Almost every conceivable electrical item nowadays contains a printed circuit board. Despite being so ubiquitous, it is not generally well known exactly what they are, or how they are made by the printed circuit board manufacturer. As they lurk inside so many everyday items, it is of interest to learn more about them, and the ways in which they are made.
Just a few everyday items using printed circuit boards (otherwise known as PCBs) are microwave ovens, televisions, computers, and mobile phones, although few electrical items don't contain PCBs nowadays. Arrangements other than the PCB do exist, but PCBs are the most economical and have the lowest production time.
All PCBs have a few basic purposes in common, namely to provide a surface for components to be mounted on, and also to provide the appropriate conductors which connect them together. The two most popular basic starting points for PCBs are called laminates, and copper-clad laminates.
To make a PCB, cloth or paper are layered with resin to create rigid, slim boards. During this process, the materials are warmed and pressurized for optimum results. These boards are called laminates, and by themselves they cannot conduct electricity. For this purpose, either the entire board is coated with copper (as in the copper-clad laminate), and any that is unwanted is subsequently removed, or else the user adds copper only as desired.
The process for removing unwanted copper is far simpler than where it must be added as required, so most PCBs are made using copper-clad laminates. Here, unwanted copper is dissolved by a special solution, in a technique known as etching.
The copper required for the circuit is protected from the etching chemicals in various ways, but the most popular method involves depositing special ink, which is resistant to the chemicals, on the areas to be kept. This is usually done using silk screen printing.
Many etching methods exist, but to summarize the basics, the required copper connections are marked onto the PCB with the special ink, and then the board is dipped in etching fluid. Unprotected copper will gradually dissolve, and the copper connections, as desired by the manufacturer, remain. Approaches to allow this stage to progress more quickly are based around moving away dissolving copper as the process continues. A popular variation is spray etching, where etching liquid is applied using sprays, the force of which will agitate the dissolving copper and bare the untreated copper underneath. The spray pattern, direction of the fluid and heat levels will be manipulated by the manufacturer to provide the most economical outcomes.
After the laminate and the conductors have been prepared, it is time to make holes for the electrical components. Laminate boards will quickly wear out a steel drill bit, leading to damage of the intricate conductors, and so extremely hard tungsten carbide drill bits are important to this stage of the process.
The techniques discussed here represent some of the most popular used by the modern printed circuit board manufacturer. Since PCBs have been manufactured since the forties, a great many techniques have been tried in that time, and so it can be seen that the laminates and tungsten carbide drill bits used, and techniques like etching and silk screen printing, have truly earned their place.
Just a few everyday items using printed circuit boards (otherwise known as PCBs) are microwave ovens, televisions, computers, and mobile phones, although few electrical items don't contain PCBs nowadays. Arrangements other than the PCB do exist, but PCBs are the most economical and have the lowest production time.
All PCBs have a few basic purposes in common, namely to provide a surface for components to be mounted on, and also to provide the appropriate conductors which connect them together. The two most popular basic starting points for PCBs are called laminates, and copper-clad laminates.
To make a PCB, cloth or paper are layered with resin to create rigid, slim boards. During this process, the materials are warmed and pressurized for optimum results. These boards are called laminates, and by themselves they cannot conduct electricity. For this purpose, either the entire board is coated with copper (as in the copper-clad laminate), and any that is unwanted is subsequently removed, or else the user adds copper only as desired.
The process for removing unwanted copper is far simpler than where it must be added as required, so most PCBs are made using copper-clad laminates. Here, unwanted copper is dissolved by a special solution, in a technique known as etching.
The copper required for the circuit is protected from the etching chemicals in various ways, but the most popular method involves depositing special ink, which is resistant to the chemicals, on the areas to be kept. This is usually done using silk screen printing.
Many etching methods exist, but to summarize the basics, the required copper connections are marked onto the PCB with the special ink, and then the board is dipped in etching fluid. Unprotected copper will gradually dissolve, and the copper connections, as desired by the manufacturer, remain. Approaches to allow this stage to progress more quickly are based around moving away dissolving copper as the process continues. A popular variation is spray etching, where etching liquid is applied using sprays, the force of which will agitate the dissolving copper and bare the untreated copper underneath. The spray pattern, direction of the fluid and heat levels will be manipulated by the manufacturer to provide the most economical outcomes.
After the laminate and the conductors have been prepared, it is time to make holes for the electrical components. Laminate boards will quickly wear out a steel drill bit, leading to damage of the intricate conductors, and so extremely hard tungsten carbide drill bits are important to this stage of the process.
The techniques discussed here represent some of the most popular used by the modern printed circuit board manufacturer. Since PCBs have been manufactured since the forties, a great many techniques have been tried in that time, and so it can be seen that the laminates and tungsten carbide drill bits used, and techniques like etching and silk screen printing, have truly earned their place.
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