Scars/Scuffs on surface of prints?

[JustMKollum]

Hello. I am trying to figure out, how to improve the quality of my prints, because I am constantly left with scars & scratches on the surface.




I referred to the Quality/Troubleshooting guide, and if I have scars like those pictured above, it could be

A. Too much extrusion
B. Need to increase vertical lift
or both.

I have tried several adjustments to both settings. right now I am trying to operate an Anycubic Mega X and here are my settings for that printer.



I've adjusted the "Retraction Vertical Lift" from 0.5mm, to 2.0mm, even to 4.0mm and I still end up getting small blemishes on the surface and if I decrease the Extrusion Multiplier with it, I get nothing but blobs & strings all over the print, delivering a messy result. I tried adjusting the retraction distance from 4.0mm to 5.0mm and 6.00mm and a barely noticeable difference.

I'm just having trouble getting a good quality surface/top layer, and I need to know what the best settings would be to make it look good?

I've owned 3 different printers in my 2 years of 3D Printing, an Anycubic Mega X (Current), a Monoprice Select Mini V2 (Current) & a Creality CR-10. All printers are having the same scuff marks.

How do I adjust the vertical lift & retraction settings without leaving blobs of filament and strings all over the surface? Thank you.

- Justin

[parallyze]

Hi,

Hello. I am trying to figure out, how to improve the quality of my prints, because I am constantly left with scars & scratches on the surface.

would you mind adding a gcode and/or factory file (File -> Save factory file as...) so others can have a look at what was going
on while printing?
Are the pictures from parts you printed using filament changes or were they printed seperately and put together before taking the pictures?

Did you watch the printer while printing the top layer on one of those things, did the z axis do the vertical lift there?

I somehow can't imagine you're still getting nozzle drag with z lift values > 1mm... I'm suspecting something like different processes
not "knowing" of other parts and/or in combination with "Only retract when crossing open spaces"/"Avoid crossing outlines" on the "Advanced" tab....

[zemlin]

On the Advanced tab, make sure "Only retract when crossing open spaces" is not checked.

[JustMKollum]

Hi,

Hello. I am trying to figure out, how to improve the quality of my prints, because I am constantly left with scars & scratches on the surface.

would you mind adding a gcode and/or factory file (File -> Save factory file as...) so others can have a look at what was going
on while printing?
Are the pictures from parts you printed using filament changes or were they printed seperately and put together before taking the pictures?

Did you watch the printer while printing the top layer on one of those things, did the z axis do the vertical lift there?

I somehow can't imagine you're still getting nozzle drag with z lift values > 1mm... I'm suspecting something like different processes
not "knowing" of other parts and/or in combination with "Only retract when crossing open spaces"/"Avoid crossing outlines" on the "Advanced" tab....

Actually, the colors you see are added one after the other, without having to assemble them. I used a "Multi-Process" split using the "Variable Settings" wizard in Simplify 3D to where I wanted the color change to be split. Therefore created a separate G-Code for each color. The printer stops printing at a certain location for the first color, then I change the filament, and resume printing the next gcode at the next layer for the second color. The colors are fused together in one print.

It does do a vertical lift, but it creates a string of filament dragging across the surface, still creating scars. And yes, "Only retract when crossing open spaces" was checked! I'll have to try it without that.

http://www.mediafire.com/file/cylt6w3ea ... code/file I provided a link to the GCode from MediaFire because it was too large to attach here. This is a big sized model, so the Factory file was even bigger to even upload. Thank you.

[parallyze]

Hi,

It does do a vertical lift, but it creates a string of filament dragging across the surface, still creating scars. And yes, "Only retract when crossing open spaces" was checked! I'll have to try it without that.

While it's propably not the single cause you should check support generation settings. I can't really see why you're using supports on this
print - but there's a lot of short support extrusions which will stick to the nozzle and get dragged along:

Video:

2020-09-19 12-54-03.mp4

(2.17 MiB) Downloaded 104 times

All those tiny extrusion are far enough from the walls to just stick to the nozzle....

Right now I can't see anything else obvious "wrong", z lift is active. So if there's more plastic than the supports hanging from the nozzle it's
hard to tell from the gcode.

Did you do any retraction tests, are they working properly/clean otherwise? Maybe you can recreate the problem using two simple boxes
or something. The factory file would be much smaller then and others could have a look at your settings.

