Simplify3D Tool change retraction

Discussion in 'Getting Started' started by Andy Cohen, Feb 16, 2020.

  1. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    217
    Likes Received:
    57
    So here's one to watch for.
    If the Tool Change retraction in the "Other" tab is set to retract AND you are using a Prime/purge and a wipe you can get a blob at the start of your tool path which you do not want!
    The tool retraction happens right before the "T" command, and the tool is parked, then a tool is picked up, purge/prime/wipe, then the gcode continues but starts with the reverse of the retraction which at this point is not what you want because you have material at the hotend ready to extrude. The hotend is over the previous layer and then extrudes the reverse of the Tool Retraction right on to your object.

    So... if you are using a purge/prime you probably want to set Tool Retraction Distance to 0.
     
  2. Nibbels

    Nibbels Well-Known Member

    Joined:
    Dec 12, 2019
    Messages:
    165
    Likes Received:
    32
    Did you try hardware retraction?

    I reconfigured this just yesterday. So simplify3D replaces the "special" retraction codes by
    {REPLACE "G1 E-1.0000 F39960" "G10"}
    {REPLACE "G1 E0.0000 F39960" "G11"}
    And my filament profiles config.g's have the
    M207 S1.0 F2400 Z0.075 ; Hardware Retract length
    included. Thus I set the retraction according to the loaded filament and my gcodes are more transferable.

    My question actually is, whether the G11 works independendly from G92 Ex.xx
    I will check this myself if nobody knows this out of memory. But It this test has to wait on my side because of other problems I still resolve.
     
  3. dc42

    dc42 Well-Known Member

    Joined:
    Aug 16, 2016
    Messages:
    458
    Likes Received:
    206
    Yes it does. But we recommend that you generate GCode using relative extrusion, then there are no G92 Ex.xx commands anyway.
     
    Nibbels likes this.
  4. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    217
    Likes Received:
    57
    So setting Tool Change Retraction Distance to 0 actually had a negative effect. The regular retraction setting does nothing on a tool change. As such I get stringing at the end of the tool path. So next I'll set the Tool change retraction distance to the same as my regular retraction distance (1.5... Nimble's not Titans), but set the Tool Change Extra Restart to the negative of the Tool Change retraction distance to ensure it does not spit out material prior to the start of the tool path.
     
    pmyrie likes this.
  5. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    217
    Likes Received:
    57
    I put the Retraction Distance to my typical for the Nimble's (1.75mm), and set the "extra restart" to 0. Why S3D calls it "Extra" is beyond me. It worked as I wanted it to. A proper retraction at the end of the tool path before the tool change and no restart extrusion at the start of the tool path, i.e., after a purge/prime.

    BTW, in S3D this can be coupled to a profile, not to mention a factory file. Which means I have predefined setups for each material.
     
  6. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    Hey Andy, I am working on TC unretraction as well. I dont have a tool changer but a IDEX I designed, also using Nimbles.

    The TC retract will retract at the tool change with the current tool to elevate stringing. This distance will later unretract when the tool is called. Extra restart distance is extra distance that is not retracted but is added to the unretract. This is useful if you have a wipe in your tpost and you want to retract more after the wipe.

    The issue I am running into is that RRF runs TC at the first time it sees a tool change, but S3D does not unretract or apply the extra restart until after a tool is used and then recalled, so that messes up the retract on the first TC to your second tool. I cant think of a way around this yet expect maybe pull my TC script out of the firmware and put it into S3D script, manual edit the G-code, or run a skirt with all extruders. I have not got it to worked out yet.
     
  7. dc42

    dc42 Well-Known Member

    Joined:
    Aug 16, 2016
    Messages:
    458
    Likes Received:
    206
    Why not do the unretract/extra reprime in the tpost file instead of relying on S3D to do it?
     
    Michael Pearson likes this.
  8. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    So put the TC retraction in Tfree, and the unretract in Tpost. I guess that would work only downside is if you get oozing from the wipe to the start of your print. I'll give it a try and see how it works out for me.
     
  9. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    Tried it, too much oozing from the wipe to the start of the print. I guess I could call a G60 in the tfree and recall it at the tpost to get closer to the print before the unretract to limit the oozing.
     
  10. dc42

    dc42 Well-Known Member

    Joined:
    Aug 16, 2016
    Messages:
    458
    Likes Received:
    206
    How about changing tpost to wait for temperature, wipe, retract, move to 1mm above print (G1 R2 X0 Y0 Z1), and unretract?
     
  11. Jonas

    Jonas Well-Known Member

    Joined:
    Sep 4, 2015
    Messages:
    71
    Likes Received:
    31
    I use tfree/tpost to do the retract/unretract.
    Then print with a prime pillar. It’s good enough for me.
     
  12. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    Oh, now I see the G60 is not needed because it save the position in S2 when it does the tool change. Giving it a try!
     
  13. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    Good suggestion! A prime pillar seems like cheating but I'm not saying I'm not going to try it.... At least for things with really quick filament changes.
     
  14. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    Jonas, After seeing how much filament I am wasting from the wipe, the purge tower idea does not seem like such a waist. It can be pretty small, just a little extra time. I'll give it a try.
     
  15. Jonas

    Jonas Well-Known Member

    Joined:
    Sep 4, 2015
    Messages:
    71
    Likes Received:
    31
    I use a small prime pillar for a multi tool print and a skirt for a single tool print. :)
     
  16. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    I agree, I think this might be the best method as it creates the correct pressure and temperature in the hotend right before printing.

    Right now I'm having a issue with blobs right after a tool change that knocks over the purge block. Currently I'm retracting 5mm tfree, and not unretracting anything in tpost because otherwise I get a blob right at the start. I'm assuming this is because of oozing since there is still filament in the hotside of the heat break.

    Maybe I'm thinking of this all wrong. Is the idea to retract the filament all the way to the cold side of the hotend? So the retraction in tfree would be more like 20-25mm. I'm going to try this next, it just seems wrong to retract the filament all the way into the cold side of the heat break.
     
  17. Jonas

    Jonas Well-Known Member

    Joined:
    Sep 4, 2015
    Messages:
    71
    Likes Received:
    31
    I retract/unretract 17mm. I have 4 Hemeras.
     
  18. 3D Printing World

    Joined:
    Mar 27, 2020
    Messages:
    8
    Likes Received:
    0
    Yep, I'm having much better luck with 20mm of retraction. I can now unretract almost all the way without any blobs. The next problem was my prime pillar was over extruding and was getting knocked over. Flow rate calculated and I am pretty happy with it so I found a scrip to reduce the flow rate for just the pillar. Now hopefully the last problem, one nozzle is oozing the other is not. Not sure why they act so differently. I also need to unretract them differently.
     

Share This Page