Rat Rig Community [Unofficial]•14mo ago

Big Layer Shifts

Been having an issue where my prints will be split partway through. I have not directly observed this in person. It started appearing shortly after I increased the velocity of non print moves from 250 to 500 (but not immediately after that change). It does not happen every print When it happens, it seems like the x and y position will be wrong. Cancelling the print will cause the head to try and move out of bounds I don't know what direction to look into fixing this besides lowering the non print speed again (which was done to avoid blobs on surfaces)

37 Replies

optimistic-gold•14mo ago

base of performance config?

DeckerOP•14mo ago

What do you mean?

optimistic-gold•14mo ago

https://github.com/Rat-OS/RatOS-configuration/blob/v2.x/templates/v-core-3-printer.template.cfg#L45 what selected in printer.cfg in this section? I think blobs on surfaces should be a sign of wrong retraction settings

DeckerOP•14mo ago

I can post my entire printer.cfg file later today And I couldn't get rid of surface blobs until I upped the non print travel speed. Could not find a combination of retraction settings or drying to remove them

optimistic-gold•14mo ago

Fixing this with travel speed seem incorrect to me

DeckerOP•14mo ago

Then my max velocity is 250 mm/s?

optimistic-gold•14mo ago

Do you have cooling on stepper drivers? Also, what is acceleration for travel moves?

DeckerOP•14mo ago

I have no cooling on stepper drivers, and the acceleration is 3700 mm²/s. I believe the same as print moves Unless the acceleration for travel moves must be set separately

optimistic-gold•14mo ago

3700 is quite low. I would try adding cooling (just any fan blowing directly to steppers) and check if 500 mm/s still skips

DeckerOP•14mo ago

3700 is what my resonance graphs came up with. This is a vcore 500

optimistic-gold•14mo ago

If your config is not basic (1.1A), but performance (1.6A) - I would say 500 mm/s must skip without cooling

DeckerOP•14mo ago

I'm likely in basic mode, I don't recall setting it to performance

optimistic-gold•14mo ago

For me stock config is for < 350, anything above requires additional steps VC500 should make it even worse, a lot more mass to move And again, surface blobs is something else for sure Maybe it is not drivers overheating but just way too low run current and not enough torque

DeckerOP•14mo ago

It did fix the blobs for me, but it's possible that it's more of a bandaid than a proper solution And also very possible that the drivers are incorrect in the config. I didn't touch them in set up

optimistic-gold•14mo ago

Thats bandaid for sure, fast travel moves just hides oozing. Might be wrong retraction or even pressure advance

DeckerOP•14mo ago

It's been my experience that the tool head is often leaky, regardless of pressure advance setting

optimistic-gold•14mo ago

What filament?

DeckerOP•14mo ago

Any of them

optimistic-gold•14mo ago

Hotend?

DeckerOP•14mo ago

Rapido 2 with UHF extender and Orbiter 2.0.

optimistic-gold•14mo ago

Flow ratio properly calibrated? What nozzle?

DeckerOP•14mo ago

Right now is a hardened steel nozzle with CHT insert, but the problem exists on other nozzles as well Flow ratio?

optimistic-gold•14mo ago

https://ellis3dp.com/Print-Tuning-Guide/articles/extrusion_multiplier.html

Ellis’ Print Tuning Guide

Extrusion Multiplier

Ellis’ Print Tuning Guide

optimistic-gold•14mo ago

https://github.com/SoftFever/OrcaSlicer/wiki/Calibration#Flow-rate

GitHub

Calibration

G-code generator for 3D printers (Bambu, Prusa, Voron, VzBot, RatRig, Creality, etc.) - SoftFever/OrcaSlicer

DeckerOP•14mo ago

Oh, good question. I can't recall the last time I checked the extrusion multiplier. I'll test that when I get home

optimistic-gold•14mo ago

This is VERY individual for different filaments and must be calibrated every time So your problem can be a simple over extrusion

DeckerOP•14mo ago

Ok then I definitely need to check that Didn't know that varied on a filament to filament basis

optimistic-gold•14mo ago

None of my filament have it 1, most of the time something between 0.85 - 0.95 Even for same filament type of same vendor the difference might be significant

DeckerOP•14mo ago

So I should check that as often as I check pressure advance values?

optimistic-gold•14mo ago

You have to calibrate filament for every vendor/type/color/options combination (usually once if vendor have good consistency over time/batches) EM/PA/Shrinkage factor If you have different printers (extruder/hotend/nozzle) - you have to repeat the same for each of them

DeckerOP•14mo ago

Current config file

printer_10_16_2023.c...

optimistic-gold•14mo ago

max_velocity:500
max_accel:3700
max_accel_to_decel:3700

max_velocity:500
max_accel:3700
max_accel_to_decel:3700

This is a hard limits for whatever you set in slicer

DeckerOP•14mo ago

right

optimistic-gold•14mo ago

# UNCOOLED TMC 2209 + LDO-42STH48-2504AC
[include config/printers/v-core-3/speed-limits-basic.cfg]
[include config/printers/v-core-3/tmc2209.cfg]
[include config/steppers/ldo/42sth48-2504ac/2209/24v-1.1a-*.cfg]

# UNCOOLED TMC 2209 + LDO-42STH48-2504AC
[include config/printers/v-core-3/speed-limits-basic.cfg]
[include config/printers/v-core-3/tmc2209.cfg]
[include config/steppers/ldo/42sth48-2504ac/2209/24v-1.1a-*.cfg]

this is basic config with 1.1A run current My guess this is not enough for 500 mm/s on VC500 So I would do two things: 1) calibrate just one filament for experiments and stick with it 2) either lower speed or go for performance profile (by adding drivers cooling)

DeckerOP•14mo ago

yea, filament specific calibration is next to see if I can eliminate the need for speed and going from there hadn't seen anyone else require stepper cooling. though it's possible I wasn't directly looking for that

optimistic-gold•14mo ago

You can try performance profile without cooling, but risk is on you I think almost everyone use performance profile, this is just obvious https://github.com/Rat-OS/RatOS-configuration/blob/v2.x/printers/v-core-3/speed-limits-performance.cfg There is no point in buying VCx and don't use it

DeckerOP•14mo ago

So I have yet to really test the outcome to see if it stops the blobbing, But you were right. My extrusion multiplier was indeed too high. If this does stop it, I can worry about cranking up the speed with performance mode at a later date

Gaming

Programming

Big Layer Shifts