(3) Colored adhesives that are easy to distinguish from green oil and circuit board materials are preferred, as they can quickly detect defects such as missing components, excessive/insufficient adhesive volume, contamination of pads/components, and empty glue, which is conducive to process control. Common adhesive colors include red, white, and yellow.
(4) Adhesives should have sufficient viscosity and humidity to ensure firm bonding between components and the circuit board before curing. Both typically increase with viscosity, and high-viscosity materials can prevent components from moving during circuit board mounting and transportation.