Apparent Y axis stepper slip
Posted: Thu Nov 12, 2015 7:09 pm
I've had this problem for quite a while now. It doesn't always happen, but often enough to deserve attention.
The bad news is it always happens at the very end of a print (last nights 14 hour print for example). The good news is I can usually salvage the printed objects.
This morning near the end of an overnight run, I heard the M2 make an unusual clunking sound and could visually see the problem while the print was still underway. I don't usually hear/see the actual problem underway.
You don't have to look too closely to see the filament draping off the side of the objects.
For reasons uncertain, it always slips in the positive Y direction. And always near the end of the print.
it might be relevant that the Y axis moves the mass of the objects. But, I print these objects at different heights, sometimes 1 up and sometimes 4 up. I don't have a strong correlation to mass on the build plate. It might be there, but the qualitatively, it doesn't appear so.
The problem is strongly correlated to the top of these objects. And as I mentioned, I print these at different heights. The one pictured are nearly the tallest ones. But I've seen the problem with shorter ones as well.
The top of these objects have these lugs for mounting with screws. In the process of printing these lugs the M2 is required to slew between different points on the object. I'm fairly confident the problem has to do with this slewing.
Here's the speed page from Slic3r: Not so sure where this came from... I've generally only adjusted speeds for the print moves to get the look I want with the transparent PETg.
Since F=MA, it is probably acceleration related. I did notice a higher acceleration number for infill. There is some infill in this print.
I don't have any idea if the acceleration numbers here are good or bad. Maybe some experts out there on the forum can render an opinion?
One of difficulties here is the M2 doesn't always do this. So its hard to lightswitch the problem. Which is one of the reasons I'm asking the forum.
And finally I did check the belts. They seem reasonably taut. I haven't seen a spec for belt tightness... perhaps I haven't looked in the right places??
bignordique
The bad news is it always happens at the very end of a print (last nights 14 hour print for example). The good news is I can usually salvage the printed objects.
This morning near the end of an overnight run, I heard the M2 make an unusual clunking sound and could visually see the problem while the print was still underway. I don't usually hear/see the actual problem underway.
You don't have to look too closely to see the filament draping off the side of the objects.
For reasons uncertain, it always slips in the positive Y direction. And always near the end of the print.
it might be relevant that the Y axis moves the mass of the objects. But, I print these objects at different heights, sometimes 1 up and sometimes 4 up. I don't have a strong correlation to mass on the build plate. It might be there, but the qualitatively, it doesn't appear so.
The problem is strongly correlated to the top of these objects. And as I mentioned, I print these at different heights. The one pictured are nearly the tallest ones. But I've seen the problem with shorter ones as well.
The top of these objects have these lugs for mounting with screws. In the process of printing these lugs the M2 is required to slew between different points on the object. I'm fairly confident the problem has to do with this slewing.
Here's the speed page from Slic3r: Not so sure where this came from... I've generally only adjusted speeds for the print moves to get the look I want with the transparent PETg.
Since F=MA, it is probably acceleration related. I did notice a higher acceleration number for infill. There is some infill in this print.
I don't have any idea if the acceleration numbers here are good or bad. Maybe some experts out there on the forum can render an opinion?
One of difficulties here is the M2 doesn't always do this. So its hard to lightswitch the problem. Which is one of the reasons I'm asking the forum.
And finally I did check the belts. They seem reasonably taut. I haven't seen a spec for belt tightness... perhaps I haven't looked in the right places??
bignordique