Issues with pressure advance since RRF 3.4

Argo

PA 0.095 is quite high for direct drive setup.
Do you also get incomplete infill lines if you increase PA further to get less bulging corners?

bot

@r4ffers One thing I would try if I were you would be to increase the E jerk a little, and drastically decrease the E acceleration. You never need that much E accel. It becomes completely pointless -- essentially no E acceleration is ever applied because there are not enough steps to interpolate speeds across.

Try E Jerk 500 and E Accel 2500.

R4ffers

@argo I've been messing around with it for the last week. I had it set at 0.055 previously. I have noticed zero change to PA when updated in config.g However I was tinkering earlier and when I change PA live using paneldue whilst printing it does have an effect. I got the corners not perfect but not too bad, updated config.g with new PA value. Ran the print again and back to crap corners again. It's almost like PA value in config.g is being ignored.

bot

@r4ffers Make sure your slicer start gcode doesn't disable PA. Check every .g file on your SD card, too.

R4ffers

@bot thanks, I've just updated that. I'll try another print in a mo.

R4ffers

@bot ok good shout

R4ffers

@bot said in Issues with pressure advance since RRF 3.4:

@r4ffers Make sure your slicer start gcode doesn't disable PA. Check every .g file on your SD card, too.

Can't see anything tha'ts disabling PA.
if I issue M572 D0 whilst printing I get PA0.095

R4ffers

@argo said in Issues with pressure advance since RRF 3.4:

@r4ffers

PA 0.095 is quite high for direct drive setup.
Do you also get incomplete infill lines if you increase PA further to get less bulging corners?

Doesn't seem to be

bot

@r4ffers Did you try this print with different E jerk/accel?

R4ffers

@bot yep. Made no change to the corners.

Argo

@r4ffers

So if you enter your PA value manually during a print - how do your corners then look?

R4ffers

@argo I'll try a print tonight, I'm on call this week.

R4ffers

@argo Hi, so started the print off issued M572 D0 to report current PA of 0.095. M572 D0 S0 to clear PA then issued M572 D0 S0.085. Issued M572 D0 to report current PA of 0.085. Here is the result.

Corners look miles better. I did notice the infill not quite reaching the internal perimeter in places.
Also note the walls on the square top layer, PA is working when manually input during print and as expected with such a high value for direct extruder.

Hope this helps.

Argo

@r4ffers

I’ll do the same test when I’m back from my business trip on Friday.

Though PA is reporting the correct value you set it to 0 and again to the value it was before and it works?

R4ffers

@argo I set it to zero 1st just to make sure it reported the change. In my config I had it set at 0.095 but I manually set it to 0.085. I'm fairly sure I used to have it set at 0.055, if I get chance tonight I'll try it at that and see what happens. I've looked through everything and can't find anything that would disable PA .

It'll be interesting to see if your PA works manually.

CCS86

@r4ffers said in Issues with pressure advance since RRF 3.4:

@argo I set it to zero 1st just to make sure it reported the change. In my config I had it set at 0.095 but I manually set it to 0.085. I'm fairly sure I used to have it set at 0.055, if I get chance tonight I'll try it at that and see what happens. I've looked through everything and can't find anything that would disable PA .

It seems like a better test might be to start the print, verify the supposed PA setting via console, let it print for some amount of time. Then, re-command the same PA value and see if the print changes.

R4ffers

@ccs86 I've proved that already.

Argo

@r4ffers

I also did the test you described but the corners are still bulging at PA 0.052 for PLA.

Wulfsta

Seeing this thread, I really wish I had spent time making that band-aid test print use a bit less plastic...

Argo

@R4ffers

I’ve looked at your print again and spotted holes in your infill lines. That’s usually due too much pressure advance. You are using your LGX lite in a direct drive setup? Then for PLA a value around 0.05 and 0.06 is usually the best value. For ABS it’s even lower.
I’m curious how your infill looks like. I’m also getting nice(er) corners with a much too high PA value (you are at 0.09?) but then also get holes in perimeters / solid fill and infill lines don’t connect anymore - what is to be expected with too high PA.

@Wulfsta
Didn’t know you are registered here. Would have mentioned that the test print was from you.