3mm / wiring forces and toolchanger docking challenge

Discussion in 'Tool heads & ToolChanger' started by phoenix, Nov 24, 2019.

  1. phoenix

    phoenix Member

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    Hello,

    I have been playing around with 3mm filament, and I think I am seeing the same challenge as Andy with the Nimble extruder: the force the wiring exercises on the tool makes it tilt and the docking becomes unreliable...

    Has anybody found a way to route the 3mm filament or any other resistant cable that is reliable?

    Or has somebody an idea how to force the holder to hold a tool into a reliable place?
     
  2. Nibbels

    Nibbels Well-Known Member

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    Thanks for the hint.

    I will have to use 3mm diameter at two toolchanger tools.
    The reason are my two other printers which use 3mm rightnow. Thus all my filament is 3mm.

    If I run into the same problems I will report back here after my toolchanger is up and running with 2x TitanAero 3mm.
    Tell us if you can resolve some issues.

    Greetings
     
    prcdslnc13 likes this.
  3. phoenix

    phoenix Member

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    After trying a lot around (Bowden and Nimble-type remote direct extruder) without success I have finally built an Aero-based extruder. Works like a charm actually and am now running my printer with 2 TitanAero 3mm (and 2x Bowden 1.75) and zero trouble.

    The remote extruder (I am using a Flex3Drive 3mm) was working but brought repeated issues when having multiple up and running as the filament and drive cable started adding up and making docking/undocking unreliable. So not recommending for multiple extruders. And frankly you can't beat the price of a simple TitanAero which reuses most existing parts anyway.
     
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  4. Nibbels

    Nibbels Well-Known Member

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    Hey,

    I just finished my first beta version of a TitanAero adapter.
    At this moment I have no clue if that works well, but the Idea is painted to a model.
    Screenshot_5.jpg Screenshot_2.jpg Screenshot_4.jpg

    I have two TitanAero 3mm here. But I already destroyed one of the grub screws to hold the steppers gear. I did not see that the front of this specific grub screw is flat / locks quite stiff. Or it was just a bad one.
    For now I do not have the dock parts but I hope that E3D processes my pre christmas order soon.
    My old printer is printing the shown adapter parts rightnow.

    Additionally I think about redirecting the cooling airflow upwards.
    And I want to steer the upper part of the airflow (comming from the cooler fan) through the blue part to have a bit of cooling effect at the stepper. That might be nice if I get the pancakes. I think that using a pancake stepper is shifting the mass to the horizontal center. But I only guess that.

    @phoenix, can you share some pictures of your constructions? Maybe I can learn something. :)
     
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  5. Nibbels

    Nibbels Well-Known Member

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    Screenshot_2.jpg Screenshot_4.jpg Screenshot_5.jpg Screenshot_6.jpg Screenshot_7.jpg Screenshot_8.jpg Screenshot_9.jpg Screenshot_11.jpg Screenshot_12.jpg

    Yes I forgot about the inner panel. I deleted that from my model early ...

    But the tool is stable nothing bends. Everything fits tight. I printed it using blue PETG.
    Now I wait until the dock parts arrive.
    I will write an update after I was able to test the tool.
     

    Attached Files:

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  6. Nibbels

    Nibbels Well-Known Member

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    My AeroTools are still developing.
    -> I have not printed yet.

    I had to wait for my dock parts another two weeks. But now they are mounted within the printer.
    The weight of the TitanAeros are different because one stepper is a slimline motor. https://e3d-online.com/slimline-motor
    I will see if that works when I am able to finally print with the tools. A slimline motor saves 100g but I have to see if the strength is enough.
    Screenshot_9.jpg
    Screenshot_11.png


    That is the look of the fully assembled tools. Only some cable ties at the yellow cables are still missing. I need to hottight it tomorrow.

    Screenshot_14.jpg
    Screenshot_12.jpg
    Screenshot_13.jpg

    And this is my Idea for the airflow trick: Note that the screw on the right side is missing to unlock the center air path.

    Screenshot_17.jpg Screenshot_16.jpg
    Screenshot_15.jpg
    So far I haven't tested if the adjusted airflow is really needed, but the ducts were initially intended to save material, but looked ideal to have a certain flow at the stepper motors. I think it is always a good thing to have a bit of cooling at the steppers. Maybe this will be the key point to optimize if the slimline stepper has to run a tiny bit at the edge of specs.

