Stratification

[bray.christopher]

Any idea what is causing this "stratification"? The spacing seems somewhat regular.

It was printed vertical and it was the only thing being printed.

Ultimaker2.

[JoeJ]

Maybe it's filament inconsistency. If the filament diameter isn't very tightly controlled, the variations can cause extra extrusion.

I've also had a printer where the vibrations caused similar layers like in your picture.

[KC_703]

The only thing I can think of is possibly the solid diaphragm infill setting under the "Infill" tab.

[bray.christopher]

The only thing I can think of is possibly the solid diaphragm infill setting under the "Infill" tab.

I wish! That would make sense. Unfortunately that was not turned on. Thanks anyway.

[dkightley]

I've also had a printer where the vibrations caused similar layers like in your picture.

I've had similar where a tall thin part was unstable, so I added pinpoint joined "rocket fins" to steady it:

The fins were twice filament thickness thick and the scarring from the joiners was minimal.

[66tbird]

My option is also filament inconsistency. Bigger the piece the narrower the distance between the lines is what convinced me. One day out of total frustration I loaded the cheapest filament I had that I bought on a whim because it was $10/lb. (HobbyKing brand) and ran the job. The vertical wall was flawless.

A roller dial indicator with pcm output for 'on the fly' adjustment has crossed my mind.

[turbocharged110]

Have you tried the same part with different layer heights? Could be a rounding error where your microsteps don't match the desired Z-height, so every X layers will be lower than the others with the same material extruded.