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 electronic components onto printed circuit boards (PCBs). They are applied using either dispensing or screen printing techniques, ensuring that components remain in place during transportation along the production line. Once the components are attached, they are placed into an oven or a reflow soldering machine to cure and harden. Unlike solder paste, which melts during heating, once cured, the adhesive becomes thermally stable and will not melt again. This means the curing process is irreversible. The choice of adhesive depends on factors such as curing conditions, material compatibility, equipment used, and environmental requirements. It’s important to select the right type of patch glue based on your specific manufacturing process.

2. Composition of LED Patch Adhesive

Most surface mount adhesives used in PCB assembly are epoxy-based, although polypropylene may be used for specialized applications. With the advancement of high-speed dispensing systems and better industry understanding of handling products with shorter shelf lives, epoxies have become the most widely used adhesive technology globally. Epoxy resins offer excellent adhesion to a variety of board materials and provide strong electrical insulation properties. The main components typically include a base resin (a high-molecular-weight polymer), fillers, a curing agent, and various additives that enhance performance and stability.

3. Key Purposes of Using LED Patch Adhesive

a. Prevent components from falling off during wave soldering. b. Prevent other components from shifting or falling off during double-sided reflow soldering. c. Avoid component displacement or standing during the reflow and pre-coating stages. d. Enable marking of PCBs and components when batches change, helping with traceability and identification.

4. Types of LED Patch Adhesive Application

a. Dispensing Type: This involves applying the adhesive to the PCB using a dispensing device, which allows precise control over the amount and placement of the adhesive. b. Squeegee Type: Also known as screen printing, this method uses a stencil or copper mesh to apply the adhesive evenly across the board, ideal for large-scale production and uniform coverage.