The working principle of the spray dispenser is the same as the working principle of the contact dispenser. It's all controlled by pneumatic glue, and there are some electric dispensing dispensers on the market. Pneumatic control dispensing valve has the advantages of simple structure and low cost advantages, the premise is the automatic glue head precision are very high, the control effect by using the amount of gum dispensing machine configuration of the stepper motor is more accurate. Spray glue with working time have a certain relationship, setting out the longer the glue glue volume is bigger, in order to spray work in near stable glue, the best in the debug link will glue volume precision control, which requires some proficient operators to control the precision glue time in debugging links to avoid change the parameters in the dispensing, so as not to affect the stability and consistency of automatic dispensing. To some extent, the viscosity of glue will affect the dispensing quantity of jet automatic dispensing machine. The viscosity of dispensing glue can be reduced by heating device, so as to increase the output and output efficiency of glue dispenser.