Ooze prevention system speed setting?

[Kenzu]

Hey

I try to use Ooze prevention system for faster anti ooze, but my extruder stepper can't keep up with the speed. It works okay when moving from one object to another, but not when shifting layers (stepper skipping or grind filament).

How do i adjust the speed for anti ooze?

My extruder config is as following:

50% before move 2.5mm retraction 0.8 move

define EXT0_MAX_FEEDRATE 1500

define EXT0_MAX_START_FEEDRATE 12

define EXT0_MAX_ACCELERATION 6000

Thanks

p.s running 0.81 firmware on arduino mega/ramps with pololu

[Highcooley]

Reduce EXT0_MAX_ACCELERATION to a value that works, depending on the type of your extruder. As you describe your problem, your extruder can handle an acceleration of 6000 but not acceleration followed by slow down at the same rate.

[Kenzu]

I have this extruder http://www.thingiverse.com/thing:8252 with a nema 17 stepper. Had no problem with marlin firmware and 9000 in MAX_ACCELERATION. To get anti ooze to work i have to set MAX_ACCELERATION to something around 100-150 and that sounds small compared to 6000-9000. Does it affect anything else?

[Highcooley]

MAX_ACCELERATION in a range between 100-150 sounds more reasonable to me (I'm working with 75 with a Rostock Max extruder). But you wrote 1'500 in your first request, which is very fast.

[repetier]

With ops retraction starts with max end speed. Acceleration is not used here. Only without ops acceleration and startspeed are used. So if your extruder stalls with ops reduce max speed.

[Kenzu]

What's a good setting to start with then? It's 20 now :-) Den 15/02/2013 20.52 skrev "repetier" notifications@github.com:

With ops retraction starts with max end speed. Acceleration is not used here. Only without ops acceleration and startspeed are used. So if your extruder stalls with ops reduce max speed.

— Reply to this email directly or view it on GitHubhttps://github.com/repetier/Repetier-Firmware/issues/73#issuecomment-13624750.

[repetier]

That depends on the extruder type and motor current. My wade extruder can du 20, my other extruder only 7(slow extruder).

[paenian]

I'm having the same issue - and turning down the EXT0_MAX_FEEDRATE doesn't seem to affect anything. This is using a deltabot with a 1.75mm Bowden, so I have the distance set to 8m, and even with the feedrate set at 5 it retracts in a fraction of a second.

[Kulitorum]

I agree, it does not seem to respect the EXT1_MAX_FEEDRATE setting (changing it in EEPROM settings in repetier host) Without the ability to set the speed, OPS in firmware is unusable. It's a shame, it would be a great feature if it worked.

[CNCBASHER]

On 22/03/13 16:56, Kulitorum wrote:

I agree, it does not seem to respect the EXT1_MAX_FEEDRATE setting (changing it in EEPROM settings in repetier host) Without the ability to set the speed, OPS in firmware is unusable. It's a shame, it would be a great feature if it worked.

— Reply to this email directly or view it on GitHub https://github.com/repetier/Repetier-Firmware/issues/73#issuecomment-15308291.

yea i agree ooze prevention is the main reason i wished to use it , but iv'e had to dump it and go back to Marlin for a far better result such a pity it's so broken to be unusable

[626Pilot]

Would be nice if this had a separate setting for retraction SPEED, like it does in KISSlicer. I've tried using this feature on my Rostock (delta robot) but it stalls the extruder all the time, even if I drop the acceleration to 25 (stock is something like 5,000 and works fine.)

[repetier]

OPS seems broken in 0.8x and is removed in upcoming 0.90 versiom sorry. It made everything too complicated and slicer can do much better prevention then firmware,