what am i doing wrong?

ok, so i posted before about chewing up my abs filament, i keep getting inconsistant results
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i printed out 2 BEAUTIFULL whistles, a heart shaped box with lid, a 40mm fan and mount

now i cant get past 1 layer, as soon as i hit layer 2 it just gives up and chews up filament
i didnt change any settings and same result, i try lower temps, same results

i KNOW i can print, ive seen it happen, i dont get what im doing wrong?

Hummm.... I think at the point you are at, it might help to take apart the extruder? Sometimes things will wear a bit, or seat themselves, especially when exposed to heat. Next thing you know, things are not lined up right... If you have the hot end off the extruder, you could clamp it shut around a bit of filament and just force it through by hand. That might reveal if it is binding somewhere.

BTW, if you can cut a radius into the idler bearing, that would really help. I've extruded about 3 lbs of ABS so far, on only three different extruders, and a radius or toroidal groove on the idler bearing allows you to put a much higher load by tightening the springs without having to worry about crushing the filament.

If it gets crushed out of round as it goes through, it can jam further downstream.

Also, what software are you using? I'm using Slic3r with Pronterface, and for some odd reason I've had a few prints where the extruder would not move up the Z axis after the first layer. That is the only times my extruder chewed up the ABS.

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Yvan

Singularity Machine

running same software on a prnterboard

how would i go about cutting that grove in the bearing?

also a side question, when i home my z axis how far off the bed should the nozzle be? dead on right on the tape? or like a .1mm above?

I've been printing on glass, so there is no real friction if the nozzle touches. Sometimes it is up a bit, about 0.1 mm, other times it touches. Some say it could plug the extruder up if it touches, but I have not seen that, maybe because I use higher pressure on the idler bearing?

I cut the groove with a Dremel tool, using a cut-off disk at a slight angle so it takes out more than a thin slice out of the outer bearing ring. I mount the bearing so it can spin as I do that, and I slow it down with my finger tip so it doesn't just free wheel like mad under the cutting disk.

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Yvan

Singularity Machine

yeah, i dont get how i printed other parts before and now cant, and its consistently the 2nd layer when it starts acting up

Just an idea... what if you try and print a very small part. Will it make it to higher layers before quiting?

The notion being that if it is heat related, it would take a certain amount of time to soak up into the extruder. If it still dies on layer 2, than maybe it is software?

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Yvan

Singularity Machine

I had a problem with the hob loading up with plastic filament. This causes a slippage and the filament stops feeding.
The hot end works great, 40 watts with a custom brass nozzle. The brass maintains the heat at a constant 235.
I tried air pressure to clean out the hob, but this process is real pain.
So I tried some heat sink paste, which I applied sparingly to the filament.
Works great!!!! THE HOB STAYS CLEAN, NO PLASTIC BUILD UP.
Just one small step for mankind and one giant leap for problem free extruders.

Did you by any chance readjust your bed height before you started having the problem? Also Are you using PLA or ABS? What is the hotend temp? Some brands of filament are rounder than others and as such are prone to causing jams or as the flat travels thru the cold end are now under insufficient tightness or may be too tight.

I see you are using the Greg Wades Extruder,

I have found a problem with it.

The idler bearing can spin freely, but

When you push your hinged idler all the way up and push it towards the hobbed bolt, does your idler still spin?

I've found that the idler bottoms out as it gets closer to the hobbed bolt.

I had to file down the area right below the idler to stop this from happening.

ABS, no i havent readujsted the bed height. before each print i do home the z. hotend is running at 229

the idler doesnt spin freely, but it does move.

consistently its the second layer, first layer is slow and smooth, but as soon as layer 2 starts it just gunks up and starts chewing up, any suggestions?

a

Edited 1 time(s). Last edit at 05/06/2013 04:49PM by matrix4721.

Have you checked to see if the Z axis motor is turning (lifting) just prior to starting the second layer?

yes the z does lift

I have also cleaned up the idler to let the bearing spin freely. Maybe when it gets to the second layer and attemps to extrude faster the friction on the idler bearing is to much?

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Yvan

Singularity Machine

Attached is a picture where I'm pointing to the area with a file, that I had a problem with.

I had to file down quite a bit material to make sure the bearing didn't grind against the bottom.

i did some cleaning up of the idler, seems to be feeding nicely, the last problem i seem to have is that im thinking the glass i have isnt exactly flat? it seems that one side is widly not as level as the center, i z everything out then print, and next print youd think that someone changed everything around on me

im planning on getting some aluminum spacers when time allows