Delta + linear Z tracking axis?

veryevil

Hi, I was wondering if it's possible to have a 5th motor which tracks the delta z position. (3 towers, 1 extruder, 1 linear Z)

I was planning on driving a rack and pinion to create a camera that tracks the nozzle so that on tall prints the camera is always on the current part of the print.

Also possibly looking at an extruder driven by the same means so that it moves up and down reducing the length of the Bowden tube.

Thanks
Steven

Veti

https://duet3d.dozuki.com/Wiki/Gcode#Section_M669_Set_kinematics_type_and_kinematics_parameters

See
9 = reserved for linear delta + Z axis

veryevil

@Veti Ah so there are plans for this but no one has implemented it yet?

Veti

you can specify additional axis, but i dont think they are automatically tracked.

see
https://forum.duet3d.com/topic/10413/video-of-delta-4th-additional-axis-sidekick-extruder

bartolomeus

@veryevil there are already some deltas built with a 4th axis for the extruder

Danal

Yes, this is available right now. Here's a post that links to video of it working:

https://forum.duet3d.com/topic/10413/video-of-delta-4th-additional-axis-sidekick-extruder/2

dc42

@veryevil said in Delta + linear Z tracking axis?:

Hi, I was wondering if it's possible to have a 5th motor which tracks the delta z position. (3 towers, 1 extruder, 1 linear Z)

I was planning on driving a rack and pinion to create a camera that tracks the nozzle so that on tall prints the camera is always on the current part of the print.

Configure a 4th delta tower and set it to have a very long rod length, then it will move almost entirely in sync with the Z height.

Also possibly looking at an extruder driven by the same means so that it moves up and down reducing the length of the Bowden tube.

Yes, see https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareDeltaPrinter#Section_Adding_additional_towers_to_carry_flying_extruders.

Quadcells

@veryevil said in Delta + linear Z tracking axis?:

Hi, I was wondering if it's possible to have a 5th motor which tracks the delta z position. (3 towers, 1 extruder, 1 linear Z)

I was planning on driving a rack and pinion to create a camera that tracks the nozzle so that on tall prints the camera is always on the current part of the print.

Also possibly looking at an extruder driven by the same means so that it moves up and down reducing the length of the Bowden tube.

Thanks
Steven

Hi, could you keep us informed on your progress with this idea of the camera tracking the print head. I am very interested and would love to implement this to my delta.

/quadcells

Quadcells

@dc42
What is a very long rod length?
My rods are 400mm, what should I make the rod length for the 4th tower which I will use for a camera.

/quadcells

dc42

@Quadcells said in Delta + linear Z tracking axis?:

@dc42
What is a very long rod length?
My rods are 400mm, what should I make the rod length for the 4th tower which I will use for a camera.

/quadcells

Try about 20x to 100x higher, so 8000mm to 40000mm. Test it very carefully, in case the maths overflows.

Quadcells

@dc42 said in Delta + linear Z tracking axis?:

@Quadcells said in Delta + linear Z tracking axis?:

@dc42
What is a very long rod length?
My rods are 400mm, what should I make the rod length for the 4th tower which I will use for a camera.

/quadcells

Try about 20x to 100x higher, so 8000mm to 40000mm. Test it very carefully, in case the maths overflows.

Wow, ok will do, could be a day or two to test it. Printing the extrusion supports now.
Thanks for your quick reply.
/quadcells

Quadcells

Hi,
A little confused about M669.
Since I am using the 4th tower for a camera to track the height of the effector and placing my 4th tower between the Z tower and Y tower. Do I need to use M669?
"You must specify the XY offsets of the extruder outputs on additional towers relative to machine centre in the M669 command, for example:
M669 X150 Y100
The M669 command must come after the M665 command."

This is my M665 line;
M665 R244.500 L400.970:400.970:400.970:8019.4 B150.0 H448.37 X-0.072 Y0.021 Z0.000

Quadcells

Hi,
Sorry for all the questions.
I would like to use E1 for the 4th tower stepper driver how do I map that drive, M584?

dc42

@Quadcells said in Delta + linear Z tracking axis?:

Hi,
A little confused about M669.
Since I am using the 4th tower for a camera to track the height of the effector and placing my 4th tower between the Z tower and Y tower. Do I need to use M669?

