In the metallographic sample preparation, pre-grinding, polishing and grinding are the indispensable procedures. The suspension needs to drop in the process of grinding and polishing, so this dropping device is just designed for the automatic dropping of the suspension. This machine is controlled by single chip microcomputer, and it is output by a precise peristaltic pump. The touch panel displays and controls the input speed. The motor is the 24V DC brush motor, used for a long time, and can completely replace the artificial drops. It has reached the purpose of timing and uniform output of the suspension. The machine can adapt to the output of various suspensions and can be used for various grinding and polishing machines. Its easy operation, compact appearance and safety make it the best ancillary equipment for metallographic sample preparation.