Failure - With solution - Something to watch for  

Failure - With solution - Something to watch for

After the fact things are obvious, but at the time, I was puzzled.

I thought I would share for those of us climbing the learning curve as something to watch for.

First, I have things dialed in to my liking. Bed adhesion, flow, surface finish, etc. I was feeling bulletproof. Lots of small/med projects (in the center of the bed) very successful, with no issues. I was over-confident.

So I needed some specialized L brackets for a project (my enclosure actually). I need 36 of them, so I decided to print them 20 at a time, completely filling the bed with the L Brackets.

Failure. But in a strange (to me) way. The prints adhered perfectly, but part way up the vertical part of the L bracket the entire thing shifted by half the period of the L brackets. The result was the tops were connected between two bottoms, rather than individuals. Print completed fine, but parts were not usable.

After some consternation, I determined the cable from the extruder had been slowly dipping down over time. With a single print in the center of the bed, that had no harmful effects. But with a periodic array of things, it caught on the parts in back and caused the X-axis to skip. A bit of work getting that cable "up" and now I have 40 of those L-Brackets with no issues.

So, obvious fact, check that extruder cable is floating above the nozzle hight. Mine was just barely, and a long print, with some vibration, and it caught just once. Once was plenty to destroy the print.

Lost a lot of filament for that lesson, and wanted to save you the same.