Invented at the beginning of the 20th century, the printed circuit board is an essential electronic element in many machines and devices. More precisely, it is a plate that connects several electronic components together. There are many types of printed circuits, which are distinguished by their rigidity, their number of layers, their stratifications or their metallized connections. In this article, discover how they are made:
WHAT IS A PRINTED CIRCUIT?
Also called an electronic board, a printed circuit can have many uses. It is found in the majority of electronic devices, ranging from calculators to PCs, telephones, household appliances and hi-fi equipment. For example, some components of a computer are typically electronic cards: memory bar, motherboard / graphics / sound or network, USB key, etc.
Concretely, a printed circuit consists of very thin layers of copper, separated from each other with an insulating material. On these layers, there are multiple pads electrically connected by tracks etched in the copper.
Furthermore, these pellets may or may not be perforated. When they are full, they allow you to solder other components to the surface of the circuit . And when they are perforated, the pads then create an electrical connection between the layers of copper or between the components soldered to the board.
Finally, the printed circuit is generally finalized with a layer of varnish which aims to protect its various elements against oxidation. In particular, this avoids the risk of short-circuiting.
THE MANUFACTURE OF A PRINTED CIRCUIT BOARDS
Regarding the manufacture of an electronic card, it can be done in an artisanal or industrial way.
In both cases, it all starts with the laminate. The base of the circuit is made of thermoset epoxy resin which encases woven fibrous layers – usually paper or fiberglass. Then a thin layer of copper is added over the epoxy. This step can be done with a manual or industrial press. It is also possible to alternate several layers of laminate.
Then, a protective varnish is applied over the entire surface. Then the copper is chemically attacked at the places where the future electronic components (pads) and tracks will be located. At the industrial level, we rather use etching and metallization to create these electronic links. If necessary, the passage holes for the perforated pads are also made. Finally, soldermask (polymer) is applied for final protection.
To finalize the manufacture of an industrial printed circuit, precise labeling is also planned, with all its specifications. Given the harsh conditions this electronic component can experience (including high heat, chemicals, and friction), a very durable label is required. It even offers mini formats, 5 mm by 5. Thus, the traceability of each printed circuit is ensured, with a permanently legible label.
Handcrafting is interesting if you are a handyman and have a specific need. As for industrial production, it offers many more possibilities, with often more precise and meticulous results.