Clogged Nozzle

[tcat007]

On about my 4th print (tall recorder-flute), and at about the last 3/8" the ABS quit coming out of the nozzle (maybe 15 minutes before the end of a 7 hour print). Nozzle at 230c. What would cause a random blockage? Hatchbox Red ABS. Best way to unclog? (I've read about a torch, sounds scary.). I tried extruding 10mm a few times, but nothing, so it wasn't the program. I plan on editing the stl and printing the last bit separately and gluing it on. Are there better nozzles out there? I'd finally worked out a stringing issue I had with some retraction, can retraction clog a nozzle?

[Xenocrates]

Too much retraction can pull melted filament into the cold zone, where it will freeze up. Other causes are carbonized filament, particles in the filament, or other impurities, not to mention low temps.

As far as unclogging it, a torch works well, as does bringing the hotend to a slightly low temp, pushing nylon in, and pulling it out. Repeat until nylon comes out clean, and the block is cleared. others prefer small drill bits or wires, and they are sold for the purpose. I once tried an acetone soak with an E3D nozzle. Didn't help. Ended up torching then re-cleaning it. A brazing torch, or creme brulee torch will clear the blockage pretty quick, and is very unlikely to harm the nozzle, beyond carbonized crap on it. I suggest cleaning thoroughly after torching.

As for better nozzles, well, I personally like the E3D V6 and Volcano, but they have more clogging issues with PLA especially, and just in general. But being all metal, they are higher temperature. I also like the PT100 sensor they accomodate (with the optional heater blocks), the variety of nozzle sizes, and the choice of steel nozzles for abrasive stuff. Others swear by the Prometheus, and it's one piece nozzle is rather impressive, and the design eliminating the need for a plastic fan shroud is also nice. But it also has some issues with PLA, although less than the E3D. The Jhead designs are excellent for PLA, but much less nice for anything else really. The Budaschnoozle seems to be a far from ideal nozzle.

For each use case, there's a nozzle that is about best I would say. The E3D is very rapidly mutable, and has good performance with exotics. The Prometheus is slower to swap around, but potentially much more flexible. J-heads rule for PLA. Other nozzles win in other cases. You might need two or more, if you want an ideal nozzle for each job. Keep with the SeemeCNC one until you cook it, or find it's limits, I'd say. Mind you, a screw in thermistor goes a long way in making it less annoying to deal with, and a heater cartridge speeds it up a bunch.

[tcat007]

Thanks! Think I'll order a spare nozzle for my stock hot end for now, and work on cleaning tomorrow. I don't print a lot, but mostly ABS (only ABS to date).

I had a retract of 5.4 and Z lift of .2. It does solve stringing, but I think I'd rather have strings than clogged nozzle!

[joseph]

Try setting retraction to 1.5 mm

[Glacian22]

A note about the Prometheus hotend: when I installed mine I had a few issues with PLA, until I switched to a geared extruder. I just needed the extra torque, haven't had a jam in a few hundred hours of printing since.

[tcat007]

Turns out it wasn't a hotend clog. While removing nozzle I noticed filament wouldn't budge through the filament tensioner. Wouldn't move in either direction with quite a lot of force (with lever pressed). Will be taking it apart this morning. Here's a photo (leaving clear cover off really helps so build up can be checked easily). Also a photo of what can happen if you put the layer fan between X and Z and you have an enclosure (moved to X/Y now, no problem).

[img]https://www.googledrive.com/host/0B4v1c ... EdlSjNQTm8[/img]

[img]https://www.googledrive.com/host/0B4v1c ... DQ3aFU3Nms[/img]

[Eaglezsoar]

Man those teeth were really clogged!
Thanks for the great photos!