So, sorry for hijacking the sticky Guide thread. I hope that someone can guide me to solve this dilemma

I'm having a strange issue with the Pressure Advance feature, and reading most of the topics here on the forum and trying different values, I am still at a lost and don't know exactly how should I proceed.

My setup is as follows:
Duet Wifi 2 controller, Firmware 2.05.1
Bowden around 250mm in lenght, E3D V6, with simple extruder, no gear reduction.
Printing in ABS, 230°C

I found my "ideal" pressure advance value to be around 0.35 - 0.4 with sharp corners and start and end lines that are quite consistent in width. In most of my parts, let's say 98% of them, I can find no fault. The rest however, whenever I have a very short travel zig-zag infill, like in the tests presented in the guide thread, I get a huge blob of filament, like I would have the extrusion bumped up to 200%. No matter what value I set, everything above 0.05 will give me this effect, even going up to 0.9 or 1.0 . It will stop and print a normal infill if I disable Pressure Advance completely or the value is extremely low, under 0.05 which will effectively disable it for my setup.
There was another similar topic here and the explanation was that during these short zig-zag moves, the filament does not have the time to compress and decompress in the bowden tube, so for such short moves, the pressure advance should be disabled. I am not sure if anybody found a solution though..

What am I doing wrong here ?

Thanks for the help.

So, sorry for hijacking the sticky Guide thread. I hope that someone can guide me to solve this dilemma

I'm having a strange issue with the Pressure Advance feature, and reading most of the topics here on the forum and trying different values, I am still at a lost and don't know exactly how should I proceed.

My setup is as follows:
Duet Wifi 2 controller, Firmware 2.05.1
Bowden around 250mm in lenght, E3D V6, with simple extruder, no gear reduction.
Printing in ABS, 230°C

I found my "ideal" pressure advance value to be around 0.35 - 0.4 with sharp corners and start and end lines that are quite consistent in width. In most of my parts, let's say 98% of them, I can find no fault. The rest however, whenever I have a very short travel zig-zag infill, like in the tests presented in the guide thread, I get a huge blob of filament, like I would have the extrusion bumped up to 200%. No matter what value I set, everything above 0.05 will give me this effect, even going up to 0.9 or 1.0 . It will stop and print a normal infill if I disable Pressure Advance completely or the value is extremely low, under 0.05 which will effectively disable it for my setup.
There was another similar topic here and the explanation was that during these short zig-zag moves, the filament does not have the time to compress and decompress in the bowden tube, so for such short moves, the pressure advance should be disabled. I am not sure if anybody found a solution though..

What am I doing wrong here ?

Thanks for the help.

I hope you guys don't mind if I hijack this topic, but it fits to my current "dilemma".

I'm having a strange issue with the Pressure Advance feature, and reading most of the topics here on the forum and trying different values, I am still at a lost and don't know exactly how should I proceed.

My setup is as follows:
Duet Wifi 2 controller, Firmware 2.05.1
Bowden around 250mm in lenght, E3D V6, with simple extruder, no gear reduction.
Printing in ABS, 230°C

I found my "ideal" pressure advance value to be around 0.35 - 0.4 with sharp corners and start and end lines that are quite consistent in width. In most of my parts, let's say 98% of them, I can find no fault. The rest however, whenever I have a very short travel zig-zag infill, like in the tests presented here in this thread, I get a huge blob of filament, like I would have the extrusion bumped up to 200%. No matter what value I set, everything above 0.05 will give me this effect, even going up to 0.9 or 1.0 . It will stop and print a normal infill if I disable Pressure Advance completely or the value is extremely low, under 0.05 which will effectively disable it for my setup.

What am I doing wrong here ?

Thanks for the help.

Excuse me, but these products have nothing to do with what you were describing in the opening post. They do have an absolute encoder for the position of the shaft, but it will not tell you the absolut position of your Z axis after a power cycle.
You have to look into absolute linear encoders. Do a google search, you will find plenty of information about them. Incorporating such encoders into Duet is another story...

Well, it's the first time I hear that there are open source (and closed source) endstops.
Anyway, here is the other side of the endstop: https://photos.app.goo.gl/ZloK0XzaNELNieJk2

It's the standard optical endstop found from hundreds of sellers on ebay.

I measured the voltage on the input signal:

no interruption: 0.99 Volt
endstop interrupted : 3.26 V
Voltage on the V-in pin : 3.27 Volt

So it gets the whole Vin voltage on the pin. I am looking again at my M574 X2 Y1 Z0 S2. S2 is now used for the Z probe to home axis, which is not my case. Should I use S1?

Later edit: I changed my M574 to S1 and M558 P4 changed to P6 and got everything working fine now. I guess I just had to RTFM better..

