The gluing process is also a technical activity. We often encounter problems in the gluing process. There are many kinds of coating processes for patch adhesives. Offset printing and dotting are commonly used:

 

COP Packaging

 

The so-called spot coating process is to apply the bonding point of the patch to the designated area of the printed circuit board through the dispensing machine. Pressure and time are important parameters of dot coating. It is necessary to control the size and tailing of the dot. The tail also changes with the viscosity of the patch. Changing the pressure can change the size of the adhesive point. Hanging wire or tail causes the "tail" of the patch adhesive to extend to the next position outside the substrate surface of the component, and the patch adhesive covers the pad of the circuit board, which will lead to poor welding. The tailing phenomenon can be reduced by adjusting the dispensing system. For example, reducing the distance between the circuit board and the nozzle, and using nozzle openings with larger diameter and lower pressure in the dot coating process can help reduce wire suspension. If the dispensing method is pressurized (which is common), any change in viscosity and limited flow rate will reduce the pressure, resulting in a decrease in flow rate, thereby changing the size of dispensing.

 

FPC Packaging Adhesive

 

Offset printing is the process of screen printing to offset the patch to the designated area of the printed circuit board. Although offset printing process is similar to dispensing process, it belongs to two different production processes.