PROBLEM WITH FANUC 6M on Amada Coma

[cristalex_it_sr]

Hi Everybody

I am writing you because i just bought an old used Amada Coma with the Fanuc 6M and i have a problem with the zero setting when i power on the machine.
Everytime i restart the machine i must make the zero of the Y axis and X Axis.
Now i have no problem with the zero of the X axis everytime the axis run to the home position decelerate and find the zero but with the other one is difficult to find the zero.
In fact the axis run decelerate but the light of the Y zero do not turn green and i have no ossibility to go ahead with the program or work.
I would like to know if somebody found the same problem and what is the cause.
Just to inform you that i have no parameter list, the only that i have is the one i wrote down the first time i made run the machine.
I also changed the deceleration micro position but nothing, sometimes the machine catch the zero inmediatelly and other times i spend long time to find it.
I also checked the brushes and all is fine, i opened also the encoder cap on the motor and cleaned the little brushes that are on it but nothing to do.
I am considering problems with the encoder but if i catch the zero after this i have no problems, maybe sometimes the machine does not return to the zero position but nothing that do not permit me to continue my work.
I was thinking to change the zero position in the parameters but i have no parameter list explanation so i do not know what is the correct parameter i must change.
I do not know if there is a procedure like in the OT to reset the zero positions after the transport of the machine.
If you have any suggestions please email me ir answer me
Will be very preciated.
Thanks

[f-bu]

When you send the machine to zero on Y axis (problematic one) and it stops without turning confirmation light on, go to diagnostic number 801 for Y (button DGNOS, page up) and check if reading is bigger than the value of parameter No.71 (in-position width). If so, push reset, go to JOG mode, move the axis minus and plus observing DGN801. Note the mean value and adjust parameter 125, so when moving machine DGN 801 is close to zero.
After that check again reference return.

[cristalex_it_sr]

dear fbu
thanks for your message i made all you wrote and i solved the problem but when i turn off the mschine for some minutes the parameter change with another number everytime
maybe i do not save but i do not know how
please consider i have the bubble memory card and the battery has charge

Any suggestion? Thanks

[WGoyer]

The feature that keeps changing the drift parameter is called "Automatic Drift compensation". It is attempting to fix what might be a bad component in either the mother board or the VCU (servo drive). You can turn it off by checking your 6M Maintenance manual for the term ADFT. I think it is either Parameter 6.7 or 7.7. You can turn it off, set the drift value by hand, and see if the Diagnostic 801 settles down. If the drift (measured and displayed by 801) changes during the day with ADFT turned off, there is most likely a hardware problem.

Warren

www.uptimecorp.com

[f-bu]

Automatic drift compensation is set by PRM 7.7, as Warren mentioned. Check if the value in parameter 125 for Y, your problematic axis is less than 255. If the value is bigger, reset it to zero and hit/release emergency stop (if PRM7.7 is still 1). With this the control will measure the drift again. For this measuring the value in 124..127 changes every time you turn on the control, there is nothing wrong youth the memory. If there is a big disperse in 125, you can expect that the servo drive or CAV cable or the mother board have problems. You can try with ADFT turned off, and adjusting parameter manually, some times it performs better.
And maybe we shall start with this: Check the grounding!

[cristalex_it_sr]

first of all thanks for your help
regarding my problem
i turned on my machine this morning all it mades the zero fine without problems
also the parameter 125 i put yesterday is in memory also today
so i turn off and on making home positions and everything is fine i made this several times without problems
i also checked the value of the parameter you gave me 125 and is less than 255 it is actually 16.
now when i put the machine in auto and push the start it makes the program fine but it does not finish or does not arrive to program end because the y axis does not return to its origin
the x axis return and turn on the home light
for this reason also with m30 or m02 at the end of program it does not permit to return to the beginning
if at this point i push reset finishing auto operation and turn the selector to retract i make the y zero without problems
it seems that the problem now is in the auto operation with the return to home position to remove the foil from the machine
i hope to be more clear with the problem
i think i do not need to change the parameter 7.7
any help is apreciated

[Dan Fritz]

Please post the last 10 lines or so of your program. Please tell me, is the machine returning to the Y home position but the home position light is not coming on, or is the Y axis stopping some distance from home position?

M02 and M30 will normally reset the program and stop the part cycle. If you are stopping with the "In cycle" light on, then there is something else going on here, which is stopping the machine BEFORE the M02 or M30.

Please run your program and get the machine to stop with the "In-cycle" light on, then press the DGNOS key to display the diagnostics and page up to diagnostic #700. You will probably see a display with a "1" in one of the 8 bit positions. Please tell us WHICH bit is a "1". The meanings of these bits are:

Right-most bit (bit 0): M, S, or T command is being executed and not finished
Bit 1: Axis motion is being executed and not finished
Bit 2: Dwell command (G04) is being executed
Bit 3: In-position check is being executed (this could be the "Drift compensation" issue)
Bit 4: Feedrate override is at 0%
Bit 5: Axis interlock signal is on, preventing motion
Bit 6: Control is waiting for spindle speed arrival signal

(these may not be all accurate for your 6M because I copied them from a 6T lathe manual)

Generally, diagnostic 700 should tell you why the control has stopped while the "in cycle" light is on. Diagnostic 701 will tell you why it's stopped if the "in-cycle" light is off.

