some basic knowledge about PCB

some basic knowledge about PCB

I saw some basic knowledge about PCB, today I summarized it and I want to share with you now.

1. Definitions:

For standard board, it is the combination of bare board and components on it. While for bare board PCB, it is called printed wiringboard. We usually call it PWB.

(1) Traces:

The base material of PCB is comprised of dielectric, heat insulation, uneasy to bend materials. On its surface, we can see thin traces, its material is copper. Originally the copper covered the whole PCB. Parts of it were etched during the process of production. Those parts left become net-like thin traces, which are called conductor pattern, and are used to provide circuit connection for components onPCB.

(2) Name of two side:

On most common single sided PCB, components are on one side, conductor pattern is on the other side. Then we would need to drill holes on the board, so that pins can put through the board to the other side. Therefore, the both sides of PCB are called component side and solder side.

(3) Gold finger:

Gold finger is functioned to connect two PCBs. We usually insert the gold finger of one PCB to the proper slot of the other PCB.

(4) Solder mask and silk screen:

The green or white oil on PCB is called solder mask, which is functioned as dielectric protective layer, can protects copper traces and also can prevent components to be soldered at incorrect place.

On the dielectric layer, a layer of silk screen will be printed. Some words will be printed to show the position of those components. It is also called legend.

2. The classification of PCB

(1) Single sided PCB

Single sided board means the conductor pattern appears only on one side. Because single sided PCB has many strict limits. On trace design, only circuit at early stage use this kind of boards.

(2) Double sided PCB

Double sided board means the conductor patterns appear on both sides of the board. However if we use the conductor patterns onboth sides, there should be proper circuit to connect two sides. The bridge between the circuits is called via. Those vias are plated with metal, such as tin, copper, gold, etc. Because the area of double sided PCB is two fold of the area of single sided, and the conductor pattern can cross with each other, so it suits to be used on more complex circuits.

(3) Multi-layer boards

In order to enlarge the area of conductor pattern, multilayer PCB uses more single or double boards. It uses several piece of double sided boards, and a dielectric layer is put between every layer of boards. The layers of one PCB represent the layer of conductor patterns. The amount of the layers is always even number. Technically we can make PCBs up to 100 layers.

For via, if we use it on double sided PCB, the whole boards will be drilled. While on multilayer PCB, if you just want to connect some traces, via may will waste trace space of some layers. Then we use buried vias and blind vias to solve this problem, because they are only drilled through several layers.

a. Buried vias only connect inner PCBs, so we can’t see them from the surface.

b. Blind vias connects several layers PCB with surface PCB.

In multilayer PCB, the whole board directly connects the ground line and power (used for preventing affection of the transmission signals on the signal). So we divide layers into signal, power, or ground. If the components on PCB need different power supply, this kind of PCB would have more than two layers of power and wire layers.

3. Components encapsulation technology

(1) Through hole technology

It means we mount components on one side, and solder the pins on the other. The disadvantage of it is space consuming. In fact, theirs pins take up space of both sides. While the advantage of it is good construction, which can bear pressure.

(2) Surface mounted technology
it means pins are soldered on the same side as components. We don’t have to drill holes  on PCB and don’t have to solder every pin. The advantage of SMT is that the components are more compact and cheaper than those in THT.

4

4. Gerber files:

Usually it comprises the layout plan of signal, ground, power, solder mask, silk screen, and drilling layout plan, etc.

