PaulKuiper

It needs to be 60C. Before this it first pulls a thin neck at printing temperature, before it cools down to 60C to cleanly break this thin neck. This forms a proper filament tip that can move up and down the material handling system.

Regular fan speed 5%. OK, so a fan speed of 5% has the same quality as a fan speed of 40% (can handle 70% overhang). So we will change the regular fan speed to 5% and the initial layer fan speed to 0% (for adhesion robustness). Thanks for reporting!

Left is 2% , right 40% fan speed. The quality in overhangs is clearly better for 40% fan speeds. Overhangs up to 70% are printed OK with 40% fan speed and overhangs up to 50% are printed OK with 2% fan speed. Also checking 5% and 10% fan speed to find a balance, but whatever the result for the regular fan speed we will reduce the fan speed in the first layer back to 0% for this print mode in Cura 5.7.

Hi Alnavasa, We only have a 0.06mm layer height print profile for the AA0.4 core. The back pressure is too high for a AA0.25 core when printing at a 0.06mm layer height, so we do not recommend that. We will re-check if the 40% fan speed is really necessary for ABS to keep good visual detail. If not we will lower it to get better part strength.

Hi, I checked the history of this setting. The 40% fan speed for the AA0.25 nozzle at 0.1mm layer height has been in there since at least 4.13.1 (I did not check versions before that). However, versions up to 5.1 have an initial layer fan speed of 0%. From 5.2 onwards this changes to be equal to the regular fan speed (=40%). In 5.2 we changed the initial fan speeds to be equal to the regular fan speed because we noticed a large build up of extrusion force with low fan speeds in the first layer leading to an elephant foot and a harder to remove brim. So we set the initial fan speed equal to the regular fan speed. Testing a variety of materials and print modes showed that this did not significantly affect the first layer adhesion and applied it to all profiles. However, we did not test AA0.25 ABS 0.1mm, it is a bit of a corner case. Thanks for reporting this, we will investigate it.

I just noticed that you also changed the layer height to 0.25, which means a 25% flow rate increase. The high speed modes have been designed to be at the edge of the flow rate limits of the cores. This change will thus cause severe under extrusion. It is better to choose the 0.3mm layer height mode in this case and reduce the layer height to 0.25mm. We have a pull request open to warn the user if the flow rates of the cores are exceeded (e.g. when changing speed, layer height, flow settings). So hopefully we will guide the user better in the future.

We have observed pillowing in the PETG AA0.8 0.2mm layer height modes (0.3mm and 0.4mm are OK), which will be fixed in Cura 5.6. We fixed this by increasing the 'Bridge wall flow' and the 'Bridge skin flow'. Try setting these to 200% to verify that it has the desired effect. Note: the top layers start with a single bridging layer. We tested pillowing for PLA, T-PLA AA0.8 modes, but never observed it. We even lowered the layer count from 6 to 5 because of this. However, pillowing can be sensitive to flow changes. The moment bridging threads break, pillowing will be inevitable (even 6 top layers will not close these gaps). We will investigate if we should also increase the bridge flows for the PLA, T-PLA and ABS for the AA0.8, 0.2mm layer heights (to much flow can cause sagging in normal bridging areas).

@UltiSpangler Great work! The higher print speeds, especially in the infill, cause the extruded material to be colder. This causes two things, less flow due to more back pressure = more voids = less surface area = less tensile strength. However the drop is too large (30%). So I suspect that we are losing entanglement in large parts of the interface that breaks (https://www.stevenabbott.co.uk/practical-adhesion/entanglement.php). Both issues can be counteracted by increasing the print temperature, which is what I will try to do for the final release. Increasing temperature also has a limit, so we need to balance a bit better in this case. Thanks for reporting this. P.S.: The engineering intent profile operates at lower speed with very little flow changes. This will give you the required tensile strength back. We will however make an effort to also improve the balanced mode.

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:

Bulging on a top layer can indicate an overextrusion of your machine for this material. Pressure can then build up when printing the dense skin layer and it is released at the edge of skin. Reduce the “skin flow” setting with 2-3% and check if it improves.

You can download the settings guide plugin for more details/images on the settings. I would guess this should work: - Choose combining “not on outer surface” (All also works but takes much longer due to many unnnessesary retracts in infill areas). - Enable “travel avoid printed parts” - Enable “z hob when retracted” - Enable “z hob only over printed parts” - increase z hop height if needed There is a known bug in Cura that avoiding parts does not work during a nozzle switch travel move. However based on your photo this does not seem to be the issue. if that is not enough: - Set Max comb distance to 1mm (basically always retract) - Enable a prime tower (to wipe oozed material from the nozzle after a switch) - make sure the PVA is dry. It appears wet (white color from water bubbles) and this can cause oozing. Same for TPU and Nylon. It needs to be super dry.

Hi, You can use a modifier mesh (for instance a simple scaled block). Increase the infill density of the modifier mesh. Move the mesh over the model were you need more strength. The intersection of mesh and model will have a higher infill density.

1) I do agree that a finer tuning of the airgap is useful, however this is hard to do. We will investigating strategies for this (internal reference PP-309). As you suggested, you can also print the support interface with a (soluble) support material in Cura. This saves a lot of print time because the bulk of the support structure is printed with model material and only at the interface layers a nozzle switch is required. 2) I assume that this offset is meant to improve dimensional accuracy of the (self) supported parts. In principle a good idea, we do something similar for outer and inner perimeters. Something we can look into (internal reference PP-308). 3) Printing with a higher flow on the layer above the first supported layer can be done when you are bridging. The bridging settings allow you to change the flow of the second layer. Due to a minor bug supported regions are often marked as bridged areas so these setting might apply (check for your model, does that work as expected?).

The linewidth of the draft shield is the same as the wall, however the speed and flow rate is lower. The speed of the draft shield is equal to the initial layer speed. You can increase the initial layer speed to the normal printing speed if you ensure you prepared your build surface with the correct glue. Hope that helped.

Hey @coseng, You currently have the wall ordering set from inside to outside. It think it will already help a lot to set it to outside to inside: The harder to print inner wall structures will have less influence on the outerwall in this case. I also noticed that you use random seam, you might want to try the front left corner instead: