WHAT IS A PRINTED CIRCUIT BOARD?
A printed circuit board (PCB) mechanically supports and electrically connects electronic components using tracks, leads, and other conductive characteristics recorded from rolled copper sheets onto a non-conductive substrate. The printed circuits can be one-sided (a copper layer), bilateral (two layers of copper) or multilayer (external and internal layers). Multilayer printed circuits allow a higher density of components. The drivers of the different layers are connected to the holes through the plates called vias that have been treated in previous blogs. Advanced PCBs may contain components (capacitors, resistors, or active devices) embedded in the substrate.
Before the printed circuit boards became the common component used in electronics, a point-to-point construction was used. This meant extremely cumbersome and unreliable designs requiring large spines and regular replacement. Most of these problems were solved directly when the PCBs went into regular production.
For prototypes or small series, the winding of the turret wire or plate can be more effective. Prior to the invention of the printed circuit board, John Sargrove’s 1936-1947 electronic circuit production apparatus (ECME), which sprayed metal onto a bakelite plastic plate, had a similar design. ECME could produce 3 radios per minute.
The Austrian engineer Paul Eisler invented the circuit as part of a radio while working in England around 1936. Around 1943, the United States started using a large-scale technology to make proximity fuses for use during the Second World War. After the war, in 1948, the United States launched the invention for commercial purposes. Printed circuit boards became common in the consumer electronics industry only in the mid-1950s, following the development of the automatic assembly process by the US military. More or less at the same time in Great Britain, Geoffrey Dummer did a similar job and then at RRDE.
Originally, all electronic components had wires and the printed circuit board had holes for each wire of each component. The component cables were passed through the holes and soldered to the printed circuit. This method of assembly is called through construction. In 1949, Moe Abramson and Stanislao F. Danko, the US Army signal body developed the self-assembly process in which the components were inserted into a model of interconnection and copper sheet immersion welding. The patent obtained in 1956 was assigned to the United States Army. With the development of laminating and engraving techniques, this concept has become the standard process currently used for the production of printed circuits. Welding can be performed automatically by passing the plate over a wave or welding wave in a wave soldering machine. However, the wires and holes are a waste because the drilling holes are expensive and the protruding wires are simply cut.
Since the 1980s, more and more surface mounting pieces have been used instead of pass-through components; this has led to smaller cards for a given feature and lower production costs, but with some additional difficulties in serving wrong cards.
Currently, most printed circuit boards are printed using multi-step methods, such as conventional vacuum deposition and photolithographic design. However, these methods have disadvantages because they require a high treatment temperature; they involve toxic waste and are expensive. With the technological advances we have seen in previous years, it is not difficult to imagine that PCBs will soon be revolutionized. It’s already starting! With the use of 3D printing, it is every time a more conventional “3D printing”. Not only that, but research institutes foresee a “greener” future for PCBs; PCBs in paper.