Posts made by LidaDida

The first samples are ready.
Firstly, I print a control sample with K=0 and without extra prime amount
It was good as expected

Next, I decreased K factor by half and got almost expected result with overcompensation

Then I printed the K=0.3 sample. 0.3 is the recommended starting point for my Bowden length. It still looks overcompensated on the text. The bottom one was printed with my default settings. For the upper one, I use @Phaedrux advice and raised extruder speed/accel/jerk settings. It's maybe slightly better, but I can't notice a difference.

Then I thought, maybe my old K calibrations are not applicable after microstepping change and I print another calibration pattern.

And it points back to K=1. Why?

Now I'm trying to print a single-walled cube test. Now my cubes look like PA isn't exist at all and the width of the layers is the same on all of the length. Even while acceleration to 80mm/s. And the cura sometimes wants to fill tiny gaps on the corners, but these are other topics for googling.
On the next step, I will try to recalibrate flow, maybe PA also affects that.

PS. All my PA samples printed with 5mm retraction, maybe I should lower it more?

@Kolbi said in Pressure advance quality issues:

it is normally recommended to use 16 with interpolation

It seems like a step in the right direction. Now it, as expected, over extrudes on the text and even primes (untracts). It's interesting because after installation I calculated steps/s and no axis exceeded the limit of 180k steps/s, mentioned on the wiki.
Now I'm printing samples to approve that theory.

@engikeneer said in Pressure advance quality issues:

@LidaDida the extruder go crazy with pressure advance

I noticed another difference with marlin, that thin wall skin prints much slower. But I think, that is because of marlin use interpolation for accel calculations.

I also pushed up my currents so my motors could keep up better, but they soon got quite toasty...

Heh, my feeder now is under active cooling with 80mm fan

Personally, I prefer the single-walled cube method described on the Pressure Advance wiki for calibration

I prefer "print another calibration cube" method))

@Phaedrux said in Pressure advance quality issues:

In addition to the above two good suggestions you can try these settings

Increasing rather than decreasing? I will try that.

@Phaedrux said in Pressure advance quality issues:

Pressure advance and marlin's linear advance are not directly interchangeable.

For the marlin, I've used K=0.6. I've noticed, that PA also tries to compensate retracts. Because of that, every second PA post suggests reducing retraction. On marlin, I used an extra prime amount and wiping for this purpose.

Thanks to everyone for replies. Waiting for samples to be ready.

Hi. I'm migrating from RAMPS1.4 onto DuetWIFI and face some troubles with PA.
My hardware is a DIY Prusa i3-like machine with 1.75 filament diameter mk10 feeder, approx. 450mm Bowden tube and 0.3 mm E3DV6 nozzle.
I've calibrated the PA factor to 1.

I got some strange defect onto embossed text or frequent small features. (Calibration cube prints without issues)

It looks like hard under-extrusion or nozzle clogging or filament grinding and affects only the outer perimeter.

With disabled PA (K = 0) quality is perfect (except this blobs, that should be fixed by PA. Ironic.)

There is my "classic" calibration pattern from K=0.00 to K=1.20. I also adopt marlin calibration pattern and got similar results.

I use:

• E max speed 60mm/s (40mm/s retraction speed)
• E jerk 10mm/s
• E accel 1000mm/s^2
• 6 mm retraction length

Here is my config.g
And cura profile
I've already tried:

• Reducing E jerk down to 5mm/s
• Reducing E accel down to 500mm/s^2
• Reducing the K factor to 0.6s and 0.1s
• Disabling ringing compensation

I have run of ideas. Has anyone encounter similar issues? Any other ideas I can to try?
Thanks.

Inventor