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My Robo3D upgrades (Smooth rod bed, z-axis stabilization, direct drive extruder)

Discussion in 'Mods and Upgrades' started by Stargrove1, Nov 1, 2014.

  1. Galaxius

    Galaxius Well-Known Member

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    The extra torque and cooling requirements, and amount of loss in extrusion resolution might be a question for @Mike Kelly
     
  2. tonycstech

    tonycstech Active Member

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    Heatsink is a very interesting idea. Do you have a picture of it ? I wonder what it looks like.
    I quickly thought of this stupid design to mount the fan at the top of the motor. It would be a Snap-On thing that would draw air from the bottom across the sides of the motor and blowing it out thru the top.
    1.jpg
    I wish i had the drive locking screw so i could test the design or print anything at all :(
     
  3. Galaxius

    Galaxius Well-Known Member

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  4. tonycstech

    tonycstech Active Member

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    Interesting.
    I dont think its good enough. Its too thick, too much heavy duty :eek:
    I was thinking about something as fine as heatsint like for a computer processor. But it depends on how much cooling is actually required.
    No way to tell until it runs.
    Stargrove1 should know by now.
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  6. tonycstech

    tonycstech Active Member

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    Thats funny how someone would drill few holes and sell it for 4 times the price claiming it to be something specificalltly designed for.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Not really a shocker :)
     
  8. Galaxius

    Galaxius Well-Known Member

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    I'm sure the ones I have will dissipate heat. If they don't work well enough then a fan on top of them will certainly do the trick, but I want passive cooling for the quiet favor and less failure points. My plan is to design a sprung fastening clip to hold it tight against the motor, possibly with some CPU grease for better heat conductivity.

    I thought about getting some heat conductive pads from eBay but I don't know how sticky they are our if they'll conduct the heat well enough.
     
  9. Stargrove1

    Stargrove1 Member

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    I didn't find much heat at all with the direct drive, the torque seems to be no problem. The geared motor is way more self heating, don't exactly know why, torque should be lower, but the speed is around the same as gregs wade extruder (similar gear ratio).

    @Tony, for the heatsink, it is made of aluminium and adds not more weight than a cooling fan.

    For the resolution, it's the one disadvantage I mentioned, the geared wade created a smoother surface than the direct drive, it seems there is a minimal lower extrusion during the microstepping due to lower torque. I think you need to check by yourself if it is acceptable, as mentioned, I haven't had one jam and the handling is nice.

    I was aware of the motor position, but wanted to keep it simple without modifying the carriage, thats why I simply turned the motor to the front. I don't think the whiplash effect causes big inaccuracy, so I didn't put too much time into this, time is valuable at the moment.

    I already have the next extruder in mind with a new feature which I'd like to work on.
     
    #29 Stargrove1, Nov 16, 2014
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  10. tonycstech

    tonycstech Active Member

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    Dont waste your time. There is thermal tape specifically for heatsinks.
    Search ebay for heatsink adhesive. Ton of things will pop.
    I ordered my self a roll :)
    @Stargrove1
    whiplash was a major issue with my printer due to cheap smooth rods.
    I could feel it being loose moving it by hand. It created all sorts of noises when printed so i had to lower steppers acceleration to make it quieter.
    whiplash also created bulging on every corner tip it would turn into on X axis, so i tell ya, i had enough of it (in my case)

    Not a worry anymore (at least for some time) now that i upgraded with precision rods, but i want them to last so i'd rather do something to prevent whiplash to develop then deal with it.


    Again thanks allot. Its all you buddy, making my printer produce quality prints.
     
    #30 tonycstech, Nov 17, 2014
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  11. tonycstech

    tonycstech Active Member

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    Got my screw and started to print.
    Seem to have no problems at all except for one thing, loading filament thru the back is pain, so 1st thing i print is the reverse versions of base and hot end clamp to have the setup face me instead of its ass facing me.

    I noticed that on a steady pace it works as normal but when it comes to retraction, it kinda goes slow (short pause). I wonder if i should mess with E acceleration.

    As far as amount of extrusion, printed 3 solid layers they were smooth with no sign of overflow so its a good thing.
     
  12. Galaxius

    Galaxius Well-Known Member

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    Looking forward to pics and your next iteration(s)
     
  13. Stargrove1

    Stargrove1 Member

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    Now that you mention the rods, I actually exchanged them along with my new y-axis, I exchanged for the same reason, they stock rods have a slightly smaller diameter, but I didn't find a significant improvement after exchanging them, so I didn't mention it.

