Nakamura TMC20 Turret Proxy

[Themanualguy]

Hi Gents

Have a new to me Naka TMC20, with Fanuc OT control. 1986/1988 approx age. She’s old but was cheap and has been belting out parts for me since I bought it.

My issue started as a nuisance situation where after a tool change mid program, it would hang there at toolchange position and would not continue the program.

When I reset the turret, and manually index the tool, it won’t move for the first click, but will actuate the turret clamp/unclamp solenoid which can be heard.
After that the turret would index fine and you could re run your program without bother until it would happen again 3/4 parts later.

This issue went away for a while and I made a lot of parts and a lot of indexes.

Well finally today it has done the same issue 2/3 times and now the turret won’t index at all.

When you hit index turret, you can hear a solenoid valve open to attempt to move/unclamp/clamp the turret but no movement.

In MDI, calling up a toolchange will not work either.

And after restarting the machine and attempting to “home” the turret won’t work either - and if the turret isn’t homed in T1 after starting up, the spindle will not run, programs will not run - however strangely it is stuck in tool 1 as it is.

So leading me to think it’s a proxy switch for the turret to say it’s clamped which has failed or needs adjustment.

Tech is coming to look next week, but thought I’d ask anyway.


Thankyou Gents

 

[Themanualguy]

Note: Just had another look,

I can tell the turret is not physically home by 1mm as the coolant transfer tube is not fully home against the turret.

 

[Tuff Luck Tom]

Could it be that your turret may be between positions? I've had experience with my turret being in-between positions. I'm not sure about the best method for your nak if it is. My lathe I am able to force the turret clamping solenoid off, force the unclamping solenoid on through the i/o diagnostic (centroid retrofit). And then manually dog the contactor for the turret motor till I am back in position and reverse the i/o process. Also if it is really close to position you may be able to rotate it with a little force by hand. Being between positions could have the curvic coupling not lining up (think meshing face gears) and would make the turret not clamped as described.