Ultimaker S5 Pro Bundle Layer Shifting

[rvipperman 0]

Hi everyone,

I've been experiencing layer shifting when I print with extruder one, specifically when the material changes through the material station. I originally believed that it was due to the CC 0.6 core I was using, but I was eventually able to narrow it down to extruder one through some extensive testing. All of the hardware has been inspected and tightened and nothing has changed. 

 

What I don't understand is the layer shifting doesn't occur when I use extruder two, even when the material changes. This leads me to believe that there is a firmware issue with extruder one. Has anyone else been experiencing this issue? Thank you.

[gr5 2,167]

left versus right core is something you should ignore.  The problem is unrelated.  But I'll try to explain anyway why there is a left/right core issue.  You are achieving a higher acceleration on the shifting layers when you print with the left core. I don't know why but it's probably the exact tool path that cura takes.  The cura tool path is quite complicated and tries not to go beyond certain accelerations and the firmware on the printer also but the firmware has many known bugs where it can go a bit over the max acceleration.

 

So let's get to what you need to do.

 

First you need to figure out if it's the X or Y axis that is slipping/losing steps.  If it's left/right slipping then it's the X axis.  front/back slipping then the Y axis.  You only have to fix the slipping axis.  No need to "tighten everything".

 

80% of the time the problem is a loose pulley.  I know you said you tightened things up but the most likely problem is the pulley on the stepper motor which ironically is the hardest pulley to get to.  Each pulley has a set screw.  You want that so damn tight you would be surprised.  The steel tool should be twisting you want it so tight.  If you use a small L shaped allen wrench and your fingers are on the short end then your fingers should hurt.  A lot.  If you have your fingers on the long end (not possible with the stepper pulley) then take it easy - you don't want to crack the set screw in half.

 

The second most likely is the other end of the short belt.

 

You can get to all the pulleys without taking anything apart if you shove the head around to line things up and if you have a long shaft allen wrench.  Metric.  2mm.

 

18% of the time the friction is too high.  Shove the head around in X and then Y and see if one has a higher resistance.  Either way try adding one drop of oil to each of the 6 (six!  not 2, not 4, but six) rods.  Careful not to let the oil get on the glass or the belts.  Any mineral oil will do.  3-in-1 is great.  Sewing machine oil is great.  Even baby oil is fine.  A light oil is preferred.  The shafts through the head theoretically don't need any oil as those are ball bearings (linear).  So try to use even less than a drop.  Or skip those.

 

Less than 2% of the time it's a bad stepper driver.  Stepper drivers shut off (very briefly) if they over heat.  If your printer is in an area where the air is > 90F/32C then that could be the issue but it would tend to not fail for the first half hour and then fail like crazy for the whole rest of the print.

[rvipperman 0]

2 hours ago, gr5 said:

left versus right core is something you should ignore.  The problem is unrelated.  But I'll try to explain anyway why there is a left/right core issue.  You are achieving a higher acceleration on the shifting layers when you print with the left core. I don't know why but it's probably the exact tool path that cura takes.  The cura tool path is quite complicated and tries not to go beyond certain accelerations and the firmware on the printer also but the firmware has many known bugs where it can go a bit over the max acceleration.

 

So let's get to what you need to do.

 

First you need to figure out if it's the X or Y axis that is slipping/losing steps.  If it's left/right slipping then it's the X axis.  front/back slipping then the Y axis.  You only have to fix the slipping axis.  No need to "tighten everything".

 

80% of the time the problem is a loose pulley.  I know you said you tightened things up but the most likely problem is the pulley on the stepper motor which ironically is the hardest pulley to get to.  Each pulley has a set screw.  You want that so damn tight you would be surprised.  The steel tool should be twisting you want it so tight.  If you use a small L shaped allen wrench and your fingers are on the short end then your fingers should hurt.  A lot.  If you have your fingers on the long end (not possible with the stepper pulley) then take it easy - you don't want to crack the set screw in half.

 

The second most likely is the other end of the short belt.

 

You can get to all the pulleys without taking anything apart if you shove the head around to line things up and if you have a long shaft allen wrench.  Metric.  2mm.

 

18% of the time the friction is too high.  Shove the head around in X and then Y and see if one has a higher resistance.  Either way try adding one drop of oil to each of the 6 (six!  not 2, not 4, but six) rods.  Careful not to let the oil get on the glass or the belts.  Any mineral oil will do.  3-in-1 is great.  Sewing machine oil is great.  Even baby oil is fine.  A light oil is preferred.  The shafts through the head theoretically don't need any oil as those are ball bearings (linear).  So try to use even less than a drop.  Or skip those.

 

Less than 2% of the time it's a bad stepper driver.  Stepper drivers shut off (very briefly) if they over heat.  If your printer is in an area where the air is > 90F/32C then that could be the issue but it would tend to not fail for the first half hour and then fail like crazy for the whole rest of the print.

Thank you for the speedy response. I went through and did everything you had suggested and nothing changed. I attached a picture with two blocks. The one on the left was printed in the extruder two slot with a forced filament change through the material station (I just cut the filament and moved it to a different bay in the station), and the one on the right was printed in the extruder one slot with the same procedure. As you can see the block from extruder two has no layer shifting but the block from extruder one has severe layer shifting in the Y-axis direction. The layer shifting only occurred after the filament went though its change cycle and the printer resumed. This is why I believe there is a firmware issue with the extruder itself. I've tried a factory reset on the printer as well as resetting my Cura profiles (which are essentially stock). I'm not sure where to go from here. The only other thing that I could think of would be a faulty stepper driver. Any other suggestions would be greatly appreciated. Thanks!

[gr5 2,167]

1) So did you have to take the metal corner cover off the stepper (2 screws I think to get that off)?  Did you have a long hex driver?  Or did you have to remove the stepper to get at that pulley?

 

I'm telling you it's almost always the stepper.  I have had 100s of people with this issue and it's almost always the pulley on the stepper.  But not always.

 

Okay - Y axis is slipping.  That's definitely good to know.  Stepper in rear left corner. 😉  For Y axis it is even less likely to be a problem with the 4 upper pulleys as there is a dual pulley that connects the motor pulley directly to one of the 2 long belts.  So you need 2 failures for it to be anything other then the stepper pulley.

 

3 hours ago, rvipperman said:

The layer shifting only occurred after the filament went though its change cycle

 

Okay - this is definitely new.  I don't know what a change cycle is.  Can you explain more?  does the printer home again?  Is this a 2 filament print?  Is this a dual core print?  I don't understand why there would be some kind of "change cycle".  Your print appears to only have one type of filament.  Do you have "pause at layer" plugin enabled?  Please elaborate.  This is certainly suspicious.