Tool changer with DDS



  • Hi All,

    I'm currently building a BLV mgn cube and thinking about a tool changer for 4 hotends. I'm wondering if there is any design with direct drive out there. All I've found are non DDS and I don't want to go back to a bowden setup.

    If I look at the price of a Palette2 for example I think it would not be more expensive to get 4 DDS hotends and my gut feeling says me that it is more comfortable as an external splicing device.

    Would love to hear thoughts of the experienced guys 😉

    Thanks, Martin



  • @MartinNYHC you can place a titan aero or a hemera on it and you have an direct drive


  • administrators

    My E3D tool changer has two Hemera tools, each one driven by a Duet 3 Tool Board. If the BLV uses the same tool plates as E3D then you may find the designs for Hemera tools for the E3D tool changer useful. Greg's original design (not using tool boards) is at https://www.thingiverse.com/thing:4008778, and my variant for tool boards is at https://www.thingiverse.com/thing:4194982.

    The Tool Changer section of the E3D forum also has posts on designs that use Bondtex extruders on direct drive tools.



  • Thanks, good starting point.



  • Awsome plan. I am thinking about buying one too. Can you already tell the precission of the device?



  • Another question please:

    I'm going with the Duet 3 and need 8 stepper drivers in total ( at least as for now 😉 ). What's the best way to extend the Duet 3? Going with the Expansion 3HC board or Toolboard 1LC? And what are the advantages/disadvantages of both options?

    Thanks, Martin

    BTW: found another interesting design for Bondtech and Mosquito using the E3D tool changer.


  • administrators

    @MartinNYHC said in Tool changer with DDS:

    Another question please:

    I'm going with the Duet 3 and need 8 stepper drivers in total ( at least as for now 😉 ). What's the best way to extend the Duet 3? Going with the Expansion 3HC board or Toolboard 1LC? And what are the advantages/disadvantages of both options?

    Thanks, Martin

    BTW: found another interesting design for Bondtech and Mosquito using the E3D tool changer.

    If you will be using direct drive extruders, then the wiring will be simpler if you use tool boards for them - assuming you have room on the tools to accommodate the tool boards.

    Expansion boards can provide higher stepper motor current than tool boards, but getting enough motor current isn't usually an issue with extruders.



  • Thanks. I'm in doubt that I have enough room for the tool board but I'll check. On the other hand cabling the hotends needs to be done only once. My gut feeling says me that I'll go with the expansion board but will double check.



  • I am currently working on a setup like this. If it helps I'd like to offer you some directional pointers.

    *Keeping the bed sensor & part cooling fan as part of the X carriage cuts down on electrical transfer points (will become clearer later)

    *Use pogo pins (see pic.) to transfer electrical points from X carriage to extruder. You need 10 for a basic setup (no filament runout) HE fan = 2 Heater = 2 Temp sensor = 2 Extruder motor = 4

    *The spring tension of the pogo pins isn't sufficient enough to warrant any extra consideration.

    *Use of the pogo pin system allows for a potential preheat next extruder scenario. Assuming the firmware/control board can support it. Early thoughts, this would consist of a tilting bar with heater power & temp signal added to contact the docked tools. Even if you were to preheat to a less than desired value, say 150 degrees, this would save time in the long run. Not to mention less risk of part cooling down between tool changes.

    All of this I believe is fairly achievable with Duet board & RRF. Hope this was helpful & good luck 🙂
    Screenshot_35.png



  • I'd love to keep as many of the components as part of the X carriage. This would also save a lot of money.

    IMHO best solution would be to only change the hotend and keep everythig else on the X carriage. Do you have any ideas/designs how to achieve this? To be honest I'm not that experienced in designing things (or better using CADprogramms) 😉



  • Changing the hotend only while keeping the extruder portion as part of the X carriage would be more trouble than it is worth. Not to mention the hotend would need to be docked to the x carriage /extruder to perfectly align the filament path. Get a headache just thinking about it...
    May I ask why do you want to have a DD toolchange? I know my reasons but what's yours?



  • Struggled for a long time with stringing and when changed to DD all problems were gone. That's the main reason. Beside of that it is more easier to change the filament. I don't see a reason at all to go back to a bowden setup. But indeed that would make life easier when building a tool changer.

    So how far are your plans/designs? Anything to share? 😉



  • I'd be happy to share, unfortunately my setup is still sitting behind a long list of things to do first. Whilst chipping away at said long list I was thinking about your question. It is possible to meet half way on the whole tool changer idea, though the complex design required may cancel that out too. You could separate the extruder and hotend from the extruder motor. This would only save you extruder drive motors (depending on how many hotends) and a handful of wiring. It would require some sort of dog drive assembly between the two parts as you would have trouble trying to align the drive gears properly. TBH the time and effort to get a system like this working would more than likely be more than it's worth.

    Have you looked into the basic fixes for bowden setup? Upgrading your feed tube, relocating extruder for a better path etc. might be a better option. I have a Tevo Tornado that is bowden and it is honestly my workhorse. I have done the basics and managed to get stringing and such to an acceptable level. What materials are you printing with mostly?



  • Since I need an extruder for each tool anyway I don't see a reason to go back to a bowden setup.


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