O que significa PCB？Postado em 07-07-2020
O PCB é a abreviatura de Placa de circuito impresso, também conhecida como placa de circuito impresso e placa de circuito impresso. É um importante componente eletrônico, um suporte para componentes eletrônicos e um provedor de conexões elétricas para componentes eletrônicos. Por ser feita por impressão eletrônica, é chamada de placa de circuito “impresso”.
The inventor of the printed circuit board was the Austrian Paul Eisler (Paul Eisler), who used a printed circuit board in a radio device in 1936. In 1943, Americans used this technology extensively in military radios. In 1948, the United States officially recognized the invention for commercial use. Printed circuit board technology has only been widely adopted since the mid-1950s.
Before the advent of printed circuit boards, the interconnection between electronic components was realized by direct connection of wires. Nowadays, the circuit panel only exists as an effective experimental tool; the printed circuit board has occupied an absolute dominant position in the electronics industry.
design do PCB
The design of the printed circuit board is based on the circuit schematic diagram to realize the functions required by the circuit designer. The design of the printed circuit board mainly refers to the layout design, which needs to consider various factors such as the layout of external connections, the optimal layout of internal electronic components, the optimal layout of metal wiring and through holes, electromagnetic protection, heat dissipation, and so on. Excellent layout design can save production costs and achieve good circuit performance and heat dissipation performance. Simple layout design can be realized by hand, and complex layout design needs to be implemented with the aid of computer-aided design (CAD).
Classified according to the number of circuit layers: divided into single panel, double panel and multilayer board. Common multi-layer boards are generally 4-layer boards or 6-layer boards, and complex multi-layer boards can reach more than ten layers.
Classified according to soft and hard: divided into ordinary circuit board and flexible circuit board.
The raw material of PCB: copper-clad laminate is the substrate material for making printed circuit boards. It is used to support various components, and can achieve electrical connection or electrical insulation between them.
PCB industry chain
Classified according to the upstream and downstream of the industrial chain, it can be divided into raw materials-copper clad laminate-printed circuit board-electronic product applications, and the relationship is simply expressed as:
Fiberglass cloth: Fiberglass cloth is one of the raw materials of copper clad laminate. It is woven from glass fiber yarn, which accounts for about 40% (thick sheet) and 25% (thin sheet) of the cost of copper clad laminate. The glass fiber yarn is calcined into liquid form in the kiln by silica sand and other raw materials. It is drawn into a very fine glass fiber through a very small alloy nozzle, and then hundreds of glass fibers are twisted into a glass fiber yarn. The investment in kiln construction is huge, generally requiring hundreds of millions of dollars, and once the ignition has to be produced 24 hours a day, the cost of entry and exit is huge. The manufacture of fiberglass cloth is similar to that of weaving companies. It can control the production capacity and quality by controlling the speed, and the specifications are relatively simple and stable. Since World War II, there have been few major changes in specifications. Unlike CCL, the price of fiberglass cloth is most affected by supply and demand. At present, the production capacity of Taiwan and Mainland China accounts for about 70% of the world.
Copper foil: Copper foil is the raw material that accounts for the largest proportion of the cost of copper clad laminate, accounting for about 30% (thick sheet) and 50% (thin sheet) of the cost of copper clad laminate. Therefore, the price increase of copper foil is the main driving force for the price increase of copper clad laminate. The price of copper foil is closely reflected in the price change of copper, but the bargaining power is weak. Recently, with the rising price of copper, copper foil manufacturers are in a difficult situation. Many companies are forced to close down or be merged, even if copper clad manufacturers accept copper foil. All copper foil manufacturers are still in a general loss state with rising prices.
Copper Clad Laminate: The copper clad laminate is a product obtained by pressing glass fiber cloth and copper foil together with epoxy resin as a fusion agent. It is a direct raw material of PCB. After etching, electroplating, and multi-layer board lamination, a printed circuit is made. board. The demand for funds in the CCL industry is not high, about 30-40 million yuan, and production can be stopped or transferred at any time. In the upstream and downstream industry chain structure, CCL has the strongest bargaining power. Not only can it have a strong say in the purchase of raw materials such as fiberglass cloth and copper foil, but as long as downstream demand is acceptable, it can pass the pressure of rising costs. Downstream PCB manufacturers.
PCB industry development status
From the perspective of output composition, the main products of China’s PCB industry have shifted from single-sided and double-sided boards to multi-layer boards, and are being upgraded from 4-6 layers to 6-8 layers or more. With the rapid growth of multilayer boards, HDI boards, and flexible boards, my country’s PCB industry structure is gradually being optimized and improved.
However, although my country’s PCB industry has made great progress. But there is still a big gap compared with advanced countries, and there is still much room for improvement and improvement in the future. First of all, my country entered the PCB industry late, and there is no special PCB R&D institution. There is a big gap with foreign manufacturers in some new technology R&D capabilities. Secondly, in terms of product structure, the production of medium and low-level boards is still the main factor. Although FPC and HDI have grown rapidly, the proportion is still not high due to the small base. Third, most of my country’s PCB production equipment depends on imports, and some core raw materials can only rely on imports. The incomplete industrial chain also hinders the development of domestic PCB series enterprises.
At present, the output value of the global PCB industry accounts for more than a quarter of the total output value of the electronic component industry, and it is the industry with the largest proportion in each electronic component subdivision industry. At the same time, due to its unique position in the basic electronic industry, it has become the most active industry in the contemporary electronic component industry.