PCB Industry applications

 PCB Industry: There are four principal areas in the PCB industry where infrared heaters and lamps are used.

 

1. Wave soldering: This is a method of applying solder to components on PCBs. The components are mounted on the top surface of the board with legs going through the holes in the board to the printed circuit on the underside of the board. The boards are coated with a substance called “solder resist” in the areas where solder is not required. The boards are passed over a bath of molten solder in which a wave of solder is induced. The bottom of the board touches the crest of the solder wave and the legs of the components are soldered to the printed circuit track. Before meeting the wave, the boards are passed over a bank of infrared heaters typically 0.5 to 1 metre long. This is to preheat the board so that it will accept the solder and also prevent thermal shock when the board meets the solder. If the board was not preheated, it would delaminate on meeting the hot solder.

    

2. Reflow soldering: Here the boards have the printed circuit on the top surface only. The components to be soldered to the board are placed on top of the printed circuit, which has already been printed with solder pastes in the appropriate areas. The solder paste will also contain an adherent, which will help to hold the components in place. The placing of the components on board is referred to as “pick and place”. The boards are then conveyed under banks of usually low wattage infrared heaters to cause the solder paste to melt to solder the components.

    

3. Electronic components are sometimes encapsulated in a resin, which will require curing either in an oven or on a conveyor passing below IR elements. This is known as “potting” components.

    

4. For desoldering purpose. The PCBs are placed under the IR heaters for some time. This softens the soldering and then the components can be easily removed.