Extruded filament curls under...is this the root issue?

Hi All :smiley:

I am really struggling with my new Taz 3 printer. After 7+ hours I have one poorly printed octopus to show :blush:

Initially I struggled with getting the extruder to feed (did not realize I needed to use the pick to clean each individual groove out of the hobbed bolt after a failure) but now I think that is mostly resolved (combo of proper tension and meticulous cleaning) and I can get consistent test extrusions. After that was resolved I used the stock settings for ABS (230 nozzle and 110 bed) and on the first try printed successfully (although iffy quality and some gaps/etc). After that I revisited the bed leveling (using the lower than caliber, higher than paper method) and tried again this time with the recommended 85C bed temp and the twisted vase gcode and failed miserably for hours with no successful first layers. The extruded filament would not immediately stick to the bed, would drag around before eventually starting to stick, then jam (before the pause command could make it through the buffer to the printer)resulting in stripped filament and the exhaustive pick/brush/compressed air cleaning process.

Thinking the bed was too high I worked with leveling/z-endstop some more this time using a .305mm feeler gauge to try and be more precise than the paper/caliber method. At some point during these hours of failure the filament started extruding oddly. Instead of coming more or less straight out of the nozzle it immediately curls back under and onto the outside of the nozzle. It also seems like it is harder than it was originally to manually push filament through the heated nozzle by hand with the tension released.

Trying to print now results in a pile of stringy mess being pushed around by the nozzle. I am not sure if this is z-endstop/bed height related or nozzle related. Also note I am trying to use the bed at 95C vs 85C since the only success I had was at 110C

Any ideas?

I am using IC3D filament in low humidity 65F ambient temps

Pics/vid here: https://www.dropbox.com/sh/vhwudd2g46ggjnt/DAHfGfMNmg

A few things, I noticed which may or not be of help. My filament will curl if it is not in contact with the bed. You need to clean off those little curls as it comes down into contact with the bed using the little brush.

When my filament extrudes and does not stick to the bed it generally the result of:

  1. none to not enough abs juice.
  2. the bed or filament is not hot enough
  3. the nozzle is to far away.

You also mentioned your extruder strugiling to extrude necessary amounts of filament, i have a thread on that here. (https://forum.lulzbot.com/t/extruder-struggling/413/1) but assuming you haven’t taken the nozzle apart you could have a partially clogged nozzle. I have had this problem with cheaper filament (I do not know if the filament you mentioned is cheap or not). If you continue to have this problem I recommend you buy some filament from Lulzbot and see if that resolves some of your issues. When I bought there filament there was noticeable difference in quality and texture of the filament.

BTW: I have mentioned this tip before but if you do end up taking your nozzle off to check for and clear a clog make sure you use some high temp anti-sieze thread protection when you put it back together.

What material are you using? Is it ABS, PLA or something else?

The above tips are a great place to start, but I’d hold off on removing the nozzle for right now.

IC3D brand ABS

I worked on this another hour so and have some results. By going up to 110C on the bed and 237C ( :astonished: on the nozzle (for the first few layers) I was able to get it to stick a little. One leg of the octopus pulled up put the others almost worked OK. Cleaning the nozzle with the wire brush and lowering the z-height some more seemed to resolve/negate the nozzle/curl issue.

I am wondering if my super-cleaning of the bed is what made things go from sticking well to not sticking well at all. It was “sticky” from the factory wasn’t it?

I have some Lulzbot filament on the way and tomorrow I will procure some aquanet super-hold…maybe one/both of these will get things on track?

Are you using ABS juice?

No, nothing on the bed. This eve I had decent luck with 237 nozzle and 110 on the bed for the first few layers. Is this going to reduce the lifespan of the bits significantly?

Well getting ABS to stick can be an issue that why most guys print with ABS juice (or a particular type of hairspay-I have never tried hairspray).

Whip some of this stuff up and put t on your bed. Here is a video by Lulzbot http://youtu.be/Rl1aU2Ix_sA

As for but life. I don’t see how 7 more degrees will adversely impact the life of the nozzle but the pros might know more.

You need the juice! Nothing will stick to my bed without it. I have a hard time with it! :cry: The parts almost always curl at the corners.

I would take the nozzle temperature back down a few notches, it should not be affecting print stickyness and there is a risk you will melt the liner.

