Monday, 20 May 2013

Important Facts About The Manufacturing Of PCB Boards

By Carissa Glenn


A printed circuit board is important in any mechanically driven devices. This is used in supporting and connecting electronic components through an electrically charged pathway from a copper sheet that is laminated to a non-conductive substrate. A PCB is densely populated with discrete devices or electrical elements that can be collectively referred to as a printed circuit assembly or PCA. Manufacturing of PCB boards involves a systematic method for which only the ones with the ropes are permitted to work.

The design of a printed circuit board is done not only based on the resourcefulness and creativity of its fabricator. Assembly, design and quality control requirements are established by the Association Connecting Electronics Industries, a trade association aiming to set standardized production and assembly of any electronic devices. That is why PCBs have to be designed initially before they are out in the market.

Initially introduced around the 20th century, modern boards were fabricated by Albert Hanson, a German inventor, which was later on developed by a famous American inventor, Thomas Edison. By 1904, Edison tried to experiment with chemical methods on plating conductors through linen paper. And around 1913, a certain company invented a print-and-etch technique using this technology.

Later on, an engineer named Paul Eister enhanced a functionality of the printed circuit for the radio set. This technology spread significantly across the U. S. By 1943 as a basic component for the proximity fuse, an explosive device used in the World War II. This automatically blew up as it drew nearer to its target.

Long before the prototypes of printed circuits were released, point-to-point construction was used. This is a non-automated system of electronic circuit construction. Some time between 1936-1947, another company developed the device and have it sprayed on a plastic board.

Prior before all those enhancements, the electronic components had certain wire leads passing through holes which were then soldered unto a PCB trace. Such construction method is popularly known as through-hole construction, an electronic approach that typically involves the use of lead on the components inserted into the board's holes and a mounting scheme. This is done manually.

Around 1980s, surface-mount technology was introduced with which electronic circuits are mounted directly onto the board's surface. This technology then led to the production of smaller boards and had eventually replaced the through-hole construction. But both technologies can be employed using the same board.

Manufacturers at present largely use copper clad laminates, laminates, copper foil and resin Pre-preg. Laminates are created through the use of thermosetting plastic resin that produces uniform thickness of integral final pieces. Common length is between four and eight feet. Standard cloth weaves, cloth thickness and resin percentage are necessary in achieving desired dielectric characteristics. The fabric or cloth utilized in the process determines the resin ratio in a laminate being produced.

The whole manufacturing of PCB boards passes through different subtractive processes as well. These involve photoengraving, PCB milling and silk screenings printing. Circuit properties also need chemical etching, the subtractive manufacturing process which is now considered very essential in the production of such board.




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