My Leadscrew based 3D printer



  • Coming Soon(tm)!

    Though not ideal, I have connections with someone who has a laser cutter, and most of the frame will be assembled from laser cur 4.5mm acryllic or polycarbonate. A few key pieces will be 10mm material for rigidity, and the Z towers will have some solid fir reinforcement

    This rendering is more colourful than the finished product will be. I 3D printed the gantry and carriage in green, the laser cut material will be (for reasons of availability) in red. It'll clash marvelously.

    0_1535487660978_Printer Render.png

    I didn't model the motors, Duet, Power supply, wires, bearings... I did model the rods because they're really simple. 🙂 I didn't include the models for the Precision Piezo underbed mounts here, but they've been added since this screen grab.

    The overall printer footprint area is a little larger than I'd have ideally liked, but it ought to be able to print an area 260mm by 275mm. I'll be putting on a 220mm by 275mm heated bed on it, so one dimension is bigger than it needed to be, to match the rods which I already have. I expect about 200mm of Z printable,

    0_1535551659379_IMG_20180828_215509.jpg
    0_1535551704919_IMG_20180829_072428.jpg

    I grossly overestimated the number of screws that I already had on hand, so I'll be getting more of those tonight to complete assembly. Right now the towers are barely held in place at all. The Duet isn't mounted, and of course the 120mm fan that sits under that Imperial Cog.

    I have to loom the wiring harness together, and run everything to their respective locations. I need a little revision under the bed for a place to mount the Precision Piezo board, preferably where I can check the LED status lights.



  • @supraguy said in My Leadscrew based 3D printer:

    It'll clash marvelously.

    I love it.

    You must be very patient to have modeled that all in TinkerCad.

    I'm very interested to see how it runs.



  • Thanks!

    Yeah, Tinkercad isn't the ideal design tool, but I've been using it for a long time for my 3D printed objects, and I'm kind of used to its quirks. I decided to model the motors, too, just because. I also changed the colours to reflect the actual build, again, just because.

    0_1535641618094_Printer Render 2.png

    I have managed to do more of the assembly, and I think that I went about mounting the towers the wrong way. As is, each one is held in place with twelve screws, which is definitely not ideal. Also, I didn't use tab/groove mounting, so getting it into exact alignment is harder than it needed to be. I'll be updating the part files to use the same tab/groove mounting style that other parts are mounted with. Same with the front and rear mounts for the Y motor and rods.

    There's a bearing holder on the front of the Y holder that has to be solvent-welded together. I believe that I will leave it that way. It seems more than strong enough, and more screws would just get int he way. Also, the way that the Y end stop is mounted (On the moving platform, because it allowed me just enough more travel before it gets triggered) the screws that hold the rod caps are really close to interfering, so I glued in a little pad to trigger the end stop. It takes my Y travel from a max of 285mm to 281mm (I have a 275mm build plate)

    Most of the mechanical assembly is now complete. The frame is very rigid, much more so than my original incarnation of this idea. I haven't solvent-welded much of it together at this point. I will probably do so with some of it, in order to prevent trouble with things as they get shaken by the movements that happen in the process of 3D printing.

    I have to do the wiring now. I don't anticipate too much trouble with that. If anything, I have more allocation for wiring this up than I'm going to need, though I'm sure that I'll find something that I didn't anticipate. I plan to use drag chains for the Y axis, and I haven't decided exactly how I'm going to mount the board for the Precision Piezo under bed sensors. I'd like to be able to see the LEDs in order to monitor it.



  • @supraguy said in My Leadscrew based 3D printer:

    Also, the way that the Y end stop is mounted (On the moving platform, because it allowed me just enough more travel before it gets triggered) [...]

    Oohhh, I like this idea! 👍 I might have to copy this for my printer. 😁



  • Well, there has been a bit of error to my trial and error. I ended up redesigning the gantry pieces to be more secure and give a bit more room for the screw motors. As it was, the hot end couldn't go all the way to the bed. (Didn't expect that problem!)

    Then during testing for the piezo sensors, the hot end got dragged over the bed a couple of times, and then the PSU crapped the bed. Some rather alarming noises, then a blown fuse on the AC power line. I don't think the Duet was damaged, when powered by USB, it seems okay, but now I need to wait for a new supply to finish testing. 0_1536006289288_IMG_20180903_134841.jpg 0_1536006308298_IMG_20180903_134715.jpg 0_1536006315570_IMG_20180903_134730.jpg
    I intend to reverse the board when I mount a 120mm fan which will cool the back side of the board. I will use a step-down dc supply to provide 12V for that fan. The fan cooling the E3D V6 is currently a 24V fan, but I'll probably change it to 12V if/when it dies, since 12V fans are much easier/cheaper to buy.



