<p>Are you using Cura? If so, this is almost surely <em>combing</em>, where it performs travel moves across already-printed material without retracting in order to avoid the time cost of retraction and work around problems some low-quality and poorly-tuned printers have with large numbers of retractions.</p>
<p>To avoid marring surfaces like this with combing, either find the &quot;Combing Mode&quot; setting and switch it from &quot;All&quot; to &quot;Not in Skin&quot; or &quot;Within Infill&quot;, or leave it on &quot;All&quot; but set &quot;Max Comb Distance With No Retract&quot; to around 1 mm.</p>
<p>If you're not using Cura, if combing is already off, or the above does not help, it's possible that you have sufficient overextrusion that the surface is bulging up above the nominal layer height, so that even an unretracted move over it digs through material. In this case you'd need to tune extrusion so as not to over-extrude.</p>
<p>Some people might also suggest Z-hop as a solution to your problem, and indeed it may help, but it usually introduces bad stringing that's hard to get rid of, so I would not try it except perhaps as a last resort.</p>

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2023-02-13T21:54:23.967Z
2023-02-13T21:54:23.967Z
R.. GitHub STOP HELPING ICE
<p>I am using a Cobra Max to print PLA. I am trying to print a computer / tablet case.</p>
<p>There are some &quot;defects&quot; in it which look like the print head dragged something.</p>
<p><a href="https://i.sstatic.net/zns3O.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/zns3O.jpg" alt="enter image description here" /></a></p>
<p>I have used a magnification lense to inspect what is going on.
It was hard to take a photo of it, but you can still see that all lines are diagonal (which gives an even appearance), but then there is one &quot;drag&quot; line. It looks like the print head went to a new position and melted the lines it met on its way.</p>
<p>That line is not raised.</p>
<p>How do I get rid of that?</p>
<p><a href="https://i.sstatic.net/ztnpB.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/ztnpB.jpg" alt="enter image description here" /></a></p>
<p>Here I have drawn lines to indicate what is regular and what causes the irregular look (a line).</p>
<p><a href="https://i.sstatic.net/xcRew.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/xcRew.jpg" alt="enter image description here" /></a></p>

<print-quality><pla>
What are these effects caused by? And can I get rid of them?
tmighty
# What are these effects caused by? And can I get rid of them?

(Asked by: username_0 on 2023-02-13)

I am using a Cobra Max to print PLA. I am trying to print a computer / tablet case.

There are some "defects" in it which look like the print head dragged something.

[![enter image description here](https://i.sstatic.net/zns3O.jpg)](https://i.sstatic.net/zns3O.jpg)

I have used a magnification lense to inspect what is going on.
It was hard to take a photo of it, but you can still see that all lines are diagonal (which gives an even appearance), but then there is one "drag" line. It looks like the print head went to a new position and melted the lines it met on its way.

That line is not raised.

How do I get rid of that?

[![enter image description here](https://i.sstatic.net/ztnpB.jpg)](https://i.sstatic.net/ztnpB.jpg)

Here I have drawn lines to indicate what is regular and what causes the irregular look (a line).

[![enter image description here](https://i.sstatic.net/xcRew.jpg)](https://i.sstatic.net/xcRew.jpg)

**Tags:** print-quality, pla

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## 1 answers

### Answer by username_1 on 2023-02-13. Score: 2

Are you using Cura? If so, this is almost surely *combing*, where it performs travel moves across already-printed material without retracting in order to avoid the time cost of retraction and work around problems some low-quality and poorly-tuned printers have with large numbers of retractions.

To avoid marring surfaces like this with combing, either find the "Combing Mode" setting and switch it from "All" to "Not in Skin" or "Within Infill", or leave it on "All" but set "Max Comb Distance With No Retract" to around 1 mm.

If you're not using Cura, if combing is already off, or the above does not help, it's possible that you have sufficient overextrusion that the surface is bulging up above the nominal layer height, so that even an unretracted move over it digs through material. In this case you'd need to tune extrusion so as not to over-extrude.

Some people might also suggest Z-hop as a solution to your problem, and indeed it may help, but it usually introduces bad stringing that's hard to get rid of, so I would not try it except perhaps as a last resort.


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