Flexible Circuits & Printed Circuit Boards

FPC three main features

1. Deflection of flexible circuits and reliability of the current FPC are: single-sided, double-sided, multilayer flexible and rigid flexible board four boards. ① Flexible single-sided board is the lowest cost, do not ask for much when the electrical properties of the PCB. When wiring the single-sided, single-sided flexible board should be selected. It has a layer of conductive chemical etching of the graphics, the flexible insulating substrate of the conductive surface layer for rolling copper foil graphics. Insulating substrate may be polyimide, polyethylene terephthalate, p-aramid fiber acetate and polyvinyl chloride. ② flexible double-sided board insulation basement membrane in each of the two sides made of a layer of conductive etched graphics. Metallized holes on both sides of the insulating material to form conductive pathways connecting graphics to meet the deflection of the design and use features. The cover film can protect the single-, double-sided component placement of wires and the location of the instructions. ③ multi-layer flexible board is 3-layer or more layers of single-sided or double-sided flexible circuits laminated together by drilling larvae L, the formation of the metal plating of holes between different layers in the formation of conductive pathways. In this way, without using complex welding process. Multi-layer circuit at a higher reliability, better thermal conductivity of the assembly and provide greater convenience for performance of functions of great differences. Layout in the design, assembly should take into account the size, layers and flexible interaction. ④ traditional rigid flexible board is rigid and flexible substrates laminated together selectively composed. Structure to the formation of metal-based conductive connecting L larvae. If a PCB is, have negative components, rigid flexible board is a good choice. But if all components are in the side, the selection of double-sided flexible board, and laminated on the back of a layer of reinforcing material FR4, will be more economical. ⑤ hybrid structure is a multilayer flexible circuits, conductive metal layers of different composition. The use of an 8-laminate FR-4 as the dielectric layer, the use of polyimide as the outer layer of the medium, from the direction of the main board out of the three different leads, each lead by different metals. Constantan alloy, copper and gold, respectively, lead an independent. Most of the structure of this mixed signal converter used in the conversion and thermal and electrical properties of the relationship between the relatively harsh conditions of low temperature, is the only viable solution. Can be connected through the ease of design and evaluation of the total cost to achieve the best price-performance ratio.

2. Flexible circuit if the economy is relatively simple circuit design, the total volume of small and appropriate space, the traditional way in most of even a lot cheaper. If the line complex, deals with a number of signals or special electrical or mechanical performance requirements, flexible circuit design is a good choice. When the application size and performance beyond the ability of rigid circuit, the flexible assembly is the most economical. On a thin film can be made from within the hole with 5mil and 12mil pad 3mil lines and spacing of the flexible circuit. Therefore, in thin films direct mount chip more reliable. May be because the free ion source Desmear retardant. These may have a protective film, and at a high curing temperature, the higher the glass transition temperature. Flexible-rigid material than the material cost savings due to eliminating the connector. The high cost of raw materials is the flexible circuit of the main reasons for high prices. Larger difference between the prices of raw materials, the lowest-cost polyester flexible circuits used in the cost of raw materials used in rigid circuit 1.5 times the raw materials; high-performance polyimide flexible circuit is as high as 4 times or more. At the same time, the flexible material during the manufacturing process so that it is not easy to automate processing, resulting in decreased production; in the final assembly process prone to shortcomings, including off flexible attachments, fracture lines. When the design is not suitable for applications, such cases more easily. Caused by bending or forming in the high stress, often need to choose to enhance the material or reinforcement material. Despite the high cost of its raw materials, manufacturing problems, but collapsible, flexible and multi-layered puzzle features, will reduce the overall size of components, materials used be reduced, bringing the total costs of the assembly. Flexible circuits industry is in a small but rapidly evolving. Polymer thick-film method is a highly efficient, low-cost production process. The process in the low-cost flexible substrate, the selective conductive polymer screen printing ink. Its representation matrix for the flexible PET. Polymer thick film screen printing method conductors including filler metal filler or toner. Polymer thick film itself was very clean, the use of lead-free SMT adhesive without etching. Addition of Technology and its use of low-cost substrate, polymer thick film circuit is the method of copper circuits polyimide film prices 1 / 10; is the price of rigid circuit boards 1 / 2 ~ 1 / 3. Polymer thick-film method is particularly well suited to the equipment control panel. In mobile phones and other portable products, polymer thick-film method for the printed circuit board components, switches and lighting devices into law polymer thick film circuit. Both cost savings and reduce energy consumption. Generally speaking, the flexible circuit is indeed cost more than rigid circuits, and higher costs. Flexible plate at the time of manufacture, in many cases have to face the fact that many of the parameters exceeds the tolerance range. Manufacture of flexible circuits is the difficulty of the flexible material.