  • 0_1536185067006_IMG_20180904_200218.png
    Work continues. I've just been informed that the power supply that was supposed to arrive last night was delivered this afternoon, so hopefully I can get back to tuning and tweaking, maybe even get a test print off soon.

    In this picture, the two wires hanging loose are the heat bed wires. You can just see the connector at the right edge of the frame.

    I put pin headers on some experimenter board that I had lying around to extend the pins for the Y axis parts. There are 2 sets of 3 pin headers (Y axis endstop, Z probe) on one side, and a set of 2 pin and 4 pin headers on the other (Bed thermistor, Y axis motor) which spaces them nicely. I'd have rather not had the extra connectors, but this does solve the problem of the wires not being quite long enough to get there, and allows them to be disconnected and changed in a location that I can get to.

    I need to fasten down the wiring a little better in a few places, set up the signal wires so that they cross the power wires at more of a right angle, but I ran out of zip ties, of all things. once that's done, then I'll be able to do the final trim on the heat bed wires and make it all nice and neat.



  • https://www.youtube.com/watch?v=mlCJIydoAzY

    It's almost there. I'm still having some tuning issues with the piezo sensors, and I think that I need to make some adjustments to things to make the base of the frame a little more rigid. I had originally planned on reinforcing the frame with angle aluminum, but then I neglected to put the provisions in place. (Not that it's difficult to drill a couple extra holes) I think that the frame reinforcements will help with the piezos, too.

    In the video, you can hear that the Z motors whine a little at probing speed. I'm running the Z motors pretty fast, because of their fine pitch, but I found that at lower speeds, the piezos didn't trigger as well. I'll try to slow them down again when after I stiffen the frame.

    I really do like the acryllic's aesthetics (Though I might have wished for a different colour) but it does require some thought to make things rigid enough.



  • Is your X axis not perpendicular to the Y axis?



  • I'm pretty sure that it's perpendicular to within about an eighth of a millimeter over the length of the rods. It would be difficult for it to be out by more than that unless the laser cutter on which the parts were made is somehow out of square. (The holes for the screws that mount the X towers are about 0.125mm larger than the screws that go through them, so there is a possibility that the towers are not perfectly centered over those holes.) This gives a +/- of about 0.019 degrees off of square. I think that I can live with that.

    The home routine moves both X and Y to the endstops first, then probes Z at the centre of the bed, then moves the nozzle back to the corner.



  • Looking good. I like the red.



  • @supraguy said in My Leadscrew based 3D printer:

    I'm pretty sure that it's perpendicular to within about an eighth of a millimeter over the length of the rods. It would be difficult for it to be out by more than that unless the laser cutter on which the parts were made is somehow out of square. (The holes for the screws that mount the X towers are about 0.125mm larger than the screws that go through them, so there is a possibility that the towers are not perfectly centered over those holes.) This gives a +/- of about 0.019 degrees off of square. I think that I can live with that.

    The home routine moves both X and Y to the endstops first, then probes Z at the centre of the bed, then moves the nozzle back to the corner.

    Must just be the angle of the camera or X axis isn't level? They look pretty far off in that video.



  • @tjb1 said in My Leadscrew based 3D printer:

    Must just be the angle of the camera or X axis isn't level? They look pretty far off in that video.

    Could be the gantry not being level. I thought that I took that after leveling the gantry, but it may have been before. The gantry is about as level as it can be NOW -- at least to within whatever accuracy I'm getting from the piezo sensors. I had a bunch of complaints that it was outside of the 1mm adjustment range that the adjustment will make automatically, so I had to do a lot of the levelling manually. (I might instead just choose to increase the avaialable adjustment if I have to fix this again.)

    Looking at the video timestamp, I can see that it was immediately after replacing the power supply, so the gantry was definitely not level. That's since been fixed.



  • 0_1536296723135_BedMap.png
    Okay, that looks a lot better. (In that it's at least mostly a plane, and doesn't look like I'm trying to print on wet corrugated cardboard, not that this is a great result!) I have a little compliance in the front right of the bed when probing, so that corner shows a little lower than it should, the rest pretty much is a sloped plain, slightly lower to the front. I had plans to figure out how I was going to make adjustments, it seems that it's time to put those into action. The map looks terrible in that scale though.

    https://www.youtube.com/watch?v=s8WD4v3DnZ8
    You can't really see the compliance in the first couple of probes (Weird, I'd have thought that any would be on the other side, since that is further from the sensors there.) Apparently the autofocus hadn't quite figured it out yet.

    tghere. This video the axes should look straighter, since I know that I had leveled the screws at this point.


 

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