Why is the first corner of every layer always like this?

Can anyone offer any advice on why the first corner of every layer is like this ?

The nozzle has lost its prime by the time it gets there. Things like e-steps and k-factor/linear advance calibration, and retraction and combing mode settings all have an affect on this.

Thanks but unfortunately I’m not familiar with the things you have mentioned.Are you able to suggest something I can try and start with ?

Ooff. Honestly? Google, and the forum search function. There is quite a bit of reading and research. You really need to know about all those things mentioned, and all of them are supposed to be done before use in order for the machine to print properly. Without them, other print settings will not have the effect that they should, and you will end up chasing your tail in frustration trying to get things to work when the underlying issue is that the machine isn’t calibrated.

This is a pretty good starter guide for beginners…

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By default, I think Snapmaker oversets “retraction” in Luban, if that’s what you’re using. It will be in your material settings, “Retraction Control” should be on. I think their default is 2-3mm.

I usually (printing PLA) use 0.5mm, at a speed of 30mm/sec (both retract and prime).

Also, if this is a fairly new printer for you - have you attempted calibration of the extruder stepping and put that into the firmware? There’s a long thread and (upon first read) seemingly daunting process, but it’s really not THAT bad, and it IS well worth it. Basically if the extruder is always extruding a little less than it thinks it is (e.g. it thinks it’s ingesting 1in of filament, but only actually took in 0.8in) it’s always a little ‘starved’ and that makes issues like this even more apparent, and weak parts ultimately.

I suggest this because your perimeter lines don’t seem to be in contact either, really. That could be either that you have a little less ‘squish’ for the first layer calibration than I prefer to use, or that you’re under-extruding.

Another option is to dial up the Flow percentage (again, in the Material settings), or in the Printing settings you can turn up the actual Line width. But best to have the extrusion calibration right.

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They absolutely do. Luban’s default retraction for PLA is 5mm@60mm/s. Cura’s default is 3mm@40mm/s, which is better, but still to high IMO. I use 1@10. And proper retraction is definitely dependent on the e-steps being calibrated correctly, otherwise the retraction distances are not correct.

I’d use “Retraction Extra Prime Amount” - it pushes a bit more plastic into the nozzle as it retracted before, to compensate for oozing and have pressure a bit faster. With my 0.4 mm nozzle I get well along with 0.25 mm³, but you may want to play around for best settings in your situation.

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Does that create problems for you in gap filling or anywhere else, and have you left the default retraction length?

Was that to me? I mean, reducing retraction is only going to end up with maybe some blebs or more stringing, if overdone. Not voids. You’re leaving the head MORE full, not less.

(Edit - never mind - re-reading, in context, seems like you’d have been asking Hauke who did not alter the primary retraction value, only the ‘prime’.)

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Sorry for answering late - Currently I use these settings: Dual Extrusion Head: Heat creep? More likely: Bad feeder! - #11 by Hauke - not perfect yet, but I’m getting closer. I do not print very often (have only done 5 prints with DX yet), so my iteration is slow.

With these settings I get a decent first layer: [First Batch Shipped Out] FAQs of Dual Extrusion 3D Printing Module for Snapmaker 2.0 - #152 by Hauke - but you can see my blue also has an edge problem. I guess I’ll increase extra prime amount even more after extruder change. Note however that I do not use a prime tower.

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The picture also clearly shows that you are under extruding, so you should fix that first. There is a pinned post, as well and many other posts, on how to correct that. There is also the Teaching Tech site, which goes over all the different things that you need to do to setup any printer. Some things don’t apply to the Snapmaker, but most of it does.