Hanging Lathe Turret Revisited

2000 Mori SL200-SMC Fanuc 18i (Mori MSC-501)

I've asked about this problem previously and have waited to visit it again until it happened again. Today on a different program the problem re-visited.

The problem is when running in Memory Mode, at some point in a program the tool change will get as far as unlocking the turret but no further. There is MTN and FIN showing in the buffer so the Servo has been told to move and the control is waiting for a Finish Signal. The Lock Pin Out Signal has been satisfied. It will not time out either. I've let it sit for 20 minutes before and nothing. Note that in all other circumstances... bar none, the turret works perfectly fine and never ever fails. Even in Memory Mode with programs that don't have the apparent aberration that causes the problem.

I seem to have found the cure, which is the control does not like going for a tool change while in G1 and wants G0 to be called before it will cooperate. I find it a little odd as they're both Group 1 G Codes. G53 doesn't seem to satisfy the turrets needs either.

I've concluded that my programming is okay and am thinking it is a bug in the ladder. Or an incorrectly written ladder more likely. It's more of a curiosity now then anything.

Just wondering if anyone else has had this problem, and if those who know about things like this think it for sure has to be the ladder? Or something else? Next time I call Mori Seiki I might ask about a ladder fix or upgrade.

For reference here are excerpts from the two programs that both failed and their cures highlighted.

T0200(SIDE 2 TURNING)
G20G40G54G80G99

G0Z0.075T0218
X1.43
G50S3000
G96S510M3
M8
G71U0.075R0.05(ROUGH)
G71P1Q2U0.06W0.01F0.012S510

Misc Blocks

(FINISH PASS)
G0X0.645Z0.15
G1G42Z0.05F0.01
X0.8745Z-0.065
Z-2.
X1.53Z-2.1891F0.008
G40X1.73F0.015
G0Z1. (Added this one block to fix it. Brought it out of G1.)
M9
G53X0.M5
G53Z-5.5

T0600(THREADING TOOL) Here's where it used to hang.
G20G40G54G80G97G99

G0Z0.25T0606
X0.975
Misc. Blocks
M30

*********************
EXAMPLE 2

T0100(TURN)
G20G40G54G80G97G98

G0Z0.1T0101
X0.92
G50S2750
G96S1100M3
M8
G99G1Z-0.8F0.012
X1.05
G0Z0.1
X0.875
G1Z-0.8F0.01
X1.05
G0X1.2 (Added this one block to fix it. Again brought it out of G1.)
M9
G53X-3.Z-5.M5

T0500(3/16 END MILL) Here's where it would hang.
G20G40G54G80G97G98

M45(C AXIS CLAMP)
G0Z0.1T0505
Misc. Blocks.
M30

Dave

I can't think of one single time where I've wanted or felt the need to change tools or index the turret in G1 feed running in automatic mode. Might supposed to be that way? Lol

Brent

yardbird said:

I can't think of one single time where I've wanted or felt the need to change tools or index the turret in G1 feed running in automatic mode. Might supposed to be that way? Lol

Brent

Click to expand...

Me neither. That's why the G53's are there. To Rapid to the selected tool change position(s). Why the control needs a hard coded G0 to operate the turret properly is beyond me.

Dave

Had some more ideas about what was holding the turret in check and it turns out dropping the G0 and simply adding G98 Feed Per Minute fixes the problem too.

I think the whole problem stems from the fact that the turret is Servo driven and shares an amp with the X axis. Operating in a Feed Per Rev mode would allow it to act in all kinds of ways depending the Servo's Parameter settings, mixed in with the speeds and feeds that are in play when the turret is called into action. So G1 linear feed is not the problem after all but Feed Per Rev is. I think the ladder is just playing it safe, and now that I know the fixes it shouldn't be a problem any longer. BTW - adding G97 Cancel Constant Surface Speed Control did not fix the turret problem. Only G98 alone did.

Still curious if others have run into anything like this. Funny how things work some times.

Dave