Building a morgan in rural US

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    • #546
      nethack
      Participant

      I’ve been messing with 3-d printing for about a year now. I have access to a Replicator 2 at work and am using it to produce the parts for a Morgan. I will post my experiences (and queries) here as I try to source the parts in rural US with its backwards measurement system…

    • #547
      nethack
      Participant

      The first issue I’ve run into is PVC pipe sizes. I was able to make the supports work with 1″ Schedule 40 PVC if I remove the “Rib anchor” from the part that goes into the pipe. It’s a snug fit.

    • #548
      Quentin Harley
      Keymaster

      The purpose of the rib is to deform the pvc slightly as you knock it in, and to give it a bit more flexibility for different pipes. If yours fits snugly without the rib, more than good enough. You can use some PVC weld to fix it permanently, but be sure to be very careful with the captive nuts… If they fall out then, you are screwed. (Don’t ask me how I know)

    • #554
      nethack
      Participant

      Two questions:
      1) The drive belts are not listed in the BOM. What belts did you use?
      2) Which of the fasteners (if any) in the BOM were use to attach the z-mounts to the bases?

      Thanks,

      don

    • #555
      Quentin Harley
      Keymaster

      Belts used are T2.5 with matching pulleys on the motors. You can use any belt, as long as it fits through the holes on the drive wheels back to back. Best if it is a tight fit, because I don’t have to use any other mounting but friction on my two prototype machines.

      I used chipboard screws to attach the Z mounting brackts, but this depends on the platform material. You could even glue it down with silicon… Be creative!

    • #569
      nethack
      Participant

      Another basic question. How solid did you print each part (how many shells, infill %)? Do any of the parts require more substance than others?

      Thanks,

      don

    • #575
      Quentin Harley
      Keymaster

      My two machines were printed on 10% hex infill, and is doing quite well despite the sparse plastic. 15% should be more than good enough for everything.

      Two shells. 0.2 looks good, but 0.4mm layers do work fine. Go 0.2mm if it is your own machine and the extra printing time is not an issue.

    • #588
      nethack
      Participant

      One thing missing from the BOM is the 6805 bearings. How many does it take? I count 2 from the assembly instructions, but I want to make sure before I place an order.

      Thanks,

      don

    • #590
      Quentin Harley
      Keymaster

      Two 6805 is correct.

    • #603
      nethack
      Participant

      I was just thinking (after I lost one of the captive nuts in a leg). Can’t all of the feet be ported? At least that provides small opportunity to correct the situation (and is one less type of part to print).

      don

    • #604
      Quentin Harley
      Keymaster

      The angles of the ported and non ported parts are different. It was a way for me to keep the apart. I will probably change them to all be ported, but with a letter or some other type of identification at the bottom.

    • #676
      nethack
      Participant

      Are outside PVC supports supposed to bend around the inner ones (under tension)? Mine do, but I end up with an upper platform that isn’t parallel to the base. I’ve cut the the supports to be 452mm and 459mm (per the BOM). Are those dimensions correct?

      Thanks,

      don

    • #682
      Quentin Harley
      Keymaster

      Don, They are supposed to be under tension. Would you mind sending a picture of the problem?

    • #683
      nethack
      Participant

      I suspected that they were supposed to be. A picture wouldn’t help much. The problem is that the top platform ends up not quite parallel to the bottom platform and causes the bearings to bind.

      don

    • #684
      Quentin Harley
      Keymaster

      You can shave a little off the pipes that turned out too long. Let me know which, and by how much.

    • #685
      nethack
      Participant

      A thought just crossed my mind…are the holders for the 8mm rods in the z-mounts supposed to be drilled out? Or are the bottoms flush with the main surface of the two mounts.

      In other words is it supposed to be 440mm from platform to platform, or from z-mount surface to z-mount surface?

      Thanks,

      don

    • #686
      Quentin Harley
      Keymaster

      450 from platform to platform. 440 gives a fit with grace, meaning you could drill out the holes to size without drilling straight through the mounts.

      The holes in the DXF are for the possibility to mount 12mm rods directly to the platforms… a feature request.

    • #687
      nethack
      Participant

      I think my problem may be that my PVC is too thick. I’m using Schedule 40 pipe in the US, which looks like it has a wall thickness of 4mm. It is very difficult to get it to flex much. I may try to find some thinner-walled pipe.

      don

    • #701
      Quentin Harley
      Keymaster

      I also use a thick walled pipe. You will just have to force it…

    • #727
      nethack
      Participant

      So far so good. Now I’m working on the z-axis. How are the bearing supposed to fit into the arms? I thought that they simply slid up against the stops inside the arms, but are those ridges supposed to fit into one of the ridges on the bearings? My bottom bearings keep falling out.

      Thanks.

      don

    • #728
      Quentin Harley
      Keymaster

      You are right… it takes a bit of force, but the bearing must fit so that the ridge slots into the bearing side.

    • #730
      nethack
      Participant

      Any tips on forcing it? I’ve pushed and twisted as hard as I can bare-handed. I may resort to light sanding to get it in.

