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Dusting off a R3D beta; issues and upgrades

Discussion in 'General Questions' started by CoenB, Dec 28, 2021.

  1. CoenB

    CoenB Member

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    I have to disagree with you on the 0.1mm. Maybe the photo doesn't show it that well, but when viewing IRL I think its not great. The 0.3mm looks good, it has a nice even wall deposit. The 0.1mm is all over the place, but at least doesn't have a terrible wobble effect as is with the 0.2mm. But I'll keep tweaking. I will look into the fixed couplers, thanks.

    I was wondering, would 2x LML8UU (either ball-bearing or IGUS/alike) of 48mm length not be better than 4x LM8UU of 2x 24mm length in series? Does it matter less with the IGUS variant than the ball-bearing ones? If so, that would be great, as I have a hard time finding any 48mm length linear dry bearings (or even ball-bearing ones, for that matter).
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The way they are mounted it is really moot.
    In general the longer ones would be stiffer, but given the way they are mounted the difference will be tough to see.
    Thing is -- you can experiment if you like :) All of the carriage/rail parts are printable (and they are on thingiverse) so if you want to experiment with other variables you can.
     
  3. CoenB

    CoenB Member

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    Ok, I'll go for the 4x 24mm length IGUS bearings. I can't find any 48mm length. I did find LM8LUU ball-bearing ones, but I'm willing to try the dry bearings (plus, they're from different webshop).

    Would you consider these to be solid? The split for the 8mm and 5mm connection is the only part that is not connected together and it doesn't have a springy section, but technically aren't solid because of it. Or is the one you linked in a different topic the best option? (this one).

    [​IMG]
     
    #23 CoenB, Jan 9, 2022
    Last edited: Jan 9, 2022
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yes, that is the solid style. It has a tiny bit more flex than the one I linked to before, but not enough to matter I imagine.
     
  5. CoenB

    CoenB Member

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    I managed to remove the bearings using the old 5/16ths threaded rods and a bearing-OD-sized printed cilinder; the 5/16ths nuts fit perfectly on the metal LM8UU sleeve :).

    Upsettingly, I could just pop in the IGUS bearings with my thumbs without any real force required (by that I mean, not like what you would generate with a press with , e.g., crankshaft bearings). They don't move that easily, but I can still adjust them inside the carriage without much required force. That's usually not a good sign in terms of tolerances and bearing fit. Furthermore, the wiggle/play of the carriage (between the X-rods and IGUS bearings) is still present. To add to that, the IGUS bearings seem to have signifcantly more sliding resistance (even with PTFE spray lubrication).
    My X-rods are 7.94-7.96mm, but the play is much more than 0.04-0.06mm. Either it is coincidence that both types of bearings are on the far under-toleranced end of the tolerance QC spec (e.g.8.1mm ID hole + 7.94mm rod = plenty of wiggle room), or something else is going on (which I am unable to locate). Not sure what to do now, it almost seems as if the old bearings are the better option.

    Unfortunately, the solid couplers have created a severe issue. The force needed to move the threaded Z-rods is immense. When using the stepper motors, there is a massive wobble and unpleasant / alarming sounds. It seems that the threaded Z-rods are not perfectly alligned with the sliding Z-rods in width from Z0 to Z200+. There is minimal wobble when rotating freely and don't show any issues. It seems the axle distance for the Z-rods in the X-rod endcaps is either further apart than the axle distance when of the stepper mounts, or shorter. Which could be caused by the cut length of the X-rods.
    At any rate, I guess I have to go back to the flexible ones. With the current setup I fear I might break something (the LCD screen already flipped out, displaying all kinds of weird symbols, something I've never seen before).

    I think I'm done throwing money at upgrading, and will revert back to the old situation. Would've been nice to finally resolve the issues and get some respectable print quality, but I guess it may be futile with this machine as it seems I have not drawn a lucky ticket in the R3D beta lottery.

    For now, I would at least like to thank you very much for your time and resourcefulness.
    Maybe there is some small thing I could try based on your (potential) suggestion, but I think this is the end in terms of hardware change-outs and severe changes etc.
     
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  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If these are the IGUS drylin bearings they aare going to loosen a bit with use (not a lot, but some). They are a good replacement (quieter as well).

