Nakamura-Tome TMC-2 Fanuc 3T

[cnc-it]

Hi,
I'm thinking of buying a Nakamura-Tome TMC-2 with Fanuc 3T(1982).
Its like new and has an extended pc type key board too.(not sure what this is used for..)
Does anybody know this machine and if its any good. I realise it will have Dc servos and I presume DC spindle motor too?
What are the limitations with Fanuc 3T.. I imagine the memory space is only small by todays standards... otherwise i would imagine it works much like 6T with the same available G and M codes..?

Thanks for any help guys..
John.

[star-turn]

The Nak itself will be an excellent m/c - possibly a bit slow by todays m/c's but rigid and will turn with excellent results.

but i don't fancy the 3T controller!!! - i never went back that far my self and started when 6T came out, which was 100% reliable i understand that 5T and earlier are somewhat..... quirky!

[Sump Cleaner]

Cnc-it,

We have 4 Nakis here. I don't have much experience with the 3T control but you can't beat the machine.

JK

[cnc-it]

Thanks guys that's the info I was hoping to hear.

Apparently it has a two speed gear drive too so should have reasonable torque!

On the Fanuc side i read that the 3T came out at the same time as 6T and after 5T.

It was meant to be a more affordable option to 6T and has Sram memory as opposed to bubble memory but uses the same 16 bit processor..

Should be ok for the simple stuff I need to do

[Dan Fritz]

You're right that the 3T has the same 8086 processor as the 6T. The 3T is very reliable, but it just doesn't have some of the optional features available on the 6T. If a simple, reliable control is what you're looking for, the 3T is it.

[cnc-it]

Thanks Dan.

Am I correct in saying that 3t can't be used with iductosyn scales either...? The one i'm looking at has a querty type keyboard so may have Fapt Turn ..?

I have a spare 6T motherboard ...can I swap it with the 3T motherboard and swap the eproms /parameters etc too or am I way off base with this idea!!

I think the 3T would be fine for what I need but thought i'de ask just out of interest!!

John.

[positiverake1]

Do you have fapt on the 3T ?

[Dan Fritz]

There is no compatibility between the 3T and the 6T boards or EPROMS. You can not replace the 3T main board with a 6T board and still use the other components in the cabinet. The 6T had a separate I/O board for the machine interface, where the 3T had these components on the main board, and all those interface signals on the Honda plugs would be completely different. A 3T-to-6T conversion would have to be considered a "full retrofit", with a lot of new interface wiring.

The 6M (for mills) had the ability to use resolvers and/or inductosyn scales by plugging in a special board for the feedback signals. I think the 6T has the same slot for the board, but the software (EPROMS) for that option are probably not available on the 6T. I don't think the 3T even had a slot for this kind of board. I've never seen a 3T or 3M with resolvers or inductosyn scales, so I tend to think that it's not an available option. If the control does have the slot for the board, I doubt that you could find one anyway. The 3T and the 6T both have pulse-coder inputs on the main boards, so you could at least plug in the same Fanuc pulse coder cables and use the same Fanuc servos. That's pretty much the limit of their compatibility.

[cnc-it]

Thankyou Dan

I can see unless the 6T was taken from an almost identical lathe complete with all the connection cables it would be like doing a complete retrofit.

Am I correct in saying that the newer Fanuc controls ie 16, 18, 21 are easier to retrofit.

I was told that if any of the eproms failed on my Hitachi-Seiki with 6T i would have a real job getting them duplicated where as the on the later Fanuc controls the cnc information can be easily reloaded without replacing eproms.

John.

[cnc-it]

On the subject of 3t I have seen machines with 3TF . I presume the F stands for FAPT.

I have a Beaver machine centre with 6ML which has the full Fanuc conversational milling option. Never seen a 6ML anywhere else!

John.

[Dan Fritz]

I think the Fanuc 6 was probably the easiest control to retrofit. Back in the 80s, you could buy a little briefcase-size EPROM programmer for the PC (Programmable Controller). This would let you do all the logic for the machine interface and burn a pair of EPROMs for the PC board.

The "Executive" EPROMs on the Fanuc 3T and 6T are easy to duplicate. If you have a set of good EPROMS now, then anybody with an old EPROM burner can duplicate them at minimal cost. Keeping spares is not necessary though. They rarely go bad.

[cnc-it]

Wow that sounds like it might be a way forward for me ..I was considering changing the servos on my Beaver which has Fanuc 6ML.

It has Siemens Dc servos and drives which are a pain in the b*t!

When the a drive card fails it tends to take the motor tacho and stack card with it costing me big bucks to repair!!

I have a set of 3 yellow caps with drives that came off a Fanuc robot that had only done demo work in a college so they are mint.

My only problem is the control has no PC board... Instead it uses a Siemens Sestep 400 micro processor controller.

Maybe I will need to have this controller re programmed or can I fit a new PC board and get the eproms copied from my Bridgeport BPC320H which also has 6MB...?

I've got to agree with you Dan though the 6t/m is so reliable ..never given me any trouble...I have 4 machine with Fanuc 6 and they are just solid day in day out.