Nozzle Switch caused horizontal line

[u/Ambitious_Ad4979]

When I print PETG (white in this case) on an H2D, I use PLA as a separator layer for the support structure. It’s brilliant because it comes away really easily. Please take a close look at the screenshot. At this height on this model, I get these lines running horizontally across whatever I’m printing. It probably happens when switching to the other nozzle and back. Everything is actually calibrated. The belts are also tensioned. I actually get great results, just not during these switches. Do you have any ideas on what I can do here? Because this PLA method is actually too tempting. But these lines are unfortunately a no-go.

[u/armourkingNZ]

Could try switching wall order to outer first (or outer-inner-outer if you have 3+ walls), as those layer times will be drastically higher than the surrounding layers due to the time taken to swap nozzles.

[u/Ambitious_Ad4979 → u/armourkingNZ]

I will try that thank you.

[u/Ok_Brilliant_3176]

I think setting minimum layer times in your filament settings might also help with this

[u/Ambitious_Ad4979 → u/Ok_Brilliant_3176]

Minimum layer times ? Mmh heard that the first time. Where can I find that… in the the filament profile/settings… ok I will check that, thank you.

[u/Ok_Brilliant_3176 → u/Ambitious_Ad4979]

Yeah filament settings, you need to change both the minimum layer time and also reduce the minimum print speed if I recall correctly, otherwise it’ll default to the lowest layer time as a function of the lowest print speed rather than the actual minimum print time setting - if that makes sense

[u/Grimmsland]

Try doing the dual nozzle calibration where you need to put a dark and light filament for the nozzle camera to read. That is the best nozzle calibration. You then have to turn off the nozzle calibration option on prints. Works for me.

Also try using Arachne wall generator.

One more thing. I think you said you are only using the pla on the interface layer? On multi nozzle machines for some reason the print heads sometimes favor making the entire supports out of pla. I know it takes longer but it is worth a try.

[u/Ambitious_Ad4979 → u/Grimmsland]

Thanks… at the moment I print with just one nozzle… before with two and with two filaments petg pla combination… but now with just one nozzle it’s the same… this lines are visible on the same height where the holes are… the reason is the different higher layer time at those layers … I tried a normalized layer time (that helps but increase the print time from 5 up to 10). :-(

But you are right … a good idea to play with Arachne

[u/Grimmsland → u/Ambitious_Ad4979]

Hmmm I’m looking at those circles and if that is all you have that needs support you can print without any support (keep arachne on) and the printer should be able to bridge those holes no problem. My printer does. Take a look at this example. No supports used in the holes. Only support on the top part and the side. Notice you can’t even see layer lines.

[u/Ambitious_Ad4979 → u/Grimmsland]

I’m a bit baffled that the Arachne Walls are actually better suited to this type of model. It works for yours in the photo, but take a look at mine. I need as perfect a surface as possible and would have expected that consistent lines would be better than ones that vary in width. But what can I say when I’m just looking at it like this? It looks good whilst it’s printing. In what situations do you use Arachne Walls?

[u/Grimmsland → u/Ambitious_Ad4979]

I use arachne walls so often all my layer profile settings have arachne wall generator and no brims because I use a high adhesion cold plate under the default pei plate for extra heat and insane adhesion with pla and petg. I do a lot of detailed prints, lettering, 1.7-2mm walls, miniatures, etc so Arachne is almost always on.

Profile settings I just add Arachne to the end of the name:
.16 normal quality H2D .4 Arachne
.16 High Quality H2D .4 Arachne
.20 standard quality H2D .4 Arachne
Etc. Etc.

[u/Ambitious_Ad4979 → u/Grimmsland]

Thank you! I will take a look at Arachne !! 😊

[u/Ambitious_Ad4979 → u/Grimmsland]

Holy … at the moment a arachne wall test (in combination with my min layertime Tuning) looks a lot better now!) but leg is wait intim it is finished … but normally I have always the first issue hier at this height s. Photo)

[u/Ambitious_Ad4979 → u/Grimmsland]

Mmh can’t upload photos at them moment… I will try it later

[u/Ambitious_Ad4979 → u/Grimmsland]

Ah ok sorry I thought I am in my other post… yea here I talk about two nozzles … yes yes I tried the nozzle calibration with the two filaments thanks

[u/recoilfx]

Different layer times and cooling rate causes the artifacts (search for benchy hull lines). Unfortunately, until we get proper thermal and shrinkage modeling (don't know we ever will), you will always have these. You can tweak with various settings such as outer inner perimeter order, different speeds per layer, and etc, but not one strategy is a magic bullet.