13.6.1 Soldering Iron

A soldering iron is the basic tool for hand soldering. It generates the heat required to heat the surfaces to be soldered and to melt the solder.

It should supply sufficient heat to melt solder by heat transfer when the iron tip is applied to a connection to be soldered. Soldering irons used for soldering electronic components consist of the following three main parts: (i) a handle, (ii) a heating element, and (iii) a bit/tip.

Handle: This is made of a good electrical and thermal insulator having an ergonomic shape so that it is comfortable for the operator.

Heating Element: This must have sufficient thermal capacity so that the set and working temperatures are, as much as possible, the same. The state-of-the-art hand irons are microprocessor-controlled. They compare the tip temperature sensed with a sensor with the set temperature. The heating element responds immediately to heat loss at tip while soldering and returns lost heat to the tip. The heating element must be properly insulated so that there is no electrical leakage appearing on the tip of the bit to cause damage to the components.

Bit/Tip: This is made of copper to provide good heat transfer. It is plated to prevent the solder dissolving them. Iron on the other hand is not attacked by solder, so iron plated copper bits are normally used. Unfortunately,...