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Solved Hopefully this helps with filament sticking issues

Discussion in 'Troubleshooting' started by tesseract, Mar 28, 2014.

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Do you agree with this information?

  1. Yes ,completely

    94.1%
  2. Nope, its way off

    5.9%
  3. Close, but not quite see why in my comment below

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  1. tesseract

    tesseract Moderator
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    Here are two images I hope will make things a bit clearer for those starting out or having filament sticking issues.

    The first images is typical cross sections at different setups points or levels users find themselves at when trying to set up the proper nozzle height.
    Each has some information but here is additional as well
    1: This is during intial setup when you are trying to ge the x axis to be level by adjusting the two threaded rods some users feel when this is complete printer is ready to go. This is incorrect. You simply have made the z axis across the bed platform but the height is not yet set.

    2: This is when you have initially set the z access height by adjusting the screw downward until you first here the click indicating it had been activated There is a significant GRAY area here as the lever action can induce some variablity.

    3: This is after new users first try to set up the printer and they think it is OK prints will usually stick but fail shortly after starting mainly because the filament is simply resting on the bed.

    THIS IS WHERE MOST PEOPLE THINK IT IS A BED SURFACE ISSUE AND TRY THINGS LIKE TAPE AND OTHER TEMPORARY SURFACE ENHANCEMENTS REPEATEDLY WITH CONTINUED FAILURES

    4: This is the optimum setting where the filament is lightly flattened this occurs because the filament is actually being pushed down onto the bed surface spreading it slightly. It has a much larger degree of surface contact so successful prints are much more likely disregarding print settings of course. Easily seen if using two loop skirts the filament is spread out just enough so that two loops actually look like a single line as seen in the second pictures This picture shows a nice solid level flattened filament line. The single raised line in the print itself was me lifitng the z axis by hand to see what would happen. This yields good informations as well as it is very likely similar to what is seen in the 2nd or 3rd image just below and while the first layer if made of entirely of these lines may have looked good it most likely would have failed for the reason shown here.


    5: Wagon wheel this is when the nozzle is just a tiny bit too low since there is not enough room to really allow the filament to go directly down to the bed the excess squishes out the sides and only leaves a very thin central area this print can recover as subsequent layers do fill in low areas it is best to make the adjustment to get it correct.

    6: Skipping or nothing nozzle is extremely low and could cause clogs as the nozzle is trying to extrude some filament does exists at the point and will collect residue from the bed that could cause cloggs so this should be avoided .

    filamentcross.jpg

    I hope this helps a lot of people in getting their printers going with the correct initial z height
    below is an actual image from one of my prints showing some of the characteristics of a good first layer with skirt.

    first layer example-small.jpg
     
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  2. SoLongSidekick

    SoLongSidekick Active Member

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    OK so I picked up my R1 directly from Robo3D headquarters here in San Diego. Avoiding shipping was a huge bonus, but the main reason I was so stoked for this was I got a crash course from Braydon himself. He showed me how to set up Matter Control and how to level the bed with MC's three-point auto-leveling. When setting the threaded rod height, he said to use a piece of paper under the nozzle and adjust it so it was just barely pinned down. Repeat for extreme left and extreme right. Then do basically the same thing with MC's bed leveling; set it up so the piece of paper is just pinned to the build platform.

    This is what I have been doing and I am starting to wonder if I am encountering situation # 6. Is the process above the way you do it Tesseract (pertaining to the 'piece of paper just barely pinned' measurement)? If not, what should I be setting my machine up with?
     
  3. tesseract

    tesseract Moderator
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    I am not a big fan of the auto height adjustment as it is based on a set of static settings adjustments that are supposed to work for everyone. In the life cycle of the robo printer there are too many unknown yet. When the actual set of settings are defined and known to be identical for every printer including filaments used etc I find it difficult to see that the process can become that automated.