    What't the problem loading the filament, I simply straighten it a little bit since it comes from the spool, then I could push down to the nozzle easily. Have you changed the path compared to my version?

    I have also a smooth finish on top, I checked the extruded material by marking the filament at 50mm above the extruder, extruded 50mm and checked if the mark is at the lever of the extruder.

    I haven't seen this retraction issue you mention, could describe it a little bit closer? Mine still extrudes and retracts like the wade, control software only changes the amount of steps per mm, but the rest remains the same.

    Glad to hear that you have a good result too, you may add a made on Thingiverse.
     
  14. tonycstech

    tonycstech Active Member

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    My X had lots of free play since day one. I would get a bulge at X corners that would just drive me nuts.

    Yes i did change the path slightly, about 1mm (not sure which way, i think about 0.75mm to the right)
    But it doest matter because i extended the guide (see pictures) from the top making it very difficult to miss. Also tapered PTFE tube at the base makes it even easier to slip in place, so it works (i guess)
    I will be able to know more when i'll have it facing me. Kinda difficult to see whats going on when its all backwards :(

    Retraction issue is probably slicer. It was a new sound that i was not accustom to so i began to be paranoid. Tweaked retraction settings in the slicer and paranoia went away :)

    Here is my 1st print of a reverse version of hotend clamp.
    DSC00017.JPG
     
    #34 tonycstech, Nov 17, 2014
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  15. Stargrove1

    Stargrove1 Member

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    Looks very nice, seems that mine extrudes a little bit more material from the look of the surface, perhaps due to the different spring, have you checked the extruded length? Is it ABS or PLA? And motor stays cool too?

    I will change the motor position closer to the belt and "front loading" for my next upgrade, I will have to edit the carriage anyway. I hope I find the time between work and family soon, I am curious if my idea may work out as expected, many unknown variables :)
     
  16. tonycstech

    tonycstech Active Member

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    Printing PLA
    Did not manually check anything, i judge by the way it looks :) If it looks good it must be right :) Am not even sure how to check it :(
    Motor is hardly warmed up running for about an hr. It makes me feel bad caz i ordered the heatsink and tape :( I feel (to say the least) dumb o_O
    Since it does not have to rotate as much with more torque, it the same as rotate more with less torque. maybe slightly more but not enough to even worry about unless printing in a chamber printer like ultimaker.
     
  17. Stargrove1

    Stargrove1 Member

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    Its better to be safe than sorry :) you may use the heatsink later.

    To measure the extruded material is very easy, as mentioned before, make a mark 50mm above your lever, heat up the hotend and extrude 50mm (I use Repetier host) and check if the mark is exactly at the lever. If not, measure the deviation and calculate the new value for e_steps, repeat until the extruded length fits.
     
  18. Stargrove1

    Stargrove1 Member

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    Meanwhile I had the time to update to metric rods which were laying around for some months now. Everything went fine, they are nearly perfect straight, you could roll them on a table without lifting in any position (Pool players know what I am talking about :) ). The work very well, I exchanged the the couplers too, one was totaly out of center, I exchanged it as soon as the were delivered. The nut were sitting to tight, I had to take 1/10 mm of at each side to have the same fitting again. The threaded rods are stainless steel and were quite cheap to get on ebay.

    It's a simple mod, I am not sure how important it is, but the z axis ribbing/wobbling no longer occurs.

    I also added some LED strips at the right and the left body, they get activated together with the nozzle fan at above 60°C. This indicates the heating as well as providing light to see what'S up with the print.

    And last but not least, I added a full graphic controller which is mounted with a small additional bracket (http://www.thingiverse.com/thing:536482) at the front. Housing (http://www.thingiverse.com/thing:87250) printed in PLA with Robo matching colors.

    [​IMG]
     

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    #38 Stargrove1, Nov 18, 2014
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  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Sure, shame me on the fact that mine how been laying there for over 6 months. ;)
    edit: OK, more like a year.
     
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  20. tonycstech

    tonycstech Active Member

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    My reverse design failed. Motor ended up too close to the belt.
    According to the design of the printer, it should have had enough clearance. But according to assembly of the printer, nothing lines up as it should.
    Had to redesign it again and will be printing new one tomorrow.
     

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