For wave soldering and reflow soldering surface mount plastic (LED SMD gum, SMA, surface mount adhesives), mainly used components will be fixed in the printed circuit board, general dispensing or stencil printing method to allocate to maintain the position of the components on the printed circuit board (PCB), to ensure that the components are not lost in the transfer process on the assembly line. Paste components into the oven or reflow welder heating hardening. It is not the same, so-called solder paste by heating and curing, re-heating is also not melt, which means that the thermal hardening process of the adhesive patch is irreversible. Smt adhesive effect will be due to the heat curing conditions, linkers, differ depending on the equipment used, the operating environment. We select the patch glue according to the production process.
The ingredients of LED SMD adhesive
Most surface mount plastic used in the PCB assembly (SMA) is epoxy resins (epoxies), although there are polypropylene (acrylics) is for the special uses. After the introduction of high-speed dispensing system and electronics industries learn how to deal with relatively short shelf life products, epoxy resin has become the worldwide more mainstream glue technology. Epoxy generally provide good adhesion on a wide range of circuit board and has a very good electrical properties. The main ingredients are: a base body material (i.e. a high molecular material), fillers, curing agents and other additives.
The intension of LED SMD adhesive
1. Adhesive sealant prevents the components of falling off in the wave soldering. (Wave soldering process) 2. Prevent another surface component off in the process of reflow (double-sided reflow process) 3. Prevent displacement of components (reflow process, pre-coating process) 4. Marking (wave soldering, reflow, pre-coated), when the volume of the printed circuit board and components change, plastic patch can mark. The classification of use of LED SMD adhesive 1. Dispensing type: dispensing equipment sizing in the printed circuit board. 2. Squeegee type: steel mesh or copper network printing scratch coating way sizing.
www.zscnr.com has marched into the stage of rapid development. Confronting to the domestic competition of adhesive, the company takes slow and steady efforts to catch up and now it has created a well-known brand among the domestic adhesive industry. The whole company will tenaciously strive to enter into the top 100 of the domestic adhesive industry.
This article is come from:http://www.game-dice.net/some-knowledge-about-led-smd-adhesive/
No comments:
Post a Comment