50 Micron Layers and Marvin

[Jackson_Moody]

Hi Everybody!

I am the proud owner of a Lulzbot Mini, and it has served me wonderfully for about a year. However, I have come across two flaws that I would like to run by you…

My first problem came when I tried to print at 50 Microns. On the Lulzbot Mini spec sheet, it says it is capable of printing down to 50 microns. However, I have had a few difficulties printing at 50 Microns. So far to improve my results, I have slowed down the printer, decreased the flow rate, increased the Z-Offset by .1 (the first layers were squished) upped the first layer height to .1mm, and given the print a ridiculous number of skirt lines (to prime the extruder). If anybody has any suggestions on how to further improve my results, I would be happy to learn! My main issue is that the extruder STILL takes a long time to start extruding anything, and when it does start extruding, the first layer is STILL squished into the bed. For the record, my bed is level (the Mini auto-levels), and my extruder isn’t jammed or clogged.

My second problem came when I tried to print Marvin. My Lulzbot Mini is generally pretty good with “torture tests” but for some reason it has a REALLY hard time with Marvin! (Picture Below)

The main problem with Marvin is his eyes and eyebrows. The lines on the eyebrows aren’t NEARLY as crisp as the other Marvin’s I have seen. The same thing goes for the eyes too. There are weird blobs hanging off of the eyes and eyebrows. Does anybody have any suggestions on how to improve my Marvin? (By the way the leg broke off, but that wasn’t part of the problem).

Any help on either of these issues would be greatly appreciated! I LOVE my Lulzbot, but being able to print at 50 microns was one of the reasons I bought the machine. In general the print quality is decent, but for some reason my machine really struggles with Marvin. Again, any help would be greatly appreciated!

Thanks so much!

Jackson

[garthvh]

Try bringing the nozzle temp down 10-15 degrees from where you print .2mm layer heights, thin layers usually need lower temp.

[Jackson_Moody]

Ok! I will definitely try this! Thanks for the tip!

[SOC3D]

More cooling. I used a 1 meter box fan to print Marvin at 100 micron. Not joking. The 40mm layer didn’t cut it.

[Snortimer]

Those are great suggestions.

What material are you using? Reducing speed a bit more can help with some issues.

Regarding the Lulzbot Mini auto-leveling, I’ve seen it cause problems and try to print below the bed surface, so some troubleshooting might be in order there. Make sure the nozzle is clean when it levels (the wiping isn’t always sufficient if the temperature is too cool).

I’ve heated the nozzle, manually retracted the filament a bit, and wiped the nozzle with folded paper or a scrubby sponge, then continued as normal with some extra skirts, and it’s helped. You can also tweak the starting gcode temperatures for better wiping based on what material you’re using or have recently used.

I’ve tried printing Marvin at 50 microns on my TAZ 4/5, and I had some success in ABS, though the edges curled so the bottom curved surfaces were a bit rough. The top was beautiful! I have yet to try PLA. I expect I can improve my results using the suggestions others have made in this thread. At the time I tried, the specs for the TAZ 4 listed 70 microns as the limit.

[tpalagyi]

Hi,

Would suggest to lower the nozzle temperature for 50 microns, as the filament spends more time in the melting chamber in the print head it don’t need high temperature 185-195 should work.

The other thing is the cooling, you need damn good and consistent cooling of your print. So make some experiments with bigger or extra fans etc. (if you have, print Marvin from with low cooling from ABS than you should see the eyes will be much nicer this means cooling is not enough or you have too high head temperature for PLA)

Also don’t bother with low first layer, print it with 0.2mm than you can change it to 0.05, also 5-6 lines of brim should be enough to make a consistent flow from the head in the beginning. If the brim is not printed correctly add some extra extrude into the start code in your silcer.

BR.,

T.

[Scholarch]

Hmm I know 50 microns is possible I’ve gone as far down as 25 with mine with success. It shouldn’t take all that long to prime the extruder. Make sure the tension on the hob gear is correct.

[Snortimer]

Thanks to all these tips, I’m now inspired to push the limits on my TAZ! I’m trying a 30-micron Marvin. I’m up to 1.4mm (-ish), and it seems to be working.

If I have success, I’ll put my settings up here (they should be very similar for the Mini).

I suspect I’ll start to have issues on the lower half of the body, but the legs are great!

[my3dconcepts]

if you want great results at 50 microns, you have to change the nozzle size - 0.35mm or even 0.25 mm. I would say with 0.5 mm nozzle you can go as low as 100microns. It’s really easy to swap the nozzle on the mini! personally I wouldn’t even try to print at 50microns with 0.5mm nozzle!

[huffworks3d]

Also consider the overhangs on Marvin. When printing the eyebrows and eyes at say, .2 layers, the overhang is minor relative to the layer height As the layer height decreases to .05mm, the overhang becomes that much greater (4 times in this case) relative to the layer height, and 4 times as difficult to maintain its form.

Lowering print temperature a bit should indeed help with this, increasing fan power if you are using PLA or Colorfabb XT that can take the extra cooling without warping.

[Jackson_Moody]

Thanks for the detailed reply!

I have already lowered my temperature, and increased the cooling to 100%. I also increased my first layer height to .2. Should this work? I haven’t tested a new Marvin with these new settings yet…

[tpalagyi]

Great! Yes these settings should work, just make a test. Also lower the print speed to 60% if its prints good then you can try also at higher speed.

Regards.

Tamas

[Jackson_Moody]

Wow! Thanks for the super detailed reply!

I am currently using nGen material (which is made by Colorfabb). As for cleaning the nozzle, is their a certain material you recommend? Should I use the isopropyl alcohol that I use to wipe down the bed? Other than that, though, I think the Auto-Leveling is working pretty good! And any minor miscalculations should have been fixed by the Z-Offset adjustments.

I as well will be trying most of the other suggestions made in this forum. Hopefully I can improve my results!

[Jackson_Moody]

Ok, thanks for the clarification Tamas!

The standard print speed for nGen is 50mm/s, so I lowered it to 25mm/s (just to be safe). I’m assuming that if it prints correctly that slowly, then I can slowly speed the printer up?

[Jackson_Moody]

Thanks for the reply!

I’m pretty sure that my tension is correct, because filament has been extruding wonderfully on my Mini (when printing at .2mm). It’s incredible that you’ve dialed in your printer so much that you can print at 25 microns! Kudos to you!

[Jackson_Moody]

Awesome!

I would love it if you posted your settings, so we could all get some standard settings that would work! 30 Microns is really low, but I wish you could luck!

[Jackson_Moody]

Hmmm. This is an interesting suggestion! I haven’t tried changing my nozzle yet! Which nozzles would you recommend for the Lulzbot Mini?

[Jackson_Moody]

Thanks for the suggestions!

I have heard from numerous people that I should increase the fan and decrease the print temperature, and that is exactly what I’ll be doing! Just for reference, I’m using Colorfabb nGen, which is pretty similar to XT, except for the lower melting temp.

[Jackson_Moody]

Thanks for the reply!

I have heard that I need to up my cooling, and it sure seems like I should take this into account!

[tpalagyi]

50 microns is really sensitive printing with FDM everything has impact on it. Temperature, speed, filament etc.

As I have just read you have a 0.5 nozzle on your machine? If yes change it to 0.3 to for 50 microns prints to get good result. also recommend to use 0.4 for normal prints its a bit better quality.

The rules:

0.5 nozzle 0.3-0.1mm layers

0.4 nozzle 0.25-0.1mm layers

0.35 nozzle 0.2-0.075mm layers

0.3 nozzle 0.2- 0.05mm layers