[kopsik]

Hi

Has anyone else encountered the problem that tool lengths keep changing? It's really annoying to find out that suddenly some parts are smaller or larger by 0,25mm/0,01inch for no reason. And if I remeasure the tool with the tool setter and run the same program, the measurements are fine. Last time I had one tool that changed 1,1mm/0,045inches in length.

[lshingleton]

You may have a bigger problem with the machine loosing position
Put and indicator on the turret and program to one position from home and repeat to see if its holding home position or G30

[mbservice]

Id say either something has come loose on the Z axis ball screw or motor

[dhardt]

Check the couplings for Z axis: Item 0230
Attachment 374172

Or X Axis: Item 0720
Attachment 374174

An additional issue that can cause "random" size error is "thermal growth".
If the part size changes as the machine temperature changes...and then, after cooling, returns to the "cold machine size" then the problem is "thermal growth" and is solved in an entirely different way by "thermally compensating" the tension of the repective ballscrew.

[KJH1983]

Hi

Has anyone else encountered the problem that tool lengths keep changing? It's really annoying to find out that suddenly some parts are smaller or larger by 0,25mm/0,01inch for no reason. And if I remeasure the tool with the tool setter and run the same program, the measurements are fine. Last time I had one tool that changed 1,1mm/0,045inches in length.

Well better late than never for this post I believe one of the wires that go to multiple thermo sensors have broken you can disable the thermo sensors parameter until you get a new sensor so far as the parameter# ? It would be in the book that should be in the main control cabinet of the machine that book has all the goodies in it,hope this helps anyone else that has this issue ?

[Baconator]

YES, we have this problem and its random and does not repeat. It returns to normal after shutting down and restarting the Puma 2100.
Tech was just here, he says its fine. He is blaming the program, but we run the same programs on the 2600 and never once had this happen.

Hi

Has anyone else encountered the problem that tool lengths keep changing? It's really annoying to find out that suddenly some parts are smaller or larger by 0,25mm/0,01inch for no reason. And if I remeasure the tool with the tool setter and run the same program, the measurements are fine. Last time I had one tool that changed 1,1mm/0,045inches in length.

[kopsik]

YES, we have this problem and its random and does not repeat. It returns to normal after shutting down and restarting the Puma 2100.
Tech was just here, he says its fine. He is blaming the program, but we run the same programs on the 2600 and never once had this happen.

Are you using any Y axis offsets in the tool page? I tried centering a tool using Y axis offsets and that seemed to make the problem worse according to the Doosan factory techs that visited me.

[Baconator]

Are you using any Y axis offsets in the tool page? I tried centering a tool using Y axis offsets and that seemed to make the problem worse according to the Doosan factory techs that visited me.

Doosan tech from the reseller disabled the X scale and said it will fix the problem, however the problems is still happening.
Some machines use a scale as well as the encoders on certain axis.
The service department is getting the scale manufacture involved.

[Impyman18]

Any updates on this? I’m having this issue in my 17 Lynx LSY

[Baconator]

Any updates on this? I’m having this issue in my 17 Lynx LSY

Does it have a linear scale?
is it enabled or disabled? Look at parameter 1815 OPT, if its 1 by X then its enabled. There are a number of other parameters to change so don't mess with it unless you have the book or tech support.
Try having it disabled, since we did it, its been working fine.
Although it lost some size twice after, which has been a mystery but since its been a month now, i hope it is fixed for good. Im wondering if it was operator error those two times after the fact.
The scale is there for accuracy, so if these machines have a problem with them, which I suspect they do, then its a defect in the design.

[DouglasR]

Hi

Has anyone else encountered the problem that tool lengths keep changing? It's really annoying to find out that suddenly some parts are smaller or larger by 0,25mm/0,01inch for no reason. And if I remeasure the tool with the tool setter and run the same program, the measurements are fine. Last time I had one tool that changed 1,1mm/0,045inches in length.

Darryl Hardt is correct. We had a brand new machine on the floor do the same. Heed his advice.

[Baconator]

Darryl Hardt is correct. We had a brand new machine on the floor do the same. Heed his advice.

Well the couplings are rock solid and the dimensions on the turret are always stable. We started measuring the turret itself with a gauge on the way.(before and after it has a problem)
The problem is in the control. The scale is disabled and the techs are stumped.
If you MDI to the tool and from the position subtract the machine from the absolute it should equal the offset of that tool but it doesn't always.
When the machine has a "hiccup" it no longer matches AND if it had made a part then the amount it has shrunken is exactly the same as the amount the number is out.
No there are no additional work offsets entered by an operator either.
Im about to call Fanuc right now.
I will update this thread when possible.

[DouglasR]

Have you had your distributor take a peek?

[Baconator]

Have you had your distributor take a peek?

Yes, they were here when it happened. The service manager did not understand why and had no advice.

[Factory Guy]

I believe this machine has box way slides. If you are having trouble holding size on diameters I would check z-axis gibs and x-axis ball screw/support bearings. If having trouble holding size on shoulders, check x-axis gibs and z-axis ball screw/support bearings. Once the gibs have been adjusted run a simple backlash program on x and z axis and set 1851(feed) and 1852(rapid) accordingly. A simple backlash program for x-axis: move x axis 1" negative, set indicator to zero, move .008" negative, then move .008" positive. If indicator goes to zero backlash is good. If it overshoots, the backlash comp is too high, if it stops short you need to add to parameter 1851. This parameter is usually in microns, so if you are .001" short change by 25.

Sample backlash program for X-axis.
G1 U-1.0 F100.; (set indicator to zero)
U-.008;(moves .004" if diameter programming)
U.008;(if backlash is good indicator should return to zero)
U1.0;
M99;(loops program)

Use single block or set dwell between moves, and adjust with feedrate override. This can be done in MDI mode. U is incremental for X-axis, W is incremental for Z-axis.

[DouglasR]

Yes, they were here when it happened. The service manager did not understand why and had no advice.

Has there been any change?

[Baconator]

Darryl Hardt is correct. We had a brand new machine on the floor do the same. Heed his advice.

Hey Douglas R.
You need to be aware that after much hassle we found a knowledgeable person. Fanuc is aware of problems directly related to the trouble we are having.
Doosan techs and Doosan reps seem to not know of these problems.
QUOTED "That's pretty old software. I know there's a few issues related to that function that are addressed in 32.0 and again 48.0."
Our Fanuc version is 19
They are going to update at our expense and frustration.