I have been having consistent with the top layer of my prints (see image #1 and #2) when printing with Eryone ASA-CF. I have been trying to figure it out myself (from settings changes to finding relevant topics with the same issues) but to no success. From the image, you can see the top layer is rough, with visible ‘blobs’ so I assumed it would be over extrusion issue, but it is not. This happens for both the High Flow and Standard 0.6 nozzles, in both the left and right positions. Before anyone asks, I did all necessary calibrations: Factory K, Flow Rate, Nozzle Temp., Max. volumetric speed, and the complete printer calibration.
The weird thing is that during the flow rate calibration, I do not have these artifacts. It mostly happens for large surface areas. You can also see that vertical lines are not affected.
What I tried:
Slowed down Top surface speed to 75 mm/s - didn’t help
Decreased Top surface flow ratio to 0.97 - didn’t help
Increase Nozzle temp. by 10C, assuming could be clogging issue - didn’t help
Tested first layer quality (see image below) for left HF and right SF nozzles - surface looks good and clean
Disabled ‘Only one wall on top surfaces’ - didn’t help, and still showed top layer issues from the outside (see image #3). Even though you can see wrappage, the other corners that weren’t wrapped have the same issue.
I feel like I am going in circles, did anyone encounter the same issues as me?
Any help would be greatly appreciated.
Yes, dried the filament for more than 12 hours at 85C before printing, and also ran the drying feature during printing. The AMS-HT shows humidity of 9%, so I assume the filament is dry.
It happens to all rolls of Eryone ASA-CF I have used so far.
What are your infill settings, and how many top layers are you printing for that surface?
I can see the top of the vertical walls of the part look just fine, that tells me you’ve got something going on just on that bottom section that’s causing this blistering.
I’d either crank up the infill %, increase the number of top layers, or go to just top and bottom layers in that section entirely.
I am using Cubic at 75% with 6 top layers. Maybe Gyroid could be better due to less spacing between the infill lines for a flatter surface, so I could try it and see if it changes anything.
Besides this, I haven’t changed any of the other settings from their default values.
Seems like I figured out what the issue was - bridge flow.
I printed test samples (cut-out from the same part) and added 2 pauses, 1 at the bridge layer just above the infill (as it has a weird orientation in the slicer), and 1 at the layer just before the final one (for you Gerrit).
As you can see, the bridge layer looks way over-extruded. That pretty much affected all layers after that, and ultimately the final top layer surface. It was so overly extruded that the nozzle was pretty much knocking against the line '“hills”.
I reduced the bridge flow, printed some more samples and started seeing some improvements with bridge flow = 0.5 (which seems crazy low).
I am printing with max. volumetric flow rate = 18 mm3/s, so seeing some improvements at bridge flow rate = 7.32 mm3/s (vs. 12.7 mm3/s from the default Bambu ASA-CF profile); so still weird.
A couple more issues I found:
I cannot change the direction of the bridge which is another issue. Changing the values does nothing, doesn’t matter which infill pattern I use.
The flow rates (for all line types) are not the same between the sample part and the original part, even though I am using the exact same parameters. I wonder what other elements affect the flow rate and how the slicer adapts it.
Some lines are printed with flow rate above the max. rate set in the material setting. I thought the max. rate value was a hard limit?
EDIT: there’s also a mismatch between the bridge direction in the slicer, and the actual printed bridge
It would be useful to create that texture on command. At least from the photo it looked like a consistent surface finish.
Thinking about ways to hide 3d printing lines. Opposite of the OP. It is not a bug it is a feature.
I have got that finish on the top surface sometimes. But it has been very splotchy. Probably the closest to a consistent similar texture on the top is over extruded Hilbert curve.
My ideas for how to get rid of it have already been mentioned.
With the high flow rate, I am guessing the problem has something to do with that. When you combine some of the other speed limiters that are not working the way you think they are.
Had you tried auto calibrating and using the default settings? Maybe with a standard filament. The goal is defining a baseline. Not the printer, or filament. might not be optimized. but they are predictable, baseline. Then you can methodicly change the settings back to the current “texture”.
I am using 50% infill. Gives me the same issues for 75%.
I haven’t tried with the 0.4mm nozzle, but I don’t have these issues with the 0.6mm when the top surface is small (see below).
For the sake of it, I tried the default Bambu ASA-CF profile, just changed the flow ratio after calibration. Everything else is the same (max. vol. flow, temp., cooling), still gave me bad results.
Gonna stick with lowering the bridge flow for now until I figure out what’s wrong.
Like a top surface fuzzy skin? Well, now you know how to achieve it
Even though this top texture looks consistent, it’s definitely affecting the rest of the print above it in terms of unpredictable dimensional tolerances and non-flat/shifted walls. So if you do want to have that texture on purpose, I would disable “Only one wall on top surfaces” parameter; might help reduce these issues.
All default profiles have the sub-flow parameters (bridge, top surface, initial layer) set to 1. So I would assume that if the flow rate calibration is done and the top surface looks good, then the rest of the flow parameters would follow. But apparently it’s not linear, and the faster/more flow you print with, the more they will differ between each other.
I’ll try printing with the default profile without even calibrating, and I will also try with another material. Haven’t defined if the issue is HW or SW.
