Retraction problems

[truckle 0]

I've started getting a lot of lines on the first layer which show up badly when the underneath of the print is examined, for e.g. this iPhone cover.

I think it is a retraction problem but I can't seem to find the right settings.

I printed this test print, first layer, at 200 degrees temp.

Travel speed 200mm/s

Min travel 1

Min extrusion 0.02

combing off

Any suggestions anyone?

Thanks in advance.

 

[illuminarti 18]

Well, make sure that retraction is actually turned on, on the basic tab - that's an easy one to miss.

BUT... it looks like the strings are happening on the moves between the 'skirt' lines?? Is that the case? Cura doesn't retract when drawing skirt or brim. And that makes a huge mess. You could try printing without a skirt - or making the skirt offset so big that no lines of skirt get drawn inside the holes in the print.

Or you could edit the Gcode by hand, and put G10 before and G11 after every G0 move in the skirt part of the first layer. (Assuming this is for an Ultimaker²).

 

[truckle 0]

No it's not associated with the skirt particularly, it happens between the "holes" inside the print. It is an UM 2. Or am I mistaken? Does the skirt mean those lines inside the holes also? In which case it is possibly a skirt type of problem. I cannot really be bothered with going into the code though.

[truckle 0]

Re-read your post - I am wrong and it looks like a skirt problem here, so I'll try printing with a larger offset ?where is that setting?

[illuminarti 18]

The skirt is the line that isn't part of your print, and gets drawn on the first layer only, around the print. This can include inside the print, if there are holes. For instance, I presume that the odd blobby shape inside the large Apple logo isn't actually part of the finished print, is it?

Well, if you don't want to mess with the code, then maybe try one of the other two things that I suggested.

 

[illuminarti 18]

Expert settings, Skirt -> Start Distance.

Not the best label for it, but it's the offset between object and skirt. if you make that large enough, you'll still get a skirt, so that will help prime the head before the print starts, but it won't put any inside the holes.

 

[truckle 0]

Brilliant! Thanks for helping out a bit of a dunce!