One of the cool things about being alive in the internet era is that it is very easy to learn from the mistakes of others without having to go through the “School of Hard Knocks” for everything. 3d printing is no exception. In this case, you get to learn from me what I should have learned from others.

A couple of weeks ago one of my FDM printers stopped working. I looked at it quickly and saw that the nozzle was clogged. I attempted to clear the clog, and when it didn’t start working properly I decided to put it into the “I’ll get to it later” category.

This weekend was “later” and I needed the printer back online, so I decided it was time.

I realized that there were two issues. The extruder wasn’t feeding and the nozzle was clogged. Knowing that these issues are sometimes related, I separated the bowden tube from the hotend to help me diagnose which end was causing the problem. It seemed to me that there was an issue on both ends. The extruder wasn’t feeding correctly and the nozzle was clogged. Great. Seemed like heat creep to me so I started investigating into sources for heat. My fans are old, maybe one of them is clogged or not working right. Fans cleaned, no clogs found. Next, I sorted out the nozzle. I ended up replacing it. It worked!

I tried a test print. My joy was short-lived when it quickly clogged up again.

I decided to turn towards the extruder. I took it apart. Everything seemed normal. The motor gear was a little worn, but still in pretty good shape. Back to the hotend.

I pulled the heat block off and disassembled the hotend components. I quickly discovered that the new nozzle that I had put on the hotend had a shorter thread than my last one. The impact of this being that there was a gap between the nozzle and the heat break inside of the heat block. This meant that when the filament heated up it would be able to creep out, and that’s exactly what it did. Sigh. I realized what I had done. I had replaced the correct component the first time (the nozzle), but I had replaced it and caused another problem, and now my entire hotend has melted black filament on it.

Fortunately, I keep a few spare components on hand. I had a spare heat block, heat break, and nozzle. I put them on, making sure to properly hot-tighten the nozzle this time, and I was back in business.

Double check everything. Take your time. Make sure that you put the right components on. Make sure that you are solving the right problem.