sebhoff

Indeed! Many thanks for your explanation - learnt something again. Will now continue my ascent on the learning curve... 😉

Thanks - will have to look into this further. Now need to sleep. Another day may bring new insights. 🙂

It was 5.2.2. Have now upgraded to 5.3.0. Same problem. So you also get very different speeds for anything between the second/third and the last three layers? Odd.

Not that I know of (but I don't know much yet...) - here's the project file. If it doesn't work, I'll try your suggestion with starting from scratch - thanks! cube.3mf

OK - I've been trying to fiddle with the speed settings, but it seems to me that whatever I change, the speed of the walls (and infill) stays at a very slow 15mm/s - or something like that. Sorry - this may be very basic, but what am I missing?

Wonderful - @GregValiant, you are my hero...! 😊 It's not perfect, but certainly a lot better (left is new, right is old...). Thank you! The first three layers and the last three layers - so basically top and bottom - have a little more bulging than the other layers, but it's not as massive anymore as before. And X and Y are much more clear. The top layer is not smooth yet, but I haven't looked into optimising that... Thanks, @ksihota - yes, I'm planning to have separate speeds/settings for the first and other layers. I haven't had any problems with adhesion at all, apart from the very first few mm after the head travels and extrusion starts again.

Many thanks @GregValiant! Yes, I'm sure it's because I'm taking corners too slow - it only started when I reduced acceleration. The problem was that there was under-extrusion at the beginning of new layers or after the head had travelled some distance (see pics above). Will try with your suggested settings and report back. Thanks again!

OK - now back from my holiday, and still struggling... 🤔 So I'm wondering whether I can use your generosity and knowledge a little more... I've now started printing stuff with more layers (using a value of 100 for acceleration instead of the default 500), and while the results are OK-ish for some basic needs, it's clearly far from ideal. So I printed a test cube and here's the result... As is quite obvious, one of the main problem now seems to be some sort of over-extrusion at corners: on the z-side of the cube, you can see that the corners bulge out. This was not the case before, from what I remember. Also, there are other things going wrong - I suppose this is called ghosting? Before I use my two left hands to fiddle with the printer: am I right in assuming that this is likely an issue of hardware rather than Cura settings? So I'll have to go looking for problems with loose screws, tight belts and the like?

OK - many thanks for the pointer! Using an extreme acceleration setting (reducing it from 500 to 100), things have now improved a lot! There's a slightly odd patch on the lowest square (in the position where there used to be a hole before), but that's a far cry from what it was before. Also, I'll obviously have to experiment a bit more when it comes to prints involving more than one layer, but at least there is light at the end of the tunnel! It's my birthday today - so this is a nice present. Thanks again!

Yes, it does appear to be a general print speed issue. It is particularly noticeable on the first layer, of course, but it seems to apply in general. I printed something yesterday with snail-like speed for the first layer, and it turned out fairly OK. But it's still not as good as it used to be with much faster speeds when I still used the stock 0.4mm nozzle (using the exact same filament roll).

Mhm - I don't have "Nozzle size" in the preferences window...

Thanks for your input! The filament is new and the house is very dry (too dry, actually). And the nozzle is brand-new, too - it's a tungsten carbide nozzle (because I'm planning to print quite a bit of highly abrasive, food-safe filament). One thing I'm not entirely sure about is whether I applied the correct torque when adding the new nozzle. But I'm pretty sure it is tight enough - just mentioning it as I'm also grasping at straws... 😉 I'm attaching the project I used to print this. Perhaps you can find something I have overlooked? (BTW, I did *not* manage to set the nozzle size in the printer settings, as suggested by Cuq, because there's no such setting in the "Machine settings" - but I did set this in the drop-down menu below "Preview".) Large_first_layer3.3mf

Just to confirm the levelling, I printed a massive 15x15cm first layer, and it came out reasonably nicely - apart from the very first cm when the beginning of the wall was printed. So I'm confident it's not the levelling/tramming, it must have something to do with flow/retraction/adhesion/temperature/whatever... 🙃 (The little bump towards the lower left corner happened when the filament got stuck a little and I had to manually intervene to get the filament to unroll again...)

Thanks. But that's naturally the first thing I did. And I double-checked that the mesh is being used when printing.

OK - a little better, but not really. I've now set things to 100% flow (although calculations based on a test-cube with 4 walls of 0.6mm line width suggest it might have to be a little lower than that). Because I was playing around (and because that's what I saw in someone's settings), I also changed first layer height to 0.28mm. But I'm still seeing these odd under-extrusion/non-adhesion issues after travel movements. I can reduce them quite significantly by printing at 50% of the speed. But if I do the same with some more detailed prints, things still are too messy for my taste. Plus, it takes ages to print... Anyway - am currently too frustrated to go on. Tomorrow is another day... 😆