What is Reflow Soldering and Wave Soldering?

In PCBA processing, There are two common soldering methods: Reflow soldering and wave soldering.

What is the function of reflow soldering, what is the function of wave soldering, and where are their differences?

PCBA is Printed Circuit Board +Assembly, That is to say, the PCB board board passes through the SMT line and DIP Line, the whole process we call it PCBA. This is a commonly used method in China, While the standard way of writing in Europe and America is PCB’A, adding ” ‘ “, which is an official idiom.

1. Reflow soldering

Reflow soldering is a process in which a solder paste (a sticky mixture of powdered solder and flux) is used to temporarily attach one or thousands of tiny electrical components to their contact pads, after which the entire assembly is subjected to controlled heat. The solder paste reflows in a molten state, creating permanent solder joints. Heating may be accomplished by passing the assembly through a reflow oven or under an infrared lamp or by soldering individual joints [unconventionally] with a desoldering hot air pencil.

Reflow soldering process:Printing Solder Paste > Mounting Components  > Reflow Soldering > Cleaning.

Reflow soldering process


2. Wave Soldering

Wave soldering is a bulk pcb soldering process used in the manufacture of printed circuit boards. The circuit board is passed over a pan of molten solder in which a pump produces an upwelling of solder that looks like a standing wave. As the circuit board makes contact with this wave, the components become soldered to the board. Wave soldering is used for both through-hole printed circuit assemblies,  and surface mount. In the latter case, the components are glued onto the surface of a printed circuit board  (PCB) by placement equipment, before being run through the molten solder wave. Wave soldering is mainly used in soldering of through hole electronic components. 

Wave soldering process: DIP > soldering flux > preheating > wave soldering > cut corners > inspection.

wave soldering process
Wave soldering process

3. The difference between wave soldering and reflow soldering

(1) Wave soldering is a solder solder that forms a solder peak to  solder components; 

Reflow soldering is a high temperature hot air to form a reflowed molten solder to solder components.

(2) During reflow soldering, there is solder on the pcb before the furnace, and only the coated solder paste is melted and welded after soldering;

During wave soldering, there is no solder on the pcb before the furnace, and the solder wave generated by the welder coats the solder on the pads to be soldered.

(3) Reflow soldering is suitable for SMD electronic components,  and wave soldering is suitable for pin electronic components.

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