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Introduction of basic knowledge of LED patch adhesive

July 10, 2019


1. the role of LED patch glue

Surface mount adhesives (SMA, surface mount adhesives) are used for wave soldering and reflow soldering. Primarily used to secure components on a printed board, usually by dispensing or stencil printing, maintaining the position of the component on a printed circuit board (PCB) to ensure that components are not lost when transported on the assembly line. After installing the components, put them in an oven or reflow soldering machine for heat hardening. It is different from the so-called solder paste. Once hardened by heat, it will not melt even if it is heated again. That is to say, the thermal hardening process of the patch adhesive is irreversible. The use of SMT patch adhesives can vary depending on the conditions of the heat cure, the materials to be joined, the equipment used and the operating environment. When using, it is necessary to select the patch glue according to the production process.

2. the composition of LED patch glue

Most surface mount adhesives (SMA) used in PCB assembly are epoxy, although polypropylene is also used for special applications. After the introduction of high-speed dispensing systems and the electronics industry, epoxy resins have become the dominant gel technology in the world for how to handle relatively short-lived products. Epoxy resins generally provide good adhesion to a variety of boards and have very good electrical properties. The main components are: base material (ie, main polymer material), filler, curing agent, other additives.

3. the purpose of using LED patch glue

a. Prevent components from falling off during wave soldering (wave soldering process);

b. Preventing the other component from falling off during reflow soldering (double-sided reflow soldering process);

c. Prevent component displacement and standing (reflow soldering process, pre-coating process);

d. Marking (wave soldering, reflow soldering, pre-coating), when the printed boards and components are changed in batches, they are marked with patch glue.

4. LED patch adhesive use classification

1. Dispensing type: sizing on printed circuit boards by dispensing equipment.

2, scraping type: sizing by steel mesh or copper mesh printing