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Printed Circuit Board

Printed Circuit Board

Printed Circuit Board

Printed Circuit Board

Printed circuit board has been developed for more than 100 years. The design of printed circuit board is mainly electronic board layout design. The main advantage of using printed circuit board is to greatly reduce errors in wire layout and electronic product assembly, and improve the level and production efficiency of automatic manufacturing of electronic products.

Before the appearance of printed circuit board, the interconnection between electronic components depended on the direct connection of wires to form a complete circuit. In contemporary times, circuit board exists only as an effective experimental tool, and printed circuit board has become an absolutely dominant position in the electronic industry. At the beginning of the 20th century, in order to simplify the production of electronic machines, reduce the wiring between electronic parts and reduce the production cost, people began to study the method of replacing wiring by printing. Over the past three decades, electronic engineers have proposed to use metal conductors as wiring on insulated substrates. The most successful was in 1925, Charles Ducas of the United States printed circuit patterns on insulated substrates, and then successfully established conductors for wiring by electroplating.

What is a printed circuit board?

Printed circuit board is a semi-finished product, not a terminal product given to consumers, so the definition of the name is slightly confusing. For example, the motherboard for a personal computer is called the mainboard, but it can not be directly called the printed circuit board. Although there are circuit boards on the mainboard, they are different. Another example: because there are integrated circuit parts loaded on the circuit board, we call it IC substrate circuit board, but in essence, it is not entirely a printed circuit board. The printed circuit board we usually say refers to the bare printed circuit board without components.

Printed circuit board is a non-conductive material printed or etched with conductive leads. Electronic components are installed on the circuit board, and each component is connected by leads to assemble or form a working circuit. The circuit board can have one or two layers of conductors, or multiple layers of conductors - multiple conductive interlayers, each separated by an insulating layer. The most commonly used circuit boards are made of plastic or glass fiber, resin composites, and copper wires. Of course, other materials are also used. Most printed circuit boards are flexible circuit board or rigid circuit board, and flexible layers can also be used in curved spaces. Components can be installed using SMD or via technology.

Printed Circuit Board

Printed Circuit Board

Printed circuit board manufacturers

If printed circuit board manufacturers are defined according to their capacity, they currently account for more than 80% of the world's PCB printed circuit board capacity. Although the printed circuit board industry as a whole is not very different, each printed circuit board manufacturer has its own expertise. The watershed of printed circuit board's technical level lies in its printed circuit board electroplating and printed circuit board etching. At present, the printed circuit board capacity of iPCB company is 3mil/3 mil for standard FR-4 printed circuit board and 1.5mil/1.5mil for HDI printed circuit board. The line width/spacing of IC substrate is 30um/30um. iPCB also has a deep understanding of microwave high frequency printed circuit boards. iPCB is a well printed circuit board manufacturer in china.

What is printed circuit board assembly?

Printed circuit board assembly is a product of the bare circuit board with electronic components installed. The electronic devices on print circuit boards can be SMT electronic devices, DIP electronic devices, and printed circuit board assemblies. For example, the server motherboard is a process of making assemblies of printed circuit boards.

How to test a printed circuit board when printed circuit board assembly is complete? This is also known as the ICT test, which requires an assembly station to install button batteries, radiators, CPU base brackets, CPU backplates, handles, some isolation mylar, Limited plastic columns, screws, etc. A server motherboard with assemblies is composed.

Printed circuit board assemblies require some external force to be applied to the printed circuit board assemblies, so the printed circuit board assemblies need to be fixed and supported on the assembled fixtures before they are assembled. Some printed circuit board assemblies need to be assembled on the soleplate, so two supporting fixtures need to be made. Support fixtures also need to pass electrostatic protection and stress tests before they are delivered to the production line for use. The standard of electrostatic protection can be referred to ANSI/ESD S20. 20. The stress test is referred to IPC-JEDEC-9704A(L).

The plastic combs we use in our life are very easy to generate static electricity, especially when the winter is very dry, the hair will fly up. When we have static electricity on our body and just touch the metal door handle, our hands will feel electric shock. Similarly, static electricity can also be harmful to electrostatic sensitive devices such as IC on printed circuit board assembly, and the printed circuit board test of the process may not be completely screened out. You can use a finger sleeve to avoid discharging and dirt when you handle the battery. In addition, the battery is polar, you need to pay attention to checking the positive and negative poles of the battery during installation.

Printed circuit board consists mainly of the following components

1. Pattern: Circuits are used as a means of conducting between originals. Large copper faces are designed as grounding and power layers in printed circuit boards. The circuit and the surface are made at the same time.

2. Dielectric layers: They are used to maintain the insulation between the circuit and layers, so they are called circuit substrates.

3. Through-hole / via: Through-hole allows circuits above the double sided printed circuit board to connect to each other, larger through holes are used as part plug-ins, and nPTH is usually used as surface mounting positioning and for fixing screws when assembling.

4. Solder resistant/Solder Mask: Not all copper surfaces need tin parts, so in areas that are not tin-eating, a layer of material (usually epoxy resin) will be printed to prevent short-circuiting between non-tin-eating routes. They are divided into green oils according to different processes. Red oil. Blue oil.

5. Legend/Marking/Silk screen: This is an unnecessary component. The main function is to label the names of parts on the printed circuit board. Position box for printed circuit board repairs and identification after printed circuit board assembly.

