Circuit board manufacture. Robot solders part of an electronic circuit board. This welding process involves the heating of a metal alloy (solder) wire, taken from the spool at upper centre, that melts at a low temperature. The solder forms a bond on the circuit board when it cools and solidifies. The bond is used to carry electric currents from one component to another. Circuit boards are made up of components such as micro- chips, diodes, capacitors and resistors, which are linked by electrical pathways. They are used in a variety of electronic devices. Robots are widely used on industrial production lines for performing repetitive operations.