Prusa MK4 Input Shaping settings for heavier bed
The PEI sheet works well, but sometimes I may want to use glass plate for some reason (to achieve very smooth bottom layer, for printing some special materials that may stick better on glass, as a backup if PEI gets damaged since replacement is expensive while glass is cheap and easily available everywhere, or whatever). But, since the glass is heavier than PEI steel sheet by roughly 150g, the Input Shaping frequency for the Y axis would be off.
As a solution, I decided to modify GCODE settings in the slicer when using glass plate. In Filament Settings > Custom G-code > Before layer change, there is this command:
M593 Y T2 F{interpolate_table(extruded_weight_total, (0,40), (300,30), (800,20), (10000,20)) }
This means that when the printed weight is 0g, the Y frequency is 40Hz, when 300g, frequecny is 30Hz, etc., and when weight is something in between, the frequency is set to something in between too. For a heavier bed plate (150g difference), this command can be changed to account for that:
M593 Y T2 F{interpolate_table(extruded_weight_total, (0,35), (150,30), (650,20), (10000,20)) }
Also, change this in the start code:
M593 Y T2 F40.6
to this:
M593 Y T2 F35
(This is all assuming that the default provided frequencies are actually properly tuned for each printer. If measured to be different, the values should be changed accordingly.)
I'm posting this for anyone who may find this useful, or to be corrected if I got something wrong.