Problem on PUMA8 of spindle speed clamp G92

[Ashu]

I have Daewoo PUMA8 lathe machine with Fanuc 10T system.Sr. no. 370249
This m/c has got a problem of G92 . Example of part program as follows:
T0303;
M41;
S500 M03;
G92 S2000;
G96 S120 M03;
G0 X22.5 Z100.0;
.
.
.
ETC.
In this program exicution spindle speed is clamp to 2000. But actually spindle rotates at maximum rpm of spindle in M41 ( low gear). and when x comes to nearer to 0 then it rotates at 4000 rpm which is max. rpm of spindle that spindle can rotate. If instead of G92 S2000;, G50 S2000; is used then spindle rotates with 20 rpm and remains at that20 rpm only. doesn't change.
One thing is noticed on m/c is all the spindle parameters(5600 ahead) are 0 in cnc parameter screen except 5602 -01100000. max. sp. rpm I thing are all given in data tables.

Also during the angle command e.g.
G1 Z100.0;
A250.0 X100.0 F0.1;
M8;

During exicution of this command only x axis movement happens it doesn't take simultaneously z movement to get the required angle.

Pls guide me in solving these two problems.

with best regards to everybody.

[tobyaxis]

This is how it should work when using SFM (Surface Feet Per Minute), with the exception of the spindle rpm going up to 4000rpm. I believe you have a bad something somewhere in your control.

Here is an example of a Fanuc 10T Program for a Dainichi BX45 1987.

%
O1212
(GM 11700 PILOT)
(DRWNG=GM11700P.CAD)
(MATERIAL=SAE 1018)
(OP1)
(DATE 12/10/03 PGMR TJD)
(DATE REV 12/10/03)
(T1=CNMG432 HORE. T3)
(T2=DNMG431 HORE. T3)
(JAWS= PRESS= )
(CYCLE TIME=M S)

G0 G40 G97 G99 T0 M5
G28 U0 W0 M9
G50 S2500 M41
M1

N1 (R-FACE/TURN)
G28 U0 W0 T0
T101 M8
G96 S500 M3
G0 X2.5 Z.2
G72 P10 Q15 W.002 D300 F.008
N10 G0 G41 Z0
N15 G1 X0 F.004

G0 G40 X2.4 Z.1
G71 P20 Q25 U.02 W.002 D850 F.01
N20 G0 G42 X1.402
G1 X1.702 Z-.1 F.003
Z-.5 F.005
X1.908 F.004
G3 X1.9576 Z-.5221 R.025 F.002
G2 X2.33 Z-.6875 R.1875 F.003
G1 Z-.76 F.005
N25 X2.4

G0 G40 Z.2 M9
G28 U0 W0
G97
T0
M1

N2(F-FACE/TURN)
G28 U0 W0 T0
T303 M8
G96 S750 M3
G0 X2.5 Z.2
G70 P10 Q15

G0 G40 X2.4 Z.1
G70 P20 Q25

G0 G40 Z.2 M9
G28 U0 W0
G97
T0
M30
%

Their are a number of things to check. First set the work shift z+ 4.0 inches away from your work peace. Next edit your program removing the G50S2000M3 and change the SFM G96S120M3 to G97S1200M3. Run your program in low rapid and see if you get the same results in spindle rpm jumping to a higher level than you programmed. If it does your spindle encoder is bad. If not, it may be a parameter problem.

One big question is how long have you had this machine?

The other problem you are having with the taper not working properly tells me that maybe there is a problem with the X axis position communication with the spindle is bad. If the encoder in the spindle doesn't know where the X axis position is it will do eratic things. If the encoder in the X axis is bad the machine should Alarm out and shut down. Runaway machines are extremely rare. The only experience I have with a runaway machine was a machine that was improperly grounded in a shop that did a lot of welding work on an extremely hot day (100+ degrees F in the shop) .

My best advise to you is to get a Tech in to look at it right away. The way that the machine is acting makes it a potential danger to you and everyone else in the immediate area.

I can't really tell you what is wrong, but I can tell you G92 is a Threading Canned Cycle. And the machine shouldn't be exceeding the (G50S2000M3) Max Spindle Clamping the RPM.

I wish you the luck that maybe it is a loose wire or an easy fix.

[pinguS]

I have exactly the same problems on a Puma 12, but also my one doesn't spin more than 2500 revolutions, unless that is the maximum, I did think it should go upto 4000 rpm. I have been virtually given this machine, no manuals, nothing. Just a machine with a 12 inch chuck and 3 inch through bore.

But I can't program angles, it is Fapt 10t, but I like using the angle command, and I'm sure its only a parameter. Other that this I can use the machine and do angles using trigonometry, i.e. x and z's all over the place.

I mainly use it for aluminium, so don't really use constant surface speed, but I have tried it and it doesn't work. (G96, G97, tried a few of them), my machine just ignores them and runs at the last programmed speed. weird. Unless the Puma 12 uses different G codes.

If this worked this machine would be excellent.

Any help would be apprieciated.