    That is the hole to adjust the TitanAero tension spring:
    Screenshot_2.jpg

    I already adjusted the grabbing mechanism. I also switched to firmware RRF3 and got the load detection for the coupler working. https://forum.e3d-online.com/threads/help-c-axis-is-not-homing-properly.3551/#post-35430

    The next step is to finally hottight the nozzles. Then to fix all the cables in place. Then to adjust the nozzle offsets.

    About the original topic "3mm / wiring forces and toolchanger docking challenge" I already thought about the magnets to have a better docking force. See
    https://forum.e3d-online.com/threads/help-c-axis-is-not-homing-properly.3573/#post-35525

    So far.

    Greetings
     
    #6 Nibbels, Jan 23, 2020
    Last edited: Jan 23, 2020
  7. Nibbels

    Nibbels Well-Known Member

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    Another update.

    I started with PETG and the slimline stepper motor ist not strong enough for PETG.
    Maybe it is for Flex or PLA.
    For now I added those gramms again and I am quite happy with the strong and compact size.

    Using my old printers with a dual-head I really hated oozing. But because the TC+Duet is such a genious construction It took my one evening to probably never see this again.
    Screenshot_16.jpg
    I added those stainless steel razorblades under the docking positions. At the second the tool is in the dock the nozzle is closed.
    Of course the blades have been filed off to loose the sharp edges. I used the blades because they are stainless steel, cheap and very thin. They can be bent and behave like a spring.

    Screenshot_17.jpg
    Simplify3d is only allowed to retract 1mm at toolchange time. The working temperature is 235°C and the idle temperature of the tool is 30°C lower. My results seem to be great. I will tell you if that changes.
    I do priming within start.g and put the tool back onto the blade instantly. (Then the bed rises the temperature and the print starts using any tool.)

    Screenshot_18.jpg

    My previous testparts have been perfect. No Ooze-Shield, No brim, No oozing.
     
  8. John Meacham

    John Meacham Well-Known Member

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    That looks super nice. I think I'll have to integrate it into my hemera filament guide[1]. Do you use the side brush purgers at all or is just docking/undocking enough, I'd love to get rid of the prime/purge on toolchange.

    [1] https://www.thingiverse.com/thing:4134689
     
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  9. Nibbels

    Nibbels Well-Known Member

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    https://cad.onshape.com/documents/0...c59ea62c25377e2e7b/e/626fa2db8cbe88c80cacc016 @TitanAero Tool Folder

    I still dont know if I completely can get rid of brushes. Because from time to time stuff is being collected at my hotends lower side. I will have to find that out why.
    - Flow ratio still a percent too high?
    - PETG without part cooling fan (I still didnt build those)

    When the tools are on the dock they are completly sealed. And it is easy to adjust the blades if you just bend them by hand or with a pliers.
    I formed this tiny ramp and did bend the blade a bit up. (The nozzle reverts it to a flat state with a tiny bit of spring tension.)
    The two screws hold the blades better than I first thought.


    Titan Aero Tool Adapter:
    I think that the air which is routed to the stepper motor is very nice. The stepper gets very hot at 1600mA. I already changed the configuration to 1500mA and I will go lower later.
     
  10. Nibbels

    Nibbels Well-Known Member

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    I added my tool adapter to thingiverse after printing alot with it:

    https://www.thingiverse.com/thing:4190989

    The latest improvements are for better toolhead grabbing. Before the whole side was flattened. I didnt like the slippery feel when I grab the toolhead every time.
    Screenshot_10.jpg

    My compact but powerfull amps are now down to 800mA at 3mm filament and has enough force.
    I print PETG.

    Using a that low current the stepper stays cool. Even with noctua fans @15V which are silent but dont blow alot.
    But I as well printed at 1500mA alot! But you dont want to touch the stepper longer than some seconds then. It should still be within specs but I dont like the heat.

    Acceleration:
    I once compared the weight of printers toolheads vs. their default acceleration. And figured that 500g might be ok with 3000 acceleration.
    Now I know that this is working with XY = 1600mA but at the upper edge. I once had a part which came out layer shifted. One of 12 similar parts. The problem was Y only where the toolheads weight adds to the x bar. (No guarantee that I actually was at the upper edge but I didnt want to risk it anymore)

    So I dropped the acceleration to M201 X2500 Y2000 for now. Long live the machine.