It may work without, but if in doubt I suggest you use X0 Y0.

dc42

@Quadcells said in Delta + linear Z tracking axis?:

Hi,
Sorry for all the questions.
I would like to use E1 for the 4th tower stepper driver how do I map that drive, M584?

Create a U axis for that drive as described at https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareDeltaPrinter#Section_Adding_additional_towers_to_carry_flying_extruders.

Quadcells

@dc42 Thank you.
I'll get back later after I try this out.

Munce31

@Quadcells very keen to see how this goes. Please let us know. Thanks.

Quadcells

@Munce31 I will. But it could take a few days. Trying to juggle work/home and hobbies can sometimes be difficult.

Quadcells

@Quadcells
I connect my 4th tower stepper to E1.
Connected the 4th tower endstop to E1 stop.
Added all lines of code for the 4th tower in confi.g.
Added lines of code for the 4th tower in homedelta.g

Nothing happened, the 4th stepper did move or make any noise. I must be missing something along the way. I will re-check again.

below is some config.g and homedelta.g code:

config.g:
M665 R244.500 L400.970:400.970:400.970:8019.4 B150.0 H448.37 X-0.072 Y0.021 Z0.000 ; Set delta radius, diagonal rod length, printable radius and homed height,4th rod length for camera is 20x more XYZ
M669 X0 Y0 ; specify the XY offsets of the extruder outputs on additional towers relative to machine centre. It may work without, but if in doubt I suggest you use X0 Y0.
M666 X-0.34 Y-0.31 Z0.66 tilt X0.00 Y0.00 ; Put your endstop adjustments here, or let auto calibration find them
; Drives
M584 X0 Y1 Z2 U4 E3 ; U4 is the 4th tower axis which is E1 stepper driver on the Duet Wifi board
M569 P0 S0 ; Drive 0 goes forwards, X tower stepper
M569 P1 S0 ; Drive 1 goes forwards, y tower stepper
M569 P2 S0 ; Drive 2 goes forwards, Z tower stepper
M569 P3 S0 ; Drive 3 goes forwards, E0 stepper
M569 P4 S0 ; Drive 4 goes forwards, 4th tower stepper
M350 X16 Y16 Z16 U16 E16 I1 ; Configure microstepping with interpolation
M92 X200 Y200 Z200 U200 E2787 ; Set steps per mm
M566 X1200 Y1200 Z1200 E40 ; Set maximum instantaneous speed changes (mm/min)
M203 X18000 Y18000 Z18000 E1200 ; Set maximum speeds (mm/min)
M201 X1000 Y1000 Z1000 E120 ; Set accelerations (mm/s^2)
M906 X1600 Y1600 Z1600 U1600 E500 I40 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout
; Endstops
M574 X2 Y2 Z2 U2 S1 ; Set active low endstops
M558 P5 R0.4 X0 Y0 Z0 H10 F1000 T6000 ; Set Z probe type to effector, the axes for which it is used and the dive height + speeds
G31 P100 X0 Y0 Z-0.333 ; Set Z probe trigger value, offset and trigger height
M557 R105 S20 ; Define mesh grid

homedelta.g:
;*** Slow homing has been configured. Change F180 to F1800 below when your configuration is working
G1 S1 X450 Y450 Z450 U450 F1400 ; move all towers to the high end stopping at the endstops (first pass)
G1 X-5 Y-5 Z-5 U-5 F1800 S2 ; go down a few mm
;*** Slow homing has been configured. Change F180 to F360 below when your configuration is working
G1 S1 X10 Y10 Z10 U10 F360 ; move all towers up once more (second pass)
G1 Z-5 F6000 ; move down a few mm so that the nozzle can be centred
G90 ; absolute positioning
G1 X0 Y0 F6000 ; move X+Y to the centre

dc42

You may need to put the M584 command before the M665 command, so that the U axis already exists when you specify the length of the rod to the U tower.