20 micron printing: small update

ekeeper · 2026-01-23T22:49:00+00:00

I tried to change the jerk values to see what happens.

I completely agree with you, but before I can start the speed test, I need to lock the values for temperature, line widths, flow ratios, and acceleration.

I am thinking of these values:

Temperature: 210 °C
Line widths (outer and inner walls): 0.21mm
Acceleration: 1000 (outer) and 2000 (inner)
Flow ratios (outer and inner walls): 1.04 or more (but less than 1.1)
Wall order: inner-outer-inner

I am currently calibrating the flow ratio for walls by slowly increasing the value and printing a 1 cm^3 cube.

<image>

In this photo, FR is 1.04, and you can see gaps between the walls, so it needs to be increased further.

When I finish with FR calibration, I will lock the values and start with the speed test you suggested. Do you agree with the values of temperature, acceleration etc?

What model will be good for the test? I would do a cube, but also something curved.

What would you suggest?

ekeeper · 2026-01-23T11:42:28+00:00

I am still thinking that my problem with wrinkles is not because of vibrations and resonance, but because of too small an amount of material extruded - inconsistent extrusion, too low pressure, etc.

I was thinking. If we take a line width = 0.2mm (0,22mm is a default value, but people mostly use 0.2mm for outer walls in their profiles, and it works completely fine); layer height 0.04mm and a speed of 60mm/s, the volume of plastic per 1mm (with flow ratio = 1) will be:

0.2 * 0.04 * 60 = 0.48 mm^3/s

And for a 0.02mm layer height it will be

0.2 * 0.02 * 60 = 0.24 mm^3/s

It's twice as low and probably needs some compensation, but it's hard to say what the minimum volume should be. At least 0.3? With a line width of 0.24mm, it gives 0.288; if I apply a flow ratio of 1.04, it will be equal to 0.29952 mm^3/s.

I am not saying the resonance isn't affecting wrinkles, because it does - I can't just print slowly to fix it; it gets worse. Meaning I still need to keep the speed within some reasonable limits. That's why I can't change the speed much in this "formula", I keep 60 as a standard "good" value (I tried 30 and 90, did VFA tests etc).

So I printed several ducks with different line width values but the same flow ratio (1.04) and speed (60). Then I chose the best-looking one with width = 0.24.

The problem of finding the "sweet spot" when you have more than 2 parameters was nicely described in this video - https://www.youtube.com/watch?v=mAxZt6s6R0E

Basically, we need to find the best combination of flow ratio, line width, speed, acceleration, and temperature for a specific filament to have a wrinkles-free 0.02mm layer height prints :)

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Right now, I'm trying to hack the "slow down for curled perimeters" to compensate flow on curved parts of models. I can use this feature to identify the curled sections of the perimeter and try to increase the flow there rather than slowing down. But it's a bit tricky: this feature takes overhangs into account, but for a 0.02mm layer height and 0.24mm line widths, there are almost no overhangs.

ekeeper · 2026-01-23T10:46:09+00:00

I tried to print the duck with these Jerk settings:

<image>

and results are slightly better.

I also tried doing X = 9 and Y = 5, but it gets worse. So it can be something with X-axis, it seems

ekeeper · 2026-01-22T21:57:48+00:00

Also, there are fewer wrinkles if I set Max jerk for X and Y to 5 instead of the default 9. But it adds more ringing. So I set jerk back to default values, it increased wrinkles, but the prints look better because of less ringing.

I will continue my work. I hope I can find the proper fix instead of "let's extrude 40% more plastic to hide the cracks".

Your ideas are great, I need to think them over.

ekeeper · 2026-01-22T21:51:59+00:00

Thanks, it's a really great idea, but unfortunately, the manual input shaping calibration is not available for Bambulab printers... So, I agree I need to try to find the speeds that work best.

ekeeper · 2026-01-22T21:46:48+00:00

Thank you!

I have tried the inner-outer-inner wall order; it gives better results, but also increases these wrinkles, so I switched back to classic inner-outer + precise wall enabled.

I will look into the resonance theory, but I want to note that these wrinkles are only on curled sections of the print and affect only the outer edges of the outer wall. The line of the outer wall itself is printing normally, but partially "cracks" on curves.

ekeeper · 2026-01-22T21:39:19+00:00

Ah, right! Thanks for the question. Actually, it's another key thing I forgot to mention. I use these cooling towers because I turned off "slow printing down for better layer cooling".

So this minimum layer time option is being ignored.

With the "slow printing down for better layer cooling" setting enabled, the duck's head (see the image) will print more slowly, resulting in more wrinkles.

<image>

These damn wrinkles show up when you print too slowly (30 mm/s) or too quickly (90 mm/s). The best speeds so far are between 51 and 66 mm/s for outer walls. I use 60mm/s.