      Thanks.

      don

    • #732
      Quentin Harley
      Keymaster

      I normally get it in using a g-clamp. if the ridge is too high I flatten it with a hobby knife. If it is your only set of parts, rather sand it…

    • #945
      nethack
      Participant

      I’m making good progress (albeit slowly). I can’t tell from the pictures, how is the eckstruder mounted on the top? Is it just a single bolt? I see a hole in the cutting diagram in what appears to be the right place.

      Thanks,

      don

    • #946
      Quentin Harley
      Keymaster

      It is mounted using just the one bolt ( the one hidden underneath the Eckstruder motor ). Because the extruder is not moving anywhere, this does not seem to be a problem.

    • #1276
      nethack
      Participant

      I’m extremely close to being done. My biggest problem is that my z-axis keeps falling off. Do you have any tips on how to make the z-axis mount grip the stepper shaft firm enough to hold the weight of the build platform?

      Thanks!

      don

    • #1277
      Quentin Harley
      Keymaster

      Where does it fall off? The motor or the shaft?

    • #1278
      nethack
      Participant

      I finally got the shaft (drill bit) wedged in tight enough that it no longer falls. The coupler is falling off of the stepper motor shaft. I’m using the 3 grub screws tightened to the point where it is actually deforming the coupler, but they still eventually loosen and the assembly falls off.

      Any hints are appreciated.

      don

    • #1279
      hoff70
      Participant

      Are your screws contacting the motor shaft? Maybe try rotating the shaft if it has a flat ground on it. You want one of the screws contacting the flat solidly.

    • #1280
      nethack
      Participant

      What it looks like to me is that the vibrations from the steppers slowly causes either the screws to loosen or to “walk” down the shaft. Maybe I need different grub screws.

      don

    • #1281
      Quentin Harley
      Keymaster

      Is the Z-motor alignment right?

    • #1290
      Quentin Harley
      Keymaster

      Ironically I just suffered the same failure…

      I will properly tighten the screws with some thread lock. The problem is that it is relatively hard to get in there with an allen key to tighten it properly. The reason why I went for this design is that the plastic on metal couplers let loose far sooner. My original Morgan is still going strong, with not even a hint of slipping, and it remains my busiest machine.

      If I need to change the couplers design to improve it, I will let you know.

    • #1296
      nethack
      Participant

      I think I may have it licked (hate to jinx it). I printed the coupler with 100% infill so it won’t deform as much. Used loctite on the grubs. Looks like I may get my first successful calibration cube.

      One other question. What rates do you use for printing? I’m using the slic3r defaults which seem a bit on the slow side.

      Thanks for such a wonderful design.

      don

    • #1297
      nethack
      Participant

      Nope. Grubs slid off again… 🙁

      don

    • #1298
      Quentin Harley
      Keymaster

      Ok… next step. Take off the motor, and right on the grub screw level and slightly below, use a file and score a slight grove on the motor shaft, to prevent the screws from slipping past it.

      Mine is holding on again.

      Come to think of it, I actually roughened up the motor shafts with a hacksaw blade to see if I could get prusa couplers to stay put. I failed, but this might be why mine does not slip down when tight.

    • #1300
      nethack
      Participant

      I may have figured it out. My Morgan is printed in PLA. The z-axis motor gets very hot during a print. I think that the grubs get hot, heat of the nuts, and they press into the plastic, reducing the grip on the shaft. Since yours is ABS, you don’t have that problem. I’m going to replace the coupler with an ABS one and see if my problem goes away.

      I’ll let you know so you can warn future builders. Ironically, I have no problem with my PLA toolhead.

      Also, one last question. What speeds do you print at? I’m printing fairly slowly right now, but wanted to know how far I could push it once things are dialed in.

      Thanks,

      don

    • #1301
      Quentin Harley
      Keymaster

      Try reducing the motor current. Use a multimeter, and adjust your Allegro based pololu driver so that the voltage in the top of the potentiometer is about 0.6 volt. DRV8825 based you can adjust to 0.8 volt.

    • #1322
      nethack
      Participant

      Looks like I might be in business. I’ve successfully printed two parts for my next Morgan. 🙂 Btw, I’m still curious about what slicer settings you typically use.

      Again, thanks for a great project!

      Don

    • #1330
      Quentin Harley
      Keymaster

      Looking good!

      I am going to post some of my better slic3r settings in the next hour.

    • #1343
      hoff70
      Participant

      Looking really good! Good to hear you got the Z coupler worked out.

      What are you using for a build surface and how is it fastened down?

    • #1347
      nethack
      Participant

      Since I’m only printing PLA, my build plate is 1/4″ Lexan. Prints adhere a little too good initially. However, as it’s gotten scratched up, it’s working better, so I may “frost” the entire surface. It’s fastened simply with countersunk bolts. I built some 10mm spacers to give me enough altitude, but I’ll probably print something similar in shape to your universal build platform.

      don

    • #1356
      Quentin Harley
      Keymaster

      I had an idea for a printable build platform, but stopped short after finding the cheap alternative.

      I could still SCAD something if you want it…

    • #1326
      nethack
      Participant

      One more try…sorry for the bad links.

      My Rural Morgan

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