linear advance

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    😯 That’s a considerable difference. Wow. Nice work. Wouldnt have thought temperature would make that much difference. I often print at higher temps to increase layer adhesion. Perhaps in future I should spend more time calibrating not only things like linear advance and extrusion multiplier but also temperature.


    By the way. Is it just the light or does that filament have a golden look to it? What is it?


    It’s the light. Let me preface this post with this
    [attachment=2]everyone lies.jpg[/attachment]
    The last print I did the temp did help but I forgot to change the settings, so what you were looking at was printed with a 5mm retract and a .2mm coast, so yeah it looks pretty good. The previous two posts were printed with this setting as well. Now for the real print 0 retract and 0 coast K1.1
    and with a 1mm retract 0 coast K1.1
    Clearly the temp change didn’t fix it, it did make it better.


    What should my expectations be around linear advance? Should I expect to be able to print with no filament retraction or is that unrealistic? How much further should I pursue this? In your experience what kind of quality gains or speed gains are realistic?


    With a bowden tube, especially of this length, you have zero chance of eliminating all ooze without combining lin andvance and retract. Its true, you absolutely need to disable those features when figuring out your linear advance length using test patterns, but once that has been established, its common practice to re tune the retract and coast variables to suit.


    Thanks, I just wanted to keep my goals realistic.

    Nev Bullnevbull

    Managed to get into the office this week – tried linear advance test patterns

    Opted for 1.8mm but then produced a nice goal net! Tried changing values as the print progressed, but little changed.

    Will try lowering temp next time


    I did some more testing and what works best for me is K1.1, 3.25mm retract, 0 coast
    did some testing on extrude temp and it looks like 195 is the highest I can go before stringing and oozing on the pillars starts. 190 still looks the best to me, the layers look the most defined, no bulging or globbiness. Is there any reason not to print PLA @ 190c?


    Nope, each color, brand and type of PLA is different. Also bear in mind, that 190deg for you may in reality be 205 deg for me. These thermistors can measure wildly different readings. Generally printing hotter results in more ooze, but better layer adhesion. Everything in 3D Printing is about finding a balance with which you’re comfortable with for the specific part you are printing. For this material, I’d stick with 190deg for most tasks unless you find layer adhesion issue or want to improve layer adhesion.


    Nev, 1.8 seems way too high to me. Why dont you try doing what Phongshader did, adjusting the K value while printing you tower? Also ensure before doing that, when you slice the tower, ensure all retraction and coasting / wiping is turned off. As the tower is printing, every few layers run M900 Kxx and analyse the results.

    As Phongshader pointed out, without retraction, you wont get it perfect, just get it as good as you can with linear advance alone, then reslice and re print this time with retraction turned on.

    Also judging from Phongshaders results, with PLA, clearly temperature is a massive factor.


    All the testing and adjustments and I still get this…is linear advance working?
    The odd thing is the stringing is only coming from the purge block not from the part. Is there something different about a purge block, settings wise, that would cause this?


    Please copy and paste the output of your log while printing as well as the output of M503

    Please check extruder jerk and extruder acceleration is the same on e1 as it is for e2


    I’ll confess my ignorance, where do I find those settings?


    Send: M503
    Recv: echo: G21 ; Units in mm (mm)
    Recv: echo: M149 C ; Units in Celsius
    Recv: echo:; Filament settings: Disabled
    Recv: echo: M200 D1.75
    Recv: echo: M200 T1 D1.75
    Recv: echo: M200 D0
    Recv: echo:; Steps per unit:
    Recv: echo: M92 X80.13 Y80.12 Z3195.42 E415.00
    Recv: echo:; Maximum feedrates (units/s):
    Recv: echo: M203 X200.00 Y200.00 Z10.00 E50.00
    Recv: echo:; Maximum Acceleration (units/s2):
    Recv: echo: M201 X1000.00 Y1000.00 Z100.00 E500.00
    Recv: echo:; Acceleration (units/s2): P R T Recv: echo: M204 P1000.00 R500.00 T1000.00
    Recv: echo:; Advanced: B S T J
    Recv: echo: M205 B20000.00 S0.00 T0.00 J0.01
    Recv: echo:; Home offset:
    Recv: echo: M206 X0.00 Y0.00 Z0.00
    Recv: echo:; Unified Bed Leveling:
    Recv: echo: M420 S0 Z0.00
    Recv: Unified Bed Leveling System v1.01 inactive
    Recv: echo:; Active Mesh Slot: -1
    Recv: echo:; EEPROM can hold 7 meshes.
    Recv: echo:; Material heatup parameters:
    Recv: echo: M145 S0 H180 B60 F0
    Recv: echo: M145 S1 H240 B110 F0
    Recv: echo:; PID settings:
    Recv: echo: M301 P18.03 I0.97 D83.46
    Recv: echo: M304 P148.98 I29.30 D504.98
    Recv: echo:; Z-Probe Offset (mm):
    Recv: echo: M851 X-25.40 Y-6.50 Z-0.20
    Recv: echo:; Linear Advance:
    Recv: echo: M900 T0 K0.22
    Recv: M900 T1 K0.22
    Recv: echo:; Filament load/unload lengths:
    Recv: echo: M603 T0 L0.00 U100.00
    Recv: echo: M603 T1 L0.00 U100.00
    Recv: echo:; Tool-changing:
    Recv: echo: Z2.00
    Recv: echo:; Filament runout sensor:
    Recv: echo: M412 S1


    here is a small part of the terminal output


    M503 isn’t giving a full report including jerk? Can you please run M205 and show the output?

    Please also take a screenshot of your repetier Host menu – “firmware eeprom configuration”? I’ve got a feeling (with marlin using repetier host) you might need to add an XML file to get it to list the full set of eeprom values . https://forum.repetier.com/discussion/6868/add-mk4duo-xml. Load that then – tools – firmware eeprom configuration. Does a different set of eeprom settings appear?

    That xml file is for MK4duo firmware connected to Repetier Host. MK4duo is a *distant(ish)* Marlin 2.0 fork. I’m pretty sure there’s one for the trunk version of Marlin, if there is I can’t find it right now. My repetier host has definitely been modded with an MK4duo XML file. ** I could be on the wrong track, adding this file make make no difference. Not m on computer or near printer till tomorrow***

    Also I notice your Lin advance K factor is .22??! This is a long way from 1.1 . Can you please make sure your have M900 K1.1 in your start gcode? Perhaps just run M900 K1.1 manually before your next print to be sure.

    I’m on my phone at the moment but will check your log when I get to my PC tomorrow morning.

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