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Hello, I've been having some issues with backpressure on my rostock. I recently upgraded to an e3d v6 lite (I had some issues with the stock one). Small prints seem to work fine but anything larger seems to build up backpressure and eventually causes the filament to get ground out by the drive gear. This happened pretty quickly on my first print. I was printing PLA at 45mm/s at 210 C. The second print made it much longer Printing at 35mm/s and 195C. I also decreased the acceleration of my extruder to 4500 (as was recommended in another forum). Anyways let me know if anyone else is having this problem and any solutions anyones found. I'd eventually like to be printing much faster.

Might have to slow down or turn the heat up. Maybe both. The E3D lite is somewhat new, not sure of the performance specs.

e3d states it can print up to 50mm/s I can try going hotter but 210 seems pretty hot for pla already. I've heard printing pla hotter can lead to more jams

Are you certain that you cut the PTFE tubing cleanly and bottomed it out against the nozzle during assembly?

Dis you reflash your firmware?

PLA can take up to 230C in some cases, depending on the formulation. What brand?

I run contrary to the advice of pretty much everyone else on the forums and print PLA at 225. Seems to be the sweet spot to eliminate stringing, at least for the brands (yes, plural!) I use.

I also coat my PLA with Pam cooking spray (canola oil), otherwise it WILL jam up after awhile.

You might also check to see how hot your stepper motor gets. If it's too hot to hold on to, it might be heating the filament so much as it feeds it that it softens it up and then eats it.

Lite6 is fully PTFE lined, so no need for oiling the filament.

I did my best to cut and bottom out the PTFE lining, not to sure how perfectly flat you can get by hand.

Firmware was flashed with updated thermocouple settings

I am currently using foxsmart PLA, on their website they recommend 185-195C

Stepper motor was easily touchable (I had the same thought)

I'm with Ben, I print with PLA hotter than most it appears. I print 2 thin wall hollow cylinders with a 20mm gap to calibrate the temp for stringing and layer adhesion. Then write the settings on the spool. Brands and even color can sometimes vary greatly.

KAS wrote:I'm with Ben, I print with PLA hotter than most it appears. I print 2 thin wall hollow cylinders with a 20mm gap to calibrate the temp for stringing and layer adhesion. Then write the settings on the spool. Brands and even color can sometimes vary greatly.

Hmm, I like this idea. I'll give it a try. It just seems that I don't see problems for a while into the print. Maybe i'll just do some really big cylinders

Do you have a fan blowing on the cold section of the hot end? You're describing "classic" heat-creep.

g.

so printing again last night, I was able to finish the vase by uping the temp to 225 and lowering the speed to about 30. However the filament was still slipping on the drive gear causing some bands in the print. (the filament was definately slipping, I felt it by hand as it printed). So printing way slower and higher temp I was still having some issue. Theres gotta be something else wrong. any other ideas?

geneb wrote:Do you have a fan blowing on the cold section of the hot end? You're describing "classic" heat-creep.

g.

Yes, I have the fan that came with the e3d on the heat sink part running whenever the extruder gets power to it.

So I think I found the problem. I decided to replace the heatblock with a volcano heatblock. When replacing there was some black buildup around the edge. I'm guessing the PTFE tube wasn't flat enough and it was leaking a bit. I tried recutting it but I'm not sure how flat i can get it. does anyone have any tips?

dylantep wrote:

geneb wrote:Do you have a fan blowing on the cold section of the hot end? You're describing "classic" heat-creep.

g.

Yes, I have the fan that came with the e3d on the heat sink part running whenever the extruder gets power to it.

As in, running off the same wires that are powering the heater itself?

no, the fan runs separately and is plugged into heat 1

So after trying to recut the ptfe I am still having the same issues. on longer prints the drive gear starts getting all gummed up with filament bits. any other ideas?

After some more experimenting I'm beginning to think the issue is with the ezstruder. This problem has occurred with e3d lite, e3d lite with volcano, and now e3d v6 with volcano hot end and with 0.4mm and 0.8mm nozzles.

I have reduced acceleration to 3250 for extrusion. my motor current (wantai motors) is set to 200 and I have tested with extrusion temperatures ranging from 185C-240C with PLA. Every time I print the filament slips and the ezstruder gear starts grinding it until it fills up.

is there anything else I could be missing? I'm really starting to get frustrated. I built this thing 6 months ago and still have not been able to successfully do a larger print.

