Calibrating Parking Spot Position

To calibrate a parking spot, we first need to find out the coordinates of the parking spot. We can either do this for an already attached parking spot, by carefully homing in on its position, or we can define the parking spot position (in the X-direction) attaching it in the process.

For both procedures, first home all axis. Then take the corresponding tool for the parking spot and hold it up to the tool changer. Press the “Couple - Lock” macro. The tool should now be attached to the tool head.

Carefully move the tool to the parking spot location using the move buttons in the dashboard of the duet web interface. I you have not attached your parking spot to the frame yet, you can also slot the tool into the parking spot and slowly move up to the back of the printer. When apporoaching the Y-limit, move in smaller increments, until you are satisfied with the position. Note down the X and Y coordinates in the top left of the duet web interface dashboard.

Fasten the parking spot if it was loose and select the “coupler - unlock” macro. Move the tool head out in the minus Y direction.

Danger

Do not move further to the back (positive Y) and do not move in X-direction!

We will now edit the corresponting tfree.g, and tpre.g files, found in the “system” tab in the duet web interface. Always work on the respective .g file. If you are working on tool 0 the .g files are tfree0.g, tpre0.g and tpost0.g.

tfree.g

G91                   ;Relative positioning
G1 Z5 F1000           ;Lower bed
G90                   ;Absolute positioning

G10 P0 X0 Y0 Z-5.9    ;Set offset back to 0

G1 X13 Y293 F30000    ;Move in front of parking spot to avoid collision
G91                   ;Relative positioning
G1 Y30 F30000         ;Move in quickly
G1 Y40 F5000          ;Move in slower
G90                   ;Absolute positioning

M98 P"/macros/Coupler - Unlock"   ;Open Coupler
M106 P1 S0            ;Turn off the fan

G91                   ;Relative positioning
G1 Y-20 F2000         ;Move out slowly
G1 Y-20 F6000         ;Move out quickly
G90                   ;Absolute positioning

M566 X400.00 Y400.00 Z6.00 C2 E120.00:120.00:120.00:120.00 P1               ; set maximum instantaneous speed changes (mm/min)
M203 X20800.00 Y20800.00 Z1000.00 C15000 E3600.00:3600.00:3600.00:3600.00   ; set maximum speeds (mm/min)
M201 X3000.00 Y3000.00 Z100.00 C500 E3600.00:3600.00:3600.00:3600.00        ; set accelerations (mm/s^2)

Changes

In the line “Move in front of parking spot to avoid collision” enter the X-coordinate you noted dwon, and the Y-coordinate minus 70. If you enter the Y-coordinate you noted down the printer will crash trying to park the tool!

tpre.g

G1 X13 Y323 F15000        ;Move in front of Tool Location
G91                       ;Relative positioning
G1 Y20 F5000              ;Quickly move into Tool
G1 Y20 F3000              ;Slowly close the gap
G90                       ;Absolute positioning

M98 P"/macros/Coupler - Lock"   ;Close Coupler

M566 X100.00 Y100.00 Z6.00 C2 E120.00:120.00:120.00:120.00 P1               ; set maximum instantaneous speed changes (mm/min)
M203 X18000.00 Y18000.00 Z1000.00 C15000 E3600.00:3600.00:3600.00:3600.00   ; set maximum speeds (mm/min)
M201 X3000.00 Y3000.00 Z100.00 C500 E3600.00:3600.00:3600.00:3600.00        ; set accelerations (mm/s^2)

G91             ;Relative positioning
G1 Z10 F1000    ;Move bed out of the way
G1 Y-40 F6000   ;Move out
G90             ;Absolute positioning

Changes

In the line “Move in front of Tool Location” enter the X-coordinate you noted dwon, and the Y-coordinate minus 40. If you enter the Y-coordinate you noted down the printer will crash trying to pick up the tool!

Try the first tool change with the bed lowered, so it does not collide with the tools and with your mouse hovering over the emergency stop.