You see the line can be irregular to broken entirely when the value is not optimal, most visible on the top lines ( red squares), but present on all except those with the optimal K-factor. Look closely at the transition from slow to fast and fast to slow. The first and last 25 mm are printed slowly, and between the marked locations ( red squares) 100mm is printed fast.
The examples below show how the lines are affected by their K-value. It will print a series of lines with different K-values affecting the speed and flow across the accelerated distance. Other nozzle sizes or materials could result in different K-values. This article mainly refers to the printer use with a 0.4 mm brass nozzle.
