how should I proceed for this configuration

  • Hello everyone

    Hardware : Duet Ethernet.
    Firmware Version : RepRapFirmware for Duet 2 WiFi/Ethernet version 1.21 running on Duet Ethernet 1.02 or later.

    Here is the project that I am carrying out, the purpose of this one being to deposit a spiral on the rotary table. The shape will have only one layer of height that I would adapt according to need. My machine is of Cartesian type and you can see this in the config.g file. The operating principle of the machine will be the following, initially, the table will rotate at a constant speed with only the y-axis moving to give the spiral effect and once arrived at the end of the spiral, the table stops rotating and the X and Y-axes make the "Zig Zag" effect at the end.
    Here is a little diagram that will probably be more explicit than my explanations.



    I know that there is no slicer for this type of printing, but basically I wanted to know if it was possible to have the X and Y axes that would work when the plate is stopped and in the initial position and to have a rotary axis and how I should take to achieve that.
    I just need to declare a new axis in the config file with a general polar config?
    Or do I have to declare a new kinematics in the Motion file using an h and cpp file where we find 3 linear axes X,Y,Z and a rotary axis U(A)?

    Hoping to have been explicit and thanking you for reading the topic and your future answers.


  • administrators

    @mickaelf First question and apologies if I have missed something, but why do you need the rotating axis at all? A normal cartesian printer can print a spiral onto the build plate.

    That said if there are other details and you have to have the rotating axis then you may be able to work around having to do a hybrid polar/cartesian kinematics. I would start with the polar printer setup and get the spiral working correctly. "Y" would be the turntable (A in your diagram), X the primary linear axis (Y in your diagram). Then you can create another axis (U) to act as the other linear axis.

    I am not sure if you need to change mode between Cartesian and polar when you switch between the spiral and the zigzag or if you can write G1 Xn Un En etc to draw the ZigZag - something to test and @dc42 can advise. If you do need to change mode (using M669) you can switch between the modes between the two different print types. probably the easiest way to do this was if you define each print type as a different tool and then use the tool change macros to switch between them but once again @dc42 can confirm if this is the best way to do it.

  • administrators

    As Tony says, you have one more axis than you need. But if you want to keep that arrangement, another way is to keep the Cartesian configuration and treat the turntable as if it is an additional linear axis. Then the spiral part can be generated using a single line of GCode because it's just a synchronised move of the turntable with either X or Y.

  • Thank you very much for your answers.
    Indeed, this printer does not have much interest but I want to make the above spiral as quickly as possible without everything while keeping a good precision. So I told myself, certainly wrongly ☺ , that a rotary table might have been necessary for such a task.
    I will try to insert your methods and you will show the result if there is one. 😬

    Thanks again


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