    The process I use severely trimmed down here is this (this assumes level and flat bed, I do more when that is not the case)

    • I use a business card to level the x axis by rotating the threaded rods I do both sides holding one rod still while adjusting the other (some creeping can occur)I focus on get the friction between the card and the nozzle the same on both sides.
    • I set the z height adjustment screw based on this height by lowering the screw until I here the switch click. At this point I still know that it is too high but I can't do any more until I actually print a skirt and first layer.
    • I do a quick print doesn't matter as it won't finish so just something quick like the cube, and follow one rule:
    1. Look at the skirt, if it looks good continue the print to the end; if it doesn't look good, stop, re-adjust and restart.
    My goal is number 4 above and it is exemplified in the lower image if I see other numbers 2,3,5,6 I adjust accordingly.

    Things to note once sent I rarely touch the threaded rods again unless I throw the nuts. and once set this way based on THE PRINTER ITSELF AND HOW IT PRINTS versus settings I find it is fairly close for everything I simply folow the rule when starting now prints at any resolution.
     
  4. Peter Krska

    Peter Krska Active Member

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    Good info on this post. Thanks
     
  5. David Mortlock

    David Mortlock Active Member

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    Good info Tesseract. Should make this a sticky.
     
  6. SoLongSidekick

    SoLongSidekick Active Member

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    So I have been having some problems all of a sudden with getting the exact opposite, my skirt is barely stuck to the bed. I am trying to think what I have done in between now and when I posted that and I just can't think of anything. Adjusting the rods and end stop don't seem to do much. I have what I once thought was a stupid question; the endstop screw is what actually sets the first layer print height right? Or is it the threaded rods?

    For example, if I observe my skirt as being too high off the bed what do I adjust to get it lower?
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The threaded rods (while the perimeter is printing is a good time)
     
  8. tesseract

    tesseract Moderator
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    Actually Mark the endstop IS what is used to set the first layer height, the threaded rods are simply the means being used to arrive at that point. Some people are actually using the threaded rods to do this adjustment but it is an incorrect way. The threaded rods are initally used to make the nuts go up and down on each rod to adjust each side so that the x axis can be made as level as possible to the bed surface.
    At that point while turning the rod on one side will make the adjustment it also unlevels the x axis. so that this becomes an ongoing adjustment that worsens the original setting each time it is done. Although easier it is not the correct way.

    The z height adjustment screw raises and lowers the ENTIRE x axis as a single level entity and that level aspect is never lost.

    All efforts should be made to make the bed as level as possible and if done the quality of prints will rise as the settings remain valid.


    So to answer your question SoLong, A little clarification though I assume you mean the nozzle is trying to print the skirt to high form the bed surface. In that case the you would turn the screw in the counter clockwise direction to raise it away from the bed which means that the entire assembly has to get lower to the bed surface to activate the stop switch
     
  9. SoLongSidekick

    SoLongSidekick Active Member

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    I think I may have figured out the problem. This was actually something I wanted to discuss with you in depth, Tesseract. I remembered one small modification I did do to my printer in between getting great first layers and getting perfectly circular, un-squished first layers: reversing the direction of the z endstop switch. I turned it around so the screw was making contact further down the metal arm, away from the actual switch head. This is what I think is happening:

    Having the screw make contact as far away from the switch head no doubt makes for much finer adjustments in Z base height. However, I think that the switches used in the stock R1 are extremely cheap, and the switch bar is incredibly inconsistent; but perhaps quality of the switch is inconsequential, I will be doing some tests to find that out. Anyways, I believe that the bar reacts differently depending on the amount of force exerted on it, thereby giving inconsistent results as to when the switch is flipped. I believe that switching the bar out with one far more stiff would rectify this issue. For now I am going to flip my switch back around the other way and see if I can get my desired results back, that will at least confirm part of my hypothesis. I will report back once I get that done today.
     
  10. JohnStack

    JohnStack New Member

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    You're mostly spot on. The wording needs to be cleaned up a bit. That graphic would be good for any use (and I might steal it for a class if you don't mind!)
     
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  11. tesseract

    tesseract Moderator
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    no problem

    Hey everyone make sure and vote this has a poll at the top
     
  12. SoLongSidekick

    SoLongSidekick Active Member

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    OK so I am definitely on to something. I flipped my z endstop back around and was able to get my beautiful flat skirt and first layer back. Testing on different switches and bars to come.
     
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