Copper foil features of flexible circuits

Posted by on January 12, 2010 No comments

Here, let’s to know the more details of copper foil is used in the flexible circuits. The cooper foil is very improtant part of flexible circuits.

1. There are two kinds of copper foil:
1>. rolled annealed copper foil(RA-copper)
2>. electrodeposited cooper foil(ED-copper)

2. The thickness:
1>. normally use 1/3oz, 1/2oz,1oz and 2oz four kinds;
2>. RA-copper: 1oz, 1/2oz, 1/3 oz or less thickness, but higher cost.

3. flexibility:
Rolled annealed copper foil is of high strength and can stand bending, two times for electrodeposited cooper.

Now, I think you know the Copper foil features of circuit boards more details. Ok, if you need more information, please do feel free to contact us.

Printed Circuit Board Technology

Posted by on November 11, 2009 No comments

Semiconductor continually refined reduction techniques, many of the original packages need to use more discrete components in order to constitute the circuit, but now live can use a highly integrated chips to replace, so some people gradually bearish printed circuit board technology. Theory is true, but the actual development is at odds with the theory of … …

Some people believe that printed circuit board (known as the Mainland of China: printed circuit) technology will become increasingly important, mainly because there is a 2:1, with the semiconductor process technology continues to improve, which requires multiple chips can be achieved effectiveness of, and now stars as long as the 1,2-integrated chip can be completed, as in the past need chipset (Chipsets) circuit can be achieved, but now available SoC (System-on-a-Chip; SoC) to achieve, so so that the number of wiring between chips declining.

Another reason is to speed up data transfer between chips, past parallel-type transmission interface is constantly being replaced by serial transmission interface, today’s high-speed serial multi-frequency approach includes mining can enjoy quickly transfer data, and the than those without parallel transmission crosstalk (Crosstalk) problem. For example, ATA into SATA, PCI into PCIExpress, SCSI into SAS, RapidI / O parallel version of the serial version of the conversion … so are examples.

So we should consider the printed citcuit board technology is also very impotant, we can’t leave it in our life.

Flexible Circuits Applications

Posted by on August 10, 2009 No comments

Flexible circuits can be used in many applications as the benefits of flexible circuits in many industries.

Highly automated fabrication methods, these ways can reduce workers handling of the flex circuits, reducing both cost and probability of error. Applications like cameras, printers, disk drives, and automotive panels.

High accuracy circuits is to handle ultra-fine lines and tight tolerances in an age of miniaturization. Such as used in aerospace and medical applications. Flexible circuits applications are most used in many industries including:

·Personal and mainframe computers, disk drives, and printers
·Automotive radios, cassette players, electronic control systems and on-board computers
·Telecommunications equipment, telephone handsets, and switching systems
·Consumer electronics like calculators, stereos, cameras, and compact disk players
·Heart pacemakers, hearing aids, and other medical applications.
·Jet engines, navigational and flight control systems
·Industrial controls, machine tool controls, and robotics

What types of flexible circuits are available?

Posted by on March 9, 2009 No comments

There are four basic types of flexible circuits(FPC) are available. These four types of flexible circuits can be used in different combinations to solve most every interconnection design problem.

1. The simplest flexible circuit is single-sided FPC. They provide maximum flexibility for dynamic applications and can withstand hundreds of millions of flex cycles. These simple circuits are also the most easily adaptable to SMT, TAB, and other developments in circuit technology.

2. Double-sided FPC consists of double-sided copper clad material with top and bottom cover films. The ability to interconnect between sides using through-hole plating helps double-sided circuits carry complex designs, and still maintain flexibility.

3. Multilayer FPC are ideal for complex, highly populated design requirements. Large numbers of conductors can be designed into a small package. Maybe flexibility will be somewhat limited by the number of layers in the design. Multilayer circuits are also the ideal problem-solving technology when confronted with design challenges like unavoidable crossovers, specific impedance requirements, elimination of crosstalk in sensitive circuits, additional shielding or ground planes, and high component density.

4. Rigid-Flex circuits are circuits combination of Rigid circuit and Flex circuits. So it have both the advantage of each other and it’s newest types used in various applications.

For more information of the flexible circuits, please do feel free to contact us.

What are the benefits of using flexible circuits?

Posted by on December 17, 2008 No comments

What are the benefits of using flexible circuits? Flexible circuits provide below major benefits over rigid circuit boards.

1>. A solution to a package problem;
2>. Reduce assembly costs
3>. Replacement for a circuit board and wires;
4>. Reduce weight and space;
5>. Dynamic Flexing;
6>. Thermal management/high temperature applications;
7>. Aesthetics.

So most designers choice the flexible circuits for most applications.

The performances of flexible circuits

Posted by on August 6, 2008 No comments

This time let’s to know the performances of flexible circuits.

(1) Base material:
PI(Polyimide) is the most common used, which is a kind of macromolecule material of high temperature proof and high strength, invented by Dupont. The polyimide made by Dupont is called Kapton. Besides some polyimide made in Japan can also be found. Its price is much lower. Polyimide can bear 10 seconds of high temperature of 400 degree centigrade. Its tensile strength is 15,000~30,000 PSI. The base material with 25um thickness is the cheapest and the most popular one. If we need the circuit board to be more rigid, we should choose 50um. Otherwise, if we need the circuit boards to be more flexible, then choose 13um.

(2) Adhesive:
It is divided into epoxy resin and polyethylene, they are all thermosetting adhesive. The polyethylene’s strength is lower. If we hope the circuit boards to be more flexible, then choose polyethylene. The thicker the base material and the adhesiveon it is , the more rigid the circuit boards are. If the circuit boards have to be bent in a large area, we should choose thinner base material and adhesive so as to reduce the stress on the surface of the copper, then lower appearance of micro crack.

