The basic knowledge of LED patch adhesive

Understanding the Basics of LED Mounting Adhesive

1. The Function of LED Patch Glue

Surface mount adhesives, also known as SMA (Surface Mount Adhesives), are essential in both wave soldering and reflow soldering processes. These adhesives are primarily used to secure components onto printed circuit boards (PCBs). They are applied using either dispensing or screen printing methods. Their main purpose is to hold components in place during the assembly line transportation, preventing them from falling off. After application, the PCBs are placed into an oven or reflow soldering machine to cure the adhesive. Unlike solder paste, once cured, the adhesive becomes thermally stable and will not melt even when exposed to heat. This means the curing process is irreversible. The performance of surface mount adhesives can vary depending on factors such as curing conditions, material compatibility, equipment used, and environmental factors. Therefore, it's important to select the right type of adhesive based on your specific production process.

2. Composition of LED Patch Adhesive

Most surface mount adhesives used in PCB assembly are based on epoxy resins. However, polypropylene is sometimes used for special applications. With the advancement of high-speed dispensing systems and a better understanding of handling materials with limited shelf life, epoxy-based adhesives have become the most widely used technology globally. Epoxy resins offer excellent adhesion to various types of PCBs and provide superior electrical insulation properties. The typical components of these adhesives include a base resin (a high molecular weight compound), fillers, a curing agent, and other additives that enhance performance.

3. Key Applications of LED Patch Adhesive

a. Prevent component detachment during wave soldering.

b. Avoid component loss during double-sided reflow soldering.

c. Ensure components remain in position during reflow and pre-coating stages.

d. Enable batch identification by marking PCBs and components with the adhesive.

4. Types of LED Patch Adhesive Application

a. Dispensing Type: This method involves applying the adhesive precisely using a dispensing device onto the PCB. It’s ideal for complex layouts and small-scale production.

b. Squeegee Type: Also known as screen printing, this method uses a stencil or copper mesh to apply the adhesive evenly across the board. It is commonly used for larger volume production runs.