Need Full Retraction When Print Is Complete



  • I did some searching and not sure I have this right. Could someone confirm that the following lines of code inserted into S3D will retract the filament out of my Mosquito hotend:

    M83
    G1 E-23 F300
    M84

    Slice Engineering told me that I should do a complete retraction after my print is complete to help with jams. I measured the length need to pull the filament out of the Mosquito heat-break, 23mm is what I measured from tip of nozzle to top of the Mosquito heat-break. Also is 300 a good speed to retract or should I change that too.



  • if they recommend this, should they not also recommend the distance for a complete retraction?


  • administrators

    I suggest you ask the manufacturers of the Mosquito. With all-metal hot ends such as the E3Dv6, if you print PLA and you try to retract all of the filament out of the hot end when it is at printing temperature, this more or less guarantees that it will jam.



  • @quadcells If you've measured it at 23 mm then I'd be inclined to use a fair bit more retraction than that - just to be sure it's all pulled out. As others have said, it is a bit unusual to retract all the filament but then the Mosquito hot end is a bit special.

    Speed wise, that's likely to depend on the filament. So is the temperature of the filament I'd have thought. Ask Spice Engineering but I'd have thought that you ought to drop the temperature to something like the glass transition temperature before pulling it all out.

    I'd be interested to know how you get on with that hot end - it looks very interesting (although a bit on the pricey side).



  • I emailed Dan at Slice Engineering and he said that the Mosquito is different than most all metal hotends and best practices is to have full retraction when the print is finished. I'll try and see what happens.



  • @quadcells said in Need Full Retraction When Print Is Complete:

    I emailed Dan at Slice Engineering and he said that the Mosquito is different than most all metal hotends and best practices is to have full retraction when the print is finished. I'll try and see what happens.

    Did he elaborate on what temperature (if other than normal print temperature) to use when retracting all the filament? Also feed rate (speed)? In general terms (and with a "normal" hot end) it's usual to retract the filament quite slowly so that the molten part gets pulled out too. If the speed is too high, it can pull the molten part out into a thin string which breaks so leaving some of the filament behind. But the Mosquito isn't like a "normal" hot end so things might be different.....

    Edit. Getting back to your OP, I'd suggest a bit more than 23 mm to be sure that you retract it fully out of the hot end but not so much that it will pull it into the extruder. I'd have thought that 300mm/min (5mm/sec) would be acceptable (but Slice Engineering might should be able to tell you what works best).


  • administrators

    It's also usual to retract all the filament at a lower temperature. For example, to retract PLA from the hot end, I heat it to about 110C, retract 30mm very slowly, then i can retract the rest quickly.


 

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