Layer Shifts and Extrusion Problems (S5 Pro 0.8 AA)

[TrueNorth 3]

Using an AA0.8 hotend, our S5 Pro produces irregular shapes on what is supposed to be a vertical or near-vertical face of the geometry. The print layers shift erratically. 

 

It appears that some layers or groups of layers are inexplicably adding steps:

 

However, layers shift both in and out but mostly out, thus eliminating the possibilty of a single axis losing steps and shifting an entire layer profile: 

 

 

Sometimes the shifts are more gradual. It still destroys the dimensional integrity of the component:

 

Another issue that I am getting is a "warty" surface texture.

 

Tuning extrusion flow rate down to 95% seemed to help, but resulted in a bulging print wall and inadvertently redefined the print geometry and dimensions (severe layer shifts continued to plague the print after tuning):

 

The above photos are of a PLA print for a machine shop fixture. Dimensional accuracy, or at least consistency, is highly desireable. 

 

PLA is not the only material to suffer layer shifting. This print is PETg:

 

If anyone can translate what I'm seeing, I'd be grateful to be able to address these issues. 

 

 

(P.S. Perhaps this is under the wrong catagory, if so feel free to retag it.)

Edited August 18, 2020 by TrueNorth

[SandervG 1,521]

Hi, could you share your Cura project too, so we can look at your full set of settings? Thanks!

[TrueNorth 3]

 

1 hour ago, SandervG said:

Hi, could you share your Cura project too, so we can look at your full set of settings? Thanks!

 Sure. I didn't have a .3mf file saved for this print, but I recreated it as best I could recall. We needed an extreme level of structural integrity in this component, so the wall count is abnormally high with 75% infill to bolster any compression loads the walls couldn't handle. Because I've had issues with oozing, I turned on coasting and increased retraction to 8mm. Otherwise it should be a stock 0.4mm Sprint profile.  

Layer Shift Profile.3mf

Edited August 18, 2020 by TrueNorth

[SandervG 1,521]

Hi @TrueNorth, thank you for your file and patience. I've discussed it with my colleagues and we would recommend to enable outer before inner walls  in Cura, and disable coasting. Since you print so many walls and such high density it is likely you build up a lot of pressure in the print cores. Currently, with the outer walls printed last, it is likely that is where this excessive pressure is going. Reverting the order, you will still have the pressure, but it will be 'released' on the inside of your print. 

 

Oh, and you mention in your last post it 'otherwise should be a stock 0.4 profile'. You print with a 0.8mm nozzle, and have layers of 0.2mm. Is this a typo or did something not match your profile in the curaproject file?

 

Let us know if this helps! 

[TrueNorth 3]

9 hours ago, SandervG said:

Oh, and you mention in your last post it 'otherwise should be a stock 0.4 profile'. You print with a 0.8mm nozzle, and have layers of 0.2mm. Is this a typo or did something not match your profile in the curaproject file?

 

My mistake on the layer height; that was definite a mistake on my part when I saved the .3mf file. It was to be sliced at 0.4mm "sprint" height. 

 

Another question that has been rattling in the back of my mind is whether the esteps need calibration. Do you think that overextrusion could be a possible side issue?

 

Thank you for your thoughts and collaborative advice. I'm looking forward to experimenting with your ideas once we get our printhead back from the warranty department. Our S5 Pro has been a very tempermental child. 

 

It may be a substantial length of time before I am able to test the theory, but once I do I'll be sure to let you all know what the results are. 

Edited August 24, 2020 by TrueNorth

[SandervG 1,521]

Thanks. No, it is 100% not an estep calibration. In all my years I've never seen that as the culprit. It could be a form of over extrusion, like I mentioned with the excessive pressure that finally gets released on the outer wall. 

 

Luckily the S5 (and Cura) has many options to configure, so we just need to figure out what settings and/or profile works best for what you're trying to achieve. The more experience you have with 3D printing, Cura and the S5 the sooner you will be able to identify that even before a print starts.