Fanuc 18-MC Rapid Problem

[Brent Wilkerson]

We've got a problem on a VMC with a Fanuc 18-MC controller.

 

For whatever reason sometimes the machine runs a program completely in rapid mode. Almost like dry run. The program(s) are fine, "proven" programs too.

 

It ignores all feedrate and interpolation calls, everything runs in rapid more a less.

 

The problem is resolved by cycling the power then it's fine. It's not consistent problem / it doesn't happens at the same time after a certain action. It's completely random.

 

Has anyone ran into this before? If so is there a solution? And or a reason?

 

Thanks in advance!

 

I posted the same question about 3 yrs ago....still haven't had any luck. We had another "mishap" and broke a good sized endmill recently.

[chris m]

I have an 18MB and haven't seen that, but for whatever reason the machine will occaisionally decide it is in G91 even though it is in G90, particularly if "G90" is not on the WOFS call line..?

 

G00 G90 G54.1 P2 X0. Y0. <===this is OK

 

G90

G00 G54.1 P2 X0. Y0. <===this isn't WTF?

 

 

We should start a Fanuc WTF thread...

 

 

C

[Flycut]

Shot in the dark here but is there a dry run button on your control?

Someone might accidentally have pressed this button and your description is what this mode does. (I think).

 

GL

[Brent Wilkerson]

Chris....we have seen that too...

 

G00G90G55.....works

and

G90

G00G55....doesn't

 

Who knows....

 

Nope dry run is not pressed. One cycle fine no problem as is...x amount cycles later....WHAM!

 

Just confusing....and I agree on the Fanuc WTF thread!

[chris m]

I'm glad I'm not the only one with a machine that decides it is going incremental on its own...

 

Brent, did you contact Fanuc?

[?Mark]

If it makes you feel any better It happens on yasnac control also...

[Rick Henrickson The Boeing Co.]

it probably happens when you hit end of file or reset!

there is a parameter for G90 or G91 on power up reset

[Guest CNC Apps Guy 1]

WOW.... scary.

 

Never seen it, never even heard of "anomalies" like that with Fanuc Controls. What I would do is the next time it happens, leave the machine in it's current state and call Service. I know it will take them a while to get there but certainly worthwhile IMHO to get that resolved....

 

JM2C

[chris m]

quote:

---

it probably happens when you hit end of file or reset!

there is a parameter for G90 or G91 on power up reset

---

Did you look at the code we posted? Ain't any power up or reset going on between 2 consecutive blocks; this is not a one-time thing, either, happened quite frequently until we surrendered and posted G90 on every WOFS line

 

 

C

[Rick Henrickson The Boeing Co.]

what does the exact code look like the example is good need to see the real code.

I assume it is not after a G91 G28 Z0 then not set back to G90?

[pip]

Had the exact same problem on a Makino a55 pro 3. Our dry run button was faulty, and after it was replaced we never had the problem again. Not saying this is your problem, bit might be..

[Rick Henrickson The Boeing Co.]

pip good call

[chris m]

This is part of a program that ran yesterday:

 

------

( T03 )

( 11/64 PARABOLIC DRILL )

( DRILL .31 DP 2X )

N90 G00 G17 G40 G49 G80 G90 G94 G98

N95 G111

N100 T03

N105 M06

N110 G90 G54.1 P3 X.575 Y-.9959 S1333 M03 T04

N115 G43 H03 Z.25 M08

N120 G98 G81 Z-.4386 R.007 F5.3

N125 X-.575 Y.9959

N130 G80

N135 M05

N140 M09

N145 G91 G28 Z0.

N150 G90 G49

N155 M01

( T04 )

( LTR Q .332 CARBIDE DRILL )

( CDRILL .59 DP 8X )

N160 G00 G17 G40 G49 G80 G90 G94 G98

N165 G111

N170 T04

N175 M06

N180 G90 G54.1 P3 X0. Y.7875 S1381 M03 T05

N185 G43 H04 Z.25 M08

N190 G98 G83 Z-.7234 R.007 Q.29 F8.3

N195 X-.5568 Y.5568

N200 X-.7875 Y0.

N205 X-.5568 Y-.5568

N210 X0. Y-.7875

N215 X.5568 Y-.5568

N220 X.7875 Y0.

N225 X.5568 Y.5568

N230 G80

N235 M05

N240 M09

N245 G91 G28 Z0.

N250 G90 G49

N255 M01

------------------

 

You can see that the 'safety line' has G90 in it, but if the G90 isn't there again on the WOFS line the machine may [or may not] decide to position incrementally

[Rick Henrickson The Boeing Co.]

is this something that just started or is this a new machine?

[chris m]

Been like this for years

[Rick Henrickson The Boeing Co.]

have you talked to fanuc about it?

I really think it is a parameter issue

[Guest]

Off topic--------

 

 

Hey Chris, have you moved to X yet or are you still using V9?

 

Just curious,

 

Happy Thanksgiving too

[romer]

A couple of quick questions.

What brand of machine?

What does the G111 command do?

 

Romer

[Greg Williams]

Shizer

 

Scary stuff. As someone said earlier could the dry run button be faulty?

 

generally when we see strange stuff like this we reload the parameters form the original base release. I would be guessing a parameter or board issue is the cause

[chris m]

John, still running 9.1 SP2; my new computer for X has been sitting in our IT guy's area for a month or two, but he's "too busy" to set it up...

 

Our machine is an Okuma-Howa Millac 438V; G111 is a G-code macro toolchange preparatory command. I don't know if G91 is in there, but if you look at the active codes the machine says G90 even when it positions incrementally.

 

We haven't talked to Fanuc because we know what to do to make the machine go [unlike Brent's problem] so we just do what we need to.

 

C

[Storkman]

I think romer might be on to something Chris. If the G111 uses a G91 it might not be showing up on your active command page. Although the "cure" for this if it is happening is probably exactly what you are doing already. Post out G90 afterwards. It doesn't explain why it doesn't work on separate lines though.

[chris m]

I'll see if I can check into that macro coding and get back to you guys with the results.

 

C

[Brent Wilkerson]

Wow....lots of posts!

 

Sorry was on vacation for almost 2 weeks...

 

Never contact Fanuc about the issue. Don't know where to stop

 

We usually see it in drill cycles but it isn't a 100%. It has also failed randomly on inter. moves too.

 

it could be soo many different things.

 

I think, what someone said, is to leave to controller on when it faults and let Fanuc come in and so whats up. Faulty dry run button could be checked but the problem goes away after cycling the power and doesn't come back after that. Once it happens it stays on the "rapid" state until cycling the power.

 

I'm just glad other ppl have this propblem too. sorry

 

Thanks

[romer]

quote:

---

I'm just glad other ppl have this propblem too. sorry

---

Misery loves company?

 

romer

[connormac]

I have set up my posts like Chris. All of our Fanuc's seem to get lost from one line to the next without the G90 in the WCS line.