3. The cost of flexible circuits in spite of the cost of the above-mentioned factors, but the price of flexible assembly is declining, more rigid and traditional circuit similar. The main reason is the introduction of the updated materials, improved production technology and structural change. The structure now makes the product a higher thermal stability, very few materials do not match. Some updated materials from copper layer can be thinner and more sophisticated system of lines, so that components are smaller, more suitable for small load space. The past, the use of copper foil roll adhesion process will be coated with adhesive in the media today, you can not use the adhesive directly on the media to generate copper foil. These technologies can be a few micron thick copper layer, to be 3m. 1 and even more narrow width precision lines. After removing some of the adhesive with a flame-retardant properties of flexible circuits. This will speed up the certification process uL can further reduce costs. Flexible circuit board solder masks and other surface coatings to enable flexible assembly to further reduce costs. In the next few years, smaller, more complex and higher cost-assembled flexible circuit will require more innovative approaches to assembly, and the need to increase the hybrid flexible circuits. The flexible circuit industry challenge is to use its technological advantages, with the computer, remote communications, consumer demand, as well as synchronous dynamic markets. In addition, the flexible circuit in the lead up to play an important role. FPC is referred to as the Flexible Printed Circuit, also known as the soft circuit board, flexible printed circuit boards, flexible circuit boards, referred to as soft board or FPC, with a high density wiring, light weight, thin thickness characteristics. Mainly used in mobile phones, laptop, PDA, digital video cameras, LCM, and many other products. FPC flexible printed circuit is a polyimide or polyester film to a substrate made of a high degree of reliability, excellent flexible printed circuit. Features: 1. Be free to bending, folding, winding, three-dimensional space can be mobile and flexible. 2. Thermal performance can be used to reduce the size of FPC. 3. The realization of lightweight, small and thin to achieve component integration of devices and wires to connect. FPC applications MP3, MP4 players, portable CD players, home VCD, DVD, digital cameras, cell phones and mobile phone batteries, medical, automotive, aerospace and military field of epoxy CCL FPC become an important species with flexible features to epoxy resin for the substrate FCCL (FPC), has a special function as a result of the use of increasingly broad-based epoxy resin copper clad laminate is becoming an important species. However, late start to be in China to catch up. Epoxy Flexible Printed Circuit Board has been since the realization of industrial production has gone through the course of development for more than 30 years. 70s from the 20th century, the beginning of industrialization into a real large-scale production until the late 80′s, as a new class of polyimide film materials available and the application of flexible printed circuit board so that FPC had no adhesive formulations The FPC (generally referred to as “second-type FPC”). Into the 90′s developed the world’s circuits and high-density coverage of the corresponding photosensitive film, made in the design of FPC has made significant changes. Due to open up new application fields, the form of its products have taken place in the concept of non-small changes, which it expanded to include TAB, COB with a wider range of substrates. In the 90′s by the rise of the latter half of the high-density FPC has begun to enter the large-scale industrial production. Its circuit to the more micro-graphic extent of the rapid development of high-density FPC is also a rapidly growing market demand.

This time let’s see the outgoing quality inspection of flexible pcb, so you can see how can we control the quality of flexible pcb. See below our test items:

1. The material of your required. Include the based material,coverlayer,stiffener,silkscreen, etc
2. Testing: Peel strength, Chemical resistance test, Bending test, Thermal stree test;
3. Finished treatment;
4. Outline dimension;
5. 100% open/short testing of flexible pcb;
6. Appearance inspect.

After these inspect items, then we will pack the flexible pcb goods, and send out.

When you make flexible pcb samples, and it with many cut-out inside, do you have the uneven issue for the cut-out areas?

We analyzed it and have the following reasons:
1, the cut-outs too much, making with a little difficulty;
2, make samples with simple tooling, so more or less will be a bit uneven phenomenon.

The solution to the problem is actually very simple, use laser cutting, or set up hard tooling. As it’s just the flexible pcb samples stage, in order to save costs, we recommend using a laser cutting, the cost is only increased by a little bit.

If you have any doubts of flexible pcb production process, please feel free to contact us.

What is the FPC panel? In fact, the shipments of FPC (flexible pcb) are single piece, there is little make-up panel shipments, unlike rigid PCBs are most panel shipment.

FPC (flexible printed circuit board) production and accounting costs to be determined by the panel design. In general, the width of the raw materials of FPC are 250mm, length control in the range of about 300mm for panel.Higher utilization of space, the lower the cost, then the offer is naturally less. So the FPC make-up panel is very important.

But the final price will depend on the FPC drawings requirements, and some with the higher requirements, the price will be higher.

If you have FPC( flexible circuits) to quote, please feel free to contact our sales staff.

