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Mazak M4 with fanuc 6T control alarm 411

mnkota

Plastic
Joined
May 25, 2020
Location
Moorhead
Ok this is my first time posting but have been reading many threads about many issues I have come across. Ok i just recently acquired a mazak M4 lathe 1979-1980 model cant read the tag. previous owner had replaced the x axes drive motor and had no success on ever getting it working again. My investment was just the transportation of this machine to my shop and have now have it up and moving except when trying to move the x axis i get a 411 alarm. press reset drives come on and can move in the z just not the x. from what i know the motor was replaced with a tested rebuilt drive. Any help would be great.

thanks
 
411 is following error.
Our M4 with a 5T control had the encoder in the motor. and a shear pin between the motor and Z axis lead screw.
Needless to say that when the shear pin broke, usually there was a large boring bar in the rear turret and a bad crash resulted.
My chronic complaining to Mazak service, about the bad design, maintaining that the encoder belonged on the lead screw coupled with the very nasty name I gave it, I was known by name in Japan, that was over 25 years ago. It appears that took my complaints seriously, because when we bought the Micro Slant, it had the X axis encoder on the lead screw so when the shear pin broke, it stopped running.

Since your problem is on X and not Z, you need to determine if the encoder will move if the motor turns, no broken shear pin, and that the axis is not seized (the motor is not able to turn when power is applied).
Does the motor try to turn? If not you may have a bad motor, check the brushes. Or a broken wire in the cable from the motor to the machine.

If the above checks don't reveal the problem. unhook the motor leads at the velocity control unit and apply 12 Volts DC and see if the motor will creep a bit. If it will, check the fuses on the velocity control unit. The alarm fuses detect a blown fuse. Many times the alarm contacts are bypassed and a blown fuse is not sensed, Those 1.3 Amp alarm fuses need to be in place if missing, that causes problems.

If the motor turns a little before the alarm 411 appears, look at the encoder and wiring. Frequently there is a flexible coupling driving the encoder, they break and can give you the problem you have. The encoder wiring may be bad or a bad encoder.

Hope this rambling reply can shed some light on things to look for.

Bill
 
I have done some trouble shooting already by removing the drive motor and checking if axis is free. moves just fine with ease. when trying to move the x axis it seemed to lunge always in the same direction no matter +/- was tried. Since the motor was "replaced" I am questioning the wire connections? not sure if this helps but I can easily move the axes with the 6mm shcs at the end of the motor and it gets a 410 alarm witch is axis moved without command. I understand it is an old machine and will have quirks to work out but was able to make a feed pass in the z and it handles the heavy cut with no grunt or chatter, much better than a newer haas I was familiar with.
 
Check parameter 006 bit 7.
1=automatic drift comp.
Parameter 124 is the drift compensation for X, and 125 is for Z.

If 124 is much larger than 125, set 006 bit 7 to 0 and 124 to 0 also. see if you still have the same problem.

Diag 800 is position deviation amount for X and 801 for Z.

Bill
 
ok after trying a few different things still no luck changing parameter 006 bit 7 to 0/ no change still alarms. watching what the deviation is on diag 800 climbs when using the hand wheel and then alarms. parameter 124 value was 0 and 125 was 10. tomorrow i am going to try taking the drive motor off and see if i cant get it to creep with when applying 12v DC I have a power probe for automotive testing just not sure if that will be enough, or do i try the test a starter method with strait leads and should spin.above you mention the 1.3 amp fuses on the vcu, one of these was white after the first power up and all was getting was a 401 alarm had no drives. I corrected that and then cleared all alarms and then was able to move all but the x axis. again thanks for all the help so far
 
"still no luck changing parameter 006 bit 7 to 0"

Do you know how to set parameters? Your wording says you are not able to change them. If this is true, I can tell you how, but it works better if you state it directly.

At this point, you have not revealed where the encoder is, in the motor or on the screw? or I don't know. After the checks below, the procedure is not the same based on location of the encoder.

When watching diag 800, what is the value when it alarms out? Hand wheeling in the smallest unit, 1 click + direction should increase the count by one, a click in the - direction should decrease by one.

Another diag to check is 713 bit 6 is a 1 pulse per turn, bit 5 is encoder channel B and bit 4 is channel a these are for Z axis. Ch A and B count in quadrature once you see how it works by hand wheeling in the smallest rate.

Now for X axis: bit 2 is the once per turn pulse, bit 1 is ch B, and bit 0 is ch A
What is X not doing that Z is doing?

Bill
 
Ok I have done some more testing, and seems like i am doing circles. X drive motor use to jump forward or backwards and now does not. I have changed par 6 and no movement this is when i checked the fusees again on the x velocity control unit and two of the three fuses where bad. these were just replaced and now i have one of 1.3 amp fuses tripped. frustrating. i have ordered new fuses. but checking things i have found that one line voltage is dramatically differnt than the rest and the transformer at the botom of the cabnet that feeds the vcu one line is dead does this have any effect that we have a wild leg in our three phase hookup?
 








 
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