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Answered Retraction Formula

Discussion in 'Troubleshooting' started by Drmike, Apr 8, 2016.

  1. Drmike

    Drmike Member

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    I've successfully got my object to print with my own gcode, but I have lots of blobs getting in the way. I realize I need to add retraction before I move, but I'm wondering if there are any useful formulas that will help. Right now I am using t-glase, and Taulman recommends a 1.5 multiplier on the length to get good flow. The ratio of translation is <area nozzle> / <area filament> * 1.5, but that is for length of travel. Is there a way to compute retraction distance, or is experiment and see what happens the only real way to tell?

    Dr. mike
     
    #1 Drmike, Apr 8, 2016
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    E3D says that retraction should never exceed half the length of the brass nozzle (actually they recommend even less about 3 mm total). There is firmware retraction built into Marlin, it is not enabled by default. Retraction will vary depending on the filament used and the temperature extruded, so I am not sure there is a hard and fast formula you could apply or even want to apply. It is usually determined by trial and error.
     
    #2 WheresWaldo, Apr 9, 2016
  3. Drmike

    Drmike Member

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    I was afraid of that. I bet someone could earn a PhD figuring out a formula based on material, temperature, extruder pressure etc, etc. Thanks! I will go play with my toys now :)
     
    #3 Drmike, Apr 9, 2016

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