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I am attempting to print a model that is too tall to print up-right and it has a large flat side that would be my first layer but ultimately would be the side of the object and I'd like it to look presentable. I'm using wood PLA, so I intend to sand and stain it.

I've had no issues with adhesion when using a raft. The slicer lays down a thick first layer that sticks beautifully. Here's the first layer of a raft - nice thick lines:

First layer of a raft

But when I try printing without the raft (even when using a brim) that first layer is not only thin, but easily moves away. Also the lines meld together creating gaps in the layer. And that's no skirt around the outside, that's the side of the model that doesn't touch the fill. I have to imagine this would be awful rough and impossible to sand out if it finished.

Printing without a raft

By the second layer, the friction is picking up the first layer and it catches the extruder and bam:

Destroyed second layer

I've done some research suggesting higher temps, both of the extruder and the plate. I did see an improvement in the lines, but it still doesn't stick well. And what is considered a good temp? how do you know if you went too hot?

Any recommended settings in the slicer to make the bottom layer smoother?

The printer is a FlashForge Creator Pro.

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  • $\begingroup$ The nozzle is most probably too far from the build plate. Please look into the answer below and test this, accept the answer if it worked, if not, update the question by edit. $\endgroup$
    – 0scar
    Sep 18 at 21:53
  • $\begingroup$ I'm not convinced that the nozzle is too far from the build plate. I have carefully leveled the plate, and watch the extrusion and it does lay it directly onto the plate. Also would that cause the fill not to touch the sides? $\endgroup$
    – Reagan
    Sep 19 at 2:04
  • $\begingroup$ Also would that cause the fill not to touch the sides? Yes, it would if there is too much space it would cut the corners, hence the hints to this distance (the images support the hypothesis). What are the temperatures, speeds, nozzle diameter, overlap with perimeter, what slicer, ... $\endgroup$
    – 0scar
    Sep 19 at 5:01
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The extrusions look great to me, it just appears to me the nozzle is starting too far from the bed. If you go in to your slicer and subtract 0.1 to 0.3 mm or so from the Z-offset that might fix your issues. Or follow the supplied directions on how to tram (level) your bed as this tends to include setting the starting Zgap.

enter image description here

If you did set the gap to your satisfaction I would recommend still changing the offset in -0.1 mm increments and checking if the print sticks better each time.

I would always recommend a thicker first layer for most any FDM printer. It conforms much better to any variations in nozzle to bed distance. For a more reliable bed adhesion.

On a 0.4 mm nozzle I use 0.3 mm for a first layer height. You may have to adjust first layers speeds to help with this. Something around half normal print speeds have worked well.

enter image description here

Bumping up temperatures as you have you have done is a way to get better adhesion but I feel this should be more of a last resort, you have other better options for bed adhesion such as a proper Z gap and thicker first layer.

20 °C is a large extruder temperature increase, this could cause cooling or warping issues later. I have spent a lot of time tuning my printers and have seen first hand the dangers of tuning out one issue only to find out later that change solved the issue I was focused on at the time but added two more issues at a later time.

I recommend adjusting settings that effect the fewest other unrelated aspects first. In this case that would be starting Z gap, clean bed surface (free of hand oils) then maybe bed temps. Unless you happen to be printing at a unusually low extruder temperature I would avoid adjusting print temperatures to solve bed adhesion issues.

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  • $\begingroup$ Thank you for taking the time to answer. I did find the Z offset in the settings, but before trying it I just jacked up the heat of both the extruder and plate, and increased the size of the first layer. It printed much better... the fill overlapped the sides and the lines all touched. $\endgroup$
    – Reagan
    Sep 19 at 2:05
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    $\begingroup$ Update my answer. I still feel the excessive Z distance is your primary issue, even if changing other settings has helped. $\endgroup$
    – Kezat
    Sep 19 at 5:33
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After some trial and error, the answer seemed to simply be to "add heat." I bumped both the heat of the plate by 15 °C, and the extruder by 20 °C.

I also increased the size of the first layer to between 0.3 mm and 0.4 mm and it's looking much better.

Printed model during mid-print showing a solid first layer

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    $\begingroup$ A layer height should not exceed about 75 % of the nozzle diameter, what nozzle size do you have? Furthermore, the issue of bed adhesion may be solved, but clearly there is something still incorrect if you look at the first layer. $\endgroup$
    – 0scar
    Sep 19 at 4:51

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