Retraction problems


#1

Retraction is kicking my butt lately. I keep getting little peaks where the retract + zhop occurs, which eventually build up enough to cause problems. Only happening since upgrade from lite 6 to V6.

Current best settings:
PLA at 185 (tried as low as 175)
Marlin firmware retraction.
Slic3r

0.8mm @ 30mm/s
.2mm zhop
-0.05mm @8mm/s recovery

Considering turning off firmware retraction so I can get slic3r to do a wipe on retraction.

I have tried playing with speed and acceleration to see if I can get faster travels, but I am well above values that will likely cause layer shifting on my big (400mm) bed.

I have also tried playing with linear advance, with no luck.

Any other ideas?


#2

Looking at my settings in S3D for PLA with Zhop or for S3D Retraction Vertical Lift

0.6mm (retraction distance)
50mm/s (retraction speed)
1mm zhop (retraction vertical lift)
No recovery (extra restart distance)

I have 3 setups for PLA for different machines and they are 0.6mm, 0.8mm and 1mm for retraction distance and the other settings the same. All have the v6 and Titan combination and all with 0.9deg steppers motors on DRV8825 drivers… if that makes any difference.


#3

Are you using any coasting or wipe?

This is what I am seeing, and it seems nothing makes much of a difference.


#4

Ignore the other problems in the first few layers (adjusting settings on the fly) but the little peak on the closest cube it the problem.

Edit: I have the titan/V6/8825 combo as well…


#5

At this point I am not and my prints are as good as i have ever done.

All I can think it’s 2 things.

Over extrusion so the pressure in the hotend despite the retraction is oozing.

Or Temperature too high.

Have you tried a different filament colour… just saying that because I have always had issues with certain black PLA’s.

Other than that I haven’t experienced what you are getting to the degree its causing an issue.

Ah one thing do… a check of your Extruder claibration. I had this issue recently gong from an old firmware to a new firmware there was something like a 7% difference… so I assumed they change the clac in the firmware at some point.


#6

Have calibrated, calibrated and calibrated. Then I found out my calipers weren’t zeroed properly (I use old school non digital calipers), and re did it all again. No dice.

So I gave up on the black PLA, and pulled some PETG I’ve had sitting in the drawers for a couple of months waiting to try.

Got the petg going nicely in calibration prints, barely more stringing than the PLA :slight_smile: so I try to print the part that was causing me problems, but no joy, same issue! So I try again and sit down to watch it, and the skipping doesn’t come from the peaks as I suspected, rather it is coming from some unreasonably high jerk settings I don’t remember changing, the machine was literally trying to shake itself apart on small infill sections.

So I probably didn’t need to abandon the PLA, I could have persisted and found this was the problem, not the retraction as I had assumed.

On the other hand I got over my ‘fear’ of PETG and this print is coming along very nicely!