In PCBA processing, two common welding methods are reflow soldering and wave soldering. What is the role of reflow soldering and wave soldering in PCBA processing, and what are the differences between them?

1. Reflow soldering: refers to the electric interconnection between the pins or terminals of electronic components pre mounted on the pad and the pad on the PCB by heating and melting the solder paste pre coated on the pad, so as to achieve the purpose of welding electronic components on the PCB. Reflow soldering is generally divided into preheating zone, heating zone and cooling zone.

Reflow soldering process: printing solder paste > mounting components > reflow soldering > cleaning

2. Wave soldering: use a pump to spray the molten solder into a solder wave crest, and then pass the pins of electronic components to be welded through the solder wave crest to realize the electrical interconnection between electronic components and PCB board. One wave soldering machine is divided into four parts: spray, preheating, tin furnace and cooling.

Wave soldering process: Insert > apply flux > preheat > wave soldering > cut corners > check.

3. Difference between wave soldering and reflow soldering:

(1) Wave soldering refers to the soldering of components with solder wave crest formed by molten solder; Reflow soldering is the process of reflow melting solder formed by high temperature hot air to weld components.

(2) During reflow soldering, there is already solder in front of the furnace on the PCB board. After welding, only the coated solder paste is melted for welding. During wave soldering, there is no solder in front of the furnace on the PCB board. The solder wave peak generated by the welder is coated on the pad to be welded to complete the welding.

(3) Reflow soldering is applicable to chip mounted electronic components, and wave soldering is applicable to pin electronic components.

Wave soldering and reflow soldering are two important processes in PCBA processing. The welding results determine the quality of PCBA processed products.