Gerber 408: Y-axis error when travelling at speed

[Mikexx]

Where the carriage moves with up arrow, ie away from me and the keyboard it can move at speed without error.

If the carriage moves with down arrow, towards me, I will get numerous errors. I can use "Reset", press down arrow for the process to repeat where the carriage moves, stops with beeping.


It's notable that it doesn't happen at low speed, such as when orienting.


Ideas and suggestions would be greatly appreciated?

 

[Vassago]

Hmm.. I would think that one of the gears or sensors is loose - almost acting as a one way ratchet due to wear. Going by the issue I'd think it would be one secured by a screw as with wear, that could give rise to such an issue.

Another possibility could be if it's not level, combined with a servo or power supply that's on its way out.

Due to the age of the machine, it's very lightly to have issues with electrolytic capacitors failing which could also cause the issue.

If you've got a multimeter, check the dc outputs of the psus for a ripple and check the machine for level, then try to manually move the gantry when powered off to see if there's any movement

 

[Vassago]

Should say ac ripple not a ripple - autocorrect is the bane of my life. Lol

 

[Mikexx]

Hmm.. I would think that one of the gears or sensors is loose - almost acting as a one way ratchet due to wear. Going by the issue I'd think it would be one secured by a screw as with wear, that could give rise to such an issue.

Another possibility could be if it's not level, combined with a servo or power supply that's on its way out.

Due to the age of the machine, it's very lightly to have issues with electrolytic capacitors failing which could also cause the issue.

If you've got a multimeter, check the dc outputs of the psus for a ripple and check the machine for level, then try to manually move the gantry when powered off to see if there's any movement

Thanks for the ideas. I have checked the linear bearings, cleaned and re-oiled them. I feel the carriage moves smoothly and that this ought not be the source of the issue.

My next idea is to take a look at connectors. I think the Y-encoder signals are reversed compared to X and Z signals, otherwise I could swap the connectors. Will check on this point.

After that as you suggest it's a look at the tower and possibly swap the driver cards between X and Y? Possibly swap X and Y cables to the driver.

I have a scope but not sure if it's a Power Supply issue as the other axis would surely be affected?? However ........

Thanks again.

 

[Vassago]

Can be either drivers or psu - faster movement = more power required. When they're getting past their sell by date which this one will be, they tend to loose capacitance so more ripple gets onto the line.

However..that said, as you said it only happens one way - I'd still think it might be a sensor or gear. Aiming more towards a gear.. It's riding over the grub screw dent one way and jamming in the other.

If you can remove the motor, just see if there's any play.