PLA Support Material leaving lines in print layers

Bambu Lab X1 Series Troubleshooting
1

I’m trying to use the special support material that came with my printer for PLA and it’s just not working. First, the support don’t just pull away clean at all. Second, the interface material is discoloring the layer it on. The part is black and every layer that has a support interface has grey/white streaks through it like the support interface material and the color are mixing. This stuff is horrible and a waste of filament.

EDIT: And now the part has broken on a layer line that has the mixed support interface material…What a waste.

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2

It would be helpful to show a screen grab of some cross sections of the sliced model in order to give you better guidance.

However, two things that you can try immediately that will improve separation from the model.

  1. Increase the support distance by 1 mm to 1.35 from the default of 0.35. This will provide a larger gap between the model and the support making separation easier and interference less.

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  2. Increase your wall thickness by one loop.

  3. Experiment with the base pattern by making it larger than the default 2.5. This will increase the caps between the supports and may make it easier to remove. Start in 0.5 increments.

  4. Experiment with the pattern angle or orientation of your model. Sometime having a 30degree angle can help with support removal.
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3

You’ll need to double check the flush volumes and ensure that “flush into infill”, “flush into support” are unchecked.

That’ll solve most issues but not do much for the support interface quality.

To get a smoother interface surface, dump the PLA Support material and go for PETG as a support interface (concentric interface, 0mm z-distance). You could also go for a soluble support interface material (I have very good experiences with well dried BVOH from Fiberlogy), but for most PLA prints, PETG will do the job adequately at half price).

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4

I have some PVA that I tried previously and it was a stringy mess so I had to dry it for 24 hours (my filament drier only goes to 65 degrees). I’m going to try it again. I’m surprised that “flush into support” would be an issue.

5

Well, if you flush a material that is meant to keep another material from sticking to it, then you’re fighting yourself.

When using support material you want to be sure you flush fully between filaments, and not let that nozzle near the print until that happens.

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I tried PVA roughly a decade ago and could never get it to print right. So with the Bambu, I went straight for BVOH. Worked like a dream. But then I found a thread in this forum suggesting the use of dissimilar materials (PETG for PLA and vice versa). Not quite as clean as BVOH, but good enough for all my prints since then.
As for flushing into supports, they tend to be more fragile than the model. As @johnfcooley mentioned, you really do not want to weaken anything on the build plate. There’s no helping re the prime tower (other than oversizing it) though.