Direct Drive, Bowden, or Remote Drive… oh my!
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I too use KissSlicer but my personal experience is that pressure advance has given me better results. Using the tuning wizards in KISS my "best" setting for preload was essentially 0; however I was able to tune pressure advance to produce very consistent extrusion. So I just run my PA tuning script on every filament at my average temp for that filament and then load my tuned PA command into the MATL GCODE tab in KISS. My machine prefix script sends this command, along with whatever acceleration settings I have set for the printer to RRF before it starts each print.
I agree 4mm is too much, was mostly posting that for reference, however you may have just explained why on my ooze tests I started seeing stringing again at about 3mm retraction LOL.
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Isn't stringing more to do with too low travel speed coupled with too high hotend temp?
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With the short retraction distances of RDD extruders, the peak retraction speed is likely be acceleration limited. So a high ratio of torque to rotor inertia is desirable.
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Thanks! Can you provide what motor you are using, or the specs for it?
https://www.omc-stepperonline.com/hybrid-stepper-motor/nema-17-bipolar-18deg-13ncm-184ozin-1a-35v-42x42x20mm-4-wires-17hs08-1004s.html - that's exactly the one I'm using. Smaller one is better because you don't need all that torque with the gearing on RDD, and the lighter rotor is easier to move.
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The peak retraction speed is very much acceleration limited and I'm am quite dubious they achieve the speeds people think they do. Easy enough to test send M207 Fx and vary their retraction increasing gradually the speed. At some point the motor will cease to turn any faster. At this stage you have to nudge the acceleration up to get it to go faster an you may stall. This presumes firmware retract is in use.
David if running at speed 200% are retracts and unretracts performed faster also? If so you'll need to leave yourself some headroom when tuning the extruder, in case you want to go a bit faster when printing.
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If running at 200% speed then retracts/unretracts specified in the GCode using G0/G1 commands will be speeded up, but not firmware retraction commands.
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Hi Msquared,
I perhaps misread your question, (synapses misfiring??). taking it as being one about print speed, as opposed to retraction speed (thought it odd). Regarding email, send again (or use contact form on website) and I should receive it, there were some (unusual) site issues toward end of last year.
re motors: Whilst motor spec is important, with the wrong order of tuning steps, an "optimal motor" will perform far below a less optimal motor tuned correctly. I have had large (long can) NEMA17s performing just as well as small NEMA14s and most others that are in between. Avoid very high inductance motors though, and use only 1.8 degree step angle type. 24v system voltage can be beneficial. Of greater importance however is the tuning. This goes from choice of microstepping, motor current and jerk set to a minimum, then dialling in on accels (in fw) and speed (in slicer).
This is simplfied but preferring to keep short on here. Ping me a message and I can assist in greater depth.
J
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If running at 200% speed then retracts/unretracts specified in the GCode using G0/G1 commands will be speeded up, but not firmware retraction commands.
Another sound reason to use firmware retraction.
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Does anyone have a good script to convert KISS's software retraction into hardware retraction? If not I am going to write one in Node.JS and I will share it here.
Why doesn't KISS support hardware retraction!? It's really interesting to me what slicers will do and what they don't. To me firmware retraction seems like the kind of feature that could be implemented in about an hour for pretty much any slicer.
SMH.
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Isn't stringing more to do with too low travel speed coupled with too high hotend temp?
Generally yes. I feel it is a combination of a few factors. travel speed, temperature, latent nozzle pressure, and retraction (one of the many ways we attempt to solve that last issue). As I am sure you already know most of the retraction / ooze tuning suggestions out there use 3 - 4 models placed at varying distances to create different travel speeds, etc. What I was noticing is that when using KISS to tune retraction distance (KISS has a tuning wizard that increases a variable every layer so that you can tune a parameter based on Z) there was a sweet spot where there was no oozing or stringing but as the retraction distance got higher the stringing / oozing came back. The filament breaking and not being retracted properly would account for this behavior which I otherwise found slightly puzzling.
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Hi Msquared,
I perhaps misread your question, (synapses misfiring??). taking it as being one about print speed, as opposed to retraction speed (thought it odd). Regarding email, send again (or use contact form on website) and I should receive it, there were some (unusual) site issues toward end of last year.
re motors: Whilst motor spec is important, with the wrong order of tuning steps, an "optimal motor" will perform far below a less optimal motor tuned correctly. I have had large (long can) NEMA17s performing just as well as small NEMA14s and most others that are in between. Avoid very high inductance motors though, and use only 1.8 degree step angle type. 24v system voltage can be beneficial. Of greater importance however is the tuning. This goes from choice of microstepping, motor current and jerk set to a minimum, then dialling in on accels (in fw) and speed (in slicer).
This is simplfied but preferring to keep short on here. Ping me a message and I can assist in greater depth.
J
Thanks Jason, will do
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Does anyone have a good script to convert KISS's software retraction into hardware retraction? If not I am going to write one in Node.JS and I will share it here.
Why doesn't KISS support hardware retraction!? It's really interesting to me what slicers will do and what they don't. To me firmware retraction seems like the kind of feature that could be implemented in about an hour for pretty much any slicer.
SMH.
I've not used KISS before, is it open source, can you put in an issue in github? I've found most 3d printer firmware teams very responsive to sensible ideas. Failing that other slicers are available many of which can do firmware retraction.
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Does anyone have a good script to convert KISS's software retraction into hardware retraction? If not I am going to write one in Node.JS and I will share it here.
Why doesn't KISS support hardware retraction!? It's really interesting to me what slicers will do and what they don't. To me firmware retraction seems like the kind of feature that could be implemented in about an hour for pretty much any slicer.
SMH.
I've not used KISS before, is it open source, can you put in an issue in github? I've found most 3d printer firmware teams very responsive to sensible ideas. Failing that other slicers are available many of which can do firmware retraction.
http://www.kisslicer.com not open source and anything but simple. That being said I have pretty much switched away from Simplify3D and started using KISS exclusively. The way it manages profiles for styles, printers, and materials is the best i've seen. Even Simplify3D doesn't support firmware retraction….
