This is a question more from curiosity than anything else.

I just printed a case for a Sainsmart oscilloscope board. The case came out perfectly, but I noticed that the sides have ripples in them (not this just print, but this one does show it more than others).

At first I thought it might be some artifact from the extruder hot-end. But looking more closely, all of the ripples are lined up from layer to layer. The side shown in the picture was printed with the head moving left to right - layers are horizontal:





Now I'm wondering if these ripples are actually there because the stepper motion isn't actually continuous, but a lot of micro-steps. That would explain why they're lined up. Maybe what I'm seeing as a smooth motion from left to right is actually step-microseconds pause-step-microseconds pause etc.

I'm not trying to change anything, just trying to learn about the process and curious.