An apparatus for the automated filling of cartridges of e-vapor devices may include a filling drum configured to receive at least one cartridge of an e-vapor device. The apparatus may additionally include a needle assembly including at least one hypodermic needle. The needle assembly is configured to transition between a lowered state and a raised state. The lowered state is where the hypodermic needle is moved down into the cartridge, while the raised state is where the hypodermic needle is lifted up and away from the cartridge. The apparatus may further include a pump assembly configured to pump a pre-vapor formulation into the cartridge when the needle assembly is in the lowered state. The pump assembly may include a variable amplitude cam system configured to adjust an amount of the pre-vapor formulation for pumping to the cartridge without changing start and stop times for the pumping.