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Board basics Time:2019-04-27 16:59:19

Circuit board


The names of the circuit boards are: ceramic circuit board, alumina ceramic circuit board, aluminum nitride ceramic circuit board, circuit board, PCB board, aluminum substrate, high frequency board, thick copper board, impedance board, PCB, ultra-thin circuit board, super Thin circuit boards, printed (copper etching technology) circuit boards, etc. The circuit board makes the circuit miniaturized and intuitive, and plays an important role in mass production of fixed circuits and optimization of electrical layout. The circuit board can be called a printed circuit board or a printed circuit board. The English name is (Printed Circuit Board) PCB (Flexible Printed Circuit Board) FPC circuit board (FPC circuit board, also known as flexible circuit board flexible circuit board is polyimide). Or a polyester film made of a substrate with high reliability and excellent flexible printed circuit board. It has high wiring density, light weight, thin thickness and good bending property!) and soft and hard The combination and development of FEC and PCB, ecchas, soft and hard combination plate, has spawned a new product of soft and hard bonding board. Therefore, the soft and hard bonding board is a circuit board having a FPC characteristic and a PCB characteristic formed by combining a flexible circuit board and a rigid circuit board by a process such as pressing and pressing according to relevant process requirements.


classification


According to the number of layers, the circuit board is divided into three major categories: single panel, double panel, and multi-layer circuit board.


The first is a single panel. On the most basic PCB, the parts are concentrated on one side and the wires are concentrated on the other side. Because the wire only appears on one side, it is called a single-sided circuit board. Single panels are usually simple to make and low in cost, but the disadvantage is that they cannot be applied to products that are too complicated.


The double panel is an extension of the single panel. When the single layer wiring cannot meet the needs of the electronic product, the double panel is used. Both sides have copper-clad traces, and the vias can be used to turn on the lines between the two layers to form the desired network connection.


A multi-layer board refers to a printed board having three or more layers of a conductive pattern layer and an insulating material interposed therebetween, and the conductive patterns therebetween are interconnected as required. Multi-layer circuit boards are the product of the development of electronic information technology in the direction of high speed, multi-function, large capacity, small volume, thinning and light weight.

According to the characteristics, the circuit board is divided into a soft board (FPC), a hard board (PCB), and a soft and hard board (FPCB).

Circuit board


FR-1: Flame retardant copper clad phenolic paper laminate. IPC4101 detailed specification number 02; Tg N/A;


FR-4: 1) Flame-retardant copper-clad epoxy E-glass cloth laminate and its bonding sheet material. IPC4101 detailed specification number 21; Tg ≥ 100 ° C;


2) Flame-retardant copper-clad modified or unmodified epoxy E fiberglass cloth laminate and its bonding sheet material. IPC4101 detailed specification number 24; Tg 150 ° C ~ 200 ° C;


3) Flame-retardant copper-clad epoxy/PPO glass cloth laminate and its bonding sheet material. IPC4101 detailed specification number 25; Tg 150 ° C ~ 200 ° C;


4) Flame-retardant copper-clad modified or unmodified epoxy glass cloth laminate and its bonding sheet material. IPC4101 detailed specification number 26; Tg 170 ° C ~ 220 ° C;


5) Flame-retardant copper-clad epoxy E-glass cloth laminate (for catalytic addition). IPC4101 detailed specification number 82; Tg N/A;


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source


The creator of the printed circuit board was the Austrian Paul Eisler. In 1936, he first used a printed circuit board on the radio. In 1943, Americans used the technology for military radio. In 1948, the United States officially recognized the invention for commercial use. Since the mid-1950s, printed circuit boards have been widely used.


Prior to the advent of the PCB, the interconnection between the electronic components was done by direct connection of the wires. Today, wires are used only in laboratory applications; printed circuit boards are definitely in an absolute control position in the electronics industry.


PCB production process:


First, contact the manufacturer


First you need to contact the manufacturer, then register the customer number, then someone will quote for you, place an order, and follow up the production schedule.


Second, the material


Purpose: According to the requirements of the engineering data MI, cut into small pieces of production plates on large sheets that meet the requirements. Small pieces of paper that meet customer requirements.


Process: large sheet material → cutting board according to MI requirements → 锔 board → beer fillet \ edging → exit board


Third, drilling


Purpose: According to the engineering data, the required aperture is drilled at the corresponding position on the sheet of the required size.


Process: stacking pin → upper plate → drilling → lower plate → inspection \ repair


Fourth, sink copper


Purpose: The copper is deposited by chemical deposition on the walls of the insulating holes.