Hint: If you run your program until it gets near the end of the cycle, then put the control into single-block (SBK), then you can step through the program block-by-block until it stops. At that point, look at the COMMAND page and see what block of the program it's trying to execute. That may give us a clue also.

The Amadas have proximity switches to detect top-dead-center on the punch flywheel. If one of those does not detect TDC, that can prevent axis motion and make you stop with the in-cycle light on. Amadas also have some "Decelleration" switches that force the axes to slow down when the punch is near the clamps. This "slow-down" speed is set by parameter, so if you are stopping near the clamps, it may be that this speed is set to zero. Parameter 107 sets this speed, so please verify that it is not set to zero.

[cristalex_it_sr]

Dear cnczone users these are other news

Regarding the diagnostic 700 the numbers when i have the problem are 00001011
i found the right parameter p125 with a number of 14 but it happens that maybe one time in the day these parameer change with values between -3 and 17 and when this happens i have problems.
The problems i have are regarding the no capacity of the y axis to reach the zero or home position.
In fact the punching machine send the axis to home position everytime the program end so if i write M30 at the end it happens that the machine does not finish the program and wait the final ok from the y axis of reached position.
In base on what Mr Dan wrote the problems are with bit 1 bit 2 and bit 4 and they are for axis motion executed but not finished and the other two for the g04 dwell comand (i do not know what is this comand) and the feedrate at zero.
As i wrote in the past messages it des not happen everytime, in fact today in the afternoon i changed the value of the parameter 125 to 14, push the off in the cnc control, made home positions, and pushed the auto button developing the same program several times and all these times the light with finished program went on so pushing another time the start the machine rebigin the program.
In this case obviously the parameter 125 remained at 14 and the diagnostic 700 was 00000000 also the diagnostic 801 was near to the zero value plus or minus 5.
On my experience the machine does not remeber the value of the parameter 125 and when it changes there is nothing to do with the auto, the program does not end.
I do not know if i make the correct procedure to save the data because i have the bubble memory card but i only change the switch to save, nothing more.
There is also no pwe like the lathes but only the switch on the motherboard.
I think i am doing the correct procedure because in some cases the parameter 125 remain at 14.
i did not made the change to the parameter 7.7 because the value of the parameter 125 is less than 255 but in base on what wrote mr Warren this excludes the ADFT.
I would like to understand if i change the parameter 7.7 and let it at zero there will be any problem with functions of the machine or not?
Also Mr f-bu wrote that i can turn off the ADFT and adjust manually the parameter, i think the parameter 125 right? but after i need to change another time the 7.7 turning on the ADFT or i must let it at zero?
Do you think i can have problems with servo or CAV cable or motherboard if sometimes the machine reexecute the program time after time without problems?

Obviously thanks to everybody for the help, anyway i solved in part the problem and just only this is a big sadisfaction.

Thanks everybody will see my post, hope it will be helpful to some other users.

[cristalex_it_sr]

Mr Dan just to answer to all your questions:
The machine return to home position but the green light of the Y zero does not turn on
The program stops one line before the end or at the end of the program M30, if i do not put M30 at the end of the program the machine remains in auto operation.
The diagnostic number hen it does not reset the program is 00001011
Regarding the fly wheel i have also a green light with the dead-center-top and it turn green without problems so i think the micros run fine because in the program there is around 30 punchs and everytime it work fine.
Regarding the Decelleration switchs they work fine i really did not saw the parameter 107 i will verify tomorrow but i think this is not the problem because at the beginig of the operations, when i make the first ero the machine run decelerate and find the correct zero without problems.
Anyway i will recheck the parameter 107 and i will post tomorrow, if you have in the meantime any other suggestion please post to me.
Thanks and have a nice day

[Dan Fritz]

Increase the values in parameters 070 and 071 by 50%.

These parameters define the "in-position" zone for the X (70) and the Y (71) axes. An in-position zone is the allowable tollerance from the true "target" position that the control will still consider to be "in-position". Since no servo can put the axis precisely on target every time due to drift and oscillation, the control needs this zone so that when the servo gets within this tollerance, the axis is considered "in position" and the program can continue.

Your diagnostic 700 indicates that an M, S, or T code is being executed AND the control is still trying to move into position AND the servo hasn't reached it's In-position zone yet. It all fits with my suggestion to increase parameters 70 and 71 a bit. These should be small numbers, like "20" or "50". They should never be set to zero.

Let me know if this works.

[cristalex_it_sr]

Thanks Mr Dan
Unfurtunatelly i am in Italy and now it is half past eleven in the night so i will change these parameters tomorrow.
In fact i think we can let more tollerance because anyway a punch machine never need a so precise position because also the foil never will be put in the exact position.
I will inform you tomorrow.
Thanks so much

[cristalex_it_sr]

Dear Sirs

Unfurtunatelly today the machine had not problems and the zero positions are fine.
It is a very misterios machine but today there was no way to make it go wrong.
Anyway i adjusted one of the two parameters 70 and 71 that were not zero.
I moved only one and it is the 71 regarding the y positions and changed from 30 its old value to 45 and anyway i had no problems anymore.
The other parameter y 70 remained the same because i never had problems with the x axis.
Now can i move only the y axis or i need to change and put the same value in both parameters?
Tomorrow i will continue to move the machine to understand if there is any other possibility of problems with these machine.
Do you think that there is the possibility of problems to the encoder axis motor or motherboards ?

Thanks
I will inform you tomorrow afternoon.