SoliForum - 3D Printing Community — Extruder problems

Re: Extruder problems

2013-03-25T15:17:10Z

I've been getting alot of clogs lately... One thing that helps is an acetone soak for the nozzle.

What most folks do is to remove and disassemble the whole hot end assembly, but I think I found a better way.

I take a shot glass that has a deep recess on the bottom, pour some acetone in, position it under the nozzle, and raise the bed until the nozzle is submerged about a half inch or so in the acetone.

Let it soak for about 20 minutes. You may need to replace some of the acetone, as it evaporates...

After the the 20 minutes, remove the shotglass, pour any leftover acetone back into the container, and heat up the hot end.

Extrusion at it's finest.

Nonetheless, I will be getting a new hot end soon, as I am tired of losing big prints to small clogs...

Re: Extruder problems

2013-03-25T08:15:05Z

I know you already tried loosening the tensioner, but that is normally the thing I would do if I was testing with it extruding in mid-air, and it was still skipping. Another possibility is trying to extrude too fast and the heater not being able to melt the filament quickly enough. Further down the list is the less likely but more painful possibility that there is an obstruction in the nozzle or the filament is fused with the plastic insert in the hotend. The latter is very unlikely unless the hotend got too hot - I haven't heard people mentioning that problem unless it went over 220, but it happened to me at 205 with my SD2. I ordered a new hotend and then disassembled mine and carefully drilled out the filament from the middle of the insert until i got to the nozzle. I reassembled and was able to begin printing, but I did switch out the hotend with the new one once it arrived a couple months later.

Re: Extruder problems

2013-03-25T00:22:13Z

ok, I fixed the bed height with the longer screw... but my filament is still skipping.

Re: Extruder problems

2013-03-25T00:18:20Z

I found a longer screw (I build rc trucks) so I;m going to try it again...

Re: Extruder problems

2013-03-24T23:10:41Z

Yeah, in Repetier, go to the Manual Control tab. Look down to where you see Speed, Extrude, and Retract. I set Speed to 200. For retracting the filament, 50-75 should be enough, but you may need to help the motor along by pulling lightly on the filament (since the drive gear is not very effective at the moment). Click the upward arrow to have the motor retract the filament. In general whenever backing out plastic, I loosen the tension and pull out the lever so I can slowly pull out the last of the filament - this is because I notice a couple boluses (bulges) of plastic near the end of the thinned filament, and I've had times where they are ripped off and left in the extruder channel, needing to be carefully fished out.

Re: Extruder problems

2013-03-24T22:57:35Z

I can see buildup on the drive wheel!

Is there a way to back out the filament using the software?
Or, do I unscrew the tension screw and pull it out?

Re: Extruder problems

2013-03-24T22:55:02Z

You may have done the obvious, but check the extruder motor drive gear as a clog will typically cause the drive gear to eat a divot into the filament (you may notice it as the plastic is retracted out of the extruder). The plastic powder coats the drive gear and lowers its ability to move fresh plastic (even if you retract it and start with a fresh end). I take a can of compressed air with the little straw and blow out the powder around the gear when that happens.

One theory might be that your z-level was out of whack and the print attempts were too close to the surface such that the back pressure of the plastic back up the nozzle caused the divot. That would lend some support to the idea that the printer later scraped the surface.

BTW, I occasionally do quick checks of filament being driven by pinching the plastic and seeing if my fingers are drawn toward the extruder.

Re: Extruder problems

2013-03-24T22:54:35Z

Flipping the switch manually did set the bed lower.

My extruder still isn't moving a lot of filament through.
It was at 200 c
It seems that the filament is skipping between the wheels... it makes a sorta popping sound.
I tried tightening and loosening the screw, it does it both ways.

Re: Extruder problems

2013-03-24T22:53:42Z

Are the switch mounting screws secure and the switch not loose to move up or down?

Re: Extruder problems

2013-03-24T22:46:24Z

This last one was a little better, the head didn't dig into the bed but it's still too low.
I think that's when the filament is skipping, it's getting smashed into the bed.

Here's the bad part, I have the Z Depth screw and the bed leveling screws all the way down.

I need to adjust it in the software but do not know how.

I have not tried to flip the switch manually but will give it a shot.

Re: Extruder problems

2013-03-24T22:40:31Z

Yes, tightening all the leveling screws will work also.. but there must something else going on if the ztab screw won't do it. when you raise the bed what happens when you activate the ztab switch on the back left side of the bed?

Re: Extruder problems

2013-03-24T22:36:35Z

that's what I thought but I have it almost all the way down and I swear it's worse.

I just figured out that you can lower the bed with the 3 screws in the face of the bed.
Trying to print again.

Re: Extruder problems

2013-03-24T22:26:05Z

turning the ztab screw CW from the top should lower the bed???

http://wiki.solidoodle.com/first-layers … e-z-offset

Re: Extruder problems

2013-03-24T22:22:08Z

How do I permanently lower my bed?

I just put a big scratch in the film over the bed... down to metal.

Re: Extruder problems

2013-03-24T22:14:46Z

make sure the temp is 200