Process: coarse grinding → hanging plate → copper-plated automatic line → lower plate → dip % dilute H2SO4 → thick copper


Five, graphics transfer


Purpose: Graphic transfer is the transfer of images on the production film to the board


Process: (blue oil process): grinding board → printing the first side → drying → printing the second side → drying → explosion → shadowing → inspection; (dry film process): hemp board → laminating → standing → right Bit → Exposure → Rest → Shadow → Check


Sixth, graphic plating


Purpose: Graphic plating is to electroplat a layer of copper on the exposed copper skin or hole wall to the required thickness of the copper layer and the required thickness of gold or tin.


Process: upper plate → degreasing → water washing twice → micro-etching → water washing → pickling → copper plating → water washing → pickling → tin plating → water washing → lower plate


Seven, unwinding


2. Objective: Retreat the anti-plating coating layer with NaOH solution to expose the non-line copper layer.


Process: water film: inserting → soaking alkali → washing → scrubbing → passing machine; dry film: placing board → passing machine


Eight, etching


Purpose: Etching is the use of chemical reaction method to corrode the copper layer in non-line parts.


Nine, green oil


Purpose: Green oil transfers the pattern of green oil film to the board to protect the line and prevent tin on the line when soldering parts


Process: grinding plate → printing photosensitive green oil → 锔 plate → exposure → shadow; grinding plate → printing the first side → baking sheet → printing the second side → baking sheet


Ten, characters


Purpose: Characters are an easy-to-identify markup


Process: After the end of green oil → cool and cool → adjust the network → print characters → after 锔


Eleven, gold-plated fingers


Purpose: Plating a layer of nickel/gold with a required thickness on the plug finger to make it more wear resistant


Process: upper plate → degreasing → water washing twice → micro-etching → water washing twice → pickling → copper plating → water washing → nickel plating → water washing → gold plating


Tin plate (a process of juxtaposition)


Purpose: Spray tin is sprayed with a layer of lead tin on the bare copper surface not covered with solder resist oil to protect the copper surface from oxidation and oxidation to ensure good soldering performance.


Process: micro-etching → air drying → preheating → rosin coating → solder coating → hot air leveling → air cooling → washing and drying


Twelve, molding


Purpose: Through the die stamping or CNC machine to cut out the shape forming method required by the customer. Organic, beer, handkerchief, hand cut


Note: The accuracy of the data board and the beer board is higher, and the handcuffs are second. The hand cutting board can only make some simple shapes.


Thirteen, testing


Objective: Through the electronic 100% test, it can detect the open circuit, short circuit and other defects that are not easily found by visual observation.


Process: upper mold → release board → test → qualified → FQC visual inspection → unqualified → repair → return test → OK → REJ → scrap


Fourteen, final inspection


Purpose: Through 100% visual inspection of the appearance defects of the board, and repair of minor defects, to avoid problems and defective board outflow.


Specific work flow: incoming materials → view data → visual inspection → qualified → FQA random inspection → qualified → packaging → unqualified → processing → check OK

Industry Trends


The PCB industry is growing rapidly


Since the reform and opening up, China has attracted large-scale transfer of manufacturing industries in Europe and the United States due to preferential policies in labor resources, markets, and investment. A large number of electronic products and manufacturers have set up factories in China, and this has led to the inclusion of PCBs. The development of related industries within. According to China's CPCA statistics, in 2006 China's actual PCB production reached 130 million square meters, with an output value of US$12.1 billion, accounting for 24.90% of the global PCB output value, surpassing Japan to become the world's number one. From 2000 to 2006, China's PCB market grew at an average annual rate of 20%, far exceeding the global average. The global financial crisis in 2008 caused a huge impact on the PCB industry, but it did not cause a catastrophic blow to China's PCB industry. Under the stimulus of national economic policies, China's PCB industry experienced a full recovery in 2010. In 2010, China's PCB output value reached US$19.071 billion. . Prismark predicts that China will maintain a compound annual growth rate of 8.10% between 2010 and 2015, which is higher than the global average growth rate of 5.40%.


Unbalanced regional distribution


China's PCB industry is mainly distributed in South China and East China, and the two add up to 90% of the country, and the industrial clustering effect is obvious. This phenomenon is mainly related to the main production bases of China's electronics industry, which are concentrated in the Pearl River Delta and the Yangtze River Delta.


PCB downstream application distribution


The downstream application distribution of China's PCB industry is shown in the following figure. Consumer electronics accounted for the highest proportion, reaching 39%; followed by computers, accounting for 22%; communications accounting for 14%; industrial control/medical instruments accounting for 14%; automotive electronics accounting for 6%; and defense and aerospace accounting for 5%.


Technical backwardness


Although China is already the world's number one in terms of industry scale, it still lags behind the world's advanced level in terms of the overall technical level of the PCB industry. In terms of product structure, multi-layer boards occupy most of the output value ratio, but most of them are medium- and low-end products with less than 8 layers. HDI, flexible boards, etc. have a certain scale but are technically superior to foreign products such as Japan. The gap, the most technologically advanced IC carrier board, is rarely produced in China.


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