5

5. Manufacture steps
choose base material, then use subtractive transfer to show the artwork on metal conductor.

 

 

Keywords:

China HDI PCB, High Density Interconnect, High Density PCB, Laser drilling PCB, Laser PCB, High integrated PCB, multilayer PCB, High layer PCB, china pcb, china pcb manufacturer, pcb manufacturer in China

Printed Circuit Board History | Printed Wiring Board

The history of printed circuit board, wiring board and PCB all describe a device that provides electrical interconnections and a surface for mounting electronic components. Although ” wiring board” is more technically correct, the term “printed circuit board” (PCB) is most commonly used.
The printed circuit board history begins with the first patents describing the “printed wire” were issued in 1903, PCBs as we know them came into use after World War II. Dr. Paul Eisler, an Austrian scientist working in England , is generally credited in history with making the first PCB. The concept was to replace radio tube wiring with something less bulky.
In the 1950s and ’60s, the history of PCBs evolved to circuitry on one side (single-sided) were the dominant variety. Still in use today, single sided boards are the simplest variety of PCB.
PCB’s history in the ’60s and early ’70s, lead to processes that were developed for plating copper on the walls of the drilled holes in circuit boards, permitting top and bottom circuitry to be electrically interconnected. These double-sided boards became the industry standard. Used today in consumer products and computer peripheral equipment, double-sided boards are slightly more expensive than single-sided boards.
As the densities and complexities of electronic components increased, the multi layer circuit board a process of sandwiching several circuitry layers together was developed. By  the mid 1980s, the history changed to multi layers accounting for the majority of Printed Circuit Boards produced in the U.S. Today’s computers, aerospace equipment, and instrumentation and telecommunications gear all contain multi-layer boards.
The history of the printed wiring board or now referred to as the printed circuit board has evolved over time to become the leading method of electronics in just about everything we use and buy.
Kingford is proud to be a part of PCB history and proud to be the preferred supplier of multi layer printed circuit boards and printed circuit boards for industry leading OEM’s and Electronic Contract Manufacturers serving the Industrial, Medical and Instrumentation markets since 1999.
Keywords:

High integrated PCB, multilayer PCB, High layer PCB, china pcb, china pcb manufacturer, pcb manufacturer in China, china pcb supplier, china pcb factory, china pcb circuit board, china pcb fabrication

PCB Companies Add Rookie And A PCB Listed On The First Business Through

PCB companies add rookie and a PCB listed on the first business through!

April 28, the Commission approved the statutory procedures for the 10 enterprises of the first application, including the Shanghai Stock Exchange 5, Shenzhen Stock Exchange small board 2, Shenzhen Stock Exchange 3, namely, Xiamen Hongxin Electronic Technology Co., Ltd., Suzhou Jingrui Chemical Co., Ltd., Shenzhen Citizen Electronic Technology Co., Ltd.

It is reported that Xiamen Hongxin Electronic Technology Co., Ltd. was established in September 2003, the registered capital of RMB78 million yuan. Its holding company Xiamen Hongxin Venture Factory Investment Co., Ltd. is one of the most successful mobile Internet industry chain integration platform, the current investment holding, equity, alliance enterprises nearly 100, the total registered capital of more than 5 billion yuan in 2013 to achieve revenue More than ten billion yuan.

Ding specializes in high-tech enterprise of R & D, design, manufacture and sale of flexible printed circuit board (FPC). It is also the only relying unit of Shenzhen FPC Engineering Technology Research Center. Company operation and management system specification and efficient, has passed the ISO9001 quality management system, ISO14001 environmental management system, QC080000 hazardous substances management system, TS16949 automotive quality management system OHSAS18001 occupational health and safety management system certification.

PCB Market Europe And The United States

,

Europe and the United States is weak, weak consumer demand for electronic products, the impact of the traditional PCB season, look forward to the second half of the year, Apple new models innovation, coupled with major brands to steal the end of the season, will continue to pour soft board, carrier board and HDI board needs ; Therefore, the overall PCB industry in the second half of the year, “eat soft do not eat hard”, soft board, load mills and revenue is expected to continue to grow up.

Hand-held intelligent products with strong demand for flat-panel computers, printed circuit board (PCB) manufacturers are exposed, especially HDI, soft board and other manufacturers in August reported better news. (2367) also has a history of the next high level, the performance is quite bright, legal person said that due to the end of the major companies will be the first to be ahead of the first quarter of the year, The introduction of new models to seize the business opportunities, and because of smart phones, tablet computers are widely used HDI, soft board and other products, the group is expected to remain bright in the second half of the results.

