AB dispenser has some dripping defects in the use of dispensing process, such as glue drawing tail, discontinuous glue dot size, no glue dot and star dot, uneven glue output, etc. Let's understand the causes of these undesirable phenomena and explore the methods to solve them.

1. Drawing tail glue
Wiredrawing / tailing is a common phenomenon in the dispensing and coating process. When the needle is removed, a thin line or "tail" is generated at the top of the glue point, and the tail may collapse, directly contaminating the product or fixture, causing unnecessary waste and trouble.

Solution: one of the reasons for drawing tailing is that the equipment parameters of the dispenser machine are not set accurately, such as the thickness of the inner diameter of the dispenser needle, the setting of the dispensing pressure is too large, and the spacing between the dispensing needle and the dispensing product is too large; It is possible that the quality of the patch adhesive is poor or expired, the plate is bent or the support of the plate is insufficient, and the parameters need to be adjusted as much as possible. For the above reasons, the process parameters can be adjusted, the needle with larger inner diameter can be replaced, the dispensing pressure can be reduced, the height of the needle from the dispensing product can be improved, and the patch glue can be changed; It can be heated on or near the glue dropping needle to reduce the viscosity, so that the glue drawing tail of the patch is easy to break.

2. Star mottle
Star mottled spots are fewer small irrelevant glue spots produced during high-speed dispensing. In dispensing, it usually occurs by tailing and needle nozzle disconnection; In non-contact dispensing, it is due to the inaccurate dispensing height. Star mottled spots can cause pollution. Solution: in contact dispensing, always check whether the needle is damaged, and the needle needs to be replaced frequently. At this time, adjust the equipment parameters to prevent tailing, so as to reduce the generation of mottled points. In non-contact spraying, adjusting the height of the jet head and PCB can also reduce the occurrence of such problems.

3. Glue breaking during dispensing
First, it is necessary to check whether there is a problem with the glue (for example, the glue contains bubbles, granular sediments, etc.). In this case, the AB dispensing machine will have the problem of dispensing and glue breaking; The second is whether the dispensing controller works normally or its own performance is insufficient, which will also cause the problem of dispensing and breaking.

4. Bubbles in fluid
If the fluid pressure is too high and the valve opening time is too short, air may seep into the liquid The solution is to check the glue in the syringe, reduce the fluid pressure and use a conical oblique needle.