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Discussion in '3D printers' started by Carl Feniak, Sep 29, 2014.

  1. JCPhlux

    JCPhlux Well-Known
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  2. Carl Feniak

    Carl Feniak Journeyman
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    I am no expert on this front, but those look good to me. They are similar to the ones on the open builds store. I don't know what the STH versus HT refers to though. Different manufactures seem to have a slightly different naming conventions.
     
  3. nexty

    nexty New
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    I have order those will keep you updated :)

    meanwhile §I have started to cut the V-slot
     
  4. Carl Feniak

    Carl Feniak Journeyman
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    I've added an "Assembly" doc to the files section. More work then I figured. I skipped the wiring/programming/tuning sections but if you have questions just ask.

    Also, inspired by JCPhlux I installed this mod just today. Goal was to use the same concept as I used on the CoreXY portion for the Z axis. Since the 20x40 extrusion is oriented in the opposite direction I had to come up with a modification. I used 20mm M5 stand off to resolve this (25mm stands would of saved me a 1/4" spacer but I couldn't source any). What do you think? I had to move the extruder to the front to accommodate.

    IMG_0914.JPG IMG_0915.JPG
     
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  5. JCPhlux

    JCPhlux Well-Known
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    you could do this to save the spacer.
    Z Bar End V4.png
     

    Attached Files:

  6. Keith Davis

    Keith Davis Veteran
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    Openbuilds sells aluminum spacers and low profile bolts of varying lengths that would reach out past the 40x20 extrusion with a nut on the outside of the outer bracket. Wouldn't a solid axle bolt for that entire length provide better accuracy and strength?
     
  7. nexty

    nexty New
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    Just so I know what the mod is about ?

    Thanks for the plan I'll take a look shortly :)
     
  8. Carl Feniak

    Carl Feniak Journeyman
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    The printed extension would work, but they require using 55-60mm bolts, right? Sourcing metric is surprising hard in Canada which is on the metric system!
    I think I could get them on Element 14 but would have to order 50, if not 100, of them. It would definitely be a better way to go then what I've done with the standoffs.
    It was mainly about symmetry and consistency with my CoreXY design as the cantilevered design was a carry over from my H-Bot. Also, there were some concerns mentioned about the Z setup so I wanted to present an alternate. This mod can be extended to work with 20x60 extrusion as well (I had created it to share but somehow deleted the files).
    The cantilevered design does work and I had my extruder mounted and wired to that leg so I didn't want to move anything. Then JCPluux got me thinking more on this when he started planning a shift to 20x20mm extrusion. This is what I came up with that enabled me to use my current 20x40 leg design. Did a test print yesterday and all is running well. I'd say either design is fine.
     
    #128 Carl Feniak, Nov 10, 2014
    Last edited: Apr 21, 2015
  9. adamcooks

    adamcooks Well-Known
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    Thanks for sharing this. I am going to start a build based on this, using mighty board electronics. I am planning on dual extrusion, 12x12 build plate with a 300 mm Z. How has using the extrusion as a linear guide for the z stage working? is there much wobble?
     
  10. Carl Feniak

    Carl Feniak Journeyman
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    I am pretty happy with the Z axis setup and I am getting excellent quality prints out of it (much better than my OB1.4 which does suffer from intermittent Z wobble). The biggest factor though is using lead screws instead of 8mm threaded rod and being carefully squared and aligned.
    For a 12x12 print bed I would recommend upgrading the Z frame assembly to use 20x60 extrusion (20x80 if you want to be extra cautious) instead of the 20X40 I use on the rear section. The idea here is not to prevent Z wobble (that still shouldn't be a problem) but to prevent deflection at the far side of the bed and reduce the force on the mini V wheels for printing large objects.
    I hope to add dual extrusion down the road. The C-Bot setup is symmetrical, so other than designing a new hotend holder there will be no extra design work required.
     
  11. adamcooks

    adamcooks Well-Known
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    I was thinking about incorporating 3 lead screws, belted to a single motor, to support the Z. Can you also tell me why you used a long spacer on the Z traveler car instead of using two rows of wheels. I can see the merit of using the x 60mm to support the extra torque of the cantilevered HBP. twin 12mm leadscrew on a x 60 bracket should run pretty smooth.

    As far as dual extrusion goes, do you think I should mount the extruders fore and aft of the X car to balance the load? with a Y toolhead offset instead of X.
     
  12. Carl Feniak

    Carl Feniak Journeyman
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    I used a long spacer instead of adding another 8 v-wheels for a cost savings. I knew from my previous design that they could handle the loading of my build plate. It would work though and would increase the rigidity as Derlin has some give to it.

    Two lead screws in the back and one in the front (or vise versa)? That would eliminate the cantilever forces and take the torque loading off the V-wheels. You wouldn't need to upgrade the rear Z bar if you did that as the V-Wheels will be acting for XY stability and alignment. Someone earlier was looking to use an 8lb heated bed so your mode would be perfect for them! Any concerns about belt backlash? What size stepper would you use to drive three lead screws?

    I was thinking of putting both hotends on the same side (which actually represents the Y axis with how my endstops are configured- see end note). It only creates a small imbalance in the bowden configuration, which I was eventually going to counter balance with print cooling fans. I see no reason why what you are suggesting wouldn't work. Just make sure you size your extrusion to handle the extra range of motion required for dual extrusion.

