I am building my next generation of R2 compatible printer using an R2 to print the parts. The next generation uses the same print head I use on the R2. The frame is made out of EU3030 extrusions. The part shown is the upper left corner. Printed in GST3D clear plastic and weighing 480 grams. Clear plastic with no color additives "should" be strongest. The banding that is visible is the 2mm belt spacing. It is both the x and y directions and can not be felt. If it was an opaque plastic it would not be visible. I can not figure out the cause of visible banding with no corresponding dimensional change. More info: On a different R2 I am using the same plastic. There are two straight runs of different lengths. The banding is ever so slightly different in length, like a vernier scale on calipers. Could this be a rounding error. Could calculations be to more digits than what is loaded into the stepper timer resulting in a periodic change of 1 bit causing more then less filament to be fed. Could a one bit change cause a visible change in density? Any ideas? Any way to define a test? I will try and do the math for how many bits must be loaded into the extruder stepper timer. I am feeding at 55 mm/sec, 141.2 steps per mm.