For bed stickyness, I see a couple things. From your pictures, you are starting too far away from the bed by a very tiny amount. Adjust the height so you are a little closer to it until it sticks. Be aware that the Height adjust thingy can migrate betweenprints from heating and cooling over time too. The best upgrade I ever did to my printer was installing a butchered micrometer as the height adjuster. ABS juice will definitly instantly help. You can also try roughening the surface of the green plastic sheet lightly with a red kitchen scouring pad (not too much, just dull the shine) Also, try printing your parts with a 3 to 5 mm “brim” in your configuration.

Should the Taz 3 bed be 110c? That was the proper temperature for the AO-10x series, but the Taz 1’s were supposed to be 85c The 3’s use the 24 volt bed though, so different heater entirely. If it’s supposed to be 110 anyways on a 3 (and i’d wait for confirmation from someone official on that) you may want to bump it up to 112 or so.

Thanks to all for the help! I was able to get several successful first layers and another full octopus last night (new pics added here): https://www.dropbox.com/sh/vhwudd2g46ggjnt/DAHfGfMNmg

I believe the key was dropping the nozzle a bit and the bed getting sticky/dirty from many failed attempts. After thinking about it the bed was sticky from the factory and only after my first print (which had no problems sticking the first layer) when I got all OCD and cleaned the bed did I run into issues.

The curling issue seems to be mostly cured/moot as well. I did clean it as best I could with the provided metal brush…not sure how much it helped but it is better now and it does not seem to be causing other issues as far as I can tell.

The new issue I am having is the tensioner is slipping on the extruder. I had 2 prints (twisted vase) that were working great (pics in folder) and suddenly there was no filament being extruder. Upon stopping and going through the hobbed bolt cleaning process (if only I could have a dollar for each time I have done that!) I noticed the tensioner was very loose. I assumed I had simply made a mistake and started the print again with special attention to tightening the tensioner (confirmed it was a little tighter than 10mm from the outside/top of the bolt head). This print was looking fantastic as well then it stopped extruding altogether again. I then confirmed the extruder tensioner was loose/around 11mm.

It seems the extruder tensioner is slipping up thus loosening. Is this a common issue? Since the surface on the right is very slick (was obviously the part that against the bed when printed) and slightly tilted back and the tensioner surface itself is almost rounded I can see how this could happen. My first thought is to rough up the surface on the right with sandpaper and if that does not work I could safety wire the extruder bolts to something lower to keep it from riding up. Surely I am not the first person with this issue? (will do a search myself in a minute :wink:

The idler tensioner bolt latch is designed to be able to lift up and release the idler easily, but it should hold the idler to the extruder body with a fair amount of force when it is down and latched. The two bolts and latch assembly should be at the bottom of the two bolt pockets in the idler itself, and it should require a couple pounds of force from your thumb to un-latch it. If it is coming loose easier than that, you don’t have your extruder bolts themselves tightened enough. You definitely don’t want the idler flattening the filliament or the hobbed bolt cutting too deep into the filliament, but you do want it tight enough that it is going to extrude with authority.

What is your nozzle size and layer height? Seems a bit much, or you are under extruding a lot (due to improper filament setting or loose idler perhaps)

Stock nozzle (.35)
I am using the lulzbot provided gcode (.2 for the octopus and .3 for the vase)

In the event the filament is undersized (say a 2.8mm diameter) and the slicer was set up for 3mm diameter filament you will be under extruding which could cause issues.
The filament grinding could be from the idler being too tight or an issue with extrusion. There might be a bit of a clog, or your hotend might not be aligned well enough with your extruder.

This is from the vase gcode:

; generated by Slic3r 0.9.8 on 2013-02-21 at 08:48:58

; layer_height = 0.3
; perimeters = 2
; top_solid_layers = 0
; bottom_solid_layers = 3
; fill_density = 0
; perimeter_speed = 80
; infill_speed = 105
; travel_speed = 130
; scale = 1
; nozzle_diameter = 0.35
; filament_diameter = 2.89
; extrusion_multiplier = 1
; perimeters extrusion width = 0.37mm
; infill extrusion width = 0.37mm
; first layer extrusion width = 0.45mm

After hitting the tensioner surface with sandpaper I printed out the entire vase (that thing is huge!) with no extruder issues :smiley: I am such a happy camper! Pics will be uploaded forthwith. I also printed out an octopus that is pretty much identical in quality to the one shipped with the printer. Win!

Link to pics has moved to here: https://www.dropbox.com/sh/chnlr1qjc18uw6g/shtz54-KRR