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Clip for Hotend Cable

Discussion in 'Mods and Upgrades' started by Lance Weston, Mar 26, 2020.

  1. Lance Weston

    Lance Weston Active Member

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    As I was testing Partsbuilt replacement board for the R2 I began to get flaky results. After much checking of the board I finally discovered it was the Hotend cable. I found that the cable flexes as the print head moves and eventually the cable becomes intermittent or open.

    I made a two piece clip that slips over the cable and mounts to it's connector. It holds the cable rigid to where the cable is rigid and will not flex. This "should" solve the problem of flaky cables.

    To repair the cable I just cut off the end of the cable, took apart the connector and remounted it to the cable. This solved my flaky problems.

    Some of these problems indicated that my system board had died, like the extruder stepper not working or the hotend failing on temperature.
     

    Attached Files:

    #1 Lance Weston, Mar 26, 2020
    Last edited: Mar 29, 2020
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  2. tkoco

    tkoco - -.- --- -.-. ---
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    What type of filament did you use to print the clip?
     
  3. Lance Weston

    Lance Weston Active Member

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    I print all parts for my printers with PLA that fails in quality for my production parts. I really don't care about finish for production printer parts.
     
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  4. tkoco

    tkoco - -.- --- -.-. ---
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    After looking at the posted images, The extruder on your R2 appears to be unlike the factory issued extruder on my R2. Did you re-design the extruder?
     
  5. Lance Weston

    Lance Weston Active Member

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    Yes, I redesigned my extruder. I use the machine for production and I needed better life and repeatability. I put in an an adjustable pressure arm for the filament feed. I replaced the LM6LUU ball bearings, which were too sloppy and would fail suddenly. I used bronze bushings at each end of the plastic. This gave me 55 mm long equivalent bearings that had zero slop, because of assembly method. The bronze bushings are rugged and will not fail.

    I set the adjustable arm pressure to match the filament I am using.

    The amount of ghosting in the print depends tremendously on how much slop there is in the print head. If you can feel any play the print will ghost. I use an assembly method with the bronze bushings where I align the rods then assemble the bushing into the head and onto the rods with a 24 hour epoxy. When the epoxy sets, this almost always gives me a head with zero slop and low ghosting. It is a real pain to assemble and sometimes the bushings align so well that I do get slop and I have to start over. Once working they seem to last for a long time. I have been running a machine 24/7 for the last year and there still is no slop.

    I have ordered LM6LUU polymer bearings from China and will assemble into the bottom plastic from an R2. My top plastic is compatible with the R2 bottom plastic once the tubes are cut off.. I am hoping to get zero slop from the polymer and want to see how long the polymer will last. I will do a write up when they come in.

    Everyone uses feed tubes for 1.75mm that are 2mm ID. I do not understand why. We all sometimes get wavy filament that is tough to pull through. My Print head will also accept, and I use, feed tubes with a 6mm OD and a 4mm ID. I never get jams in the feed tube. The tube will pass the most wavy filament without a problem.

    If anyone is interested I will make available the step or STL files.
     
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  6. tkoco

    tkoco - -.- --- -.-. ---
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    My guess is that parts used in the design were based on production costs over the life of the manufacturing. Kind of like how Detroit auto manufacturers shave off costs to maximize profit.
     
  7. Lance Weston

    Lance Weston Active Member

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    I think that the design is pretty good. the bearing block holders are the only weak parts in the carriage and I redesigned them to use open loop belting and no springs. The LM6LUU bearings are used by a lot of manufacturers. I am trying to get my machine to work as well as very expensive machines and I have improved the output. The cost though is in time and fitting. I have the time and am enjoying learning how to tune a printer.
     
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