Extruder Settings help please  

RE: Extruder Settings help please

doesn't matter, it resets on power on

it manually moves the extruder motor (assuming it's heated up)

RE: Extruder Settings help please

The only important thing is that when filament is loaded, dialing the E-Axis positive extrudes filament, and dialing negative unloads filament.  So you'll want to make sure to go back to a small positive number to ensure filament is extruding before leaving ... else the next print will not have been primed.

RE: Extruder Settings help please

Thanks @david-a66, @tim-m30.  Good explanation Tim. 

What should I clean my nozzle with because I am finding that the filament, when purging, wants to curl up and stick to the brass nozzle.

RE: Extruder Settings help please

Generally I use a paper towel and wipe the nozzle while it is a extruding temps.  I'll also use a brass brush infrequently to remove some of the dark residue the paper towel doesn't get.  It's inevitable plastic will curl and stick, I personally don't it when it happens, but have - so far - never found a cure. Even new nozzles do it, so why worry when an old one does it?    One cause of curl is the fan... another is micro-burrs on the brass... and contaminants on and in the filament itself (oils and moisture).

The best defense against curl is a clean bed that the plastic will stick to. 

RE: Extruder Settings help please

also get a silicon sock (from e3d) for the heater block - no more mess on the block and no extruder temp drop when the part cooling fan turns on

RE: Extruder Settings help please

Posted by: Tim

The only important thing is that when filament is loaded, dialing the E-Axis positive extrudes filament, and dialing negative unloads filament.  So you'll want to make sure to go back to a small positive number to ensure filament is extruding before leaving ... else the next print will not have been primed.

Well the purge and perimeter lines would sort that out. 

RE: Extruder Settings help please

Posted by: canquest

[...] What should I clean my nozzle with because I am finding that the filament, when purging, wants to curl up and stick to the brass nozzle.

For basic uncoated nozzles (e.g. the cheap brass ones) a soft brass wire brush can be used for cleaning. For coated nozzles, wire brushes aren't recommended. I've found a strip of cardboard gives me a bit of stiffness to allow cleaning off stubborn filament at temperature without leaving lint on the nozzle when done. As it gets fouled, I just trim a few mm off the cleaning end.

I am a fan of silicone socks and coated nozzles. I've spent most of the last day trying to use up an especially tricky recycled PET filament for large (3-6 hour) prints using a 0.80mm nozzle. This stuff really wants to create a Blob of Doom. So far, the coated nozzle and sock have prevented this.

RE: Extruder Settings help please

Posted by: Texy

Posted by: Tim

The only important thing is that when filament is loaded, dialing the E-Axis positive extrudes filament, and dialing negative unloads filament.  So you'll want to make sure to go back to a small positive number to ensure filament is extruding before leaving ... else the next print will not have been primed.

Well the purge and perimeter lines would sort that out. 

Well, not really. Purge doesn't move that much filament. If the E-Axis is backup up -40 mm, purge will miss.

G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

RE: Extruder Settings help please

Posted by: Tim

[...]  One cause of curl is the fan... another is micro-burrs on the brass... and contaminants on and in the filament itself (oils and moisture).

Michael Hackney of KISSlicer fame has an interesting post on polishing your nozzle tips before printing. I've seen this cited elsewhere as well, although it hasn't gotten a lot of attention. I do give the nozzles a vigorous rub on my jeans when doing swaps. "Nozzle stroping" should get more attention. A bit of nozzle care helps with many of the stringing and quality issues I've encountered.

RE: Extruder Settings help please

Interesting; I have often thought of trying to burnish my nozzles before installation to see if it would affect surface texture caused when the nozzle changes direction.  But a part of me is afraid to try because it will just move the quality issue one level higher. "How plumb does the nozzle need to be? Is my extruder actualy vertical? Is my X-Axis properly aligned?"  ... and yet another rabbit hole to descend into.

RE: Extruder Settings help please

Thanks to all that contributed to this conversation.

