I have been having a number of challenges with my 3d printer, specifically the Prusa i3MK3s. At this point, it is I believe 30+ months old, and has been running nearly constantly, so I cant say that it has not been reliable. In fact, it has been for the most part rock solid, and very consistent. However, with age, comes challenges. So I figured I would list out a few of my more recent lessons learned, in the hopes that someone else may benefit. These are specific to FDM printers, but obviously are brand specific – your mileage may vary for similar printers. I may post something related for my resin printer, though honestly it has had very few issues.
- Parts not sticking – this is a common issue with many printers, and frequently caused by insufficient grip to the print surface. With other printers, special surfaces or glue sticks, or even hair spray, helps with the adhesion. With the Prusa, they come with a specially treated metal sheet print surface, which rarely has any adhesion challenges. However, I have found that eventually miscellaneous residue will build up, so every few weeks or months, I give it a solid wash in a sink. I use dish soap, and my hands only (no brush), and simply rub down all surfaces. Then I carefully rinse all soap off while holding it on the edges only, and dry thoroughly. Once it is back on the print bed, a heating cycle of the bed itself clears any remaining moisture. And the plate tends to be far stronger with adhesion.
- Curling of parts – related to the first concern, sometimes we encounter models that stick, but have corners or edges that curl up. This can either lead to a warped part, or eventually the printer pulling the part from the print bed itself. If you are modeling, there are ways to minimize this – avoid sharp corners, add curves, etc – all documented by many other sites. But if you are printing an existing model, those options are not possible. In that case, the best option is a brim, I typically use about 5 mm around the model. That provides enough surface to remove it cleanly after printing, and generally provides enough additional surface to hold the model. If your brim is not easy to clean off, leaving a jagged bottom surface, utilize a reaming tool. It is designed for metal pipes, but easily handles most 3d prints, and with minimal practice gives a nice smooth surface.
- Extruder “drift” – not really a model issue, but a mechanical issue with the Prusa. In my case, I noticed that over time, the cooling part of the nozzle assemble slowly unscrewed. It was not very noticeable at all, but I found that occasionally the Pinda probe lost its settings, and would not register within its tolerances. In each case, I had to progressively lower the probe slightly, until it was several rotations lower – just to keep it close to the nozzle height. Eventually, when dealing with other issues, I realized it was loose, and after correcting, had to re-raise the Pinda by several millimeters. Functionally, it isnt a big deal, but be aware that when you change the nozzle or clear a jam to check that the cooling part is still seated well against the heat block.
- Jams, leaking, and broken filament – I lump all these together, because for my machine, they all lead to the same challenges – removing and clearing the extruder assembly. Although I have replaced the nozzle a few times, since I print only PLA, I honestly feel that they were all unnecessary. In each case, I had a print issue, and thought it was a clogged nozzle, but after the swap the problem continued. In all cases, I only solved the problem by removing the extruder assembly, unscrewing the cooling tower, and then clearing the PTFE tube. In one case, I replaced the PTFE tube as well, but that was mainly due to some unrelated damage. Make sure the PTFE tube is inserted in the correct direction. Then re-attach the cooling tower, screwing it all the way down against the heating block. Push the PTFE tube as far in as it will go (it will still stick out a short bit). Then, make sure the entire assembly is reinserted properly to the extruder motor, and that has resolved most of my issues. I have spent many hours with needles, heaters, and other tools trying to clear jams or broken filament, and it really is simpler just to remove the PTFE tube, clear it, and re-install. Make sure you re-run the bed level calibration after this operation, since your 0-point may have shifted slightly.
- “Clicking” and Extruder feed issues – I had this problem for the longest time – my print would run normally for a bit, and then the filament would jam and result in the feeder gears clicking. Very distinct sound. If I ignored it, it sometimes would clear itself, but normally it would fully jam resulting in a failed print at best, or a break in the filament at worst. For my printer, this was caused by a leak in the extruder – I had allowed the cooling tower to separate a few rotations from the heating block, causing filament to seep out due to the pressures. That leak then would cool, and clog the extruder. The fix was a cleaning, and then a proper seating of the cooling tower and PTFE – I have not had the problem since. However, much of the content only suggested heat creep – resulting in suggestions to increase or decrease print temperature – none of which impacted my situation.
As of today, my printer is running well again, following a recent broken filament. Moving forward on my backlog of projects.