A few thoughts...

Are you overretracting? Have you tried a test print with 0 retraction?
Does this happen with more than one brand of PLA?
Does this happen with ABS?
When it jams, can you feed the filament by hand?
Is your drive gear clean & free from debris?

BenTheRighteous wrote:A few thoughts...

Are you overretracting? Have you tried a test print with 0 retraction?
Does this happen with more than one brand of PLA?
Does this happen with ABS?
When it jams, can you feed the filament by hand?
Is your drive gear clean & free from debris?

my current retraction is at 3mm. I will try less but the grinding seems to occur during extrusion rather than retraction
This has happened with every filament I have tried, PLA, ABS, Woodfil
The extruder is not jamming so yes I can still push it through by hand
The drive gear is coverd in debris (see picture two posts above). It starts off clean but during printing the drive gear starts grinding away at the filament until the gear is too full of debris to extrude.

Maybe it's retraction speed? Are your retracts too fast? I do about 20 mm/s for PLA, 90 for ABS.

I'm somewhat out of ideas. If you can push it through by hand no problem (all the way through the bowden tube, right?), that eliminates a lot of the usual suspects. You said the stepper motor was cool to the touch, but I'd try pointing a fan at it anyway. And try some canola oil on the filament if you haven't already.

I still think you should try running a test print with 0 retract and see if that helps things any.

3mm is right on the edge of what you can get away with on an E3D without it jamming, I'd certainly try disabling retraction and see if that resolves the issue. I usually run 2mm for PLA, but running a print with 0 will rule out an issue if it still happens.
I assume you've tried different filament? You see the occasional roll that is slightly oversized or that has air bubbles intermittently in the filament, those will jam at the entrance to the bowden tube, and subsequently it's hard to diagnose because the wider section is pretty much eaten by the extruder. You might want to try examining 3 or 4 meters of filament closely for any issues.

BenTheRighteous wrote:Maybe it's retraction speed? Are your retracts too fast? I do about 20 mm/s for PLA, 90 for ABS.

I'm somewhat out of ideas. If you can push it through by hand no problem (all the way through the bowden tube, right?), that eliminates a lot of the usual suspects. You said the stepper motor was cool to the touch, but I'd try pointing a fan at it anyway. And try some canola oil on the filament if you haven't already.

I still think you should try running a test print with 0 retract and see if that helps things any.

My retraction speed is set to 15mm/s. I have also tried the canola oil but I just wiped down the first couple of cm of filament with it so the surface was shiny. should I use more than that?

the motor is a little warm but I don't think its anywhere near hot enough to cause problems. I definitely wouldn't call it hot.

I'll try 0 retraction next time I get a chance

Polygonhell wrote:3mm is right on the edge of what you can get away with on an E3D without it jamming, I'd certainly try disabling retraction and see if that resolves the issue. I usually run 2mm for PLA, but running a print with 0 will rule out an issue if it still happens.
I assume you've tried different filament? You see the occasional roll that is slightly oversized or that has air bubbles intermittently in the filament, those will jam at the entrance to the bowden tube, and subsequently it's hard to diagnose because the wider section is pretty much eaten by the extruder. You might want to try examining 3 or 4 meters of filament closely for any issues.

I have printed with 3 different rolls of PLA (from the same company) 2 ABS's (from different companies) and a woodfil. I had the same exact problem with each. I have also used most of these filaments in my other printer with no issue (though my other printer is direct drive)

Tried a no retraction print. It failed even faster. I think the problem is coming from some sort of back pressure maybe? maybe in the hot end or the bowden tube?

I am having the same exact issue. I have been printing with ABS so far without any problem. I just started to use PLA yesterday after 15-20 minutes of printing the material back-up in the extruder and jam. First try, 200C. Second try 205C. Third try 210C. However, I was able to print more material before it jammed as I increased the temperature.

What I found out is: as time goes by, the whole nozzle assembly gets warmer and the filament starts to melt in the nozzle closer to the tube and stick. The last time it happened I removed the tube attached to the extruder, set the temp of the nozzle to 200C to be able to pull the filament and nothing happened. The filament was stuck in the nozzle. I had to wait several minutes while gently pulling on the filament until it came out.

I have a fan installed at the nozzle and I dont know what to do. Is my temperature too high? Still too low? Are the extrusion speeds all messed up?