    End note- my configuration treats the 12" (left to right) as the Y axis and the 8" side as the X-axis. Why? It has to do with my endstop locations/the auto home feature/ and Marlin restrictions. I wanted to keep the endstops stationary, the auto home feature homes X then Y, Marlin doesn't let you home to X-max or Y-max for a CoreXY setup.
     
  13. NickM

    NickM New
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    Hi Carl,

    Thanks for the design, I thinking I would try and build one, or at least use it as a starting point.

    I'm having some trouble with the "hot end parts.stl" though, it seems that the clamp that holds the extruder is sitting above the surface, so it can't print unsupported. Any chance you could redo the file with everything at the same level?
     
  14. Carl Feniak

    Carl Feniak Journeyman
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    Are you using sli3r? If so, just go "split parts" and it will drop everything to Z=0
     
  15. NickM

    NickM New
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    Thanks Carl, that fixed it...
     
  16. nexty

    nexty New
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    hey guys, quick update on my side, I just received the motor :)

    still trying to print the XY mount (somehow I had some issue printing larger file, the filamenent extrusion isn't working as it should)

    I will soon order the electronic, so RAMP kit is the way to go, regarding the hot head, what the advantage of the 1.75mm version? my e3d v6 version is a 3mm nozzle and all the filamenet I have is on 3mm

    thanks
     
  17. Carl Feniak

    Carl Feniak Journeyman
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    The benefit with 1.75mm filament versus 3mm filament is the force required on the drive is less. For the same pressure at the tip of your hotend you need to apply less force with the smaller diameter (area). P=F/A ... Pressure = Force / Area.
    It is also helpful in a bowden setup as the filament can bend and flex easier.
    You don't necessarily need to change your hotend though, but I would recommend a geared extruder with 3mm filament.
     
  18. nexty

    nexty New
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  19. JCPhlux

    JCPhlux Well-Known
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    That price looks a bit high but if it is local it might be worth it. I usually find the parts individually for a lower cost. If you dont might getting it slow there is a kit on fasttech http://www.fasttech.com/products/0/...rinter-arduino-compatible-mega2560-r3-ramps-1
     
  20. nexty

    nexty New
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    thanks JC for you're link, will get one of those over,

    I wonder - what type of software do you use to design you pcs? I'm in need to actually splitt the larger pieces as for some unknow reason doing large print isn't a real success with my printer (filament feed stop working at some point) for example, took me at least 6 attemps to get the XY motor mount done, I'm using the e3d v6 hot head

    so I'm wonder what soft you use to open the STL and split them? Spaceclaim isn't working well for me
     
  21. JCPhlux

    JCPhlux Well-Known
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    I have not had split any prints yet but I think Slic3r has that option.
     
  22. NickM

    NickM New
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    Hi Carl,
    For the BOM, was it meant to have M3 Nyloc nuts in it?

    Also, I found that I can't get the mini wheels to spin freely, unless I put a shim on either side to stop the wheels binding to the spacers, so I assemble them Bolt Head-washer-plastic-spacer-shim-wheel-shim-spacer-plastic-washer-nut. I'm not sure how you managed to get them working without the shims.
     
  23. NickM

    NickM New
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    Hi Carl,

    In the BOM you have the back slide and the top slide as the same length.

    I don't think this is correct, it top slide needs to be longer than the back slide, probably by 40mm.
     
  24. Carl Feniak

    Carl Feniak Journeyman
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    The M3 Nylocs aren't required, but I was planing on using them for the XY bar idler pulleys.
    As for the spacers, it seems Open builds sends out two types, ones that work with your mini V-wheels and ones that wreak your mini V-wheels by pressing on the seal shroud! The ones on the bottom right are the correct ones. If you have the ones on the left then you will need to use the shims you mentioned.

    IMG_0913.JPG
     
  25. Carl Feniak

    Carl Feniak Journeyman
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    ****, you are correct. I'll update ASAP.
     
  26. NickM

    NickM New
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    Hi,

    I'm using a 20x60 for my z axis slider. Here are the modified z-bar ends I'm using.
     

    Attached Files:

  27. Carl Feniak

    Carl Feniak Journeyman
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    Looks good, thanks for sharing. What size bed are you planning on using?
    I am sure folks with a front to back bed size of greater than 8" will be considering using these.
     
  28. NickM

    NickM New
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    Hi,
    I'm trying to build a 400mm x 400mm bed, with about 400mm for the z axis.
     
  29. adamcooks

    adamcooks Well-Known
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    Any chance i could get you to split the H bar ends STL? I am getting a weird issue with mesh when i use my normal take it to tinker-cad and drag some large rectangle holes over the parts i dont want.

    upload_2014-12-9_12-39-40.png
     

    Attached Files:

  30. Carl Feniak

    Carl Feniak Journeyman
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    Yep, as soon as I get home. Another thing you can do is "split" the two ends apart in slic3r, delete one, and then export the stl file instead of G-code.
    Do you still have a question about extrusion lengths or did you figure that out?

    Aside: I have some new parts to post.
    -New XY bar ends that allow you to run an LED strip behind it. Otherwise identical.
    -A dual hotend carriage
    -An alternate Z endstop
     

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