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3 singel controlled Z-Stepper Driver

cryzecryze
edited August 2016 in Motor Control
Hi Guys,

i have a Ramps 1.3 Board, with this board i actually can use 3 Stepper for de Z-Axis but just with 2 Stepper-driver.
Now i´d like to changed the schematics and the layout from the Ramps that i can connect one more stepper-driver.
My question is can the repetier firmware handle this?


Comments

  • RepetierRepetier
    Yes, firmware can handle this, but since it is a own board the board definition will not match. So go to pins.h for your board and add a new extruder pins definition with the new pins used for this. Then selecting Extruder 3 (E2_...) in config tool would use that new socket.
  • cryzecryze
    can i also use my Z-Probing to correct the bed leveling wiht the 3 Z-axis stepper?

  • RepetierRepetier
    Yes, that is how sparkcube for example does hardware leveling. Motor 1 is reference height and you define 2 extra stepper whcih are identical with the 2 other z motors and it will use these to move them individually to level on hardware side.
  • cryzecryze
    Excellent, thx for the great support :)
    Do you have a tut that shows how i must define the firmware?
  • RepetierRepetier
    Check sparkcube website (use google translate to understand). They even offer downloads and have also some tutorials and videos on this. It is a bit tricky I admid as you assign 2 motors also to extra motor drivers and use these to change height during mechanical bed leveling. Key point is to assign right coordinates to motor positions and define the motors correct.
  • cryzecryze
    Okay, i´ll take a look of this site and i am from Austria so i dont need the google translate :D
    Thx a lot ;)
  • N37N37
    Hello, i have got one little question, 

    I'm designing new printer frame, as a closed box, and i want to make it able to full hardware auto level.
    I'm going to use the tension-meters under the printing head , just like RF2000 uses.

    And to make it fully automatic i plan to use 3 or 4 lead screw pillars for moving the Z axis.

    Questions:

    1. What will be better 4 independent pillars/stepper motors/drivers, or 3 is just fine ?

    2. If I use 3 motors driving 3 independent pillars, how the triangle should be designed ?
    exactly, do the pillars have to be in exact distance from each other ? isosceles triangle or can it be a triangle with 2 same flanges and third shorter (situation when two steppers are on a left side in corners of bed, left front and left back, and third stepper on right in the middle of right edge of bed ?


    What configuration you prefer to use with repetier ? or it does not matter since the probe will probe the three points that are near to the pillars and i assume that I'm setting those 3 fixed points for extruder in my case to hit in order to detect the surface ?


    So in short can I use 4 steppers for stability ? or only 3 and does the geometry of triangle that pillars create matters ?
  • RepetierRepetier
    1. Currently only 3 stepper is supported. In a month or so I hopefully get a printer with 4 z motors so I can implement also the 4 stepper solution. That is a bit more tricky as it is statically undefined preventing bigger corrections. 3 Motors will be always the more easier solution to handle but after it is once corrected there will be  no big error so 4 should also not get any problems.

    2. You define the rod positions and normally take measuements close to them. That is good for preventing bending as additional error source. Exact position is not that important as we interpolate the plane we measure to the fixpoints.
  • N37N37
    edited December 2016
    Ok, Thank you for your answer.

    Right now i'm trying to figure out a most easy and on the other hand stable way of fixing the build plate to the 3 or 4 rods.
    It is not so simple as the every plate/rod mount point needs to have flexibility to give plane move for bed when other rod is moved in leveling action.

    It has to be some kind of connection like some kind of coupling bar / pull rod.

    I was thinking about one more solution/addon to the printing bed - to mount accelerometer module and use that for additional leveling data, or even two one on the bed it self and second on frame, and to calculate differences in those two, but that was just an idea. I do not know if it could be useful.

    I,ve got a frame already designed for 3 steppers for Z,  two in front, and third in back, I think that 3 steppers will be good choice because additional 2 steppers are needed for coreXY, and next 2 steppers for printing head (dual head)
    So it takes 7 steppers and it is hard to find electronics that could support 7 stepper drivers on the market to build the prototype fast.

    4 steppers in Z would make it even harder to build....

    Do you know any good electronics with 7 or 8 stepper drivers ?

  • RepetierRepetier
    Not sure what you want to do with accelerometer - firmware does not support them.

    For AVR boards the Azteeg X3 Pro supports 8 steppers + 2 with additional board.
    For Arduino Due the RADDS supports 6 motors + 2 with extension board.
  • erik23erik23
    Hi,

    a year later now: are the 4 steppers for z already implemented? Any docs to read somewhere about this?
    (Radds)
  • RepetierRepetier
    FEATURE_FOUR_ZSTEPPER allows moving z with 4 drivers. But all move identical. YOu can add them then as motor driver additionally to move them individually.
  • erik23erik23
    Question aimed more for the 3Motor - Autoleveling with 4 motors, but I already changed to a 4 Motor design imitating 3 Z Motors (two Motors synchron with a bar in between, bed attached to the middle of the bar). So I only have to manage the 3Z-Motors autolevelling setup.
  • RepetierRepetier
    For 4 motors we have currently no solution. Never got a printer to write and test that feature.
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