    You are always better off with a printer that works, but is not as clean or high resolution of an output than one that doesn't work at all :)
    The LCD -- reflash the firmware and make sure that the LCD is enabled in that firmware. That may sort it. If not then swap in a new LCD. They are fairly cheap and they are a standard Made In China part.

    The one good thing wih the beta is that it is easy to work on and upgrade when you want to. Simple 3D printer or at least about as simple as they come. I'd still take a working one over a better one that is not working ...
     
  7. CoenB

    CoenB Member

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    Printer works better now with the old couplers; no grinding / scraping / obnoxious sound coming from the endcaps and Z-rod carriage nuts. However, the Z-wobble is back, now also at 0.3mm. It will most likely be related to the seating position of the rods and couplers, so I guess I have to keep tweaking that. Unfortunately, without a potential systematic approach, apparently, as it is randomised in its behaviour.

    The LCD is enabled, it just weirded out for that specific moment. After a power reset everything was fine, fortunately.
     
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  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If the wobble is due to the rods (being bent) you can replace just those. The beta used 5/16 threaded rods and those can be found for about $10-12 each in a number of places (Amazon has several, there are other online stores with similar). Pull the ords and roll them on a flat table surface to see if they are in fact bent. If they are not bent that is one less thing to look at. As you noted it could be the mounting with the couplers (either coupler-to-rod or coupler-to-stepper shaft). I used some teflon tape to secure mine in the couplers which may or may not actually help, but I felt like it did :)
     
  9. CoenB

    CoenB Member

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    Update

    I was finally in the mood to start tinkering with the printer again. I had ordered a new GT2 pully and 8mm rod (FYI, the linked amazon page in earlier posts were incorrect for me; I measured a 5mm axle on the bed motor, not 6.35mm. 5mm bore and 20 teeth was correct though). Bed pully is almost without wobble now. I think its mechanic fault lies in the nature of its manufacturing process. Tthe original one appears welded/soldered, or at least consists of two joined parts, while the new one seems lathed/milled out of one piece.

    While experimenting with the couplers, I think I've discovered the main influencing factor in the apparent Z-wobble. It appears it is mostly affected by clamp insertion length / height. When I inserted less length of the rods in the coupler (i.e. only at the clamping part and stopping before it starts at the bendy part), the majority of the Z-wobble effect was gone. It has now transformed from regular, patterned layer placement variation to irregular. Which I interpret as the mechanical issues relating to thread pitch being resolved, and that I now have to start with the extruder settings (flow, diameter, etc.). Consequently, replacing the 8mm Z-rods for new 8mm rods was no longer necessary (the current ones are fairly straight anyway).

    See the images below (click to enlarge) for a 0.1mm layer height (no infill, shell print) and 0.3mm layer height (7% infill). I'm very happy with the 0.3mm performance. The E3D seems to struggle a bit with the 0.1mm with the current slicer and slicer settings, most likely due to inconsistent chamber and nozzle volume fill of the thermoplastic material due to its reduced printing volume per line and layer.

    0.1mm left; 0.3mm right; topdown hard spotlight (the worst lighting scenario)
    [​IMG]

    0.1mm left; 0.3mm rightl side hard spotlight (ok-ish lighting scenario)
    [​IMG]

    0.3mm outer wall
    [​IMG]

    0.1mm outer wall
    [​IMG]

    Also did some minor work like installing Ziggy's Z-axis stabilisers, fixing my lighting wiring, re-seating the E3D hotend heater orientation, fixing my LCD controller mount and currently redesigning the cooling system for better flow. Trying some CFD simulation comparisons. Seems I need to order another GT2 pulley for the extruder X-axis, as that pulley is slightly wobbling as well (re-seating doesn't help). Also need to figure out a better alternative to the stock cable sleeve solution. And I lost one ball bearing from the Y-axis bearings, but it doesn't seem to impact performance and quality. Which makes sense give its fairly static state during printing.

    Unfortunately, I suspect the massive play between the new IGUS bearings and X-rods doesn't really help with any layer deposition accuracy as well. Might fix that, might not (good quality, low tolerance shafts are expensive).

    This is good enough for now, print-quality wise. I can work with this for prototypes etc.

    Cheers for all the help, thoughts and suggestions.

    Kind regards
     
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