Extruder stops - filament issue?

My Reprappro Huxley worked almost flawlessly with the filament supplied in the kit. However, after trying a new filament I have had nothing but problems. The extrusion often stops mid print, ruining the print. The hobbed bolt digs into the filament, but the extruder stepper motor works just fine. In other words, the printer prints in mid air.

I have searched the forum, and it seems that many have had the same issue. Some say that this could be caused by to low temperature (making the filament to hard to extrude), while some say the temperature might be to high (making the filament melt to high up on the hot end). I have tried everything between 185 and 210 degrees and the same problem occurs after a while. I also have a fan at the extruder.

I have tried to tighten the hobbed bold feeding the filament with no result. When I drag out the filament after this issue and clean the hobbed bolt, a new print can be started immediately with no problems, so there seems to be no issue with the hot end itself. However, the new print often stops with the same extruder filament digging after 10-30 minutes.

Now, I suspect that the root cause of the problem is the filament and not the printer. I measured the filament diameter to be between 1.75 and 1.98mm! Could it be that the filament is to wide to be pushed through the bowden tube? (I have ordered some faberdashery filament, hoping this filament is way better than the crap I have at the moment). In the meantime, could there be other issues with my printer that I should inspect?

Edit; Forgot to tell that the filament is PLA

Edited 2 time(s). Last edit at 08/16/2013 03:15AM by Jokek.

I've been having similar problems using 3mm PLA. I'm using the Magma nozzle which seems to suffer from heat travelling up the filament and causing it to jam. I've seen recommendations to tighten the idler more but that doesn't seem to help. Even without jamming it's fairly easy to have the hobbed bold gouge out the side of the filament so it stops moving. There seems to be some dissatisfaction with the Magma's performance with PLA.

I'm considering just switching to ABS for now until I've got this sorted out. It seems the Magma nozzle might need some heat sinks and I might need to run the nozzle hotter than 185C for PLA.

I'll be interested to see what others have to say about this.

Measured the filament again. It seems circular, but is 1.95mm on average. Anyone else supporting me in the hypothesis that this is the main cause of my problems?

i had similar experience just recently. My printer was printing fine no issues with the two main suppliers I use (LulzBot and Ultimachine 3mm PLA/ABS) but then I decided to try out a different supplier (wont name dont want to talk poorly since I've only tried one spool from them). Always fails to extrude some point during the print. Tried a different range of pressure on the guidler, different temps, etc. nothing worked. Finally got another shipment in from ultimachien and everything is printing beautifully again. So it is quite possible that I just had a poor quality roll

Now I can confirm that my filament was rubbish. Recently I received my faberdashery order, and the printer now works flawlessly on hour-long prints. It seems that all my debugging trying out different settings and temperatures was useless, albeit I learned a alot. I will never order cheap crappy filament again. It is not worth the struggle.

It seemed that the cheap filament (which measured 1.95mm) gave too much resitance through the extruder mechanism and the Bowden tube.

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Happy printing,
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Im having a sort of similar problem. My I2 was printing like its normal finicky self (mainly nylon). I bought some PLA (first time I orderd, my used I2 came with a roll of pla and nylon, now on my 3rd spool of nylon) and now my flow seems to start "drying up" after about 1/2 way into my prints. The walls become thinner and fill stops connecting and then just printing in mid air. IF I pause the print and turn the extruder wheel by hand, comes out fine. I thought it may be the pla filament being that Im still new to pla, but it looks like its happening when I use nylon also. I put on a new nylock nut on my hobbed bolt (the person I purchased my I2 from had a printed nut on there)and tighten it with no avail. Im about fed up with it at this point.