Byspeed axis plausibility errors

[laserfab]

thread380-237055

Greetings,

We are having the identical issues on our byspeed which were noted by asw04 in the previous thread from Feb 09.
Loss of position while cutting, etc. Bystronic indicates that we need the encoder strips to be upgraded from optical to magnetic. I am not sure I see this as a final solution?
At time we get an e-stop from an axis plausibility error and some time find that machine continued to operated after making a random shift while in the middle of a part.

We also see that when an axis plausibility error occurs and we check the controller, it looks as is if one axis (Y) is still getting a motion signal althought the machine is sitting still due to the e-stop. I would would be interested to hear any similar feedback and would love to hear the out come of the aws04 thread.

 

[krugtech]

Is the problem just in one axis? Is the light on the encoder staying green throughout it's travel? As for upgrading, I hear the new magnetic system does not need to be cleaned as often but I have no personal experience with it.

When I come across this problem I find the encoder read head is dirty, the strip is dirty, the read head is not set at the correct distance or the strip is damaged. If the existing system worked fine up until now, then an upgrade isn't the only solution, you could just replace what's damaged. Look at the strip and see what it looks like.

Should you upgrade? Maybe if you spend too much time cleaning the strip it would be worth it, but then again maybe if you need to clean it often then your dust collector isn't working.

Also, air blows on the read head and encoder strip to keep it clean, I've seen cases where oil in the customers compressed air overcame the air filters in the machine and melted the lacquer coating off of the strip which makes it hard to read.

Check the LED on the encoder read head, look at the strip and let us know what you find.

Chris

Chris Krug

http://krugtech.com/

 

[laserfab]

We get the all green on the encoder lights. We keep the strips clean. The reader heads were swapped a month ago which releaved the condition for a while but the problem seems to be back on the same axis agian. Also, the "drift" seems really strange. With the machine not moving due the plausability error, when the door is closed and the servos are energized the control panel shows the axis to be "moving" as if receiving a signal?

 

[HenryRollins]

What nozzle body do you have? Copper or the ceramic with teflon shield?

 

[krugtech]

Henry Rollins! I'm your biggest fan! Question, how can the nozzle body type affect the issue laserfab is having?

Chris Krug

http://krugtech.com/

 

[HenryRollins]

Just a shot in the dark. I was reviewing some old documents thinking it may have been do to the old style nozzle body.

 

[aws04]

Our byspeed still had this problem even after the new style
read strips and read head (were replaced bystronic free of charge for some reason even though out of warranty period). Part program shift or holes shifting was really
bad sometimes but the problem didn't happen very often so was hard to fix.
Last time it happened it was so bad and would not go away.
But this time after 2 years off and on we got a direct answer for a change and was asked if tag at end of cut turned on. Which was yes, and was our tag length longer than 1.2mm??
if so we were told this was the cause - we set the tag 0.5mm problem has never come back.
did you have the tag option set at the time ? if so what value?

 

[laserfab]

That is very interesting. We have been running with the new magnetic encoders for 2 weeks and have not had a reoccurrence of the problem. However in the past we swapped reader heads on the encoder and the problem when away for a while?

Could you provide any more detail re the "end of cut tag"? what is the g code for this line, I am not familiar with it. Do you use bystronic software or 3rd party product?

*note re previous post our nozzle body is copper with the ceramic ring.

 

[HenryRollins]

If I understand you correctly, you are putting micro joints at the lead in? If you are using Bysoft, what version? Generally, we would not place micro joints at the lead in. If you are using the micro joint set up values then you have no choice because it will always stop short of the lead in using the width of micro joint feature in the machine parameter.