Printer won't extrude with 0.1mm layers?

I've been struggling with this for about a week and I'm curious if any of you guys have any ideas. Here's my setup:

FLSun Kossel Delta, built in 2016
Board: MKS Gen L 1.0
Firmware: Marlin 1.1.9
Hotend: Genuine E3D v6

My problem:

The printer will not extrude when I set a layer height of 0.15, 0.1, or lower. I can feel the extruder motor twitching while the head moves, but no plastic is extruded. I've ruled out a nozzle jam since it prints completely fine at 0.2mm.
Using the exact same settings besides layer height, I compared the two gcodes used for a 0.1mm print and a 0.2mm print. The code is nearly exactly the same. Yet the extruder motor doesn't turn on the 0.1 print, but does on the 0.2 print. Any ideas what's happening? Is there some minimum layer height built into Marlin somewhere for certain nozzle sizes (I'm using a 0.4mm nozzle)?
I have printed at 0.1mm layer height within the past few months, and haven't changed any software or parts since then. I did move apartments though, so something may have gotten damaged in the move.

The first several lines of each code are posted here because they were too large to attach:

0.1mm layer height print:
M107
M190 S70
M104 S205
G28
M420 S1
G1 Z30 F3000
M109 S205
G21
G90
M82
G92 E0
G92 E0
G1 Z0.12 F7200
G1 E-4 F2100
G92 E0
G1 Z0.62 F7200
G1 X5.004 Y18.845 F7200
G1 Z0.12 F7200
G1 E4 F2100
G1 F1200
G1 X-5.004 Y18.845 E4.06504
G1 X-6.009 Y18.811 E4.07157
G1 X-7.021 Y18.718 E4.07817
G1 X-7.374 Y18.667 E4.08049
G1 X-8.939 Y18.355 E4.09086
G1 X-9.907 Y18.083 E4.0974


0.2mm layer height print:
M107
M190 S70
M104 S205
G28
M420 S1
G1 Z30 F3000
M109 S205
G21
G90
M82
G92 E0
G92 E0
G1 Z0.24 F7200
G1 E-4 F2100
G92 E0
G1 Z0.74 F7200
G1 X-5.004 Y18.315 F7200
G1 Z0.24 F7200
G1 E4 F2100
G1 F1200
G1 X-5.979 Y18.282 E4.02534
G1 X-6.763 Y18.215 E4.0458
G1 X-7.573 Y18.099 E4.06706
G1 X-8.764 Y17.853 E4.0987
G1 X-9.134 Y17.756 E4.10863
G1 X-10.034 Y17.483 E4.13308


Thanks,
Aflactheastronaut

your E stepper motor is simply not strong enough to extrude through a 0.1mm gap.

You may be able to increase the stepper current limit on the stepper drivers.

I temporarily raised the nozzle offset just to check that. The nozzle was 2mm away from the bed, but it still wasn't extruding plastic. The motor was still twitching too

Quote
aflactheastronaut
I temporarily raised the nozzle offset just to check that. The nozzle was 2mm away from the bed, but it still wasn't extruding plastic. The motor was still twitching too

Sounds like a nozzle jam.
You can try to clear it with a "cold pull". Heat your head up to a value like 150C, push the filament in with your hand and pull it back out. This tends to grab gunk and pull it back through the tubing. If you can't pull it back out, gradually increase the temperature until you can. If you can't ever get the filament back out then you have a jam and will need to disassemble the hot end to clear it. Usually I'll start this process by removing the nozzle and doing the above process again. I keep a bunch of replacement nozzles around...

Good luck,
DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.

Nozzles are dirt cheap, and even some of the Chinese suppliers are making decent quality parts these days. I just keep a bunch of nozzles around and if one gets jammed, I replace it. I ordered 3 sets of 4 via ali-express a while back and examined the nozzles under a microscope, inside and out, and found that half didn't look very good inside and the other half looked great. I separated them into two bags and marked then "great" and "not so great". Nozzle jams happen about once every couple years, so I'm good for a long time to come.

Edited 3 time(s). Last edit at 06/24/2019 01:38PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Well it's not a nozzle jam. I unloaded the filament from the nozzle and extruder, and told it to print again, at 0.1mm layer height. The extruder motor didn't turn, even when it wasn't touching any filament. That seems to me like a bad extruder stepper, but it prints 100% fine at 0.2mm layer height. I just loaded the filament back in and printed a Marvin at 0.2 with no issues.
I'm at a real loss here. I think it has to be something with Marlin, so I'll try a fresh copy and report back tonight

Also, at the beginning of each print, it moves to the very center, does a retraction, then starts printing. Even at 0.1mm layer height, it completes the retraction (pulls 4mm filament out, and puts 4mm back in), then starts twitching as it tries to print the skirt

what is your e-step's mm perhaps it is so small a value that 0.1mm is sub 1 step?

Are you using DRV8825 stepper drivers? The skip usteps at low speeds, and printing in 0.1 mm layers is going to be very low speed for extrusion...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Alright, I'm back. A fresh install of Marlin didn't do anything but give me a headache. I did some math though, and with an extruder steps/mm of 171.17, those G1 commands are moving the stepper about 1 step each for the 0.1mm print, vs about 3 steps each for the 0.2mm print. I'll try increasing the extrusion width to something crazy and see if the extruder stepper moves.

It worked! With an extrusion multiplier of 150% on the first layer, it turned! And then it kept turning, even when it had moved onto higher layers!
It must be a minimum extruder steps/G1 command or something. I've never run into it before, but now I know what to expect. Thanks guys for helping!

May your lines be straight and your nozzles never clog,

Aflactheastronaut

Quote
aflactheastronaut
It worked! With an extrusion multiplier of 150% on the first layer, it turned! And then it kept turning, even when it had moved onto higher layers!
It must be a minimum extruder steps/G1 command or something. I've never run into it before, but now I know what to expect. Thanks guys for helping!

May your lines be straight and your nozzles never clog,

Aflactheastronaut

I take it that you are not using a geared extruder? Trying to do a .1mm layer with a .4mm nozzle probably means that you simply do not have enough resolution in your extruder to extrude that small amount of material. A geared extruder will typically give you 300-700 steps per mm of filament. non-geared ones may get as little as 80 steps. There are a boatload of plans on Thingiverse to make your own geared extruder. The layer resolution improvement is amazing.

IMO,
DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.