SMD Adhesive is also called Surface Mount Adhesive.Before soldering, components with pin contacts or SMDs are often bonded to the PCB with adhesive. This allows, for example, several capacitors, electrolytic capacitors and coils to be positioned on a circuit board and cured within just a few seconds to prevent their falling over or sliding out of position on the PCB. The secured components can then be reflow-soldered in a single work step, which saves time and speeds up production.
The SMD adhesive refers to the adhesives of hardening agents, pigments and solvent switch are evenly distributed in the red paste, which is mainly used to fix the component on the printed board, and generally it is assigned by the method of point coated.smt adhesive should have the following characteristics:
1.Connection strength: adhesive patch must have a strong connecting strength, after being hardened, and it is not peeled even at the solder melting temperature.
2.The feature of dispensing: the allocation of the printed circuit board uses the method of dispensing frequently, thus the plastic patch is required the following properties:
(1) The several of mount technologies
(2) It is easy to set the supply amount of each component.
(3) Simple adaptation replacement parts varieties.
(4) The amount of dispensing is stable.
3. Adapt to the high-speed machine: now the SMD adhesive must meet the high-speed dispensing and high-speed mounter, specifically, high-speed dispensing without drawing.Furthermore, in the process of high-speed mount and in the transmission of the printed circuit board, the plastic patches viscous have to ensure that the components do not move.
4. No drawing and no slump: Once the patch glue stick on the pad, components cannot be achieved with the electrical connection of the printed circuit board,adhesive sealant must have no drawing, no slump in the coating to avoid polluting the pad.
5. Low temperature curing: in the process of curing, with wave soldering and welding good does not have to go through the reflow furnace heat-resistant cartridge components, so they request that the hardening conditions must meet the features of low-temperature and short time.
6. The feature of adjustment: reflow soldering, pre-coating process, the plastic patch is cured first before the solder is melted, the fixed component, and it will hinder the components sank solder and self-adjustment.