Toolhead preheat prior to a tool change.



  • I was hoping for some sort of look ahead function during printing that will set the standby temperature to active on an inactive toolhead 'x' number of gcode lines ahead of the tool change 'T#' so as to cut down on print times waiting on the hotend to re heat during tool changes.


  • administrators

    We plan to implement this on Duet 3, by having 2 readers reading the same GCode file. Reader #1 will do the printing, while reader #2 will run in simulation mode and stay ahead, so that it can tell #1 in advance that a tool heater should be switched to active temperature, or (for a mixing extruder) that the mix should be changed.

    On Duet 2 there probably isn't enough RAM to do this easily, because of the additional DDAs needed to run a simulation in parallel with a real print.

    Cura has a facility to advance tool heating and I believe some users have it working with Duets



  • Why not just implement a pre-processor, more or less like the simulator, to add the heating G-Code lines? This is something one can do using a Python or Perl script, before sending the G-Code to the Duet, but it should not be difficult to implement it on the Duet itself, and should not need much RAM...


  • administrators

    @fma said in Toolhead preheat prior to a tool change.:

    Why not just implement a pre-processor, more or less like the simulator, to add the heating G-Code lines? This is something one can do using a Python or Perl script, before sending the G-Code to the Duet, but it should not be difficult to implement it on the Duet itself, and should not need much RAM...

    To handle forseeable cases such as needing to advance tool heating by 20 seconds when drawing curved perimeters that take 0.1 seconds per segment of the curve, you would need to buffer up to about 200 moves. That would need too much RAM to do it on the Duet.



  • Sorry, I was not clear: I was thinking the pre-processor to really pre-process the file, and add some lines to it (on the SD card) without printing. Then, just run the new file as usual...



  • Maybe it would be possible to write a simulator for DuetWebControl so it runs in a browser. This way you could prepare the g-code at upload time by using the computer resources



  • @fma said in Toolhead preheat prior to a tool change.:

    Sorry, I was not clear: I was thinking the pre-processor to really pre-process the file, and add some lines to it (on the SD card) without printing. Then, just run the new file as usual...

    That would do - I guess you are thinking of much the same way as I advance the tool change point in the gcode file for colour changes. As you say, a Python script or some such.


 

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