More strange pressure advance behaviour
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I also ran these prints with firmware settings similar to yours:
[c]M92 X80.00 Y80.00 Z2560.00 E97.009 ; Set steps per mm
M566 X833 Y583 Z3000 E1800:1800 ; Set maximum instantaneous speed changes (mm/min)
M203 X18000 Y18000 Z400 E3600:3600 ; Set maximum speeds (mm/min)
M201 X833 Y583 Z3000 E1800:1800 ; Set accelerations (mm/s^2)
M906 X765 Y850 Z850 E850 I30 ; Set motor currents (mA) and motor idle factor in per cent[/c]Obviously none of these firmware settings or slicer settings are ideal, its just how I have been testing pressure advance in an unrestricted way….. eventually I will move my accelerations to be 3000mm/m to be in line with the 300mm/s printing speed test article but I wanted to align everything with what you had to see the kind of results I could achieve with it.
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Previously I had much higher maximum speed changes and still had great results but not into the 120mm/s range…. So I lowered those for now but will eventually see how high I can push them.
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Also one of the reasons I dont want the slicer getting in the way of my printer tuning is because i dont want the printers optimum performance to be reliant on the slicer. In my opinion the slicer should only compensate for different filaments. By tuning the printer to a baseline on ABS or PLA for best quality at the highest speed possible then the slicer can then be brought into the picture for minor tweaks when needed between filaments and the same gcode could theoretically be used across a number of printers if they were all tuned in the same fashion and hence all giving the same great results regardless of kinematics.
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Which firmware version are you running?
As for slicer, I'm not going to start playing around with the settings that have taken my many hours over many months to optimise. The same applies to my other printer settings. My prints are just fine apart from a touch of over/under extrusion at the ends of long moves which pressure advance fixes but causes other issues.
If I have to choose, then I'll simply not use pressure advance and live with the over/under extrusion at the ends of long moves (I can always print slower to eliminate them if I have to). In any case, this has nothing to do with slicer speed. Whether it's first layer at 45mm/sec, inner perimeters at 90mm/sec, outer perimeters at 75mm/sec or small perimeters at 25mm/sec, they all exhibit exactly the same behaviour.
I think what David is hinting at is slicer behaviour in that there might be variations in extruder speed during small segmented moves which screw up or interfere with pressure advance. The only way to check that is to go through the gcode file, somehow find an arc, then check each X Y move and see if the E move is correspondingly proportional. That's proving hard to do so I think I'll create a simple 1 wall thick circular object, slice it and then check the gcode E moves which ought to be the same.
If they aren't then it will mean that pressure advance with Duet is slicer dependent. In which case I'll have to live without using pressure advance as slic3r is the best of a bad bunch when it comes to multiple (more than 2) extruders.
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Also one of the reasons I dont want the slicer getting in the way of my printer tuning is because i dont want the printers optimum performance to be reliant on the slicer. In my opinion the slicer should only compensate for different filaments. By tuning the printer to a baseline on ABS or PLA for best quality at the highest speed possible then the slicer can then be brought into the picture for minor tweaks when needed between filaments and the same gcode could theoretically be used across a number of printers if they were all tuned in the same fashion and hence all giving the same great results regardless of kinematics.
Of course, you should set up your basic printer parameters first but you'll find later on, when you've gained a bit more experience that slicer settings are very important and to some extent machine specific as well as object specific. Things like whether extra perimeters are needed, detecting thin walls, detecting bridge perimeters, whether you want to avoid crossing perimeters, seam position, infill type, whether you want a skirt and or brim, etc etc but speeds are especially important . To get the best out of your printer you'll find that you need different speeds for internal perimeters, external perimeters, small perimeters, top and bottom layers, infill, solid infill, support material, bridges etc.
Anyway, this is all getting way off topic.
Let's get back to pressure advance behaviour please.
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Does slic3r not have the concept of profiles and processes? With S3D I have known processes that work then i just add a new process that i open up for tuning the firmware. switching back is just a matter of changing processes and commenting out my test firmware settings.
With S3D the extruder speed gets modified if the box is checked for speed overrides for layers under "X" seconds but i run with this turned off.
I know in Cura there is something similar but called something completely different i just cant remember the name of it….
I have never used Slic3r but maybe there is something similar in it.
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Deckingman, maybe try the capricorn ptfe tube. the differences in amount of retraction and pressure advance needed are huge and the print quality is much better. As you can see by the following thread others who have installed Capricorn have experienced the same thing.
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Can we just keep this on topic please.
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Wasnt trying to derail the topic, there is obviously some difference that is causing pressure advance to perform differently for each of us. I was just wondering if maybe that difference is because of the PTFE tube. Which would make sense considering that is what pressure advance compensates for and why direct extruders use significantly lower pressure advance settings.
Your multi extruder setup could very well be more sensitive to the lack of tolerences in a standard PTFE tube. I do not have a multi extruder setup and mine as well as others definitly were.
Just trying to be helpful and brainstorm ideas, i dont have a diamond hotend in front of me to test those ideas which is why I am sharing them with you.
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The topic is about pressure advance screwing up circular perimeters and jerky carriage behaviour during those circular moves. How is PTFE tube going to affect XY carriage behaviour?
Edit. You still haven't told me what firmware version you are using - that would be useful info
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The same could be said about how pressure advance would affect xy behavior.
