3 weeks in, same issue

dc42

For 500mm Capricorn tubing I would expect 6mm to be sufficient retraction, assuming that you are using collet clips or similar to make sure that the Bowden tube does not slide relative to the collets when you retract filament.

Do the blobs correspond to points where extrusion stops and a travel move starts, or not?

Plecto

@dc42:

For 500mm Capricorn tubing I would expect 6mm to be sufficient retraction, assuming that you are using collet clips or similar to make sure that the Bowden tube does not slide relative to the collets when you retract filament.

Do the blobs correspond to points where extrusion stops and a travel move starts, or not?

Ive been mostly using 5.7mm retraction and the results are mostly the same.
The blobs correspont to points where the layer starts, so on end of travel move between layers.

Ive been printing with outside-in direction, but switching changes nothing.

deckingman

So it's blobs on layer change which mostly means that you just need to tune the retraction. Someone pointed out above that your jerk and accelerations are high. A quick squint at your config.g shows that for your extruder, this is the case. It's entirely possible that during retraction this could "break" or "stretch" the molten filament, rather than pull it it back from the nozzle tip. So try significantly lower extrusion acceleration and jerk and/or a slower extrusion speed. Also, you have a slight Z hop. Depending on how fast your bed moves, this could introduce a pause so try disabling that too.

dc42

Do you have retract on layer change enabled in the slicer?

deckingman

@dc42:

Do you have retract on layer change enabled in the slicer?

David,

The OP stated above somewhere that he's using a post processing script to add G10/G11 commands in S3D (not sure why).

Quick question regarding Z hop in G10 - does it do the retract, then move the bed or do they happen concurrently? If it's the latter case, then Z hop might slow the retraction speed down if the bed moves slowly?

dc42

To put it another way: is the OP doing retraction on layer change, either by enabling it in the slicer and having the post processing script convert the retraction/reprime commands to G10/G11, or by inserting them in post processing?

Plecto

Since this post process script cought your attention here you go.
all it does it to change the retraction defined in s3d with g10/g11
So ive enabled retraction in s3d set retraction distance til 1.00mm and 6000 speed.
However these values do nothing since they are overwritten with g10/11

{REPLACE "G1 E-1.0000 F6000\n" "G10\n"}
{REPLACE "G1 E0.0000 F6000\n" "G11\n"}
{REPLACE "G1 E1.0000 F6000\n" "G11\n"}
{REPLACE "G1 E0.0000 F1800\n" "G11\n"}
{REPLACE "G1 E1.0000 F1800\n" "G11\n"}

and just to clarify ive used slic3r with firmware retraction and it produces the same issues.

Plecto

Doing a test cube now with following settings:

Force retraction between layers is uncheck in s3d

M201 X900 Y900 Z60 E3000 ; Maximum accelerations (mm/s^2)
M566 X600 Y600 Z60 E300 ; Maximum jerk in mm/min

M572 D0 S0
M207 S6 R0 F6000 T6000 Z2

dc42

@Plecto:

Force retraction between layers is uncheck in s3d

So your retraction settings will have zero effect on those blobs. Try checking it.

Plecto

Result:

Plecto

Im printing another now

Force retraction between layers is checked in s3d

M201 X900 Y900 Z60 E3000 ; Maximum accelerations (mm/s^2)
M566 X600 Y600 Z60 E300 ; Maximum jerk in mm/min

M572 D0 S0
M207 S6 R0 F6000 T6000 Z2

Plecto

No changes. I've swapped filament. It seems like it's as good as it gets…

dc42

Are you printing outside perimeters first, or the other way round?

Maybe it's time to enable pressure advance.

Plecto

@dc42:

Are you printing outside perimeters first, or the other way round?

Maybe it's time to enable pressure advance.

Inside first, however ive tried both to same result.
Below example is inside-out

M572 D0 S0.1
M207 S4 R0 F4500 T4500 Z2

whosrdaddy

Apart from the obvious cooling issue, the 2mm z-hop seems a bit much, try changing that to 0.2mm (or don't use z-hop at all)

M207 S4 R0 F4500 T4500 Z0.2

My experience:
I used bowden setup at the time on my i3 clone (P3Steel), replaced it with a titan+pancake motor, the print quality difference was night and day

Plecto

Im still at it and yet to find a sollution, however i think it actually has something to do with the speed of the print.
I belive it might have something to do with the speed overrides and adjusting print speed for layers below x sec.

Still trouble shooting