Big box with no Endstops

Discussion in 'BigBox General Chat' started by KNM3D, Jan 29, 2018.

  1. KNM3D

    KNM3D Well-Known Member

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    is there documentation on how to get the bigbox to operate like the Prusa I3 MK3, to where you don't need endstops?
    because that is just perfect.
    also,
    I for some reason was thinking there is a heated bed being made for the bigbox that is similar to the Prusa bed where it locates spots using the pinda probe?
    is this correct?
    because in my mind those are a couple things that the big box now needs, well at lease I would love mine to have it.

    any help would be awesome
    thank you,
    RKM
     
  2. Ephemeris

    Ephemeris Well-Known Member

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    You should be able to do that with the Duet controller using its stall detection ability. I have to ask though, why?
     
  3. KNM3D

    KNM3D Well-Known Member

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    just a thought. didn't know if it is totally needed.
     
  4. dc42

    dc42 Well-Known Member

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  5. KNM3D

    KNM3D Well-Known Member

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    so this a board that replaces my "rumba" that they used in the Bigbox?
    and I don't need drivers they are in the board. and the stuff they use in the Duet board is better than the new Trinamtic drivers?

    and this quiets down the printer a lot?
     
  6. Ephemeris

    Ephemeris Well-Known Member

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    The Duet drivers are preinstalled and soldered to the board. The upgrade to it is pretty simple. The HUGE advantage is no more messing about recompiling firmware for a small configuration change. Instead the machine definition is in a text file that you can edit, reboot the Duet, and you're good to go.
     
  7. KNM3D

    KNM3D Well-Known Member

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    where do you suggest I look for a list of stuff I need to get to make this upgrade?
    and I could change my dual bigbox to a single then correct?
    and stuff to read up on. I have trouble with wiki stuff. but if it is laid out well I think I can follow it.


    ****
    side note question.
    on the lead screws for the z axis and all the linear rods. do you guys recommend using an nice grade oil or a good white lithium grease?
    and linear bearings, what size are they? and what is a really good upgrade replacement for them?
     
  8. KNM3D

    KNM3D Well-Known Member

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    maybe a stupid question.
    can I just put an einsy board in the bigbox?
    or does that not support the PT100?

    or is there just a lot more programing/typing that I have to do for updating the firmware?
    mind you I have no idea how to do that stuff so my verbage may be wrong or off, when asking these questions
     
  9. dc42

    dc42 Well-Known Member

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    I'm biased (I am one of the designers of the Duet) but here goes. The Duet WiFi and Duet Ethernet use TMC2660 drivers. These support the same x256 microstepping, microstepping interpolation and stall detection as the TMC2130 drivers used on the Einsy, however they can handle around double the motor current: 2.4A instead of about 1.2A. The Duet WiFi also supports resume-after-power-fail, like the Einsy. The difference is that is doesn't need a special interface to monitor the mains power, because it has built-in power monitoring. The Duets are mature and well-proven - the Duet WiFi was launched in August 2016 and the Duet Ethernet almost a year ago. Many thousands are in use, both by home 3D printer builders, kit manufacturers, and manufacturers of industrial 3D printers.

    On top of this, the Duets are 32-bit, provide a web interface, and firmware configuration is done using a text file (which can be edited in the web interface) instead of having to recompile and re-upload the firmware.

    So I really don't understand why some people are making such a fuss about the Einsy, which is way behind the Duet in terms of functionality and arrived more than a year later.

    On the subject of sensorless homing, although it works it is IMO a bit of a gimmick because it is less accurate than traditional homing with microswitches. For a new printer design, it might make sense to use it because it simplifies the wiring; but it's hard to see any point in removing the homing switches from an existing printer.
     
  10. KNM3D

    KNM3D Well-Known Member

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    that is exactly what I was looking to hear.
    ill have to read up and maybe start this install this summer.
    I know its not a hard swap, I just need to understand the "interface"/enduser" easability, I know those aren't words. but I really suck when it comes to understanding stuff like this. I think I "nuke it"/ over think things.

    so I inadvertently block the learning of it.

    ****
    side note question.
    on the lead screws for the z axis and all the linear rods. do you guys recommend using an nice grade oil or a good white lithium grease?
    and linear bearings, what size are they? and what is a really good upgrade replacement for them?
     
  11. Ephemeris

    Ephemeris Well-Known Member

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    Generally I think lithium grease is less likely to damage plastics. If your leadscrews are stainless steel, you might consider Delrin leadscrew nuts which let you run the leadscrews dry (no lubrication).
     
  12. MyMakibox

    MyMakibox Well-Known Member

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    I'd appreciate your thoughts on stall detection, which sounds great in theory. Does it usually work to save prints that would otherwise fail because of missed steps?
     
  13. dc42

    dc42 Well-Known Member

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    Good question, and I don't have the answer. I have not had a print fail because of missed steps for over a year. I tried to configure my Delta printer for stall detection but I haven't yet found settings that work when I deliberately obstruct the carriages but that don't cause false positives. I suspect the speed range and acceleration of my Delta are too great for it to work, also the motors in it are optimised for speed (low inductance) rather than for stall detection. My Cartesian printer doesn't yet have a generation 2 Duet in it, but when it does I'll try it.
     

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