Good article on polishing nozzle tips.  Will definitely look closely at my first nozzle replacement.

How will I know it's time to change the nozzle?

To stop the curling of the extruded filament, which may stick to the nozzle, I have discovered that if I use a long pin type of instrument, such as a mechanical pencil end, and gently pull the filament loop/curl downwards just enough to have the loop fall straight down but not to break it off/apart, then that creates enough weight to keep pulling, straight down, any new extruded filament, thus no more curling.  This extra extruded filament comes off with the sheet to tip start-up procedure.  In the past I thought I had to make sure all dangling filament was removed before the file start-up procedure.

It's great to get feedback and share the little tricks we all learn.

RE: Extruder Settings help please

another note and something  to also check, after cleaning your nozzle as suggested above, is that an indication that the tension on the extruder idler screws are too tight is tight curling of the filament just as it exits the nozzle. You want the filament to drop straight down as it flows out when the extruder is up in the air away from the build plate.    When loading filament, if it is right, you will get a little cobra coil when the filament does finally hit the build plate

Of course, there will always be some slight curling occasionally, but if it happens all the time without fail then that could be it.

This older Prusa video has good info on extruder tension adjustment.

RE: Extruder Settings help please

Thanks @jbinfl, I will keep an eye out for too much extruder tension.  The filament does come start down.  I get the little curls, on the end, when I remove the excess filament that dribbles out & the new filament slowly weeps out due to internal extrusion pressure.  I think I got it working good now.

RE: Extruder Settings help please

I've had filament curl and stick to the nozzle since day one.  Generally it will "fall off" by itself, but once in a while it'll hang on for a while until the weight hits that threshold.  I've had it with brand new E3D nozzles, used nozzles, nickel plated anti-stick nozzles.  If there is even a wisp of old melt on the nozzle tip, I think you'll have the filament curling as it extrudes.

RE: Extruder Settings help please

If you do not now , press the button on the prusa printer for longer time, then you can adjust the z.

You could try, to clean out higher temps filament, if you are now using pla,

set temps to abs, 255, purge pla , lower temps again, and purge pla again with 210 temp.

Now abs will come better loose.

Also you could try a few retraction of the filament, in the hope that it cleans the nozzle.

You could order needles to clean the nozzle if you think something is stuck, use very  small ones, because you could damage the nozzle.

RE: Extruder Settings help please

Posted by: canquest

Thanks @jbinfl, I will keep an eye out for too much extruder tension.  The filament does come start down.  I get the little curls, on the end, when I remove the excess filament that dribbles out & the new filament slowly weeps out due to internal extrusion pressure.  I think I got it working good now.

Is it bad enough to disrupt prints? I used to dread printing skirts and supports because a bit of filament would invariably stick to the nozzle, drag across and mess up a layer. Since I started trying to be meticulous with nozzle and PEI care and using a silicone sock, I don't have the problem nearly as much. Coated nozzles seem to help, but good bed adhesion and that Live-Z are the most critical factors. Finding a good temp balance between nozzle and bed helps as well. I'm able to print supports at 0.25mm without issue if I do the prep work.

If I over-extrude, some filament will accumulate on the nozzle. I try to calibrate a good extrusion rate for each filament.

I keep the nozzle tips clean with my strip of cardboard and don't have nearly the issues I had a few months ago.

RE: Extruder Settings help please

Thanks @peter-m26, I like your "Z" tip about holding down the control button.

Thanks @bobstro,  I should have more conversations with you regarding the issues with creating supports.  I recently tried to print a piece that was small in diameter with a taper from .375" dia to .190" dia by 6" long, so I thought I could print it in the horizontal position using supports.  Yah, that didn't work.  Trying many times, several different cleaning & prepping methods.  Could not get the support structure to print without them moving, balling, or lifting the first layer of support.  I eventually printed this part in the vertical position.  Print quality was OK but did have a little waviness in the last 1" of print.