Gears turn but filament will NOT extrude

Hello,

I am working with RepRap I2. I have printed with it multiple times before, I know it has the potential to work. After sometime printer were not as neat because the filament was not coming out smoothly, which may have been due to inconsistent filament diameter since it was some mystery sample of PLA. Anyway I have cleared out the old PLA I was using by taking apart the extruder and just heating it up so I could pull the jammed filament out. I have also cleaned the teeth on the gear that is suppose to pull the filament down. Now that I have new PLA filament I thought I wouldn't have anymore issue. However when I loaded the filament some of the old filament leaked out (expected), however I still cannot get the new filament to extrude. I am trying to extrude in in 5mm increments, and it works up until a certain point, then it doesn't pull the filament anymore. It reverses perfectly fine, but I can see some "chewing" on the filament. The filament I am currently using is 1.75mm and I am printing at 185 degrees. I'm not sure how tight the tension screws should be, but they seem fine, I think.

Has anyone run into this problem before? I am almost certain it is not a filament jam since I just cleared an old one. I'd love to hear any suggestions and and I am happy to provide any additional information and images.

Thank you.

Increase the tension on your extruder. There should be enough tension so that the motor skips rather than the gear chews the filament. If your motor does skip, then you know you have some kind of jam issue.

You might want to try different temperatures... some filament (e.g. black) is more thermally conductive than others (e.g. clear).

Check the manufactures suggested temperature, if marked upon the filament

185 is a bit low for PLA maybe try it at 195 or 200

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Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)

Is the best way to increase tension on the extruder to adjust the tension screws? I have tightened them all the way down and it did not make a difference, and I have also removed the springs on the tension screws and tightened them all the way down. Neither of these made a difference. How do I increase the tension enough so the motor skips and the filament isn't chewed?

The makers of the filament recommend between 180 and 210

Quote
adenton
The makers of the filament recommend between 180 and 210

In this case, I would set the hot end temp to 195
To get that figure do the following (180 + 210) / 2 = 195
Then adjust up/down 5 degrees (if needed) each time but don't go above 210

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Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)

I'd say power the machine off
Take the hot end off.

And then feed filament through by turning the gear by hand.
With the hot end off, you can observe the teeth mark left by hob.

Tighten the pinch wheel until you get bites in the filament along the lines of the depth in the picture here.
Don't worry about the distance apart, that's possibly a different drive gear. But the depth should be similar.

Also observe to make sure the filament is still round when it comes through
If it's oval, you have it too tight.

Other than that, make sure that the voltage for the extruder stepper driver is correct

And try higher temperatures.

I'd say if you get to this point, you probably have a blockage in the nozzle.

You could try the cold pull.

You could try putting something up the nozzle to unblock it, I generally use a like 3 strands from a piece of wire twisted together.
As well as do a cold pull afterwards.

Edited 1 time(s). Last edit at 12/08/2016 03:53PM by FA-MAS.

What's a cold pull? I'm getting some okay teeth marks but I can't seem make tension screws any tighter though. I think I might disassemble the hot end again and just run a small pin through there. Also, is it possible that the filament in slightly missing the hole that it is suppose to be feed through? I've tried cutting an angled tip on the filament to help guide it but that didn't seem to do the trick.

I had an issue with misalignment.

You'd know if it was catching on a transition somewhere
If you feel it hang up when you first put the filament in, you can estimate it might be when it first enters the hotend
If it's further down, it's probably the transition from heatbreak to nozzle.

Cold pull is where you heat up the hotend to whatever your regular printing temp is for the filament you use.

Then lower it to the point where it's in a slightly gummy state
And then pull it out

It will grab onto anything that might be clogging the nozzle and pull it out.

http://bukobot.com/nozzle-cleaning

It works best with nylon, but you can do it with ABS and PLA too.
Just gotta get that gummy temperature right. It might take some trial and error.

I found it to be about 95c for PLA

Edited 2 time(s). Last edit at 12/08/2016 05:28PM by FA-MAS.

Probably if you have teeth marks on the filament, you have enough tension.

I'd also be looking at the hot-end. I'd be trying things like pushing the filament down by hand... sometimes you can feel if the edge of the filament is catching on a ridge inside the hot end, and twist and push past that point.

Measure the actual diameter of your PLA... I had some that was way too big, and wouldn't even fit down the hole in the hot-end.

Thanks! I'll give some of these a try tomorrow!

Maybe it's just some dirt blocking the nozzle. If you have a spare nozzle, try that one.

Fwiw,I had what i thought was a blocked nozzle,e.g.no output,gears turning intermittently,stepper very hot to the touch.(wade's type extruder,clone v6 hotend)
After completely pulling the extruder system apart,the problem turned out to be the printed small gear.
It has a pocket for an m3 nut,to fasten the gear on the stepper shaft.The plastic on the outside of this pocket had fractured,due to some fool(me) overtightening the setscrew.
Therefore causing the gear to slip on the shaft,until the filament jammed.
Since your gears are still turning,this is probably not your problem,but if you have a wade's extruder,it may be worthwhile to check the small gear for cracks.

In the past 2 days I have taken apart the extruder and x-carriage. I cleared our the extruder by just heating it and scraping out any remains with a small tool. I've gone back and forth with 1.75mm and 2.85 filament but still no luck. Actual, the 1.75 filament seems to get tangled in the nozzle. However the gears are still pulling the filament in to the extruder up until a certain point. Then the hob bolt seems to think its a cheese grater and starts to shred the filament. This happens with very little tension too. I think I want to replace my hob bolt. Would someone be able to provide me with a link to one that they would recommend? Also, I'm thinking about replacing my extruder tip/nozzle. I don' know what kind/brand I am currently using, but if anyone has any recommendations that would be great.

http://e3d-online.com/Hobb-Goblin-8mm-Shaft

You probably don't need unless your current hobb is completely amateur and inconsistent teeth.
Sounds like you're dealing with a blockage or a temperature vs speed issue

Generally the grating is that the force to overcome whatever reason the filament isn't moving is greater than what the extruder can push.
Wade's style extruder is usually 5:1 gearing so you should have quite a bit of torque.

You may want to adjust the stepper driver voltage down. It should actually lose steps rather than grind the filament.

I'd say for the mean time take the extruder out of the equation.

Undo the pinch wheel all the way and feed the filament by hand.
It should be fairly easy to do so
If it doesn't there's probably still a blockage in the nozzle

If it moves easily, you're probably clear on the blockage, and temp should be ok
It could be a speed thing.

What speed is it trying to extrude at?

Edited 2 time(s). Last edit at 12/14/2016 03:16PM by FA-MAS.

Quote
adenton
Is the best way to increase tension on the extruder to adjust the tension screws? I have tightened them all the way down and it did not make a difference, and I have also removed the springs on the tension screws and tightened them all the way down. Neither of these made a difference. How do I increase the tension enough so the motor skips and the filament isn't chewed?

Correct me if i am wrong, have you re-fitted the springs, afaik it relies on the springs to set the pressure on the fillament.