Part cooling Fan standby mode



  • I have an idex machine (quad to be precise, but no relevant) – I am having an issue when the unused extruder parks -- and the fan is on, it has trouble getting back up to temperature -- that is only an issue because it parks on specifically designed platforms with spring steel to prevent oozing -- it causes the part cooling fan air flow to bounce up cool off the nozzle. I red-did the temp tunning with fan on, but that results in an overly aggressive heat up parameters and during normal printing it triggers overheat errors. So what I need to do is be able to turn the fan off when the hotened parks. Best I could come up with is when the hotened parks it triggers an endstop (x end stop on it's side) and I can use the signal from that end stop to feed into a relay board and turn the + side off going to that fan. I'd rather no have a relay clicking, and rather not have to use a separate board to do this -- but there is nothing in the M106 command which would allow -- 1 to turn on a specific fan 2, turn it off and turn it back on to original setting -- I'd have to hard code fan specs in the tool change routines which I'd rather not do.
    Also because of an S3D bug, I had to tied all the fans together in firmware -- so for now M106 turns on/off all the part cooling fans, pending an S3D fix, or pending me writing a Gcode post processor.


  • administrators

    If you connect each print cooling fan to a separate fan output and use the fan mapping facility in the M563 tool definition, then only the fan in the currently-active tool will run.



  • @dc42:

    If you connect each print cooling fan to a separate fan output and use the fan mapping facility in the M563 tool definition, then only the fan in the currently-active tool will run.

    Just tried doing independent mapping, and it doesn't work as you say. Fan setting is sticky to the active tool. I set fan M106 S255. Switch tools, and fan keeps on spinning on the inactive tool, and I have to run M106 again on the active tool to turn the fan on, and I can't turn the fan off on the inactive tool. That is why I tied them all together in using M563.


  • administrators

    Have you tried turning off the fan on the tool that is becoming inactive in the tfree#.g file, quoting the fan number explicitly in the M106 P parameter?



  • @dc42:

    Have you tried turning off the fan on the tool that is becoming inactive in the tfree#.g file, quoting the fan number explicitly in the M106 P parameter?

    I can do that, but sorta defeats the purpose – how do I turn it back on to the previous value when the tool becomes active, consider that if I'm printing petg or pla, I'd have different active values defined by the slicer, I'd have to alter the tfree script for each print -- that's not practical.
    Also, unless this was newly added/fixed M106 P# S# doesn't do anything -- P# is ignored.
    I've wired the first fan into a relay so it no turns off when the tool parks -- it's mechanical, but it works. Please consider adding this to the firmware, M106 P only works to set temperature threshholds, not controlling a specific fan. Also please consider adding memory to active fan value, so when the tool becomes active it can resume the previous fan value.


  • administrators

    Doesn't the fan on the new active tool come up to speed automatically at the end of the tool change? That's what it is supposed to do.



  • @dc42:

    Doesn't the fan on the new active tool come up to speed automatically at the end of the tool change? That's what it is supposed to do.

    nope



  • @kazolar:

    @dc42:

    Doesn't the fan on the new active tool come up to speed automatically at the end of the tool change? That's what it is supposed to do.

    nope

    consider what happens – T0 is active
    M106 S200

    T1

    then you're saying tool change should do M106 P0 S0

    Ok, that works, then what sets it back to S200? S3D will have to be a lot smarter than it is now to turn the fan back on after a tool change


  • administrators

    The firmware is supposed to handle the change in the print cooling fan number(s) automatically when you change tool. I will test this.


  • administrators

    I just checked the code. It doesn't set the speed of the print cooling fan on the new head automatically, but it should do so if you include command M106 R2 in your tpost#.g file.

    [EDIT: changed R to R2 in the M106 command, because although just R works at present, future firmware versions may required R2.]



  • That worked. Thank you too bad I added a bunch of now unnecessary wires to track end stop triggers…oh well. This is much better. It does in fact hand over the fan setting off properly, now S3D fan bug is not as irritating.


  • administrators

    I've updated the IDEX wiki page to include this in the examples. I've suggested using just M106 S0 in the tfree#.g file to turn off the fan on the outgoing tool, so that the fan number needs to be defined only in the M563 command.

    The reason this works is that all the fan speeds are recorded at the very start of the tool change sequence. M106 R2 restores the speed of the "default" fan to the recorded value. Currently the same set of recorded fan speeds is used for both pause/resume and tool change, but just as pause/resume and tool change record different sets of head coordinates that can be recalled using R1 or R2 respectively in G1 commands, so I may use different sets for recording the fan speeds in future firmware.



  • I did the tfree#.g with M106 P0/2/4/6 S0 – and that works very well in conjunction with M106 R2 (that was the trick to restore/transfer fan setting between tools)This was a real annoyance since S3D doesn't issue M106 commands per tool, just per layer -- now that's no an issue anymore. Huge relief. Tool change is much faster without the part cooling fans blowing on the parking platform. I got a bit inpatient and broke out the trigger wires for the 4 axis to trigger relays - it actually worked, but obviously this is a lot better. I will repurpoose those breakout lines and maybe run some LEDs or something on the outside of the printer to indicate end stop hits. I don't use pause/resume, so this I believe is the last thing I needed to get my IQUEX? finished up... Thank you David. My YT build series should start soon -- the 6+ month build is nearly done.


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