Clearing a nozzle clog without disassembly

- [Instructor] Occasional nozzle clogs are an inevitable part of filament-based printing. When this happens, there may be material intermittently missing from your print and the printer may stop extruding entirely. The nozzle will keep moving, but nothing will be coming out. This is often accompanied by a clicking sound from your extruder as the motor loses torque and skips backwards. Your extruder may also begin grinding filament and you'll need to clean the gears before trying to print again. When your extruder can't push filament through, the causes fall into two categories, which we'll call clogs and jams. Jams happened when the unmelted filament encounters too much friction and stops extruding. This video will focus on clogs, which happen when there's something other than plastic inside the nozzle that obstructs the flow. A good way to fix this as what's called a cold pull, or in some circles an atomic pull. - [Narrator] The cold pull process uses a cycle of heating the filament to its extrusion temperature, or even a bit higher, so it flows around the clog. Then you cool it down so that it hardens before pulling it out. You want to do this at a temperature that's just hot enough to make it pliable and able to pull away from the sides without getting hot enough to turn liquid and leave some plastic behind. Most plastic will stretch significantly in this process. When this happens, it turns into thin strands that will break if you're not extremely careful, leaving some material behind. Nylon filament works particularly well for this purpose. It often allows you to pull out a solid filament with a perfect impression of the nozzle's interior. When you remove the filament entirely while it's still mostly solid, any foreign particles that might be clogging the nozzle will be embedded in the plastic and will come out with it. - [Instructor] This can also be an effective way to remove scorched plastic or other stuck on material from the inside of the nozzle. If you see burned or discolored edges or remnants of another material, you should cut off the end and repeat the cold pull process until the nozzle is clean - [Narrator] To perform a cold pull, start by heating the nozzle to printing temperature and unloading the filament. The rest of the process will be easiest if you can bypass the extruder's feed mechanism. This can usually be done either by disconnecting the printer's Bowden tube, if it has one, or by releasing the filament idler. If some plastic is getting through, you can attempt to ram purge. This involves waiting for the nozzle to heat to fully melt the remaining plastic. Then you manually push in cold filament to press out the old plastic before the new one has time to melt. Once your filament is in, turn off the heat. If your nozzle isn't fully clogged, some material will continue to ooze out. To prevent an air bubble from forming around the material you're trying to remove, maintain a gentle pressure on the filament until it cools enough to stop flowing out. Continue to let the nozzle cool below the recommended platform temperature for that plastic to ensure that it's fully hardened, then start heating again. You should start pulling on the filament immediately, so that the plastic will start to come out at its lowest possible temperature before its core fully melts. You'll want to pull firmly, but slowly and brace against the top of the printhead to ensure that you're not transmitting force to linear motion components. - [Instructor] If you can't get anything to come out of the nozzle and if you can't see light when looking down the nozzle after trying this, there may be a bit of metal or other unmeltable material stuck too hard in the nozzle. The next step is to try to break up or dislodge this clog. The best implement for this is one of the small needles with handles are now sold for the purpose. Some manufacturers even include one with the printer. In a pinch, you can also use a bit of thin music wire or pull a bristle from a wire brush. Although some cleaning kits include them for this purpose, you should never try to use a drill bit to unclog a nozzle. Tiny drill bits are too brittle and are likely to break off inside the nozzle. Their hard, sharp edges can also easily deform the orifice of the nozzle, which is usually made of soft brass. The nozzles used for cleaning have a springy temper, unlike sewing needles, which are also fairly brittle and usually too thick - [Narrator] In order to insert a wire needle, the nozzle will have to be hot. If you're using a bristle or wire, you want to hold it with a pair of needle-nose pliers to keep your hands away. Poke at the clog to try to dislodge it, while applying gentle pressure on the filament from the other end. Once the plastic starts flowing, do a cold pull to ensure that the clog doesn't come back. Some users still recommend an older alternative to the cold pull method in which you remove the nozzle and heat it with a butane torch to melt the plastic out before reinstalling it. This leaves you with charred plastic inside the nozzle, though, and often on the nozzles threads, as well. This charred plastic can lead to more problems down the road and we recommend against this procedure. - [Instructor] The worst case is that you have burned material in your nozzle or you have a deformed PTFE liner. If you've recently tried to print something at temperatures that's higher than your printer is rated for, this might be what's going on. Most printers will not prevent you from trying to go to a temperature that's too high and the result can be burned material in the nozzle. Then most likely, you'll need to replace the nozzle. Nozzles clog sometimes. It can be a little tedious to clean out a clog, but being methodical about it and trying to figure out why it happened can make it happen a bit less often.