Major components of a circuit board
Understanding the raw materials of printed circuit board is a must to understand how its whole system works. A circuit board is generally composed of diodes, resistors, circuit chips, transistors and more.
Its substrate is mostly made of glass fiber with copper foil connected to both sides. The copper used is either plated or non-plated; the plating process covers it with lead to prevent rusting.
Methods of connecting its components
Printed circuits are composed of numerous components that have to be linked together. Connecting these circuits is made possible by either of these two methods:
• Through-hole technology –
This requires a drilled hole where wires and leads pass through and soldered to connection pads of the circuit components on the other side of the board. The combination of friction and gravity keeps everything in place while all circuits and wires are soldered.
• Surface-mount technology –
This method requires the circuit components to be glued and soldered at the contact points, holding all parts in place. This goes on until everything is connected after the fusing point is melted and all components are finally interconnected.
The second method undoubtedly requires more precision and accuracy during component placement. However, it saves you time from drilling small holes and the space in the board for pads. Nevertheless, both methods are simultaneously used in electrically connecting all components of a printed circuit board.
Process of manufacturing
Manufacturers have different ways of creating circuit boards. Ideally, the manufacturing environment should be clean and free from any materials and chemicals which may cause contamination.
• Creating a substrate –
Fiberglass is imbued (either by spraying or dipping) with epoxy resin. Afterwards, it is rolled in a roller to determine the thickness of the substrate and remove excess resin.
Afterwards, it passes through the oven again and is cut into panels. The cut panels are heated to finally melt the resin and have the copper foil merge with the surface of the substrate.
• Drilling and plating holes –
The panels are stacked one on top of the others and drilled according to the patterned size of the holes using the CNC machine. This is followed by plating the part of the hole designed to be a circuit conductor.
• Making the printed circuit pattern –
There are two ways on how to create patterns in the substrate. First is additive method where coppers are plated according to the preferred pattern, leaving the rest of the holes non-plated (the number of plated or non-plated holes depends on the manufacturer). Second is the subtractive method, in here, the whole substrate surface is plated first. Afterwards, the plate on areas not included in the pattern is removed.
• Fastening contact fingers –
Printed circuit and the substrate are connected by fastening the contact fingers at the brink of the substrate area. This is also plated with tin-lead, nickel, and gold.
• Fusing the tin-lead coat –
The tin-lead coat are melted in oven with hot temperature to turn into a thin, shiny surface. This method prevents it from oxidizing.
• Sealing, attaching and cutting –
Panels are covered with epoxy to prevent damage while all its other components are being attached. This is done through the use of different machines and technology. When everything is in place, the panels are cut into pieces.
• Packaging –
Each printed circuit board is individually packed in plastic cover.The printed circuit board industry is dynamic as it responds to the demands of the consumers and electronic manufacturers when it comes to size and capacity. Therefore, it’s safe to say that more developments in manufacturing are in store.
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