    Some print pictures without brushes, without cooling fan, without priming tower, without ooze shield, PETG:
    Screenshot_11.jpg
    Screenshot_12.jpg
     
    #10 Nibbels, Feb 28, 2020
    Last edited: Feb 29, 2020
  11. phoenix

    phoenix Member

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    Thanks for sharing - I definitely love the air flow use for cooling the motor :)

    Have you found a way yet to add a print fan? The whole unit is quite bulky. Only place I can see on my setup is possibly behind the stepper (but of course don't have the mounting places the Hemera would have, so maybe glue?)
     
  12. Nibbels

    Nibbels Well-Known Member

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    Hello phoenix,

    I'd like to tell more but I did not continue adding part cooling fans. But a 3rd tool as Hemera instead (no PCF as well).
    I my goal is to add one of those flat laptop fans. Maybe underneath the stepper motor.

    If that wont fit I probably design some air channel / pipe to be used with a moderate/high static pressure radial fan atop of the tool.
    But that are just plans rightnow.

    I still have to research some effects which I cannot understand. And I need a better solution for nozzle cleaning/wiping.
    My static brushes in front of the dock catch the filament bubbles but when I leave the dock they get caught again. Tomorrow morning I will see if they are better than nothing.
     
  13. John Pickens

    John Pickens Member

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    Hi there, I've been building a Flex3Drive based toolhead as seen here:

    https://forum.e3d-online.com/threads/mdl-flex3drive-direct-drive-extruder-tool.3691/

    [​IMG]

    Anyway, just like the Zesty Nimble, the flexible driveshaft imparts a good bit of twist to the parked and parking toolhead.
    So far, in testing, it picks up the toolhead perfectly every time. However, when it parks the tool, the departing dock mechanism pulls the
    toolhead off the magnet by about 1 cm when it leaves. So I need to find out how the tool clamp is hanging on the tool socket, and how to prevent it. I also thought, as noted above, that a stronger magnet might help, but I am thinking that another alignment mechanism, like a sloped bar alongside the parking prongs might be able to force the tool to stop twisting.

    Another idea was to change the cam locking sequence to pause the dock for a second after actuating the locking servo before moving the dock away from the tool. As it is currently, the servo actuation and the movement of the dock seem to be almost simultaneous.

    Any thoughts would be appreciated.
     
  14. Spoon Unit

    Spoon Unit Well-Known Member

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    When one experiment went wrong, I ended up using a socket head screw in place of a grub screw for the magnetic 'grab'. The socket head screw seems to provide a MUCH greater grabbing force than the grub screw, but doesn't affect the ability of the system to pull the head off the tool resting pins.
     
  15. John Pickens

    John Pickens Member

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    Do you think the socket head screw gave more magnetic attraction due to its larger mass? Anything helping the pull force would be welcome.

    And in my description above, my referring to the dock was in error, I meant the tool changer.
     
  16. Spoon Unit

    Spoon Unit Well-Known Member

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    Could be the bigger mass, or the distribution of the mass in relation to the magnet. I've attached the STL if you want to try it. I used an M3 10mm SocketHead in the hole instead of the grub screw.
     

    Attached Files:

  17. John Pickens

    John Pickens Member

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    Thanks for the response and the file! What do you think about using a niobium magnet oriented properly for mating to the dock magnet?
    Too strong? Anyone ever tried this?
     
  18. Marcus Mendenhall

    Marcus Mendenhall Active Member

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    Docking magnets together often isn't a good idea. The materials are very brittle, and they may chip or crack as they clank together. Much better, in general, to dock a magnet to fairly soft iron or steel.
     
  19. dc42

    dc42 Well-Known Member

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    If you are looking for more holding force then I suggest docking magnets together with a piece of ordinary adhesive tape or Kapton tape over the end of one or both magnets, to hold them slight apart and cushion the mating force.
     
  20. Spoon Unit

    Spoon Unit Well-Known Member

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    The magnet itself is already forcible cushioned by air as there's a 1/4 mm or so of metal that the metal sits on. If you really wanted a magnet in the tool too, you could employ a similar mechanism to prevent crashing and smashing.
     

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