We purchased a MACH3 6-axis controller board, in case the number of stepper motor drivers that can be attached to the RAMPS 1.4 controller is insufficient for our project.
However, as the 5-axis RAMPS 1.4 controller board is sufficient for the 4 stepper motor drivers in the microsyringe system and 5 stepper motor drivers in the micropipette system, we decided to use RAMPS 1.4 instead of MACH3 as our control board.