Single Sided PCB
SIMPLE AND SMART !
The printed circuit boards have been a massive step in the electronic history. Simple, smart, the concept of the single-sided PCB is still the same since a long time but it benefits from the latest innovations in production process and materials. New technology is always expensive. This can be easily explained by the costs of development, production, new machines or patented processes. But with the passing of time, those technologies become more accessible. All this made single side more advanced but also more affordable
PCB : WHAT ARE THEY MADE OF ?
A single layer Printed Circuit Board is made of insulating material, also known as substrate. Most of the time, this material is a glass fiber reinforced (fiberglass) epoxy resin or phenol resin, on which copper layer is laminated to leave the pattern desired. The copper circuits are coated with a layer of tin-lead to prevent oxidation and help for soldering process. Others finishing are also available, like OSP (Organic Solderability Preservative) or chemical gold. Contact fingers are plated with nickel, and finally electrolytic (0,025 to 2µ gold) for excellent conductivity. Different options are possible like silvercross or carbon connections, carbon contacts and different types of solder mask either silkscreen or photoimageable process.
Those materials are used in every days devices, who don’t need a big amount of technology. They are made of paper and phenol. Cheap, easy to build, but they have a poor resistance to heat (130°). The FR1 is still available on the market but it is gradually replaced by CEM1/FR3 and even FR4 material.
CEM-1 Composite material composed of woven glass fabric surfaces and paper core combined with epoxy resin. Easy punching, excellent electrical properties and higher flexural strength, CEM-1 provides excellent mechanical and electrical properties, and punches well up to .093″. The CEM-3 is very similar to FR4. Instead of woven glass fabric a ‘flies’ type is used. CEM-3 has a milky white color and is very smooth. It is a complete replacement for FR4 and has a very large market share in Asia. It is a kind of flame retardant epoxy copper-clad plate glass material, is generally used in electronics with double sided-pcb boards
FR is for “Flame Retardant”. As a printed circuit board is made to work with electricity, it is supposed to resist against heat. FR4 have a much better heat resistance than FR1/XPC thanks to a different layers composition. The FR4 PCB core is made of fiberglass epoxy laminate. It is the most commonly used PCB material. 1.60 mm (0.062inch). FR4 uses 8 layers glass fiber material as a standard. The maximum ambient temperature is between 120° and 130°C, depending on brand and filer. FR1 is the cheapest option you can find but nowadays, FR4 is affordable. FR4 is the best selection to make PCBs in market. Some materials may be cheaper but it can only be used to make one-layer boards, and the reliability of the boards made by these materials is not good. So they are only used for one-layer and very simple boards.