How to fix a clogged nozzle

This is one is fun....not. This is not a real easy process but it seemed to work for me and it may not be the best way.
One thine I would do as a check first is the list
make sure extruder is heated to at least 175 move the z axis up about 20mm and hit the extrude button if filament comes out you probably do not need to do this procedure, also I would try going through the changing filament process and see if it can indeed be pushed through. If not proceed at own risk.

Step 1 remove not end from chassis, two screws on the side of the chassis just in front of the extruder motor need to be removed. These are long screws and actually hold everything in place so be careful taking them out.As they do come out the hot end may simply drop out and it is made from PEEK and could break if it just dropped out so be careful and allow the hot end to gently slide out. You will also have to remove the Kapton tape so have some more on hand to hold things in place again when you are done.

Step 2 the nozzle at this point should be simple to unscrew from the PEEK part but due to heat expansion and the different materials involved it probably won't unscrew easily. The trick I found was to heat the extruder again and as it heats up there should come a point where it does unscrew fairly easily but things will probably be too hot too hold easily I used a two wrenches and gently applied pressure to unscrew them. Again the materials are PEEK and brass and can be damaged so be careful. The heat may also soften any material left behind which may also be hold things in place.

Step 3 PEEK SECTION: Once the two parts are apart. Examine the PTFE plastic tube inside the PEEK it should be in fairly normal condition Mine had some residue which easily scraped off with just my finger nail and had some build up at the tip which I also cleaned after that the PTFE tube looked pretty good. ALL this was done while it was in the PEEK. The PEEK and the PTFE tube must look in fairly good shape if either are melted they need to be replaced and it means thing got way too hot at the HOT END.

Step 4 NOZZLE: The trick here was getting into the nozzle hole, I found that a single strand of 20 Gauge stranded wire would fit nicely so I cut 2" piece stripped the plastic casing and removed a single strand. So from the nozzle end I used that to try and push back any material.From the other side, where the PEEK assembly screwed in I used a small drill bit and simply twisted it with my finger to try and catch on any material that may exist and take off little chunks of it and then tip it over and tapped it on the surface to dislodge anything that did loosen up working form both side as best as I could I managed to get the wire through the nozzle to come out the other side freely. At this point I used the wire like a little scrubber by pushing it through from the nozzle side until a large segment of wire was through and visible on the other side I then crumpled up the wire on that side into a small bundle of twisted wire not to tight but enough so it would be hard to pull directly back through the nozzle. I then did just that I pulled it from the nozzle side and forced teh wire to straighten out before coming through, I was also twisting on it to have the wires act like small little scrapers to try and remove any excess material I could. If the hot end is clogged really badly you can try heating it your an oven to try and get the material to a softer point and the follow the procedure above and repeat as necessary. IF the material you think the nozzle is clogged with has a solvent like acetone the soaking the nozzle itself will also soften the material inside or eventually dissolve it completely. Only do this to the brass nozzle.

Step 5 Once the nozzle and PEEK are both cleaned to an acceptable point simply screw the pieces back together and replace the assembly back in the chassis. You may see two small grooves in the slot on the PEEK where those first two screws held it in place. It is kind of key to get those lined up with holes in the chassis and with the nozzle tip also postion where it was originally on the left side and squared to the front when viewed form the front. This may be tricky but everything must also be tight. Do not break the PEEK though.When it is done the assembly can be slid into the chassis and the two screws replaced I would do this very very evenly as the screws themselves may help align the PEEK slot back into its original position so both screws can be screwed in completely. Remember these are only screws and you do not want to break one of these off inside the chassis. If this does happen you will most have to print or buy a new chassis piece. Once both screws are back in replace the kapton tape hold in the wires in place for the heater and thermocouple and you should be done.

Good luck and all I can say is this is how I did mine there may be other ways possible sorry if it is too long but it should be complete.

 

It may not be clogged up but jammed up you may need to look at the PTFE plastic tube inside the PEEK piece which means going trhough the process I described above at least to determine what kind of condition the tube is in if it is melted or anything you have a different set of issues have you been running a fan on the hot end or just by itself.

After the filament goes into the hot end the next thing it hits is that PTFE tube if it is messed up that would be the most likely source

 

I would also check to make sure the filament is entering the top in a directly downward direction, going in at an angle could be allowing the filament to come off the hobbed bolt to the side and force the jamming but after that point it is most likely internal

 

I have the E3D all metal one seems to be doing well and is a good price only issue is it is out of England and is about a 3 week turn around. It is supposed to fit right in the same whole but the locking mechanism may be an issue(those two bolts) on mine they seemed like they actually cut into the PEEK abit. That will be hard to do for aluminum without breaking the bolt I think Cambo is working on an alternate method to lock it down.

At this point I am still using the one that came with ROBO

 

The simple test for this is to change to a new filament. when you open the filament loading area by loosening the two bolts be on the lookout for little scrapings inside while this does not prove the nozzle is blocked just make sure the hobbed bolt is not filled in with filament scrapings blow out any residue put new filament in the hole and before you close up push downand see if filament comes out the bottom. If it does then your nozzle is most likely not blocked. I would then close it all up and raise the z axis and have the system do an extrude of say 50mm if it comes out again then it may have been that the hobbed bolt was just clogged up. If it does not, open up the filament chamber again and see if it is still clean. If it is jammed up in side and shows a lot of residue you may have a melted PTFE tube that is blocking the filament from going down easily

 

you can also use a single strand from 20 Gauge stranded wire just remove the casing and use a single strand