Selective soldering is a soldering process that targets specific areas of a PCB (Printed Circuit Board) without affecting the entire surface or all electronic components on the board. During selective soldering, the PCB is first fixed within a frame, and all subsequent operations are automatically controlled by a pre-programmed process in the automated control system.
For each soldering point, the machine operator controls the flux, preheating duration, and specific position of the solder, aiming to minimize adverse effects on other solder points on the circuit board. Unlike wave soldering, which treats the entire PCB, selective soldering requires the identification of individual solder points. Each soldering operation is completed independently, soldering one point at a time until all soldering on the entire circuit board is complete.
The typical process for selective soldering involves:
- Preheating the areas where selective soldering will occur to activate the flux.
- Soldering each solder point according to the soldering plan, with one point soldered at a time.
- Optionally, the selective soldering process may include movements such as “drop-down” and “drag” to solder multiple points in close proximity or along a long connector by dragging the solder tip sequentially across them.
While the specifics of selective soldering processes may vary, the general workflow remains the same.