PCB News - Circuit board soldering skills

Any electronic product, from a rectifier composed of several parts to a computer system composed of thousands of parts, is composed of basic electronic components and functions, connected by a certain technological method according to the working principle of the circuit. Although there are many connection methods (for example, winding, crimping, bonding, etc.), the most widely used method is soldering.

Soldering circuit board skill 1:

The selective soldering process includes: flux spraying, circuit board preheating, dip soldering and drag soldering. Flux coating process In selective soldering, the flux coating process plays an important role. When the soldering is heated and the soldering ends, the flux should have sufficient activity to prevent bridging and prevent oxidation of the circuit board. Flux spraying is carried by the X/Y manipulator to carry the circuit board through the flux nozzle, and the flux is sprayed onto the soldering position of the PCB circuit board.

Circuit board soldering technique 2:

The most important thing for the microwave peak selective soldering after the reflow soldering process is the accurate spraying of the flux, and the micro-hole jet type will never contaminate the area outside the solder joint. The minimum flux point pattern diameter of micro-point spraying is greater than 2mm, so the position accuracy of the flux deposited on the circuit board by spraying is ±0.5mm to ensure that the flux is always covered on the welded part.

Circuit board soldering technique 3:

The process characteristics of selective soldering can be understood by comparing with wave soldering. The most obvious difference between the two is that the lower part of the circuit board is completely immersed in liquid solder in wave soldering, while in selective soldering, only some specific areas are Solder wave contact. Since the circuit board itself is a poor heat transfer medium, it will not heat and melt the solder joints adjacent to the components and the circuit board area during soldering. Poor solderability of the circuit board holes will cause false soldering defects, which will affect the parameters of the components in the circuit, resulting in unstable conduction of the multi-layer board components and inner wires, causing the entire circuit to fail.

The so-called solderability is the property that the metal surface is wetted by molten solder, that is, a relatively uniform continuous smooth adhesion film is formed on the metal surface where the solder is located.