Have been looking around here a bit and people talk about the 6t and using a g50.

Not knowing what that is all about I do know the owner was talking about adjusting the g50 to get final size/tolerance

Now it seems from other post this is not that desirable but me being a noob at cnc lathe and still kind of new to cnc mill I am unsure what you guys are talking about with the g50.

Can someone please explain what it is and how it works and why it is different to how it's done now days

Cheers

[Al_The_Man]

The installation manual suggest using a rotation meter for the 3 phases before hooking up, as the drives do not like the incorrect phasing.
Make sure you get ALL the documentation.
Al.

[Deano7/11]

The installation manual suggest using a rotation meter for the 3 phases before hooking up, as the drives do not like the incorrect phasing.
Make sure you get ALL the documentation.
Al.

Is that as simple as taking note of the wire colors prior to decommissioning the machine and hooking it back up with the same color wires on the same terminals?

Should I be employing a cnc tech to commission the machine?

[Al_The_Man]

Is that as simple as taking note of the wire colors prior to decommissioning the machine and hooking it back up with the same color wires on the same terminals?

Should I be employing a cnc tech to commission the machine?

That would only work if the phase rotation was identical to the original site where it was used.
If you know someone that knows his stuff, it may be worth it?
Did you get the operator/maintenance manuals etc?
Al.

[Deano7/11]

That would only work if the phase rotation was identical to the original site where it was used.
If you know someone that knows his stuff, it may be worth it?
Did you get the operator/maintenance manuals etc?
Al.

I am still waiting for the owner to get back go me re some final detail before the deal is done. It comes with a nak book and fanuc book. Unsure if it is a maitainence man tho. Will have to ask.

I spoke to the cnc tech that looked after the machine for the last 20 years and he is local (within 60km) so sounds like I best get him to commission it

[Deano7/11]

well i spoke to the cnc tech and he said it is not really necessary for him to commision it as it is just a pick up and drop off and i am up and running

i mentioned the phase rotation and he said the best bet is to wire it up and then turn on the hyd pump (after checking oil level). it the pump is not making hyd pressure then the rotation is wrong and to swap 2 legs/phases around to get he pump rotation going the write way. then start making chips. i will be getting the sparky to wire it up.

[Deano7/11]

home shop- do you have three phase? the dc servo drives(if tthey are 6047 yellw cap motors) can be rigged for single phase, but the spindle needs 3 phase and might not like a phase converter...

we had a small shop for a couple years, did a few rebuilds, found out the old dc spindle drives needed true three phase, had to rent a big generator for testing before we shipped it. I did run some ac spindles on our phase converter just fine, but the old dc one just wouldnt accept it... just wanted to mention.

personally, I loved the 6TB-2 control, we bought probably 200 of them from 1984~maybe '90 before we switched to the zeroes reluctantly... the 6 was easy to repair(if you have board level prints) they were ultra reliable, really only weak spot was the reed relay outputs on the i/o card(s)- they get sticky...the old 6 was like a old ford pickup, nothin fancy, but very dependable. Last one I 're-retrofitted' was back in 1998, remember distinctly because i did the wire wrap 'connection unit' to keep me busy in the waiting room while my 9 day old son was having his first open heart surgery...that machine was just pulled offline a month ago, and this summer we are going to rebuild it again, likely will keep the 6 on it too- its the last one of the 6s in our shop, but weve still got a bunch of controls upstairs...I keep trying to talk my boss into letting us resurrect more 6s, as we are running low on zeroes,this might be the year...they are dinosaurs, but run great. I'd like to keep at least one of those 1984 controls up 'just because'... the geometry issue is a issue- but I think you can just buy new firmware- call fanuc. if its not a 'B2' version, the control is pretty crippled...we had two of the '6-A' as some referred to it, one didnt even have a crt, but the old led/cursor crap off a 5T...didnt like that control at all. the 'B2' versions have a 'ROM' card, the 6-A had all the firmware chips across the top/left side of the mother board...like 2 rows of 8~10 sockets... that control was far inferior to the 'B2' versions.



dc servos kinda suck- the 6045 or older SCR style drives with the 'black cap' motors are really bad, I didnt like those at all, we were always having issues with them... hopefully youve got at least the yellow cap 'M' series servo motors and 6047 drives- they were kinda ok, easy to fix...but the magnets in the yellow cap motors come unglued if they get hot.
theres a lot of 6050/red cap stuff out there that can be retrofitted easily... my garage bridgeport has 6047 yellow caps, but running at reduced output (running it off a single 120 volt 15A plug) the little motors really cant heat up... we went thru tons(literally) of 10m/20m yellow caps over the years, always because magnets came off, damaged the armature...eventually replaced ALL of them with redcaps by the early 90's

in my opinion a 6_B-2 with 6050 drives, or a Zero-A with 6050 drives would be my first choices in controls. easy to maintain/fix, only bad thing, parts are becoming 'old', that alone causes issues...

dozin at the keyboard- bedtime
Tim

Motors are black cap and have recently had new brushes fitted and servos tuned

[Al_The_Man]

Motors are black cap and have recently had new brushes fitted and servos tuned

Both Fanuc and Mitsubishi initially used Gettys (black) DC brushed motors.
Then Fanuc partnered with Getty's and the motors were known as Fanuc-Gettys.
Fanuc then brought out their own Yellow-cap version which was identical and virtually interchangeable with the Gettys.
Al.

[tc429]

something to keep in mind for down the road on black/yellow cap dc fanucs with built in encoders:

the little brass oldham coupling eventually (they last a loooong time, but eventually all will wear) will get a TINY bit of backlash between it and the pulsecoder, the servo will get buzzy...turning gain down will help for a while, but thats not good... if you carefully remove the encoder- mark housing/encoder then pull straight off/immediately mark the shaft so you dont put it back 180 out, remove the brass oldham coupling, take a small sharp centerpunch and add a dimple or two to the shiny sides where its worn, put it back on with a dab of thick black moly grease, the slop will be gone for a few years and the gain can be run normal...

if you want to get fancy, I spotfaced some to recieve a very short piece of silicone fuel tubing for a model airplane, used it like a 'rubber spring' to keep the key snug in the encoder/motor shaft...but a punch/grease works just as well and just takes a couple minutes.

the drives for the black cap motors were the weak point in my opinion...most of ours were power supplies on the first drive that failed too often, the motors were maybe more reliable than the yellowcaps as they had a sealable junction box instead of a non-watertight amphenol connector that could short out... but the 6045 drives I was not a fan of at all...still some 35 year old ones out there running, so obviously they werent all bad, but from what i saw, we had a LOT better luck with the 6047 drives...6050 ac was a awesome improvement though

[GPena]

Nakamura is a good machine, Fanuc 6 control is great for lathe applications. I would say that if the pice is right go for it...

[Deano7/11]

Well the deal is done. Couldn't run the machine as much as I wanted. The guy that owns it didn't really know how to run the machine properly. He used to leave that to the employees
It has
10inch chuck
Spare screen and some circuit boards
Programmable tail stock and quill
12 tool holders
About 20 sets of soft jaws in various diameters
Fanuc and nac manuals
Chip conveyor and chip bucket

Was running the warm up program for bout an hour.

Now just got to get it here and learn to use it.

[Deano7/11]

Being a 6t control it has a bmu board, I couldn't find where the batteries go to keep memory alive but if seems they don't require batteries.
Owner has never replaced the batteries and didn't know where to look either


Sound right guys?

Really don't want to loose parameters when the power gets turned off