Pause between outer walls

chompworks

I'm getting a strange momentary pause between outer walls on my Maestro-upgraded Ender 3. I hadn't noticed it, until I was printing with some metallic filament and looking at the first layer quality, and theres blobbing where wall loops move out towards the seam. Watching the printer print these, theres a strange momentary pause between walls, which manifests as
Wall 1
PAUSE
Wall 2
PAUSE
Wall 3 (outermost wall)

Whats odd to me is that the pause doesn't seem to manifest later on when the head suddenly changes and goes in opposite directions for standard zig-zag infill.

I figured it was config settings, so I've had a bash at pushing the X, Z and E values up:
M566 X450.00 Y450.00 Z450.00 E450.00 ; Set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E6000.00 ; Set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z100.00 E500.00 ; Set accelerations (mm/s^2)
But it doesn't seem to have noticeably improved the pause at all.

Gcode doesn't show anything massively untoward either:
G1 X76.299 Y181.697 E0.03752
G1 X76.036 Y180.575 E0.03833
G1 X75.893 Y179.514 E0.03561
G1 X75.845 Y178.471 E0.03473
G0 F3600 X75.444 Y178.471
;TYPE:WALL-OUTER
G1 F1800 X75.495 Y177.372 E0.03659
G1 X75.648 Y176.261 E0.0373
G1 X75.923 Y175.111 E0.03933
G1 X76.3 Y174.011 E0.03868
G1 X76.803 Y172.913 E0.04017

This is on FW version: 2.02(RTOS) (2018-12-24b1)

have I just missed something stupid?

Phaedrux

Your Jerk values are still fairly low. Particularly the extruder.

What slicer are you using?

chompworks

@phaedrux said in Pause between outer walls:

Your Jerk values are still fairly low. Particularly the extruder.

Ah, ok. Thanks for the sanity check with those. I had tried to base them on what seemed to be the conversion from the marlin values I'd found to work well. I'm guessing that conversion was an order of magnitude out! lol
Whats a better standard set of jerk values for a cartesian setup on the duet?

@phaedrux said in Pause between outer walls:

What slicer are you using?

Cura 3.6 for this. I've changed over to RepRapFirmware flavoured gcode and firmware retraction, but its not doing anything in terms of attempting to override the existing accel/jerk settings. (been hit by Cura trying to do that in the past and disabled it.)

Phaedrux

From what I've seen a jerk value of 10mm/s on X and Y is pretty doable for most machines. So that's 600mm/min, so you're not that far off, really. For the Extruder try increasing the jerk to 1000 and see if it makes any difference to your pauses.

Also, could you export a 3mf file in Cura and post it? That will include the STL, and the printer and print settings all in one file. That will let people see the full settings used.

Perhaps consider updating to Cura 4.1?

What have you configured your firmware retraction settings to be? Is it actually doing a retraction during these pauses?

Do you have pressure advance enabled?

chompworks

@phaedrux said in Pause between outer walls:

From what I've seen a jerk value of 10mm/s on X and Y is pretty doable for most machines. So that's 600mm/min, so you're not that far off, really. For the Extruder try increasing the jerk to 1000 and see if it makes any difference to your pauses.

I left that going overnight. Unfortunately there isn't much of an improvement.

I'm trying some ridiculously higher extruder acceleration settings now just to see if the pause is still there:
M566 X1000.00 Y1000.00 Z1000.00 E1000.00 ; Set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E6000.00 ; Set maximum speeds (mm/min)
M201 X600.00 Y600.00 Z120.00 E2000.00 ; Set accelerations (mm/s^2)
Edit: Unfortunately there's still the pause even with these settings above.

@phaedrux said in Pause between outer walls:

Also, could you export a 3mf file in Cura and post it? That will include the STL, and the printer and print settings all in one file. That will let people see the full settings used.

No problem, here you go:
3mf file

@phaedrux said in Pause between outer walls:

Perhaps consider updating to Cura 4.1?

I've tried 4.0 and 4.1 and its not been working particularly well for me, and so I ended up sticking with 3.6 until they've ironed out a few more mac bugs. Fingers crossed for 4.2

@phaedrux said in Pause between outer walls:

What have you configured your firmware retraction settings to be? Is it actually doing a retraction during these pauses?

FW retraction setting is:
M207 S5.5 R0 F3600 Z0.1
One of the things I tried yesterday was to see if it was just poor retraction settings but theres no stringing or underextrusion at the start of a layer. Pushing it up or down started to show signs that I was moving away from the sweet spot for this printer.

Looking at the gcode though, it isn't actually retracting for these pauses, theres just a single non-extruding G0 like the example in my first post. If I didn't know better, it almost feels like the printer hits that and is either really slow on that G0, or doesn't know whats coming next.

@phaedrux said in Pause between outer walls:

Do you have pressure advance enabled?

No, to be honest, I haven't started using that on any of my printers yet.

Phaedrux

I think I know what it is now. Maybe...

@chompworks said in Pause between outer walls:

M207 S5.5 R0 F3600 Z0.1

You've got a slight amount of Zhop.

@chompworks said in Pause between outer walls:

M566 Z450.00 ; Set maximum instantaneous speed changes (mm/min)
M203 Z180.00 ; Set maximum speeds (mm/min)
M201 Z100 ; Set accelerations (mm/s^2)

And your Z speeds are very low.

Does it improve if you set M207 Z0?

Unfortunately the 3MF file from Cura 3.6 only imports the model for me on Cura 4.1, so I can't see the printer profile or the print settings.

chompworks

@phaedrux said in Pause between outer walls:

Does it improve if you set M207 Z0?

Thanks for the suggestion with that one. Sorry I didn't get a chance to try it yesterday, but watching it now, its made no difference.

Looking through the sliced gcode, theres no G10/G11 retract between walls, only a small G0 move like this:
...
;TYPE:WALL-INNER
...
G1 X75.845 Y178.471 E0.03473
G0 F3600 X75.444 Y178.471
;TYPE:WALL-OUTER
G1 F1800 X75.495 Y177.372 E0.03659
...

To make sure it isn't some kind of slicer weirdness, hopefully sometime today I'll get the opportunity to get a Pathio slicer profile set up for the machine and see if that has the same issues between walls.

dc42

You have one non-extruding move (G0 without E parameter) separating two extruding moves (G1 with E parameter). Using the default jerk policy, the motion will come to a stop at the start and end of the G0 move. Whether that gives a noticeable pause will depend on your acceleration parameters. On my delta, it doesn't.

If you are running firmware 2.03 then you have the option of allowing jerk to be used between those moves, by including P1 in the M566 command. Then the motion won't come to a stop between those commands. It may still slow down, depending on your jerk settings.

chompworks

I saw this in the M566 documentation via the release notes for FW 2.03:
When mesh bed compensation is used, movement may be jerky if the allowed Z jerk is too low, because the Z speed needs to change abruptly as the head moves between squares in the mesh.
So I doubled Z speed, acceleration and jerk parameters just in case. Sadly no difference due to those either.

chompworks

@dc42

You just posted that while I was reading about the newer firmware!

I'll try the upgrade now, add P1 to M566 and see what happens. Thanks!

chompworks

@dc42 That did it! Thankyou so much for that suggestion, and thankyou so much to @Phaedrux for all the previous suggestions in working through it with me too.
It's hard to make a comment on a forum read as genuine sentiment, but this has been driving me up the wall for a few days, and the help from both of you has been really, massively appreciated.

Phaedrux

Very interesting. I'll have to keep playing with M566 P1. I didn't notice a difference when I tried it, but I didn't know what to look for.