In the second quarter in the PCB manufacturers, the most outstanding performance of the soft board, revenue growth of about 15-20% over the previous quarter, as the carrier board is affected by the impact of the earthquake, the quarterly increase of about 6 to 7% (8046) benefited from the CPU carrier board to improve the yield, mobile phone customer orders increased, driven by the CPU carrier board and packaging board growth, but also drive the gross margin back to temperature; but the other side of the hard board factory Jian Ding (3044) by the PC, TV sales as expected, the impact of photovoltaic panels and other product lines, the overall performance of PCB hard board factory as soft board.

(6269) EPS to 2.79 yuan to win, a record high record, Jia Lianyi (6153) after-tax net profit of 591 million yuan to earn the most, while the Asahi Soft (3390) consolidated gross margin up to 30.56% ranking first, but the other side Yi Jia (2402) due to output efficiency and poor yield under the drag, the loss of the dilemma, the first half of the loss of 0.69 yuan per share after tax.

In fact, the soft board industry has been oversupply in the past, so there speculative competition, but since last year, thanks to smart phones and other commodity demand warming, performance gradually shine this year, become the PCB industry, the most watched ethnic groups, even the (8213) in order to expand the product line, also decided to enter the main ring (3267), as Taiwan Table Branch (6278) also continued to invest with the Thai.

Legal users said that not only Apple new products continue, the United States Intel (Intel) introduced Ultrabook laptop to become 3C market, is also the focus of the second half, Intel can sell and become a tool against the iPad, but also Taiwan’s soft board, HDI board In the next year’s performance focus.

Pcb Manufacturing Processing

1,Cut the material by cutting machine like this :

blob.png

2,Drilling of pcb manufacturing—the first drilling to make all the plated through holes :

blob.png

3,Planel plating ,make the holes drilled at step2 and the whole panel have copper

blob.png

4,Place the dry film(photosensitive material) on the board by this kind of machine.

Then Use some software (protel99 , office ,ACD, photoshop ) print the circuit on the negative film ,put this film on the board ,put them in the exposure machine ,the transparency parts of the film will feel the light; then put board into the developing machine, the parts that felt the light of the films will be melted by developing machine .

blob.png

blob.png

 

 

5, Pattern plating(of course ,before plating , the board will be clean ): make copper cover the reveal parts according to requirement of copper thickness àTin plating : make tin cover the reveal parts to protect the circuit .

blob.png

7,Etching of pcb processing: first of all ,clean the dry film by NaOH ,and copper uncovered by tin will be cleaned by CuCl2(Cu2++NH4OH+ NH4CL ) and left the circuit covered by tin ,second of all tin that was used to protect the circuit will be cleaned by HNo3 ,after that we will get the formed circuit covered by copper.

8,Middle Inspection step of pcb manufacturing processing: To check if some not good boards ,or some boards can be fixed

9,Solder mask and screen marks : solder mask to protect the circuit and make board looking good ,

blob.png

screen marks marking the position and orientation of components to make assembly easy.

10,Surface treatment :purpose is to offer the soldering interface ,make pads and some holes with some conduct material ,such as HASL :the tin is the conduct covering the pads ,ENIG: nickel and gold is the conduct covering the pads .

11, Appearance shape: Punching à V-CUT àClean outà Inspection

Pcb is finished

blob.png

12,TEST:Flying probe or E-test

13,OQC:FQC workers inspect all boards

14,Package and label

Quick Detection Of PCB Board Failure Problem Method

Quick detection of PCB board failure problem method

PCB board is not a simple process to do the board, drill holes on the components like. PCB production is not difficult, it is difficult to produce after the completion of the troubleshooting. Whether it is personal enthusiasts or industry engineers, PCB circuit board in the debugging when the problem is quite a headache, like the programmer encountered BUG the same.