Today we have a look at the aluminum PCB production process. Please see below details.

First, Cut matetial;

Second, drilling holes

Third, the dry / wet developing
1, Dry / wet film developing process: nogplate – film – exposure – developing

Fourth, the acid / alkaline etching
1, Acid / alkaline etching process:  etching – Stripping – dry – check board

Fifth, silkscreen soldermask and characters.

Sixth, V-CUT outline;

Seventh,  testing, OSP;

Final, FQC, FQA, packaging, shipping.

The aluminum PCB production process is almost the same as other rigid pcb. CMD Cirsuits have a very strict qualtiy control system for the aluminum pcb and flexible pcb products, we pride ourselves on our quality and this is our selling point. Please contact us for any inquiry.

Today let’s have a look at the PCB design and cost controlling, in order to allow the PCB cost the lower the better, there are many design factors must be taken into considerations:

1, The board size. Smaller board, the lower the cost. Part of the PCB size has become the standard, as long as the cost according to standard size as it will naturally decrease.
 
2, The cost of SMT is lower than THT, because the parts on the PCB will be more intensive (also small).

3, If the board is very dense with components , then the trace must be more detailed, we should use the advanced equipments and expensive material. The cost of these questions, much more than the cost of reduce the PCB size.

4, The more layers, the higher the cost, but less PCB layers usually result in an increase in size. The cost of multilayer pcb much more higher than single-sided pcb
 
5, Drilling will take time, so the holes the less the better.

6, Buried holes compare tp through plated holes is expensive. Because the buried holes must be drilled before stitching.

7, The size of the holes on the board in accordance with parts to determine the diameter of the pin. If the board has a different type of pin parts, then because the machine can not use the same drill all the holes drilled, Comparison of the relative time-consuming, so it represents to  increase manufacturing costs.
 
8, Fly test, usually expensive than optical methods. Generally speaking, optical test is sufficient to ensure no errors on the PCB.

To know the PCB manufacturing process is very useful, which allows us to know where we should to control. So we know these can be taken into account when we design PCB, and reducing PCB costs.

Would you like to know the flexible pcb production capabilities and tolerances of CMD circuits? Please see below CMD can make for you.

1. tolerance of overall thickness   +/-0.03mm
2. positional and dimensional tolerance of edges and holes   about +/-0.10mm
3. minimum trace width and spacing (1/2 oz. copper)     0.05mm/0.05mm
4. minimum distance of traces and holes to an edge of the flex pcb 0.15mm, better is 0.20mm

These are the most common tolerances of the flexible pcb, if your board have more strict required, please send us to check if we can make.

CMD Circuits specilize in making flexible pcb, flexible circuits, rigid pcb, aluminum pcb.

Now the popular of the FPC surface plating is ENIG, but what’s the ENIG? It’s Nickel Immersion Gold.

The flexible circuits copper surface is plated of Ni/Au. The deposition thickness of the inner Ni layer is generally3~6um, the deposition thickness of the outer Au thin, usually 0.03 ~ 0.1um. Ni as the barrier layer between Cu and soldering tin. Welding, outside Au in the solder which melts rapidly with soldering tin and then turn into Ni/Sn intermetallic compounds with inner Ni. The gold-plated to prevent Ni oxidation during storage or passive, it should be enough gold plating density, the thickness can not be too thin.

CMD Circuits almost all flexible circuits are with the ENIG plated for customers, all of our staff are with the many years experience in line, and our customers are very satisfy with our quality when they compare with others’.

Relative Posts:
1. The structure of FPC;
2. the whole thickness of FPCs;
3. Flexible Circuits Production Process.

There are normal three kinds of coverlayer of flexible circuits(flexible pcb), please see below thickness:

1)12.5UM:     PI：12.5UM    AD：15UM           Thickness：27.5UM

                         PI：12.5UM    AD：25UM           Thickness ：37.5UM
             
2)  25UM:     PI：25UM     AD：25UM            Thickness：55UM

If you need any other information of flexible circuits and flexible pcb, please contact us anytime.

The structure of double-sided aluminum pcb is generally divided into three layers: first layer of a copper foil; the second layer is the thermal insulation materials; third layer is the aluminum substrate.

The fundtion of these three layers of double-sided aluminum pcb: first layer copper foil is made as circuits(conductive). The second layer is the key to check if it has the ability to play the fast passed the heat generated LED to aluminum substrate, it is necessary to know the resistance of thermal insulation materials. The function of the third layer is the aluminum substrate pass the heat from thermal insulating material to lamps again. It also has a installation function.

Thermal conductivity of aluminum pcb is not only has a relationship with the lamps, the most critical depends on the performances of thermal insulation materials.