The main components of the screw dispensing valve are the screw and the matching stator. Its particularity is that the stator and the screw can form several closed cavities. The glue liquid is pushed forward by the screw in the closed cavity. The larger the rotation angle is, the more the glue volume is. It can ensure the linear and stable glue output, and can be used for measuring the glue output. Its structure is relatively large due to its rear feeding port and eccentric rotation. If the screw does not rotate, the glue will not come out even if the feeding port is pressurized. Screw valve is a contact dispensing valve, but it is a mechanically driven valve, which can be applied to many high viscosity glues. At the same time, its glue output will also be affected by various factors:


1. The rotation speed of screw dispensing valve has a great influence on the amount of extrusion, so the appropriate driving speed should be adjusted according to the different amount of extrusion. During rubber extruding, the rotation speed of the motor must be accurately controlled, and the change of the rotation speed will lead to the change of the rubber extruding amount.


2. The same screw valve can be equipped with different types of needles. To obtain small glue points, use a needle with a small inner diameter, and the extrusion flow rate decreases exponentially with the decrease of the inner diameter of the needle. Increasing the inner diameter of the needle can increase the glue extrusion, but when the needle increases to a certain value, the glue extrusion amount will not increase. At this time, it is necessary to consider increasing the screw rotation or using a large-size screw.

3. Among the screw structural parameters, when the screw cross-sectional area changes by changing the depth and width of the screw groove to the same value, the depth of the screw groove has a greater impact on the extrusion amount. And with the increase of the depth of the screw groove, the extrusion strength decreases.


4. The increase of the inlet pressure of the dispensing valve will cause the increase of the extrusion amount, but the increase of the inlet pressure also has a very negative impact. The appropriate inlet pressure should be selected according to the actual situation. When designing and using the screw valve of dispensing machine, the influence of various parameters must be comprehensively considered.