1. Piston pressure type

 

This method uses a closed-loop dispensing machine, relying on the matching piston and cylinder to work, the piston moves downward and pushes the glue. The volume of the cylinder determines the glue volume control. A certain amount of glue and shape can be obtained. The advantage of this method is that the speed is faster than the first two methods, and the high-viscosity fluid can be transported. At the same time, it supports the opening. The outlet flow rate can be adjusted by controlling the air pressure. Because of the size of dropping point, the time required for glue will not change. Therefore, it is easier to achieve rapid dispensing, precise dispensing, repeatable dispensing, and suitable for dispensing adhesives with different viscosity. The disadvantage is that the equipment needs to be cleaned regularly, the cleaning process is complex and the equipment investment is large; when the glue contains large particles, it is not suitable for dispensing method.

 

SMT Patch Processing

 

2. Time Pressure Method

 

This method was originally used for SMT gum volume control, time and pressure control to obtain a predetermined amount of glue and adhesive diameter. The volume of droplets dispensing with increasing time is a time function of applying glue pressure to syringes.

 

 

 

3. Fluid injection dispensing

 

Spray dispensing is a recently developed technology. The basic principle is similar to that of inkjet printer, which allows the material to be separated automatically by applying sufficient force to the fluid, and the glue fills the gap between the needle and syringe under the action of colloid pressure. Firstly, the compound moves upward under the action of air pressure and keeps at a high position for a suitable period of time. The needle moves downward under the action of spring force. The spherical surface of the end collides with the base. The amount of glue produced is controlled by the amount of glue cut. The glue at the lower end of the spherical surface sprays out at a high speed to form glue droplets. Then the needle stays at the lowest position for a period of time, and then the needle moves upward to start the next movement cycle.

 

Fan fluid spray valve

 

4. Screw pump dispensing method

 

This method uses the rotary pump pressure technology to drive the coating, which has high repeatability and can be used for coating with poor bonding performance. It uses the motor driver to rotate the screw at a precise distance or angle, and its working mode produces more repeatable droplets than the time pressure method.

 

Screw dispensing valve