How to completely eliminate Priming!
Someone over there at Prusa Research... PLEASE try this!!!
In PrusaSlicer, Printer Settings, Each Extruder... "Set Retraction when tool is Disabled" to the distance from the outer tip of the nozzle to right above the melt zone for each extruder. On my E3D Toolchanger that distance for the E3D V6 was 17mm. This rather long retraction pulls the material out of the melt zone which minimizes any drooling from the parked tool. Be sure to leave the Extra Length on restart to zero. I've tested it on both the E3D machine as well as a Mendel IDEX. With very small and very large prints. It has worked 100% of the time. No need for priming wipe towers. No need for any Ooze shields. No need for any priming at all. No wasted material. No wasted time. No impact on reliability and... no need to carefully monitor the machine! This really is a game changer!
RE: How to completely eliminate Priming!
How exactly is the molten, liquid filament being extracted….
I’m not doubting that a long retraction will reduce the drooling, and that there is a bit of a ‘suction’ going on, but I don’t think it is actually pulling the material like you think it is, unless you are getting it lower than its Tg/melt temp.
RE: How to completely eliminate Priming!
I do have one of the four extruders that seems to keep drooling while parked. However it’s a very small amount and the tiny amount gets wiped off by my bungee cord and pad wipe. The other three draw all the material up and out of the melt zone and they don’t drool at all. Not sure why that one extruder is doing that probably because of the material. Perhaps a small amount breaks off when retracted. On the idex I use nozzle blockers. I designed them for the Tenlog TLD3 IDEX;
https://www.thingiverse.com/thing:5696424
i also designed an equivalent for the toolchanger, but it inhibited movement while parking and you don’t want to do that on a toolchanger. It makes for tool accidents.