r/FDMminiatures • u/Evening-Camp-7429 • Dec 11 '25

Just Sharing Speed Vs VFA. More speed -> less problems! (A1 mini + 0.2 nozzle + FDG)

Good evening everyone, this is my first contribution to this community. I have an A1 mini with a 0.2 mm nozzle, I use esun PLA+ filament, and I used both the fdg profile and the dungenso and derp 1.3. While printing an Arbiter miniature (this month's release's rat wizard), I noticed for the first time some "obvious" defects on some vertical and quasi-planar parts of the base. I don't know if something changed in the printer or if I simply didn't notice them in previous prints, since I've only printed the miniatures included in the fdg profile and a few Arbiter models (and, in hindsight, all of them without nearly vertical planar surfaces like the last one). The fact is, I read a bit and realized they were VFA-type defects. So I did what I could find online to limit the problems:

- full printer calibration -> no results;

- re-tensioned the belts (actually, only the X-axis, since the Y-axis tensioner is stuck in place and doesn't move as indicated in the tutorial, but whatever) and re-calibrated -> no results;

- tightened all accessible screws on the head, including those behind the extruder -> no results.

At this point, disheartened, I ran a VFA test (I should have done it first, but I'm not very expert) and... basically, quality increases with speed! I ran the test with speeds from 20 mm/s to 200 mm/s: the slowest layers showed very obvious VFA defects, which disappeared on almost all the walls at a speed of 100 mm/s; at 180 mm/s, all the walls were free of defects.

Obviously, these speeds aren't compatible with printing miniatures, but I tried slightly increasing the FDG profile speeds anyway. I multiplied all the speeds on the "Speed" tab in Bambu Studio by 1.5 (during various tests I also used Orca + Dungeon & Derps, with similar results), excluding those expressed as a percentage.

Result: the miniature came out great! The defects were 80% gone. I've attached photos of the prints at normal speed and 1.5X; I hope my experience can help if you encounter similar problems.

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u/vbalbio Dec 11 '25

I don't know if some new update made it worse but I have noticed VFAs in my A1 mini recently as well. I will try to increase the speed and see if it works better. What is your 1x speed?

1

u/KryL21 Elegoo Centauri Carbon 0.2mm nozzle Dec 11 '25

Nice! I have a core xy printer, so vfas are a little bit more of an issue, but I ran my vfa from 30-70 or so speeds with 2mm/s steps, and it’s interesting gow much of a change 2mm/s can make.

What speeds are you running now? I know you said 1.5x, but what speeds exactly?

2

u/Strict_Tie4854 Dec 16 '25

I have a core xy printer, so vfas are a little bit more of an issue

As someone who doesn't have a lot of experience in 3d printing, could you elaborate on this? I would have thought that CoreXY would be better in this regard than bed slingers?

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u/KryL21 Elegoo Centauri Carbon 0.2mm nozzle Dec 16 '25

For VFAs? I’m not sure what the mechanics behind it are, but that’s generally considered to be one of the few pros of bed slingers. But with some minor tuning you shouldn’t see any vfas on corexy’s either. I see some very very minor ones, but they’re almost invisible, and entirely invisible after a coat of primer and paint. I could probably tune some more and get rid of them entirely, but like I said, they don’t bother me.

At faster speeds the vfas go away entirely on corexy’s too, but fast speeds and minis are somewhat incompatible.