PCBA Soldering Technologies

PCBA soldering technologies are broadly categorized into two main categories: mainstream batch soldering and auxiliary soldering/rework.

1. Mainstream Batch Soldering
This type of technology is used to solder large numbers of components onto a PCB at once and is the cornerstone of modern production.

a) Reflow Oven

Process: Solder paste is first applied to the PCB pads using a stencil and solder paste printer. Components (SMC/SMD) are then placed in their proper locations using a placement machine. Finally, the process enters a reflow oven. The oven is heated according to a preset temperature profile, causing the solder paste to melt, flow, and wet the pads and component pins. It then cools to form a permanent electrical and mechanical connection.

Main Application: Surface mount components.

Core Equipment: Solder paste printer, placement machine, reflow oven.

Features: High efficiency, high consistency, and suitability for large-scale automated production.

b) Wave Soldering

Process: Through-hole components (THT) or specially treated surface-mount components are inserted into a PCB, and the soldering surface of the PCB is exposed to the molten solder wave, achieving soldering.

Main Application: Through-hole components. Sometimes also used for soldering the THT side of a single-sided mixed-panel board (one side with surface-mount technology and the other with only THT).

Core Equipment: Wave Soldering Machine.

Features: Suitable for soldering through-hole components, offering high production efficiency, but not suitable for high-density SMT boards.

c) Selective Soldering

Process: This can be considered a "precision" wave soldering process. Using a micro solder wave nozzle, it selectively solders only specific through-hole components on the PCB, or a small number of components that cannot withstand reflow soldering.

Main Applications: Soldering a small number of through-hole components onto a completed SMT board (which has undergone reflow soldering); or soldering heat-sensitive components that cannot withstand the high temperatures of full reflow soldering.

Core Equipment: Selective Wave Soldering Machine.

Features: High flexibility, minimal thermal shock, but relatively slow speed. It is a highly efficient alternative to manual soldering in mixed-panel board production.

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