No per tool downward fan control

Discussion in 'Tool heads & ToolChanger' started by Andy Cohen, May 29, 2020.

  1. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    216
    Likes Received:
    55
    I like to print in PETG and use PLA for my dense support... but I recently got a heater fault which I believe was caused by the cooling fan blowing air into the object which then directed the air back to the nozzle. I realized that the cooling fan was on and at 100% for the PETG tool. Not at all what I wanted. But it seems ... at least with S3D... that you cannot control the downward fan per tool. It's whatever the setting is and it goes to all the tools.
    Is this just mine and my use of S3d or is this controllable using another slicer???

    Edit:
    DOH! Forgot about the fan control line in the tpost files!
     
    #1 Andy Cohen, May 29, 2020
    Last edited: May 29, 2020
  2. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    216
    Likes Received:
    55
    But... still S3D does NOT generate the M106 P(x) S255 per tool. Instead it does a M106 S255 once or twice across all the gcode. The only way I see to control the downward fan per tool is by setting the gcode in the tpost file for the tool.
    Do other slicers do it????
     
  3. Krayn

    Krayn Well-Known Member

    Joined:
    Aug 11, 2019
    Messages:
    48
    Likes Received:
    11
    Not as far as I'm aware. You could probably fix it in S3D in the scripting tab but IMO you don't really need it. PrusaSlicer does the same thing, it throws out a generic fan control command. Duet seems to handle it properly though and only applies the fan control to the currently selected tool and has the ability to recall fan speed if you want to turn off the PCF during idle time. I just ensure that all fan speed commands are done AFTER a tool is selected, something that PrusaSlicer doesn't do properly but is trivially easy to flip the lines with a python script.

    Recently I have been leaving the PCF fan on during idle, it makes keeping a consistent temperature easier if you don't keep turning the PCF on an off for prints that don't have a ton of tool downtime.
     
  4. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    216
    Likes Received:
    55
    Actually you may really need it. One of my typical use cases for the TC is printing the object in PETg and using PLA for CAD generated support objects. It makes perfect bridge undersides.
    Ah well... fahgetabout S3D fixing it.
    So the only way we can actually control it per tool is in the tpost files. As such if one tool is PETG I rem out the fan gcode for that tools' tpost file or perhaps least set the speed down.
     
  5. Krayn

    Krayn Well-Known Member

    Joined:
    Aug 11, 2019
    Messages:
    48
    Likes Received:
    11
    Yeah, I have a prusa slicer profile for exactly this scenario. Prusa Slicer gives off a fan speed per tool swap so its a bit easier in this respect.

    I have printed this using PETG and PLA as support material: [​IMG]
    Prusa slicer's fan control gcode looks like this:

    Code:
    T0 ;Change to PLA hotned
    M106 S252.45 ;Set fan speed to just under 100%
    G10 P0 S215 R215 ; Set Active and standby temps to 215 (This is to minimize toolswap time for this current profile which has very little downtime while tool is in use)
    M116 P0 S5 ;Wait for tool to be within 5c of temp
    M98 Pprime0.g ;Tool specific prime procedure

    Code:
    T1 ;Change to PETG hotend
    M106 S127.5 ; Set Fan speed to 50%
    G10 P1 S240 R240 ; Set Active and standby to 240c
    M116 P1 S5 ; Wait for temp to be within 5C
    M98 Pprime1.g ;Tool specific prime
    
    Notice how my M106 fan speed commands are completely generic, but I can confirm that at least for me on Duet FW 2.05.1 generic fan speed gcodes only apply to the selected tool and not to any tools not currently in use. I'm not sure why your M106s are applying to all tools.


    --- Specific to your situation---
    You should be able to recall fan speed that was set for this tool previously using M106 R2. You can turn off your fans in Pfree and turn them on in Ppost. So at no point do you actually need "tool specific" M106 commands, you just need to have your fan speeds recalled after a toolswap.
     
  6. bcprint3d

    bcprint3d Member

    Joined:
    Mar 8, 2020
    Messages:
    4
    Likes Received:
    2
    With the default configuration, control of the PCF requires the P(x) parameter. If you add an F parameter to your M563 lines in the config file, that will allow M106 to control the fan on the active tool. You should then be able to change the M106 in the Tpost to M106 R2. This will turn the fan on at the speed set the last time M106 was called without a P parameter.

    See here for the post about altering M563 in the config file:
    https://forum.e3d-online.com/threads/omnibus-list-of-configuration-changes-i-needed.3535/

    See here for altering the tpost:
    https://github.com/e3donline/RepRapFirmware-SD/pull/6
    and
    https://duet3d.dozuki.com/Wiki/Gcode#Section_M106_Fan_On
     
    Rene likes this.

Share This Page