Ultimaker Cura 5.5 beta released - CPE Print Quality

[Gero 54]

@MariMakes
 

I have tried it again with custom parts for a customer, the material here is CPE Yellow from Ultimaker. The error pattern is the same since cura 5.0. The material flow is not 100% at the nozzle here and shows up at the Z-seam with under-extrusion. 
I can therefore not take any of the standard profiles from Ultimaker without adjusting the settings for simple customer parts, despite Ultimaker printer and Ultimaker materials. 

I'm afraid I can neither understand nor confirm the opinion of the printing experts at Ultimaker that these would work. 

[LePaul 322]

17 minutes ago, Gero said:

@MariMakes
 

I have tried it again with custom parts for a customer, the material here is CPE Yellow from Ultimaker. The error pattern is the same since cura 5.0. The material flow is not 100% at the nozzle here and shows up at the Z-seam with under-extrusion. 
I can therefore not take any of the standard profiles from Ultimaker without adjusting the settings for simple customer parts, despite Ultimaker printer and Ultimaker materials. 

I'm afraid I can neither understand nor confirm the opinion of the printing experts at Ultimaker that these would work. 

 

Is that printed on an Ultimaker machine?

I know I have added frequent core cleanings to my routine and amazed what comes out using the cleaning filament sticks from Ultimaker.

 

I find the default profiles for Ultimaker machines tend to work alright.  However, on my other machines at work and home, I stick to calibration testing for each material.  Temp Tower, Slicer Flow settings and then on the retraction tests just to be sure.  I print large, multi-day prints so I try to get it right the first time.

 

[Gero 54]

34 minutes ago, LePaul said:

 

Is that printed on an Ultimaker machine?

I know I have added frequent core cleanings to my routine and amazed what comes out using the cleaning filament sticks from Ultimaker.

 

I find the default profiles for Ultimaker machines tend to work alright.  However, on my other machines at work and home, I stick to calibration testing for each material.  Temp Tower, Slicer Flow settings and then on the retraction tests just to be sure.  I print large, multi-day prints so I try to get it right the first time.

 

This was all printed Ultimaker-only.
Ultimaker with the Cura 5.5 Beta on an Ultimaker S5 Pro Bundle with Ultimaker CPE Yellow. 
The nozzles are only cleaned occasionally. I could ramp up our maintenance routine and clean the nozzles more frequently and regularly. 
I will try this and see if the results improve. Thanks for the advice!

However, these problems would not occur so dramatically immediately if the order of the walls were the same as with any other manufacturer in the slicer. 
I had described the exact printing method of BambuLab in the Cura 5.4 post, where the last two outer walls are always printed together without any interruption, which always creates a full material flow in the nozzle. Under-extrusion due to tough material or retraction will not be visible in the outer wall. 
In my opinion, for the Ultimaker printers by Bowden extruder the best solution...

[3dprntz 4]

8 minutes ago, Gero said:

I had described the exact printing method of BambuLab in the Cura 5.4 post, where the last two outer walls are always printed together without any interruption, which always creates a full material flow in the nozzle. Under-extrusion due to tough material or retraction will not be visible in the outer wall. 
In my opinion, for the Ultimaker printers by Bowden extruder the best solution...

what do you mean by this?

[Gero 54]

1 hour ago, 3dprntz said:

what do you mean by this?

that cura should slice the walls in the same way?

[PaulKuiper 11]

Hi Gero,

The quality of the prints you shown is indeed not OK.

The CPE profiles have not changed in the 5.5 release, only the PLA, T-PLA, PETG and ABS profiles have been altered. The remaining materials are still work in progress. I quickly checked the retract settings of CPE. I assumed an AA0.4 nozzle with an 0.2mm layer height. The retract settings are 45mm/s retract and unretract speed with 8mm retract distance.
I cannot see any retract losses for these settings in a quick test print I did yesterday (0 to 10mm retract distance from bottom to top, print direction from left to right):


Figure: Retract distance scan from 0 to 10mm distance from bottom to top of print. Retract is on the left side. Unretract on the right side. So the retract settings seem to be OK for the CPE. You can even lower the retract distance from 8 to 6mm (which we probably do when we update the profiles for this material later).  

CPE is a very moisture sensitive material, which can cause oozing during retracted travel moves (leading to under extrusion after a retract). You can try drying the spool and keeping it conditioned in a Material Station after having dried it: https://support.ultimaker.com/s/article/1667412438817. I hope this solves this issue.

Otherwise, please send me the project file and I will check what is happening in this specific print.

Concerning the walls, Bambu prints them in the same way as we do. However, we print the outer wall first to get more dimensional accurate prints, this can cause a less nice seam if retraction is not tuned properly. We print inner wall first in our Visual intent mode (not yet available for CPE). You change the wall ordering yourself if you want to try it:

  

 

 

[Gero 54]

@PaulKuiper

Thank you for the reply and the test of the retraction settings. 
The print images shown were printed with an aa0.4 nozzle and the engineering settings, ergo 0.15mm layer height. 
We print 90% of everything with the engineering profiles. Since visual quality on parts for customers is also very important to us, we may try the profiles for visual quality more often. 

The CPE roll was dried in a PrintDryPro3 before printing and then stored in the Material Station. Here, I think we are absolutely following Ultimaker's recommended steps. 

Regarding the comparison with BambuLab: The printing sequence of the walls is not the same even with the "From inside to outside" setting. 
Enclosed is a print image of a component with 2 outer walls. Here all inner walls are grouped and finally the outer ones. If the distance between the two outer walls is too large (i.e. if the component were larger), there is a retraction between the two red outer walls and there is either a blob or an under-extrusion in the outer wall. 

The same part in the Bambu Slicer will be printed differently from the wall order. Here, the walls from the Inner Outer Wall are grouped first, then the walls from the Outer Outer Wall. There is no extrusion break between the outer walls, so printing defects due to extrusion irregularities are not visible.

[MariMakes 198]

Hey @Gero and @PaulKuiper,

 

I split off your discussion on wall ordering settings, to keep the focus of the original thread on newly introduced bugs.

 

Good luck with troubleshooting ❤️💪