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..?
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.
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.
Last edited by Dan Fritz; 10-25-2007 at 08:16 AM.
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.
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.