I bought a secondhand “Open Box” entry level Monoprice Maker Select 3D printer to augment my rover printing factory. As expected, there were cosmetic blemishes on the machine, but that’s not important at all. The next task is to level the print bed. The wear on the print bed shows the printer to be well used, but the bed not remotely close to level. This is not a big deal – it is highly probable that something shifted during shipping.
After the print bed was back to level with the print axis, a test print attempt was foiled by the next problem: a clogged nozzle. This is also fairly common in 3D printers, so out came the unclogging tool: a 0.4mm diameter drill bit. It immediately restored filament flow, but only briefly. The nozzle quickly clogged again. Whatever is causing the clog, it must not have been broken up by the drill bit, only pushed aside and maybe rearranged.
Which means it’s time to bring out the next tool: Monoprice Cleaning Filament. For small clogs that can be cleared by the drill bit, it’s fine to just use whatever printing filament was on the machine. But when we start looking at a more serious clog, using filament formulated for the purpose hopefully makes the job easier.
The material causing nozzle jam was fortunately a dark color, making it easy to see when the white cleaning filament manages to dislodge some and carry it out of the nozzle. After some small bits were removed, the nozzle would quickly jam again requiring a push with the 0.4mm drill bit to rearrange the pieces and hopefully breaking apart the debris for more removal.
This cycle was repeated several times. Each time the drill bit was used, a little more debris is removed by the cleaning filament, and we could run a little longer before nozzle jams up again. Eventually the nozzle was clear enough for the cleaning filament to extrude unimpeded for five minutes, and also coming out clean.
The cleaning filament did its job, the printer is back in business.