Printed circuit board types

There are many kinds of printed circuit boards. We can divide them into single-sided printed circuit board, double-sided printed circuit board, multilayer printed circuit board, flexible printed circuit board, high-frequency microwave printed circuit board.

1. Single-sided printed circuit board

Single-sided printed circuit boards use copper-coated boards on only one side to make copper foil wires, while the other side only prints component models and parameters without electrical characteristics to facilitate the installation, debugging, and maintenance of components. Single-sided printed circuit boards do not need to pass holes, make simple, low cost printed circuit boards because only one side is coated with copper. It is widely used in printed circuit board electronics with low area requirements.

2. Double-sided printed circuit board

Copper foil wires can be made on both the top and the bottom sides of the insulated base plate. The bottom side and the single printed circuit board work the same. On the top side, in addition to the type and parameters of the printed components, copper foil wires can be made on the same side as the bottom layer. Components are generally still mounted on the top layer, so the top layer is also called the "component surface", and the bottom layer is called the "solder surface". In order to solve the connection between the same wires at the top and bottom, circuit board engineers also made metalized crossings. The use of double-sided printed circuit boards effectively solves the problem of crossing wires at the same level, while the use of crossings solves the problem of connecting wires at different levels, compared with single-sided circuit boards. The component density and wiring density of the printed circuit board is greatly improved.

3. Multilayer printed circuit boards

Layered printed circuit boards are complex in structure. They are bonded alternately by electrical conductive layers and insulating layers. The cost of multilayer printed circuit boards is high. The number of conductive layers is generally 4, 6, 8, etc. The middle layer (i.e. internal layer) generally connects the power supply and ground network with the most number of pins of components. The electrical connection between layers is also achieved by using metalized holes between layers. In the multilayer circuit board, the multilayer structure in the circuit board can be fully used to solve the electromagnetic interference and shielding problems in the wiring of high-frequency printed circuit boards. At the same time, because the internal layer solves a large number of connections between the power supply and ground network, the wiring layer connection is dramatically reduced. Therefore, the circuit board has high reliability, small area, and in the computer printed circuit board, Automotive printed circuit board, microwave printed circuit boards and other products are widely used.

4. Flexible printed circuit board

Flexible printed circuit board is also known as FPC, flexible printed circuit board is popular for its light weight, thin thickness, free bending, and folding. With the rapid development of the electronic industry, the design of printed circuit boards tends to be more accurate and high density. Flexible printed circuit board is a highly reliable and flexible printed circuit based on polyester film or polyimide. By embedding a circuit design on a bendable thin plastic sheet, a large number of precision elements are stacked in a narrow and limited space to form a bendable flexible circuit. This kind of circuit can bend freely, fold lightly, has a small size, good heat dissipation, is easy to install, and breaks through the traditional interconnection technology. In the structure of flexible circuits, the materials consist of the insulation film, conductor, and adhesives.

5. Microwave printed circuit board

Microwave printed circuit board purpose in high-frequency circuits, such as power divider, antenna, coupler, combiner, power amplifier, dry amplifier, base station, microwave circuit board used by radio frequency microwave antenna.

Printed circuit board

Printed circuit board design

We can use free printed circuit board software for printed circuit board design. The ultimate goal of our circuit board design is to design a correct, reliable and beautiful PCB printed circuit board.

Before printing circuit board drawing, all aspects must be well prepared. If the schematic diagram is drawn correctly, enter the appropriate pin encapsulation for each schematic element according to the actual element. Plan the shape and size of the printed circuit board according to the size or design requirements of the electrical enclosure. The type of printed circuit board is determined according to the density of circuit board components and the complexity of wiring. Measuring circuit has positioning requirements for the positioning dimensions of components, such as potentiometers, the distance of various sockets from the border of the circuit board, the size and positioning of the mounting holes, etc. For more specific components, if a suitable package cannot be found in the printed circuit board package library, the home-made printed circuit board component package must be designed, manufactured and invoked.

After the printed circuit board is planned, the component pin packaging and network can be loaded. Generally, various errors may be encountered when loading the component pin packaging and network. At this time, according to the error prompts, you should go back to the schematic diagram to modify, and then reload the component pin packaging and network until the error is eliminated. After loading the pin packages and networks of the components, the components can be automatically laid out and manually adjusted according to the layout principle to make the positions of the components conform to the product layout requirements and to facilitate wiring.

After the component layout is completed, printed circuit board wiring can be done. Wiring generally combines automatic wiring with manual wiring. Before automatic wiring, automatic wiring rules must be set up to determine wiring level, wire width and other parameters to prepare for automatic printed circuit board wiring. In general, during the process of automatic wiring, the system lays emphasis on the traverse's distribution rate, which leads to the result that there must be some traverse lines that bend too much and are too long to meet the requirements of electrical characteristics. At this time, manual modification must be made. At the same time, according to the actual needs and the requirements of improving the anti-interference ability and reliability, copper cladding, installation holes, teardrop filling can be added to the printed circuit board. Also modify and add component labels, dimension labels, text labels, and so on.

After the printed circuit board design is completed, the printed circuit board design and fabrication can be sent to the circuit board manufacturer according to the number of printed circuit boards produced.

Printed circuit board fabrication

iPCB has advanced printed circuit board equipment and sufficient printed circuit board manufacturing materials in stock, We provide standard custom printed circuit board services. If you have a conclusion of printed circuit board, please contact iPCB.