These are the endstops that I use: http://www.geeetech.com/images/v/Geeetech_IMG_5412_1.jpg

I will measure the voltage on the endstop input pins when I get back home later in the evening and will post the results.

The printer was build by me from the ground up. 2mm thick stainless sheet is opaque enough. Leds are turning off completely. Why should anything change on the hardware and electrical side by burning another firmware?

Thank you for replying, David. I checked everything I could check, wiring is fine, leds are working as they should.
The thing is, 1.20RC1 is working, I am flashing 1.20RC3 or RC4 and suddenly they don't any more. Checking with M119, they don't get triggered when interrupting the opto-barriers. I flash back to 1.20RC1 and everything is back to normal.

I noticed something. I am using M574 E S1 and M558 P4 in my config. Should I use M558 P6 instead and get rid of M574 E ?

Regards,
Romeo

Maybe someone with more experience can help me tune my setup to get rid of this small issue.

I have tuned my extrusion rate and I get really nice accurate parts with perfect infill and top surfaces. Measured wall thicknesses, 100% layers look solid and without over-extrusion whatsoever. I am printing with a E3D V6 fitted with a 0.3mm airbrush nozzle so even a small error in the extrusion rate is visible.
Also, my retract settings are also tuned in, so that I have perfect quality on prints (no blobs, no holes).
The problem is when it gets to small island or perimeters (2-4mm²) than it goes crazy into the over-extrusion and I have to reduce manually from the Duet Web Client from 100% to almost 65-70% to get a correct extrusion without blobs and monsters. A perfect test STL would be the hollow calibration pyramid from Thingi…

A little about the setup:
-Bowden system around 60 cm long (I still have to measure it)
-1.75 filament

• E3D V6 with airbrush nozzle
• Pressure advance in firmware 0.25
• S3D with following retraction settings:
• retract 7.5mm
• extra restart 0.15mm
• vertical lift 0.15mm
• retraction speed 90mm/s
• coast at end 0.7mm
  no wipe
  Retraction between layers active
  Only retract when crossing open spaces

Does anybody have an idea where and what I could tune (slicer or duet firmware) to get an even extrusion regardless of perimeter size ?

Thanks in advance!

P.S. I have to say.. wow.. this forum grew up so fast! almost 1600 users and 4000 Threads in such a short time!

So… sorry for pushing this, but is there something I can do to fix the end-stop issue and run on the latest 1.21RC1?

Hi David,

I tried with 1.21RC1 as well, but the printer started acting strange. When homing, it drove the axis in the wrong directions (or it was the Pause script automatically loaded?) and endstops were also not triggered.
I have optical end-stops.

Please ignore the comments, they don't reflect the settings…
This is my movement section:

[[language]]
M584 X5 Y6 E3:4:0:1:7:8
M569 P0 S1                          ; Drive 0 goes forwards (change to S0 to reverse it)
M569 P1 S1                          ; Drive 1 goes forwards
M569 P2 S0                          ; Drive Z goes backwards
M569 P3 S0                          ; Drive 3 goes forwards
M569 P4 S1                          ; Drive 4 goes forwards
M569 P5 S0
M569 P6 S0
M574 X2 Y1 Z0 S2
M574 E S1					; set endstop configuration (X and Y endstops only, at low end, active high)
M906 X700 Y900 Z900 E1400 I50           ; Set motor currents (mA)
M201 X1600 Y1600 Z15 E20000            ; Accelerations (mm/s^2)
M203 X20000 Y20000 Z450 E15000       ; Maximum speeds (mm/min)
M566 X1800 Y1800 Z30 E1800              ; Minimum speeds mm/minute
M208 X330 Y285 Z340					; set axis maxima (adjust to suit your machine)
M208 X0 Y0 Z0 S1					; set axis minimum (adjust to make X=0 and Y=0 the edge of the bed)
M92 X80.5 Y80.5 Z1605					; Set axis steps/mm
M92 E146:146                     	; Set extruder steps per mm
G21                                 ; Work in millimetres
G90                                 ; Send absolute coordinates...
M83 

Z-Probe Section:

[[language]]
M558 P4 X0 Y0 Z1 H0.7 F100 T5000	; Smart IR Z probe, used for homing Z axis, dive height 3mm, probe speed 200mm/min, travel speed 5000mm/min
;G31 X18 Y-35 Z3.95 P500           ; Set the probe height and threshold (put your own values here) - 0,3 nozzle
;G31 X18 Y-35 Z5.15 P500	; 0,6 nozzle
;G31 X18 Y-35 Z4 P500		;0,2 nozzle
G31 X18 Y-35 Z3.90 P500		;0,3 nozzle
M557 X18:330 Y0:285 S50

I have read all the release notes and what to pay attention to, but maybe I forgot or not understood some of it..

Regards,
Romeo