New Machine Build Programmable feasibility of dual Z-axis / Spindle CNC operation

Results 1 to 2 of 2

Thread: Programmable feasibility of dual Z-axis / Spindle CNC operation

  1. #1
    Member Eric1's Avatar
    Join Date
    Oct 2021

    Lightbulb Programmable feasibility of dual Z-axis / Spindle CNC operation


    I have an idea to upgrade my 3-axis CNC custom build to have an additional independent Z axis with another spindle directly behind (opposite) the existing Z-axis. The purpose of this additional Z axis would be to:

    1. extend my working area from 24" to around 40" (because I have a lot of unaccessed space that could be unlocked without modifying the X and Y stages at all)
    2. allow for bigger tooling, presumably er20, on the second spindle (my current spindle is er11 so only up to 1/4" shanks)
    3. increase production efficiency by (theoretically) 3d reliefing a large wood piece with both Z axes acting simultaneously, or one at a time.

    After briefly researching this configuration, I found it difficult to find many builds and experiences with this setup. Mechanically and electrically this can definitely be done but I am mostly concerned about the programmable feasibility of this setup.

    For example, I use vectric aspire to set up toolpaths and mach3 to run gcode. Assuming I have two independent Z axes with two independent spindles, how easy/difficult would it be to set up tool paths and set up mach3 to:

    1. run either spindle by itself
    2. run a job with one spindle running the first half, and the second spindle running the second half
    3. run two jobs with both spindles running simultaneously on separate jobs
    3. run a large job with both spindles running simultaneously on the same job

    Some general guidance and/or specific examples of mach3 solutions to this configuration are very welcome. Thank you so much for your time.

    Similar Threads:

  2. #2
    Join Date
    Nov 2013

    Default Re: Programmable feasibility of dual Z-axis / Spindle CNC operation

    I suspect Mach3 is not up to the task. In particular you might do 1). You could do 2) but not simultaneously.

    I used Mach3 years ago but for the last 8.5 years have used Mach4. Mach4 is vastly better for this sort of thing, but it too would be limited.
    It would do 1) and 2) consecutively, but not 3) or 4) or at least easily.

    The problem is synchronization. Mach4 has up to six axes which are coordinated. Thus, with some tricky dicky code you could have two three axis programs running simultaneously.
    In addition to the six coordinated axes you may have six out-of-band axes, all of which operate independently of the six coordinate axes.

    Lets say you try the 'two machine in one' approach. X,Y,Z will be the axis names of the first or primary machine, but A,B,C will be the axis names of the three linear axes of the second machine.
    A,B,C are usually reserved for rotary axes, but there is nothing to stop you from setting them up as linear axes. A snippet of code might look like this:

    g1 x20 y30 z5 a20 b30 c5
    g1 x30 y40 z10 a30 b40 c10

    So, this code would cause all six axes to move simultaneously where the X and A axes move identically, the Y and B axes move identically and so on.
    The question has to be asked 'even if I can get this machine to operate as if there are two independent three axis it practical to do so?'
    It would in effect mean you av to write all the code by hand, or perhaps write some sort of tricky dicky post processor. Is this something you want to do?


Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts


    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on

Our Brands

Programmable feasibility of dual Z-axis / Spindle CNC operation

Programmable feasibility of dual Z-axis / Spindle CNC operation