PCB Assembly refers to the connecting of electronic parts to a printed circuit board. PCBs are used to mechanically link and support electronic parts using conductive paths, traces or tracks which are etched from copper sheets laminated onto a non-conductive substrate.
As soon as the PCB is finished then electronic components can be connected to produce a printed circuit assembly. The leads of the elements are placed through holes in the PCB, and in surface area mount building and construction, the electronic elements are put on lands or pads on the outer surfaces of the printed circuit board. The part leads in both types of this construction are then mechanically repaired to the PCB with soft metal molten solder.
There are all sort of various techniques for attaching elements to printed circuit boards, and many very high volume production is normally produced by device positioning and bulk wave soldering or reflow ovens.
In some cases really knowledgeable service technicians are used to solder extremely little parts by hand under a microscope. This is attained by utilizing tweezers and a very great soldering suggestion. Some parts such as ball grid selection plans are impossible to solder by hand.
Really typically, surface area mount and through the hole building should be combined on a single printed circuit board, as a few of the required electronic parts are just available in surface area mount plans, while others are just available in through hole plans.
One need to use both of the above methods is that surface mount techniques use up less area and will go largely unstressed, while through the hole mounting can offer necessary strength for any elements which are likely to withstand any physical stress. When the printed circuit board or PCB has actually been constructed or populated with the wanted elements, it can be tested in a variety of different ways and these may consist of:
o Power on; functional test, checking if the PCB is doing what it is created for
o Power on; in circuit test, physical measurements
o Power off; visual examination & automated optical inspection
o Power off; analogue signature analysis, power off testing