Max volumetric flowrate test - fixed for 0.35mm layer height

Why

When determining the maximum flowrate for a specific hotend/filament combination I always use the poop method, in which blobs of filament are extruded and weighted to assess the capabilities of the setup tested, but this time I wanted to try the racetrack test by CNC Kitchen. I quickly downloaded the stl but I couldn't figure out why the horizontal notches in the model couldn't line up with the discrete layers produced when using 0.35mm layer height. This is because the test was initially used with 0.2mm layer height, later changed to 0.35 possibly to allow more flowrates to be tested without reaching the maximum speed of 100mm/s. 

This model is the same as the original, but scaled down to 87.5% in the z direction. This results in two things: 

• notches are now at multiples of 0.35mm layer height
• half of the time at a specific flowrate, as in my experience issues would be quickly visible

Setup

Follow the CNC Kitchen instructions, with the following important additions which would make the test not work in certain cases:

• set both layer height and first layer height to 0.35mm
• disable minimum layer time, otherwise higher flowrates would end up being slowed down since a single layer would take too little time
• disable skirt, and possibly brim, as I didn't notice issues with them being turned off (this just saves some print time)
• set the maximum speed for the first layer to 100mm/s as well, since there isn't complex geometry that would make the filament not sticking well

For filaments that would start at a lower flowrate than 10mm3/s (like TPU) add an additional custom gcode at the second layer (since you can't seem to be able to add it to the first one) and set your starting flowrate there (like M220 S40 if you want to start at 4mm3/s). Flowrate changes will now be made every 1.75mm, so layer 6-11-16-21-26-31-… This results in 5 layers printed at each flowrate

I want more layers printed at a given flowrate

Easy! Scale up the model to 200% in the z direction, and place custom gcodes every 3.5mm, so layer 11-21-31-41-… This results in 10 layers printed at each flowrate