Most people are unaware of what a printed circuit board really is, never mind how they are created by a printed circuit board manufacturer. With most household appliances and many other common items containing them, it is interesting to look at what they are and how they are created.
Some examples of products containing printed circuit boards (PCBs for short) are televisions, computers, microwave ovens and mobile phones, although most electric appliances nowadays contain some sort of PCB. Electrical goods can be made without using PCBs, but this technique has proved to be the cheapest and fastest way.
PCBs are completely integrated into the electrical circuits in appliances. Components are fixed to the board as desired, and wired up via appropriate electrical conductors. The most common PCBs are those known as laminates, and copper-clad laminates.
A PCB looks like a thin, stiff sheet of material with electrical components mounted on it. The sheet itself is called a laminate. It consists of layers of cloth or paper, impregnated with resin under precise temperature and pressure conditions. In copper-clad laminates, copper will be applied to the entire laminate, to later be stripped away, leaving whatever conductive path is required. Alternatively, users may add copper to the bare laminate only as required.
The process where copper is added only as required is quite elaborate. The more popular method utilizes PCBs which already have a copper layer. In this approach, the unwanted copper is eaten away by chemicals, leaving only the conductors needed by the user. Removing the copper in this manner is 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.
Although various advanced techniques are now used in etching, one basic approach would be applying the protective ink to the board in the desired configuration and then submerging it in etching chemicals. The copper then dissolves, leaving the required circuit connections. Manufacturers make this process faster with methods which help to remove the copper as it is eaten away, for example by using sprays. In spray etching, the etching fluid is actually sprayed at the PCB. The manufacturer can direct the spray, as well as the type of jet and its temperature, for the best results.
Before components can be added to the PCB, holes must be drilled for each one. Due to the properties of the laminate board, steel drill bits would be blunted very quickly, resulting in tearing of the fine copper connectors. This problem is overcome by using special tungsten carbide drill bits.
The processes looked at here are some of the most common practices used by the printed circuit board manufacturer. PCBs have been made industrially since the 40s, and through the decades many manufacturing techniques have been explored. But after all that time, laminates, etching, silk screen printing and the use of tungsten carbide drill bits still remain at the forefront of PCB manufacture.
Some examples of products containing printed circuit boards (PCBs for short) are televisions, computers, microwave ovens and mobile phones, although most electric appliances nowadays contain some sort of PCB. Electrical goods can be made without using PCBs, but this technique has proved to be the cheapest and fastest way.
PCBs are completely integrated into the electrical circuits in appliances. Components are fixed to the board as desired, and wired up via appropriate electrical conductors. The most common PCBs are those known as laminates, and copper-clad laminates.
A PCB looks like a thin, stiff sheet of material with electrical components mounted on it. The sheet itself is called a laminate. It consists of layers of cloth or paper, impregnated with resin under precise temperature and pressure conditions. In copper-clad laminates, copper will be applied to the entire laminate, to later be stripped away, leaving whatever conductive path is required. Alternatively, users may add copper to the bare laminate only as required.
The process where copper is added only as required is quite elaborate. The more popular method utilizes PCBs which already have a copper layer. In this approach, the unwanted copper is eaten away by chemicals, leaving only the conductors needed by the user. Removing the copper in this manner is 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.
Although various advanced techniques are now used in etching, one basic approach would be applying the protective ink to the board in the desired configuration and then submerging it in etching chemicals. The copper then dissolves, leaving the required circuit connections. Manufacturers make this process faster with methods which help to remove the copper as it is eaten away, for example by using sprays. In spray etching, the etching fluid is actually sprayed at the PCB. The manufacturer can direct the spray, as well as the type of jet and its temperature, for the best results.
Before components can be added to the PCB, holes must be drilled for each one. Due to the properties of the laminate board, steel drill bits would be blunted very quickly, resulting in tearing of the fine copper connectors. This problem is overcome by using special tungsten carbide drill bits.
The processes looked at here are some of the most common practices used by the printed circuit board manufacturer. PCBs have been made industrially since the 40s, and through the decades many manufacturing techniques have been explored. But after all that time, laminates, etching, silk screen printing and the use of tungsten carbide drill bits still remain at the forefront of PCB manufacture.
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