Edit:
Here one of those support extrusions stuck to the top on the last layer:

[JustMKollum]

Hi,

It does do a vertical lift, but it creates a string of filament dragging across the surface, still creating scars. And yes, "Only retract when crossing open spaces" was checked! I'll have to try it without that.

While it's propably not the single cause you should check support generation settings. I can't really see why you're using supports on this
print - but there's a lot of short support extrusions which will stick to the nozzle and get dragged along:

Video:
2020-09-19 12-54-03.mp4

All those tiny extrusion are far enough from the walls to just stick to the nozzle....

scars_2.JPG

Right now I can't see anything else obvious "wrong", z lift is active. So if there's more plastic than the supports hanging from the nozzle it's
hard to tell from the gcode.

Did you do any retraction tests, are they working properly/clean otherwise? Maybe you can recreate the problem using two simple boxes
or something. The factory file would be much smaller then and others could have a look at your settings.

Edit:
Here one of those support extrusions stuck to the top on the last layer:
scars_3b.JPG

That's a good idea for the small boxes test! I'll give that a go.

I also should let you know, there are supports generated, because there's a keyhole on the bottom of the print, so people can hang this on their wall with a nail. This is a product I intend to sell, once I perfect the scars issue.

Thanks!

[parallyze]

I also should let you know, there are supports generated, because there's a keyhole on the bottom of the print, so people can hang this on their wall with a nail. This is a product I intend to sell, once I perfect the scars issue.

The gcode you added does have supports, yes. But there is absolutely nothing requiring them... unless the gcode file is only showing parts of the print. But the supports inside the hole are pretty useless - there's nothing to support on top...

If you intend to sell this you might want to have a further look at calibration/extrusion multiplier. It's hard to tell by pictures but it looks like a bit
more material could help. There's some gaps between the perimeters and solid infill isn't really "solid".

Once you're happy with your results you might want to have a look at using a bigger extrusion width. This can speed up prints with lots of solid infill
dramatically (and wouldn't require as much perimeters to reach the same stability/thickness).

[JustMKollum]

I also should let you know, there are supports generated, because there's a keyhole on the bottom of the print, so people can hang this on their wall with a nail. This is a product I intend to sell, once I perfect the scars issue.

The gcode you added does have supports, yes. But there is absolutely nothing requiring them... unless the gcode file is only showing parts of the print. But the supports inside the hole are pretty useless - there's nothing to support on top...

scarf_4.JPG



Remember, this GCODE is only part 1 of 2. I split the model into 2. I should have provided the 2nd part for less confusion. In fact, here you go.

http://www.mediafire.com/file/9m16sybab ... gcode/file

The 2nd part is colored black that you see in the pictures, and it's a 2nd GCODE or 2nd process. That keyhole you see eventually gets sealed at the top, so that's what require's support, so the top doesn't cave in.

[parallyze]

Remember, this GCODE is only part 1 of 2. I split the model into 2. I should have provided the 2nd part for less confusion. In fact, here you go.

http://www.mediafire.com/file/9m16sybab ... gcode/file

The 2nd part is colored black that you see in the pictures, and it's a 2nd GCODE or 2nd process. That keyhole you see eventually gets sealed at the top, so that's what require's support, so the top doesn't cave in.

I didn't notice you were using seperate processes _AND_ separate gcode files. Most people just do a color change and resume printing using
a single gcode file, as far as I can tell... so you're printing the first (purple) gcode file, then swap filaments and then start the second (black) one? The second one does include homing all axes..?
(And the first one ends at 4.18mm height, the second one does start at 4.5mm using 0.2 layer height, 1st layer @90%...is that gap on purpose?)

Keyhole: With that many solid layers on top I'm pretty sure this should work without supports (and maybe 1 layer of bridging).

Anyways, all the tiny spots all around at layer 18+ (first gcode file) have nothing to adhere to and will get dragged all over the surface (there's 30-40 of them on the in- and outside).

And looking at it... I actually don't understand how you expect this to be a nice print. The black part is much bigger than the purple one:

There's absolutely nothing supporting the black part all around...?! You should definitely check your support generation settings.... ^^

[JamesFitts]

It is a really helpful discussion for beginners.