Left side shows the PLA print (upside down) and right shows the support with a single layer of PETG (black).
The issue is that the first layer on top of the black support layer has not printed evenly, which is in turn causing issues for the layers on top of that one. How could I fix this?
I’m printing with 0.4 nozzle and 0.28mm Extra Draft (I’m using this for speed - this print already takes nearly 8 hours when I print 6 of them and I need many more).
Can I perhaps change the layer settings for this particular layer, e.g. its print direction or its layer height? I experimented with the height-specific settings, where I can change the layer height, but not the direction the first layer on top of the support is printed - I’d like that first layer to print diagonal or across (left to right in the image). Can I do that?
Or would the use of the PLA Support filament that came with the printer (P1S+AMS) give better results?
I am using latest Bambulab software. I’m also attaching the 3mf file here.
Actually, with looking at the individual Line Types in the slicer I was able to tell that the layer on top of the support filament is called Bridge, and using the search function in the left pane (where all the settings are), I found “Advanced: Bridge direction”. So I’m trying that out now (angle: 45°), along with swapping the PETG for “Support for PLA”.
Um, this is a material issue with your filaments not your slicing or printer. PETG generally does not want to stick to PLA. Make sure to thoroughly dry PETG before use it may help it adhere more to the PLA that it kind of wants to repel.
Hope this helps.
I would suggest to use the PLA you have to print the supports not PETG. PETG is not good PLA support because it does not want to stick to PLA generally. So better off using the PLA you got to spare for supports.
I initially used all PLA, including for support, and that caused trouble separating the large bridge because the separation layer is not smooth enough. So I switched to PETG and that worked better.
I hear you about the dryness though. Initially, the AMS was below 10%, but now it’s over 25%, so maybe the PETG sucked up moisture. Will run it thru the dryer.
If you are using different materials for interface layers and main body make sure the interface gap is set to 0. the same material has a gap layer to help is not adhere well. Sometimes it sticks too good.
Have not seen you model details. But a problem with mixing material on a single nozzle printer is even after purge there is a small amount of the old material sticking to the inside walls of the nozzle. This causes a weakness in that layer. Does that matter to its use?
It might be better to use the standard support and just hit the surface with some sandpaper to remove the support remnants. Making lots of assumptions of the use.
another hint is to model the support. If you know how and why to bridge. It can create the faster prints. by adding a support at the end of the Z BS will bridge the short distance. this is an advanced technique.
I opened the file you sent.
it has 0 gap layer. My bad for not checking first.
For the manual support you would also need support around the holes.
with bridging it will not be as good of surface finish. But is that needed on that surface?
The surface doesn’t need to be pretty, but should be fairly even, as it’ll be layed onto another existing surface. The biggest problem with the above picture was that the opposite side, especially at the center that is flatter, was uneven, and that caused problems with the connecting surfaces.
But since I added the Strength modifier to rotate the print direction of the bridge layer for that particular height, the problem went mostly away. So this is practically solved, though I wonder if there would be an easier one that doesn’t require this modifier.
I suspect that the problem here was that the bridge layer (PLA) on top the PETG layer just didn’t stick enough to the PETG, and that causes the lines to get loose and folder over each other - and by me changing their direction I effectively shortened these lines, allowing them to stick to each other better.
But the strange effect is that since then, the PETG sticks more to the bridge layer (the one on top of it) than to the support layer below the PETG - whereas before, as you can see in the pic above, the black PETG stuck well to the support structure, which is the intention. Did you see my other post (see my previous comment) regarding that? Do you have some input on that as well? I mean, would you have an idea what makes the interface layer (being PETG vs. PLA) stick better to one side than the other?
I am guessing it is academic at this point. Sounds like it is printing adequately, if not done.
you might swap materials. main part PETG and interface PLA.
The reason it sticks better is probably a temperature difference between the two martials. (just guessing)
Another suggestion is to apply paint on support. only at the tip and around the holes.
Oh, I had not realized that I could “draw” where to use supoprt, and choose only specific spots that way - I had so far always chosen the entire surface.
Will give that a try next time. For now, I’m done with these prints, however.
As with most programs, we only use a fraction of what is available. And we get used to doing what has worked in the past. It is challenging to not be the monkey. learning how that “bug” is a “feature”. When you can use the bug to an advantage.
