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Filament flakes and shoddy lines
#1
I finally got my old extruder running and I need to print out my new carriage design for the mk9. But I'm getting really bad prints. Not as bad as before but I think my extruder keeps getting clogged. Now for the gears stripping filament. Is it because of heat creep or the gears are too tight? I've noticed stringy prints with spider webs from only a temp of 208C. I don't know what the problem is. I just unclogged my extruder by hand yesterday with acetone and I used a needle to scrape out the hardened abs. Then today it clogged again on the first print.
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#2
Please anyone? Can a clog cause the gears to strip the filament?
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#3
check if the spring is not too strong for the filament you are using, if the filament is naturally soft you may need to use a less strong spring to avoid a dirty drive gear
another thing come in my mind is: extruder may be not cooled enough, so gear is hot, making the filament smoother, and then making the spring too strong and will dirty drive gear

but can be others root causes of course
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#4
Arghh I'm getting sick of this printer. I loosened the gears a bit and it's not chewing but it's essentially doing the same thing. The filament doesn't seem to go down at the right thickness. If I change it from .4 to .1mm it makes no difference. I even changed the hotness with a clean de clogged hotend that I cleaned any spec of abs out of. Yet still I have the same problems. Here's a pic of the abs mess I'm printing.


[Image: image-4.jpg]
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#5
Changing temps don't really have an effect on the prints either
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#6
Since no one has any ideas left. I modded the davinci carriage to hold my mk9. Since I couldn't print the carriage. I will see if I still get jams on the mk9. This will tell me it's the filament. But I don't think its the filament because I opened a new cartridge and it still jammed.

Does anyone know the tolerance the gears should be set at? Is there a way you can tell if the gears are too tight? Right now my mk9 has very light teeth marks in the filament when I run it through the gears. Should there be any light teeth marks?
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#7
By the looks of your pictures it looks like you need to come down with the extruder or bring the bed up. Most important before doing anything is to get your print bed as level as humanly possible. Then after that you can adjust your hieght of the extruder.
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#8
Man, i can understand your frustration, those are horrible. To answer your question the extruder jams for two reasons, one being creep in the heatbreak that softens the filament too early and causes a plug to form after retractions, and two the nozzle is too close to the bed causing back pressure.

A clog will cause the gears to shave off filament, as well as not having enough tension between the gears. Look at your idler bracket to make sure its not hitting the notch already, effectively not letting the gears clamp down tight enough.

Kieth had a good writeup on this in the hardware section I believe.

U didnt happen to clear a previous jam by sticking something hard up into the nozzle did ya? Brass is very soft and scored easily by a harder metal. If the nozzle is full of scores from this, it will forever be prone to jamming. When u manually extrude, does the filament drop down straight, or does it spit out at an angle? If its not comming out straight down, you still have something clogging the nozzle.

If you just wanna print your carriage out so you ditch the stock gears, oiling your filament with olive oil will probably get you through it.

Edit: I just saw your post on stainless steel PLA, pretty much answers the question concerning nozzle scoring, unless you are using a stainless steel nozzle. Wink
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