What I do know is that you use radically high pressure advance settings and are having issues. Obviously from my photos I do not struggle with those same issues. So I am trying to brainstorm things that might not have crossed your mind.
You say that you can turn pressure advance off and just live with pressure buildup and everything would be fine.
When I printed with high pressure advance and high retraction i had all kinds of strange things going on.
The effect of PTFE tolerences with a single extruder was huge and I can only imagine that effect gets amplified with the more entruders you add… if its the 3 or 5 extruder setup.
What if because of this higher sensitivity to tolerences that multi extruders have... that pressure advance isnt handling it well and it could all be resolved with a lower pressure advance settings and tighter tolerence tubes....
Just my thought process and what I would try if i had a Diamond hotend sitting in front of me, but I am of the type that tests all different configurations with different hardware .... it comes from my days of being a lab junkie in the isilon systems server farm.... i ran through a lot of itteration and testing of code on different platforms everyday before sending servers out into production.
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Oh for goodness sake! I get the same behaviour with 0.1 pressure advance and you don't with 0.2 so don't tell me it's because I'm using radically high values!
Watch the video - then you'll maybe understand the issue.
You still haven't told me what firmware version you are using which might be something useful.
This thread has now got completely diluted and off topic. I'll post no more and instead just pm David with my findings.
In fact - I'm out of here completely. Goodbye all and good luck…....
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Sorry I wont respond to your posts anymore. I didnt realize I was upsetting you.
To answer your question I was following along with you, same firmware 1.18.1 then move to 1.19beta8 when you did. I even changed my accellerations to match yours because I was trying to keep my testing inline with yours while i explored pressure advance.
Good day sir.
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Sorry too - frustration made me hasty.
Anyway, I have found the problem - or at least the source of the problem. It's multiple extruders. I defined a simple tool using just a single extruder, started printing the same part and there is no problem with curves using pressure advance.
That's the reason I have the problem ad no one else does. Now it's over to David (as and when he gets chance).
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Sorry too - frustration made me hasty.
Anyway, I have found the problem - or at least the source of the problem. It's multiple extruders. I defined a simple tool using just a single extruder, started printing the same part and there is no problem with curves using pressure advance.
That's the reason I have the problem ad no one else does. Now it's over to David (as and when he gets chance).
Interesting! When you say a tool using a single extruder, do you mean that you are not moving the other 2 extruders at all?
When you observed the problem before, were you using a 33/33/34 or a 97/1/1 mix, or something else?
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Interesting! When you say a tool using a single extruder, do you mean that you are not moving the other 2 extruders at all?
When you observed the problem before, were you using a 33/33/34 or a 97/1/1 mix, or something else?
Correct. That is to say, commenting out all my tool definitions and mixing settings and adding a simple tool defined thus…...........
M563 P0 D0 H1
................does not exhibit any problems printing curves using pressure advance values up to 0.4.
My "default" tool definitions are as follows.
M563 P0 D0:1:2 H1 ; Define tool 0
G10 P0 X0 Y0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C
M568 P0 S1 ; Enable mixing for tool 0
M567 P0 E0.90:0.05:0.05 ; Set mixing ratios for tool 0
M563 P1 D0:1:2 H1 ; Define tool 1
G10 P1 X0 Y0 ; Set tool 1 axis offsets
G10 P1 R0 S0 ; Set initial tool 1 active and standby temperatures to 0C
M568 P1 S1 ; Enable mixing for tool 1
M567 P1 E.05:0.90:0.05 ; Set mixing ratios for tool 1
M563 P2 D0:1:2 H1 ; Define tool 2
G10 P2 X0 Y0 ; Set tool 2 axis offsets
G10 P2 R0 S0 ; Set initial tool 2 active and standby temperatures to 0C
M568 P2 S1 ; Enable mixing for tool 2
M567 P2 E0.05:0.05:.90 ; Set mixing ratios for tool 2
M563 P3 D0:1:2 H1 ; Define tool 3
G10 P3 X0 Y0 ; Set tool 3 axis offsets
G10 P3 R0 S0 ; Set initial tool 3 active and standby temperatures to 0C
M568 P3 S1 ; Enable mixing for tool 3
M567 P3 E0.34:0.33:0.33 ; Set mixing ratios for tool 3Most of the testing was done using tool 0, so with 90:05:05 mixing ratio. Using this tool, I had the jerky movement and M122 reporting step errors and driver open load errors (only when using pressure advance). IIRC, I did try tool 3 (mixing ratio of 34:33:30) and it exhibited the same problems as tool 0.
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I'm tied up with other things for the rest of this week, so please remind me to look at it next weekend.I bit late as the weekend has passed but here is the reminder.
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@CaLviNx:
Here Let me pick your dummy off the floor, there there its not so bad…..............
Are personal snipes really necessary?
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@CaLviNx:
Here Let me pick your dummy off the floor, there there its not so bad…..............
Lighten up a little my friend its not as if it's life or death
I'd like to point out that Ian already apologised here https://www.duet3d.com/forum/thread.php?pid=18656#p18656.
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Thanks David,
I'm just trying to keep this thread on track so that we can seriously address these pressure advance issues, but it keeps veering off topic, which makes me angry and frustrated. Now I have personal snipes to contend with as well.
