For the last several weeks, the 3d printer has sat idle and quiet, waiting for the next projects. Some of the reason was that I was a bit overloaded with the rush to finish the Pathfinder boxes (which was nearly so urgent since the game was delayed), but since then, it was just being overly challenging again.
As anyone with a 3d printer can attest – printing reliably and consistently is a challenge. I have learned a lot in the last year of efforts and attempts, and I continue to learn.
My lesson these week was temperature. I had switched back from the copper PLA to my general use grey PLA, and also switched back to a plain glass surface. In theory, everything would be great. In reality, I starting having surface adhesion issues almost immediately – the part would start cleanly, but then after a dozen or more layers would separate from the surface. I would end up with at best an unfinished part, but more typically a blob of PLA stuck to the nozzle with a chaotic mess of a part attached.
Logic and past experience told me “lower the bed temperature” (it was at 50 deg C) – this apparently has worked well to increase the adherence, and made sense since PLA warps when it cools, thus it would peel from the surface and separate if there was a temperature difference.
However, I was thinking about the problem all backwards. It is not the temperature difference between the material and the surface that matters, but rather the surface and the nozzle. By lower the bed temperature, I was actually making the problem worse – the difference was getting larger. Instead, the proper action was to increase the bed temperature and reduce the gradient.
As soon as I adjusted the print bed to 70 degrees, the next print ran smoothly, evenly, and with no warping.
My appreciation to MatterHackers, and their article, https://www.matterhackers.com/articles/how-to-succeed-when-printing-in-pla, for helping me correct my logic and thinking.
PLA filament – glass surface, 70 degrees C
