Filament detection problem, the source of all evil?

While disassembling one of my extruders, here’s what I found:

This is the filament detector. It’s a simple push button. As long as it’s pushed, the printer knows there’s filament going through the extruder. See how it’s angled? See why? The clog under the pcb… A cold solder? Mmmh…

Let’s take it apart, resolder this clog, eliminate the excess of tin, flatten it:

Place it back on the extruder backface

That’s looking straight now! With room to align it before tightening it strongly with the screw on it’s rear face!

Mount it back on the printer. My printer’s been running since now about 11 hours, no false detection…

The other one has my accessory on, that also helps, give it a shot, it’s simple to print!


I won’t create a new thread but instead bump this one. I had a problem with some filaments triggering falsely and decided to investigate instead of giving up runout detection. Turned out my extruder had the lever that didnt engage the micro switch well enough, it could not be adjusted so I just shimed the part that clicks the switch with a piece of paper soaked in super glue. I used very thin paper and later sanded it and tested incrementally and now I know there is no way the runout could be detected if the filament is less than 1.5mm in diameter. Dont go too far with this because if the filament is thick enough it will be hard to feed it trough and the micro switch will be pushed way too hard.


I know this is an old thread… but I have another solution! I tried shimming up the board with several layers of Kapton tape… but it failed again. Basically, the filament is wearing flat surfaces in the metal pins, so I tweaked the extruder part and fitted a new microswitch.

Give it a try :slight_smile:

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