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I'm using Cura to slice my prints. I've noticed that when printing the bottom layer (and also the top layer, if it's flat), it first prints three walls, then fills in the middle by moving back and forth in straight lines.

I've noticed that for my parts, the walls look much nicer than the zig-zag pattern in the middle, and it also seems that the zig-zag part detaches from the bed quite easily, whereas the walls don't.

My parts would look much better, and possibly also stick better to the bed, if I set the number of walls to 100 or so, so that the parts would be entirely filled in with walls. But then the parts would be completely solid, which isn't what I want. So what I want to achieve is that the bottom layer (and if possible also the top layer) are printed as if the part was composed entirely of walls, but the other layers are printed with three walls as normal. Is this possible in Cura?

N. Virgo
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2 Answers2

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I found the answer myself just after posting - I'm posting it because it might be helpful to other Cura novices.

There is a setting for this, it's just that it's not shown by default. In print settings, you have to click on the three lines next to the search box, and select "Show All Settings". Then you can find a setting called "Top/Bottom Pattern". Setting this to "concentric" does what I described.

Actually this setting affects not just the top and bottom layers, but all layers that are part of the top and bottom shell. This seems like a good thing, but if you really want to affect just the bottom layer, there's a setting "Bottom Pattern Initial Layer" that does this. There is also a setting under "Experimental" called "Top Surface Skin Pattern" that I think does the same for just the top layer.

In addition to "Concentric" there is also a "Zig Zag" option that's quite similar to the default "Lines" mode.

You can also change the visibility of settings in the preferences menu, to make these settings show up by default.

N. Virgo
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  • The Zig-Zag pattern is likely to give you better stability though. – Simon Richter Oct 20 '19 at 12:42
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    @SimonRichter Can you explain what you mean by stability? Bed adhesion or something else? – Robert Oct 21 '19 at 04:02
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    @Robert, if the plastic doesn't fill out the space completely, you end up stacking the gaps on top of each other, so the surface would break more easily. The zig-zag pattern avoids this by rotating each layer. – Simon Richter Oct 21 '19 at 07:38
  • @SimonRichter Makes sense. Any downside to a single concentric bottom layer? – Robert Oct 21 '19 at 17:42
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    @Robert, you mean, a single concentric layer, then zig-zag over that? Would work, I think. – Simon Richter Oct 22 '19 at 11:08
  • Note that this does not work if the product is a little more complex or has holes in it, using "concentric" gives a very strange (mozaic) infill, not just perimeters... you do get a few more perimeters but also a strange mozaic infill. – 0scar Oct 31 '19 at 14:45
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The latest Cura that I have (4.2.1) includes "Ironing" in its options. When I enabled this, it prints the top layer twice. The first time with extrusion and the second time with just a little bit of extrusion (default is 10%) at 90 degrees to the first one. This effectively "irons out" the zig-zag pattern giving you a nice smooth top to your parts. I was very impressed at how well this works (YMMV of course :-) ).

Roger Lucas
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  • I tried this also. It works quite well, though it leaves its own distinctive texture. There is also an option to do the ironing in a concentric pattern, but I found that didn't work so well, at least in combination with the other settings I used (which included a concentric printing pattern for the top layer) - it pushed the edge of the top surface outward, forming a lip, like an upside-down version of the elephant's foot issue. – N. Virgo Oct 21 '19 at 07:55
  • @Nathaniel if you are getting an "elephant's foot" on the top layer, you might want to turn the ironing extrusion down from 10% to maybe 5% or even just 1%. It sounds like your printer isn't generating very solid prints by default. – Roger Lucas Oct 21 '19 at 16:11
  • I think it was to do with having both the ironing pattern and the top/bottom pattern set to concentric. Because it's going over the same lines I think the lines from the previous layer can get sort of squished around by the ironing step, and that's why they got pushed outward. Some time I will experiment with the settings for that and see if I can get better results. With the ironing set to a different pattern it worked quite well. – N. Virgo Oct 21 '19 at 17:33