Error 403 Z axis software limit overtravel

[designerpatrick]

I am a noob to CNC, but I am working hard at it.

I get the title overtravel message on my 2003 MB-20 mill running a Cent 6 controller. I've run some tests before and not recieved this. I brought in a new NC file to drill holes in some birch ply. It did well at first then it crashed the pointing tool into the part (indeed broke it). I figured I might be hitting the lower Z stop switch so I ran a dry run test with the quill lowered. It would instead rapid return to a higher and higher plunge start point at each hole...then the 403 alert (I get the alert before it is close enough to acually hit the Z overtravel switch).

I've carefully set and confirmed the g54 xy zero's and I physically touched-off the tool Z offsets. I am using FeatureCam for NC output, I looked at the code and there are no G92 calls. Also the numbers appear right for the Z heights for drilling and pointing. I look at the G92 settings in the MB20 nothing there. Perhaps it is an absolute vs relative thing.

I am befuddled... any thoughts would be appreciated.

[One of Many]

You might write a small program to do some rapid and feed Z moves to check if it is repeating. It sound like the Z axis is losing encoder counts or slipping. That may also be the cause of the original crash if it was running fine on that same program.

The error is a soft limit which the machine knows it will over run in the next block. If the encoder was slipping, it wouldn't realize it was getting close and trip the over travel first. So that adds to the mistery.

If the program isn't too big, you might post that for a better idea of the environment it is running under. Provided it is a G-code file. Conversational is different.

There should be a G90(absolute) in the header not a G91(incremental). The Z to clearance can be a G31, more often seen as G0 Z 0.1

DC

[jpawelk]

Error 403 is a Z axis software limit overtravel alarm. The alarm is most likely caused by telling the axis in a program to go to a location that the machine is not capable of going to. Make certain that your tool lengths are set properly and all of your Z axis moves in your program are not too great.

[rmkscrambler]

We have a 93 MB20 (upgraded to centurion 6) and a 2006 RH20 centurion 7
since your machine is a 2003 it should have the yaskawa ac servos Same as the RH20 when we first recieved this machine it would not compleate a peck drill cycle without reciveing an error 403 becouse it was still under warranty we had a service rep look at it he explaind that they were trying to tweek tool change specs and push the servos above their limits he just enterd the param screen and allowed the machine 1 sec more accel decel time for z axis servo and it fixed the problem. I know nothing to do with over travel but still gave same error. had the same basic problem with spindal the machine would e-stop for any tool change over 3000 rpm. We had to adjust accel decel time on spindal also we now have a 20 sec tool change(8000rpm to 8000rpm) insted of 7 but at least it works.

[jpawelk]

Originally Posted by rmkscrambler We have a 93 MB20 (upgraded to centurion 6) and a 2006 RH20 centurion 7 since your machine is a 2003 it should have the yaskawa ac servos Same as the RH20 when we first recieved this machine it would not compleate a peck drill cycle without reciveing an error 403 becouse it was still under warranty we had a service rep look at it he explaind that they were trying to tweek tool change specs and push the servos above their limits he just enterd the param screen and allowed the machine 1 sec more accel decel time for z axis servo and it fixed the problem. I know nothing to do with over travel but still gave same error. had the same basic problem with spindal the machine would e-stop for any tool change over 3000 rpm. We had to adjust accel decel time on spindal also we now have a 20 sec tool change(8000rpm to 8000rpm) insted of 7 but at least it works.

An error 403 is a Z axis software limit overtravel alarm. It has nothing to do with the spindle. It also has nothing to do with a tool change with the exception of the G32 (Z axis to tool change height). It seems extremely odd that someone increased your accel/decel times for the spindle. Doing this wouldn't have anything to do with an error 403. In most cases, the error is in the program or a tool was not touched off properly.

[rmkscrambler]

Im sorry if my post was confusing. accel/decel time on the z axis moters has to do with table to table tool change time (if the head gets to the changer quicker you have a quicker tool change. they were pushing this to hard.
the spindal was another seperate problem with the machine that did not get the error it just killed the machine
my point was they were trying to advertize a 7 sec tool change when the machine is incapable. loose some time on your tool change or peck drill cycle and things run smoothly.( the mb20 probibly dosen't have a tool changer but they use the same defalt param settings across the bord.)

[One of Many]

Originally Posted by rmkscrambler Im sorry if my post was confusing. accel/decel time on the z axis moters has to do with table to table tool change time (if the head gets to the changer quicker you have a quicker tool change. they were pushing this to hard. the spindal was another seperate problem with the machine that did not get the error it just killed the machine my point was they were trying to advertize a 7 sec tool change when the machine is incapable. loose some time on your tool change or peck drill cycle and things run smoothly.( the mb20 probibly dosen't have a tool changer but they use the same defalt param settings across the bord.)

What jpawelk is trying to convey is that the error 403 has to do with the control comparing a move to where it is at currently and if it can go to that point. If the distance to move is greater than the distance on the absolute position, the error 403 will be flagged. Your particular error was probably a different code.

DC