Toolchange movements, coordinate space

  • Most likely this has already been explained here and I'm just not smart enough to find it …

    Anyway, I created the Mark2 magnetic tool changer for the Ultimaker2. Now it's time to add a third head. For doing this we might replace Ultimaker electronics and our customized firmware by Duet3D. Like before offsets and tool changes should be handled within the firmware. We actually attach and detach head 2 or 3, with a z offset, while the standard head always remains in place. Extra heads are parked in two corners.

    So, what coordinate space I'm in when e.g. switching from T1 to T0? In other words, do I have to adjust the docking position within tfree1.g using the T1 offsets?

  • administrators

    Hi Marcus, I really like the magnetic tool changer work you guys have done (for the benefit of others on this forum who may not be familiar with it can you link a good video?)

    David will confirm, however each tool has an offset defined by the G10 command when that tool is setup. So your primary tool, on the extruder could be X0,Y0,Z0 and each of the other tools might be X0, Y40, Z-1 and X0,Y-40, Z-1 or whatever. I don't think you have another co-ordinate space on tool change because you are still in the X,Y,Z co-ordinate system, just with tool offsets. The Idex is a bit different when you have another axis and you shift to a U axis.

    Try this:
    In Tfree1.g
    G90 ;Absolute axis movements (should be in that already but just to confirm)
    G1 Xnn,Ynn,Znn Fnnnnn; Move to whatever position you need to be to start to park T1
    G1 Xnn,Ynn,Znn Fnnnnn; finish the parking. (do you have some electromagnet to turn on/off?

    Then in Tpre1.g you would have the pickup code for T1

    Same for T2.

    For T0 presumably you need no Tpre code (as its always present) and no TFree code (because retract is probably better handled by the slicer).



  • administrators

    In tfree the coordinate space of the old tool is used. In tpre the head reference point is used. In tpost the coordinate space of the new tool is used.

  • Hi guys,
    Thanks for the fast reponse.

    Videos about the Ultimaker toolchanger project can be found here:


Looks like your connection to Duet3D was lost, please wait while we try to reconnect.