Streaks in pla print

Help with printing with specific plastic filaments.
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albrown
Posts: 3
Joined: Thu Mar 21, 2019 9:06 pm

Streaks in pla print

Post by albrown » Thu Mar 21, 2019 9:12 pm

Printing matterhackers black pla. 0.38mm layer height. Why does it streak like this around the logo? Is there any way to prevent this? I’m using a lulzbot mini.
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ritmopat
Posts: 100
Joined: Wed Feb 13, 2019 9:22 am

Re: Streaks in pla print

Post by ritmopat » Fri Mar 22, 2019 5:27 pm

good question..... following

Brent.I
Aleph Objects | LulzBot
Posts: 502
Joined: Mon Jan 20, 2014 8:21 am

Re: Streaks in pla print

Post by Brent.I » Mon Mar 25, 2019 1:14 pm

albrown wrote:
Thu Mar 21, 2019 9:12 pm
Why does it streak like this around the logo?
Those paths will be due to your top layer settings within Cura LE. Essentially what is happening, due to your model geometry and lettering there it is trying to optimize the travel path for the tool head. It will change directions, and leave a gap to come back to later. You can view this in layer mode for that layer, and drag the slider to see where the tool head moves for that layer.

To fix this, you can try different top layer patterns to see what matches better to your wording. You can also try the "ironing" feature to come back over the flat surfaces and iron them out. Just be sure to check layer view before hand if you are trying to nail down that specific issue.

albrown
Posts: 3
Joined: Thu Mar 21, 2019 9:06 pm

Re: Streaks in pla print

Post by albrown » Tue Mar 26, 2019 1:02 pm

@Brent.I Thank you. I guess I just don't see why the printer head needs to take a path around the logo. I would think it would finish the final top layer before moving onto the logo.

Brent.I
Aleph Objects | LulzBot
Posts: 502
Joined: Mon Jan 20, 2014 8:21 am

Re: Streaks in pla print

Post by Brent.I » Tue Mar 26, 2019 1:37 pm

albrown wrote:
Tue Mar 26, 2019 1:02 pm
I would think it would finish the final top layer before moving onto the logo.
As the letters will have "space" above the base of the letter, the slicer will leave gaps there and just print infill for that section. This means when printing the flat area "solidly," it will get to under your letters and say "print infill here" instead of a solid piece of plastic. This gap for those layers is what changes that top layer infill pattern. Increasing top/bottom layers can make that print solidly, but you would have to have top/bottom layers set to an equal or greater height of your letters to accomplish this (wasting a lot of material and print time.)

Feel free to play with the settings, and then check layer view after it is sliced. This will help visualize how these different settings affect the outcome of your print dependent upon design.

b-morgan
Posts: 302
Joined: Fri Aug 11, 2017 8:53 am

Re: Streaks in pla print

Post by b-morgan » Thu Mar 28, 2019 1:13 pm

In CuraLE, it appears you can set the number of top layers and the number of bottom layers independently.

If you set Relative Extrusion (a Special Modes setting that is enabled with Settings, Configure settings visibility...) then it would be possible to do some creative cutting and pasting of multiple gcode files to get the best top layer and the best logo if you wish to avoid the added material and print time.

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