Switch between FFF and CNC



  • Hello,

    as E3D released the ASMBL tool, I want to know if it is possible to switch between CNC and FFF during a print.

    And what I have to consider?



  • afaik e3d is using duets for their motion system; so possible yes.

    i'd look closer at https://github.com/AndyEveritt/ASMBL for the details on the produced g-code



  • @bearer I know how the create codes. The question is if I can switch to CNC mode during a job is running.
    The alternative is, that I just control the motor true a pwm manually. E3D don't tell how they handle it in the firmware

    As soon you define a Spindle with M453 the firmware automatically switches to CNC Mode



  • its all open source https://github.com/e3donline/RepRapFirmware-SD e3d doesn't have any special firmware for the tool changer.

    i.e. the fusion plugin would show how/if they switch beween fff and cnd mode or not, might not be neccecary for their use.



  • @bearer On this source it is just FFF. Nothing about CNC.

    The gcode generated with fusion just call a tool like for any other print T0, T1 and so on.

    So everything is handled by the firmware.

    The main question is, what does the firmware in the background if I switch to CNC Mode. Is it clearing some offset, resetting stored coordinates, expecting another gcode flavor?



  • main difference is G0 are travel moves which goes full speed while G1 are work moves which travel at the set feed rate.

    m452 doesn't define a spindle, it selects cnc mode (and sets up the spindle as part of that, as opposed to the other way around).

    seems you should be able to just put m451, m452 and m453 in the tool change macros and set any offsets there.



  • @bearer said in Switch between FFF and CNC:

    main difference is G0 are travel moves which goes full speed while G1 are work moves which travel at the set feed rate.

    m452 doesn't define a spindle, it selects cnc mode (and sets up the spindle as part of that, as opposed to the other way around).

    seems you should be able to just put m451, m452 and m453 in the tool change macros and set any offsets there.

    With M453 you define a spindle!
    https://duet3d.dozuki.com/Wiki/Gcode#Section_M453_Select_CNC_Device_Mode

    It defines with PWM is need to get a specific rotation speed, which pins the tool have and so on 😉



  • I was wondering the same thing and looked at the config + macros posted by Greg Holloway on thingiverse (config is at the bottom):

    https://www.thingiverse.com/thing:4206827/files

    M453 doesn't seem to be used anywhere in his config.g or macros.

    From the Tool 3 macros, I think Greg just uses a PWM fan output to set the spindle RPM.


    This recent thread was requesting extra functionality for integrating a VFD
    https://forum.duet3d.com/topic/18039/vfd-integration-m3-m4-m5-macros-and-rpm-measurement?_=1599601459470

    So maybe this is another future advantage (?) for using CNC mode.

    I don't see why you couldn't switch into CNC mode for subtractive tools and back to FFF mode for additive, but I don't know what other advantage there may be.

    Hopefully someone has insight?



  • @jpomo10 Oh I didn't noticed that he attached a config to thingiverse.

    I he is directly controlling the digital pin for PWM with M42



  • @smoki3 Here's the tpost3.g to turn the spindle on:

    ; tpost3.g
    ; called after tool 3 has been selected
    
    ;ASMBL on
    M280 P7 S80
    
    ;mesh levelling on
    G29 S1
    

    and the tfree3.g to turn the spindle off:

    ; tfree3.g
    ; called when tool 3 is freed
    
    ;Drop the bed
    G91
    G1 Z4 F1000
    G90
    
    ;mesh levelling off
    G29 S2
    
    ;Drop the brush
    G1 A45 B45 F5000
    
    ;ASMBL off
    M280 P7 S40
    
    ;Move In
    G53 G1 X304 Y150 F50000
    G53 G1 X304 Y180 F50000
    G53 G1 X304 Y230 F50000
    G53 G1 X304 Y243.5 F5000
    
    ;Take a Photo
    M98 P/macros/Camera
    
    M106 P0 S0
    
    ;Open Coupler
    M98 P/macros/Coupler - Unlock
    
    ;Move Out
    G53 G1 X304 Y150 F50000
    
    
    


  • @jpomo10 you are able to control the pin with M42 and M280.

    But I will go for CNC Mode that I am able to set directly the turns per minute instead of the PWM signal


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