3.2 Electronic and mechanical systems GapFill

Many electronic products are made in high volume using  pick and placesurface mountpumpone-off assembly techniques where machines work with great speed and accuracy. During high-speed production,  wave solderingmanual assemblybrazinga rivet is used to join components to the circuit board.

Electronic systems make use of many standard components, with resistors being one of the most common components. Resistance is measured in  millimetersvoltsfaradsohms. Resistors have colour bands around the outside to indicate their value. A black colour band indicates a value of  1045.

Printed circuit boards are the most common method used to make circuits and are coated in a thin layer of  nylonpaintcopperaluminium, a very conductive and relatively low cost material.

Solder, which is the material used to make connections between the circuit board and the components, is made from tin and  silvercarbonleadcopper and it melts at a relatively very low temperature.

The outer PVC coating needs to be removed from an insulated cable to expose the wire inside and  wire strippers arepliers area desoldering pump isside cutters are used to remove this safely.

Other mechanical systems include  boltssprocketswasherschains, which are used to spread the load exerted by a nut when done up tight, whereas  bearingspullieswing nutssprings are used to reduce the wear in rotating systems. Properties such as the surface hardness of an aluminium hand-held torch can be modified through a technique known as  stainingvarnishingtemperinganodising, which is a process that also allows the colour of the surfact to be changed.

Metal products such as chains and sprockets are subject to a great deal of wear, and use of  galvanisinganodisingwaxinglubricants helps to reduce the wear.