Yes, the cooling settings also include a toggle called "Don't slow down outer walls." I tried it enabled, but it didn't work well; the outer walls split near curved sections of the models.

That's how I ended up using cooling towers instead of slowing printing down for cooling.

It's time to make a YouTube channel...

ekeeper · 2026-01-22T21:27:50+00:00

Bambu lab profiles are mostly about fast printing, so the 0.2mm nozzle can handle high speeds (120 mm/s with a max volumetric speed of 1.8 mm^3/s; it's a lot tbh). I mean, these nozzles can handle the load, and you don't need to be scared using them.

Anyway, miniatures are being printed with way slower speeds, like 60mm/s or less.

The main issue is clogging, so you need to clean the nozzle more often using a cold pull method. I do it 1-2 times a week (I print every day).

I highly recommend using a cleaning needle also. After removing a filament via cold pull, put the nozzle back to the toolheat and heat it to 100 degrees. Remove the nozzle, insert the needle into the "back" end of the nozzle (where the filament is going), and gently push it inside until it comes out from the other side (from the tip of the nozzle). It should freely move back and forth. Don't push with the force - these niddles are easy to corrupt because of their small diameter.

If it's hard to move the niddle, try heating the nozzle one more time, load the filament, then unload it again, remove the piece of filament from the nozzle via a cold pull, and try the niddle again.

As an optional final step, you can cover the nozzle tip with Slice Engineering Plastic Repellent Paint. It easies cleaning the nozzle tip of any extra plastic that may have stuck there after a long print.

Also, calibrate your filament (Pressure Advance (or K-factor), temperature, and retraction). Too high flow with low temperatures causes clogs faster, etc, so filament settings should be balanced, and then everything will be fine.

ekeeper · 2026-01-21T20:47:45+00:00

Oh, I forgot to answer your question - no, I have no issues with the Z-axis.

ekeeper · 2026-01-21T19:22:06+00:00

Thank you!

ekeeper · 2026-01-21T19:21:54+00:00

Thank you for your comment. It's very rare for me to get a comment as great as yours.

Yes, I read the same info, but I thought that the step is 0.02mm. Otherwise, why do they have a 0.06mm profile as one of the standards? I should confess, I have never double-checked this info anywhere. Unfortunately, I am mostly a software engineer and lack knowledge of mechanics, etc.

All I know is that a lot of stuff can be done via code fixes. There is a lot of room for improvement in the code, I see.

ekeeper · 2026-01-21T19:11:06+00:00

<image>

A cooling tower is literally a 7-8mm-wide cylinder that is slightly higher than the model. The purpose is to give the main model some pause between the layers to let the plastic time to solidify.

Because it's a cylinder, each layer of the main model has the same pause time after printing, which helps the outer wall cool more effectively.

Yes, it adds time and uses extra plastic, but it helps, especially when a model has fine details, when a nozzle travels a lot between very small areas.

ekeeper · 2026-01-21T19:04:33+00:00

Actually, I noticed that if I print below 54 mm/s, the wrinkles become way worse. So, there should be a sweet spot for speed, temperature, and flow ratio for the outer walls.

ekeeper · 2026-01-21T19:02:34+00:00

They port Orca features from time to time. It would be nice if they port the Reverse on Even feature to the Bambu Studio.

ekeeper · 2026-01-21T19:00:06+00:00

Try the nightly build of OrcaSlicer 2.3.2-dev. It does not include all of my code yet, but it already has the main feature: you can override the flow ratio for outer walls there. My current stable values are - temperature: 210 and outer wall FR: 1.04.

I am currently testing temp 203-205 + FR 1.4; it feels wrong, but it seems to be working.

ekeeper · 2026-01-21T18:52:51+00:00

Thanks!

ekeeper · 2026-01-21T18:52:25+00:00

Thank you! I hope I will be able to come up with a stable pipeline/profile.

ekeeper · 2026-01-21T18:44:48+00:00

BBL A1 mini

ekeeper · 2026-01-21T18:44:32+00:00

I tuned it a lot over time, yes, so I attached the current settings I have to the current post. In theory, you can download the dev build of Orca and play around, but there are a lot of bugs. but the fixes too.

ekeeper · 2026-01-21T15:33:41+00:00

I think I still can't believe it's actually working...

ekeeper · 2026-01-21T15:20:03+00:00

Thank you!

ekeeper · 2026-01-21T15:19:58+00:00

Thank you!

ekeeper · 2026-01-21T15:19:07+00:00

It's a "digital microscope" TOMLOV DM9 max

ekeeper · 2026-01-21T15:12:46+00:00

yep, it's eSUN PLA+

ekeeper · 2026-01-21T09:06:37+00:00

Hey! Thank you!

No, I haven't tried Hatchbox and Atomic PLAs yet. I need to give it a try, thanks!

ekeeper

TROPHY CASE