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linear advance

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Viewing 15 posts - 76 through 90 (of 92 total)
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  • #1518
    phongshader
    Participant

    I did measure the filament, it’s 174-175mm

    #1519
    dan
    Participant

    Wow, good filament. Even the best filament ive used seems to be regularly out by ~.05 – ~0.1. If the filament is correct, cross that out and move on.

    #1520
    phongshader
    Participant

    What does linear advance accomplish? I was under the impression that it was supposed to cut down on the blobbing on corners, and stops as well as thin extrusions on starts. I must be truly turned around. I did some testing on just k factor settings and got results that I was not expecting. This went from a k factor of 1.1 to 0, notice how the corners sharpened up?
    [attachment=2]kfactor-nokfactor.jpg[/attachment]
    I did another test to see what affects different k factors had. This started from 0 and went to 2 in .2 steps in value, changing every 10 layers or approximately every 2 mm.
    [attachment=0]kfactor01.jpg[/attachment][attachment=1]kfactor02.jpg[/attachment]
    Based on these tests linear advance is making the problem worse not better. I’m probably doing something very wrong because a lot of people much smarter than me have made this work but these results really are confusing.

    #1521
    dan
    Participant

    My experience is the opposite with a similar thin walled cube. When I go too high in linear advance , the corners of my cube become thin and eventually the corners don’t print at all if I go too high.

    Can you see if you can replicate this? Perhaps go up and up in ridiculously high incriments?

    Failing that, perhaps this issue would be best posted (With logs, config files and pictures) to the Marlin firmware forum. Devs are usually floating around to help :

    https://reprap.org/forum/list.php?415

    #1522
    phongshader
    Participant

    What do you suggest as a strategy to test? Start with jerk or acceleration? I’ve been editing the gcode to to make changes every 10 layers. So would changing the ejerk settings every ten layers or should I start with acceleration?

    #1523
    dan
    Participant

    Sorry edited last post instead of replying… please see last post.

    #1524
    phongshader
    Participant

    I posted on the reprap forum, 41 views and no replies. I guess I’ll have to figure this out on my own. I haven’t done anymore test prints…I’ll try some today with really large k values to see if that makes any difference. https://reprap.org/forum/read.php?415,870167

    #1525
    phongshader
    Participant

    dan wrote:


    The obvious solution is to switch to 32Bit Architecture.


    Have you looked at this board? https://github.com/Aus3D/RUMBA32 It’s currently out of stock but it seems to address some of the shortcomings listed in your post.

    #1526
    dan
    Participant

    Sure have. Grossly over priced though considering the sum of its parts. Also, connecting MKS touch TFT while possible ties valuable pins being only a 100 pin processor.

    The BTT SKR Pro has 144 pins, essentially has the same features and is more extensible while being far cheaper. That’s what we’ve gone with for the new product.

    Or if you reaaally want to do some crazy stuff, their new product : https://www.biqu.equipment/collections/control-board/products/bigtreetech-gtr-v1-0-bigtreetech-m5-v1-0-11-axis-3d-printer-motherboard

    #1527
    phongshader
    Participant

    I actually picked one up for $29 US so no too bad. What firmware are you running on the BTT SKR Pro? The GTR is way out there. Would either one of those boards be a good upgrade for the beast, no limitations on firmware size and capabilities as on the Rumba?

    #1528
    dan
    Participant

    The RUmba 32 will be an easier change if you’re up for it, it should drop right in, but requires different firmware. The BTT SKR Pro is a better board though. I do all sorts of experiments on my board and having 144 pins, gives me the freedom to make those changes.

    Ive never used either on the Beast V2. Never found a need except for the additional memory to use for distortion mapping, which IMO isnt needed anyway.

    #1529
    phongshader
    Participant

    Some more testing. I don’t know what is up with the Marlin firmware I’m using, according to the docs linear advance should be adjusted between 0-2 for v1.5 and 0-200 for v1. What I’ve found doing tests with whatever version I have works 0-10. Any value above 10 make no change. Based on this test I would chose line 1 or 2
    [attachment=2]IMG_1349.jpg[/attachment]
    However after testing on a cube to see what the corners look like I would go with 4 or 5. The cube starts at 0 and goes to 10 changing every 10 layers or every 2mm.
    [attachment=1]IMG_1353.jpg[/attachment]
    You can see the corner starts to deteriorate at a value of 5 and is completely gone by 10
    [attachment=0]IMG_1354.jpg[/attachment]
    At the higher k values the print starts to slow down quite a bit and the extruder is actually retracting. I guess I can up the jerk and acceleration to counteract the slowness?

    #1530
    phongshader
    Participant

    Well printing at a k4.5 is not an option the 1st layer fails. It looks like the extruder isn’t extruding in the corners at all and the filament doesn’t stick to the bed. With lin adv turned down the 1st layer is fine. 😥

    #1531
    phongshader
    Participant

    Seems like I’m getting nowhere with testing, test patterns give me settings that don’t work with real prints. More research needed, I found this https://github.com/MarlinFirmware/Marlin/issues/14728 not sure if this is what’s happening with my prints but I do have S-Curve acceleration enabled and the issues I have with the prints are all in the accel/deccel areas.

    #1532
    phongshader
    Participant

    I disabled S-Curve acceleration, did some more tests. I picked k1.0 as the best line.
    [attachment=1]0-2linadv.jpg[/attachment]
    tested again between k0.9-1.1
    [attachment=2]0.9-1.1_linadv.jpg[/attachment]
    printed a cube k0.9-1.1 with k0 between each value
    [attachment=0]IMG_1365.jpg[/attachment]
    Linear adv is not working for me, at least the print quality is not improving, unless there is some other way to figure this out I’m abandoning it for now. Clearly running without it gives better print quality and speed…ironic because that is the whole purpose of Lin_Advance 😥

    I’m open for advice, different settings, methodology…

Viewing 15 posts - 76 through 90 (of 92 total)
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