Delta with 4th axis for extruder

  • I recently installed the 4th axis for the extruder on my delta printer.
    DuetWifi with Firmware 2.05.1
    See it in action (2min30):

  • administrators

    Thanks for sharing!

  • I like it. I need to do this to my big delta, and reduce the current 1.1 meter bowden to a few cm.


  • Moderator

    @AndreS nice! Can you share your config.g and homedelta.g files?


  • homedelta.g

    ; Homing file for RepRapFirmware on Mini Kossel
    G91				; use relative positioning
    M584 P4				; unhide 4th axis
    ;******* Change 320 in the following to a higher value if your Kossel has taller towers
    G1 H1 X340 Y340 Z340 U340 F2000	; move all carriages up 320mm, stopping at the endstops
    G1 H2 X-3 Y-3 Z-3 U-3		; move all carriages down 3mm
    G1 H1 X6 Y6 Z6 U6 F150		; move carriages slowly up 6mm, stopping at the endstops
    M584 P3				; hide 4th axis
    G1 Z-5 F2000			; down a few mm so that we can centre the head
    G90				; back to absolute positioning
    G1 X0 Y0 F2000			; centre the head and set a reasonable feed rate

    Relevant parts in config.g

    ; Axis and motor configuration
    M569 P0 S1				; Drive 0 direction
    M569 P1 S1				; Drive 1 direction
    M569 P2 S1				; Drive 2 direction
    M569 P3 S0				; Drive 3 direction (Extruder)
    M569 P4 S0				; Drive 4 direction (4th axis)
    M574 X2 Y2 Z2 S1			; set endstop configuration (all endstops at high end, active high)
    M584 X0 Y1 Z2 U4 E3			; create axes
    M574 U2 S0				; 4th axis endstop, high end, active low, connect to E0stop
    M665 L215.000:215.000:215.000:130 R101.791 H221.788 B85.0 X0.131 Y0.014 Z0.000
    M666 X-0.380 Y0.336 Z0.044 A0.00 B0.00
    M669 X-22 Y0				; position of extruder pivot mount relative to machine center
    M350 X16 Y16 Z16 U16 E16 I1		; Set 16x microstepping with interpolation
    M92 X80 Y80 Z80	U400 E412		; Set axis steps/mm
    M906 X1000 Y1000 Z1000 U1000 E750 I60	; Set motor currents (mA) and increase idle current to 60%
    M201 X800 Y800 Z800 U400 E2000		; Accelerations (mm/s^2) E1000
    M203 X20000 Y20000 Z20000 U3000 E7200	; Maximum speeds (mm/min)
    M566 X800 Y800 Z800 U500 E2400		; Maximum instant speed changes mm/minute E1200
    M208 S1 Z0.0				; set minimum Z
    M208 U0:500				;  set travel of 4th axis
    M584 P3					; hide 4th axis
    T0					; select first hot end

    I had to play with the value of rod length of 4th axis in M665 (its a bit more than the tubes length) and offset value in M669 (its less than actual) so that the bowden tube stays how I want it.

    Hope it helps.

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