Some people have a strong interest in debugging PCB circuit board, as programmers in the solution of BUG, common PCB circuit board problems and many common problems in addition to circuit board design, electronic components damage, short circuit, components The quality of PCB circuit board disconnection failure a few.

blob.png

Common PCB circuit board failure is mainly concentrated in the components above, like capacitors, resistors, inductors, diodes, transistors, FET, etc., integrated chip with crystal clear damage, and determine the components of the more intuitive method of failure Eyes to observe. There are obvious damage to the surface of electronic components have a more obvious signs of burning. Like this type of failure, directly to the replacement of the new components can be resolved.

Of course, not all of the damage to electronic components can be observed with the naked eye, such as the above-mentioned resistance, capacitance, transistor, etc., in some cases damage can not be seen from the surface, need to use professional inspection tools for maintenance , Commonly used with the inspection: multimeter, capacitance table, etc., in the detection of an electronic component voltage or current is not within the normal range, indicating that the components or a component of the existing problems, direct replacement and then check to see if it is normal.

blob.png

Components, such as broken, whether it is observed with the eyes or instrument testing, can be detected, but sometimes when we are on the PCB board components, will encounter problems, but the circuit board and can not work Case. Many novice encountered such a problem Mozhe, and can only do a board again, or buy a piece. In fact, encountered this situation, a lot of time in the installation process components, due to the coordination of various components of the work, there may be performance instability.

In this case, the instrument has been unable to help, you can try to determine the current voltage according to the possible range of failure, as far as possible, experienced engineers may be able to quickly determine the fault area, but the specific components which is broken But can not be 100% sure. The only way to try to replace a suspicious component is until you find the problem element. Last year, my notebook motherboard water, in the master when the maintenance also encountered a fault can not detect, and in the maintenance process to replace the three components, namely the power supply chip, diode, USB charging components (that is, notebook blue Jack that, shut down the state can be charged to the device), and finally through a wave detection with the investigation to replace the suspicious chip, only to determine the edge of the South Bridge chip a short circuit.

blob.png

The above is actually the problem of electronic components, of course, since the PCB circuit board as a foothold of components, then the circuit board failure is certainly there, the simplest example of the death of tin parts, due to the production process, PCB corrosion process, there may be disconnection problems. Encounter this situation, if you can not make up the line, then only use fine copper wire to fly to solve.

PCB circuit board failure is not significantly damaged in the case, check up really very troublesome, and in the investigation process, there will be a focus on the spirit, to be identified after the problem will be inexplicable sense of accomplishment, the programmer to solve BUG is This feeling, I often like to troubleshoot some difficult to repair the board, I think it is a pleasure.

LED Chip Offer Pick Up? Crystal Electricity: Just Stabilized Flat

For foreign investment, Crystal said that the price is not a comprehensive product prices are space, especially in China’s wafer plant continues to open new capacity under the circumstances, because China is the world 90% of LED lighting manufacturing, LED lighting chip prices just no longer crash, showing flat down, but as long as the supply is still greater than the demand, the future is still the possibility of falling; crystal to disperse the product layout to adjust the structure to get rid of the pressure on the price of lighting, this season has been effective.

Foreign investment pointed out that the three blue LED chip prices in May began to rise 10%, and Hua Chan chip prices are also close to the rate of nearly 1 percent, with the crystal power to freeze after the production price is indeed good, the factory is also synchronized Follow-up to raise prices; chip factory price adjustment will help adjust the profits of lighting, crystal power is currently the proportion of Blu-ray revenue is still up to 60-70%, prices will help to operate positive.

“Since the beginning of May, part of the LED chip prices have risen 10%,” the news, according to LEDinside asked Sanan company to get the reply is that they do not have a large price hike. But some of the Chinese chip manufacturers part of the LED chip items have a slight hike, mainly because some of the second-tier packaging manufacturers in order to ensure that the supply, so prefer to use a little higher prices to the market getting goods.

At the same time, LEDinside also confirmed from the relevant person in charge of Hua Can, Hua Chan some varieties of products have price hikes, but also because customers are worried about the tight supply and demand of the market, in order to obtain a more stable supply of chips and take the initiative to raise prices, There is no plan for full price increases