Firmware speed extrusion multiplier = f(target extrusion rate)
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Hi David,
Yes, I'm a bit disappointed with the results. To be clear, this was with a single filament using a single extruder. So my extruder should have been running at the same speed as yours (E3D Titan). It was with the 3 colour version (I swap between the 3 and the 5). So filament was loaded into the other two inputs, but the mixing ratio set to 1.00:0.00:0.00 so they would have been stationery.
I'm wondering if it's the nozzle size? Mine is 0.5mm what is yours?.
Alternatively, it could be the melt chamber size and\or be some interaction between them. My thinking is that although filament is loaded into the other two, some may ooze out of these chambers as the nozzle heats (there is certainly a lot that oozes out of the nozzle). This might then mean that the "unused" melt chambers aren't completely full and act as a buffer to absorb the pressure increase. I have no idea really. It seems plausible to me but I can only speculate.
No idea why increasing the extrusion multiplier didn't help. It could be as you say or it could be that there is some "grinding" of the filament or wear that reduces the diameter but doesn't produce visible flakes. Another possibility is that I've been running quite light extruder pressure lately. This is because firmware retraction of all filaments concurrently can wear any "unused" filament or those that run slowly. I'd have thought that slippage due to light extruder arm pressure ought to show up as visible "flaking" but you who knows?
I'd really love to graft a transducer into one of the inputs to measure the pressure and get some idea of what really happens inside the hot end. Unfortunately I don't have the resources (funds or otherwise) to do it.
If I get time, I'll repeat using all 3 or 5 filaments\extruders. This is going to be time consuming as I'll have to mark and measure all filaments then sum the results to get the total. But it will be interesting to see what happens and also if all 3 (or 5) extruders behave the same way or if there is any inconstancy between them.
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Im late to the party here . Loving the data points that the filament monitor allows to be recorded.
My question is this…
Does either non-linear extrusion or pressure advance do anything to retraction or do they just solely address this issue via speed and extrusion? Im no expert, but would increasing retraction as speed increases help at all? i could see Deckingman, who has issues with over extrusion during fast prints, wanting the opposite of linear extrusion.... can you supply negative values in the gcode? would linear retraction also be a valuable tool?
Do you think it would be possible to roughly quantify nozzle pressure by say....
doing a bunch of printing moves 1 layer high at a specific speed and then stopping the extruder but continue to move the print head in a line on the bed. My Im guessing you could get an idea of the relative nozzle pressure by the length of the line printed before the nozzle stops oozing.
Im looking forward to getting a filament monitor so that I can come to the data point party.
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Nonlinear extrusion and pressure advance are not applied to retraction, reprime and other non-printing moves. But pressure advance reduces the amount of retraction you need, because pressure advance reverses the filament movement before the end of the deceleration phase of a fast extruding move.
