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I’m just getting my feet wet with 3D printing, and I’ve had a few prints do this. Curious if anyone has any ideas for me that might help clean this up? (I don’t really have anyone in my personal circle who can help out, so hoping this community can :) )

Edit 5/23 The first layer of the print is inconsistent in the way it’s deposited. Some areas feel correct while others are very thin. Usually there are large gaps like in the pictures below. After the first layer, the rest of the print seems to be fine. I’m curious is anyone has any insight into what could be causing the inconsistency.

I try to level the bed before each print, but I’m not sure if it’s at the correct height as the instructions I got with the printer are pretty subjective: “use a piece of A4 paper and you should be able to pull it with some resistance”.

enter image description here

enter image description here

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  • $\begingroup$ Hi and welcome to SE.3DP. Whilst the photos are great, and a picture is worth a thousand words (etc.), could you edit your question and describe what is wrong with the print? In particular, what are the series (or areas) of small lumps in the center? Are they gouges in the print? $\endgroup$
    – Greenonline
    May 24 at 1:47
  • $\begingroup$ @Greenonline thank you for your input. I’ve updated the question, please let me know if that looks better. $\endgroup$
    – hugmungus
    May 24 at 3:34
  • $\begingroup$ Much better, many thanks... WRT the paper, some resistance means barely perceptible, not that it is a struggle to pull the paper through. $\endgroup$
    – Greenonline
    May 24 at 11:16
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It looks like your nozzle is a little too close to the bed, if there is not enough space, you can see through the layer and pressure can build up and ooze out when there is a little more room in a different location (if the bed isn't completely flat/straight).

You could level with a thicker piece of paper or add a Z-offset to the whole print ( e.g. in your slicer, or change the G-code by redefining the Z height).

You could also increase the first layer a little when slicing.

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  • $\begingroup$ Thanks for your answer Oscar. This sounds right to me, but I want to try your suggestions before I accept the answer. I’ll post a new comment if I’m still seeing this afterwards. $\endgroup$
    – hugmungus
    May 24 at 3:37
  • $\begingroup$ Thanks again @Oscar. It was a combination of poor leveling on my part and having the extrusion force too low. Adjusting both of them seem to be producing higher quality prints for me. $\endgroup$
    – hugmungus
    May 26 at 23:46
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It looks like a bed adhesion problem to me. Some additive information: What is your bed material?

Z-calibration problem isn't the only suspect. I've seen the same problem with my printer before. There were defects in some parts of my glass print bed that prevented it from sticking.

The molten filament from the hot nozzle has two adhesion chances; full adhesion to the bed or adhesion next to the previous extruded filament. If the previous filament is not stuck to the bed, it means you are printing on the air shown in the pictures.

Without forgetting, your images also seem to have a Z-calibration problem, but as I said, I don't think it's the only suspect for blobs. It will be useful to clean the surface.

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  • $\begingroup$ Thanks for your input. It was a combo of the z-axis height and the extrusion force. I can see how my magnetic mat might need to be cleaned soon as well as it’s getting messy with remnants of old prints. $\endgroup$
    – hugmungus
    May 26 at 23:48
  • $\begingroup$ Yes, extrusion force could be another story about the nonstick problem. $\endgroup$
    – user30878
    May 27 at 8:35

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