(3) Copper:
It is divided into rolled annealed copper foil and electrodeposited cooper foil. Rolled annealed copper foil is of high strength and can stand bending, but its price is higher. Electrodeposited copper foil is much cheaper, but of low strength, easier to be bent.

When we choose to use rolled annealed copper foil, we should pay attention to the direction of the copper. The direction of the copper has to be the same with the bending direction of the circuit boards.

(4) Coverlay with adhesive:
25um coverlay would make the circuit board more rigid, but it is cheaper. Therefore to the circuit board needing to be bent greatly, we’d better choose 13um coverlay.

The adhesive is also divided into epoxy resin and polyethylene. The FPC using epoxy is more rigid. After thermosetting, there are some adhesive squeezed out at the edge of the coverlay. If the soldering pads are larger than the hole on the coverlay, the adhesive squeeze out would reduce the size of the soldering pads and lead to irregular edge. Therefore, we’d better choose 13um adhesive.

These are more details about the performances of the flexible circuits. If you still need more information, please do fell to contact us.

The structure of FPC

Posted by on March 5, 2008 No comments

This time let’s talk about more details about the structure of FPC(flexible circuits). Normally, according to the layer of conductive copper, FPC is divided into single-sided, double-sided, multilayer, dual access, etc.

The structure of single-sided FPC is the most simple. Based material FCCL: PI + adhesive + copper and adhesive + coverlay top layer. Firstly, the copper needs to be etched to get the traces, while the coverlay needs to be drilled to expose corresponding soldering pad. Make the plating for the exposed soldering pads to protect from oxidization. At last, FPC is punched into corresponding outline by required.

The structure of mulilayer FPC: The most typical difference between multilayer and single layer FPC is that the multilayer FPC is added with plated through holes to connect the copper on every layer. The first workmanship of Based material FCCL: PI + adhesive + copper is to make plated through holes(PTH). Later the technique is almost the same with single layer FPC.

The structure of dual access FPC: dual access FPC has soldering pads on its two sides, mainly used to connect with other circuit boards. Although it has similar structure with single layer FPC, its technique has great difference.

These are the more details of the structure of types of FPC, if you need more information, please don feel free to contact us.

The knowledge of via in PCB

Posted by on November 4, 2007 No comments

As is known to all, via in PCB is full of pad, and connect the traces of two sided. via is the most improtant part of mulitylayer PCB.

Simply speaking, every hole on printed circuit board(PCB)  may be called via.

We can divide vis into two types in function: firstly, used for electro-connection among layers; secondly, used for fixing components. We also divide it into three types in technology: buried via, blind via and though hole.

Buried via is connecting holes which are located in the inner layers of the PCB and won’t extent to the surface. Blind via is connecting the inner layer traces with the top and bottom surfaces of the PCB. Through hole goes through the whole PCB, which is used to realize inter-connection or used as components mounting position hole. Due to the simple technique and low cost, most of PCBs use it rather than the other two via.

Now you can know the via in PCB well, for further information, please don’t hesitate to contact us.

Circuit boards Electrical testing methods

Posted by on July 3, 2007 No comments

This time let’s talk about the electrical testing methods of circuit boards, there are: Dedicated,Universal Grid,Flying Probe, non-contact electron beam, conductive cloth (plastic), Capacity and ATG-SCAN MAN), of which there are three most commonly methods:Dedicated,Universal Grid,Flying Probe.To better understand the functions of various equipmenst, the following will compare the characteristics of three major methods.

1. Dedicated test
The reason for the specific type, mainly because they use fixtures only applies to one material number, different number of board material can not be tested and can not be recycled. Test points, the single panel in the 10,240 points, 8,192 points within each two-sided test can be made, the density in the test, because the probe head and the thickness of the relationship between the pitch used for more than the board.
2. Universal Grid test
The basic principle is the Universal test circuit PCB layout is based on the grid (Grid) to design, generally refers to the so-called grid line density,while the Universal test is based on this principle. Therefore making the fixture simple and fast, and explore needle can be reused.Universal test points is usually more than 1 million points.
3,Flying Probe test
Flying Probe test principle is very simple, only needs two probes for x, y, z movement to each of the two end points of each line tested, so no additional production of expensive fixtures. However, as is the end-point test, so very slow speed, about 10 ~ 40 points/sec, more suited for samples and small circuit boards production.

If you need more information of flexible circuits and printed circuit boards, please don’t hesitate to contact us.

PCB board electrical testing Introduce

Posted by on March 2, 2007 No comments

PCB board(printed circuit board) in the production process, will inevitably cause defects on the electrical due to external factors, such as short circuit,open circuit and leakage power, coupled with continued in the high PCB density, thinner pitch and multi-layer evolution, if failed to be screen out defective boards, and allowed to flow into the manufacturing process,the cost will inevitably cause more waste, so in addition to improved process control, improve the testing technology for the PCB manufacturer can also provide reduce scrap and improve product yield solutions .

In the electronics manufacturing process, due to the cost of the damage caused by defects in various stages of varying degree, the easier it will lower the cost of remedy. “The Rule of 10’s” is a commonly used to assess the process at different stages of PCB was found to be defective when the cost to remedy. So PCB board E-testing is the most improtant.

In the PCB manufacturing process, there are three stages to be tested:
1, inner layer etching
2, after etching the outer line
3, finished

Each stage usually 2 to 3 times the 100% testing, screening out bad board for further re-processing. Therefore, the PCB board E-testing is also a question of process data collection point, the best source, by the results, get open circuit, short circuit and other insulation of the percentage for rework inspection, the use of quality control methods to find root of the problem to be solved.

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