PCB production

Normally PCB manufacturers specially prepared PCB prototype and PCB manufacturing for all positions, not only in style but also need to be prepared with difficulty PCB prototype Multilayer pcb style.

The fact is, PCB production updated with the latest manufacturing technology, it is merciless comes to provide the necessary products, is using PCB. Therefore, people now days are very lucky because modern electronic products and commodities as processing and manufacturing of these important printed circuit board. As a fact, a variety of PCB has become larger and more widespread prosperity. These recent developments led the company's efforts in the pursuit of greater efforts to meet the demand of these products should have. Therefore, processing, manufacturing, and design have become the effective implementation of the PCB in their field. This is not surprising, because the company is equipped with advanced high-end PCB equipment is critical to achieve and prototype stages of the product.

The placement of the elements must be clear plans must also have a range of levels, the so when there is a modification in the technical one without redesigning the complete PCB. Add or change a smaller can help prepare an upgrade PCB thus saving a lot of cash. Typically, a single production difficulties PCB likely require more than a skilled, for the number of pilot projects. In these kinds of cases, PCBs are usually at very high price, take a lot of tiles you want to create.

Wonderful PCB Limited has been in the PCB industry for over 17 years, providing high quality PCBs at competitive price. For more about us, please visit us at: www.wonderfulpcb.com. Thanks.

PCB production

Normally PCB manufacturers specially prepared PCB prototype and PCB manufacturing for all positions, not only in style but also need to be prepared with difficulty PCB prototype PCB style.

The fact is, PCB production updated with the latest manufacturing technology, it is merciless comes to provide the necessary products, is using PCB. Therefore, people now days are very lucky because modern electronic products and commodities as processing and manufacturing of these important printed circuit board. As a fact, a variety of PCB has become larger and more widespread prosperity. These recent developments led the company's efforts in the pursuit of greater efforts to meet the demand of these products should have. Therefore, processing, manufacturing, and design have become the effective implementation of the PCB in their field. This is not surprising, because the company is equipped with advanced high-end PCB equipment is critical to achieve and prototype stages of the product.

The placement of the elements must be clear plans must also have a range of levels, the so when there is a modification in the technical one without redesigning the complete PCB. Add or change a smaller can help prepare an upgrade PCB thus saving a lot of cash. Typically, a single production difficulties PCB likely require more than a skilled, for the number of pilot projects. In these kinds of cases, PCBs are usually at very high price, take a lot of tiles you want to create.

Wonderful PCB Limited has been in the PCB industry for over 17 years, providing high quality PCBs at competitive price. For more about us, please visit us at: www.wonderfulpcb.com. Thanks.

The Fundamental Information of PCB Board

Nowadays, printed circuit board is widely used in electric & electronic field. This article introduces the fundamental information of PCB in details, including the definition, Gerber file, NC drill file, solder mask, silk screen, as well as the PCB finishing before ordering a PCB. Hope this tutorial can help our customers to improve their Aluminum pcb knowledge.
The definition of PCB
For standard PCB, it is the combination of bare board and components on it. While for bare board PCB, it is called printed wiring board. We usually call it PWB.
What is Gerber File?
The Gerber format is a file format used by printed circuit board (PCB) industry software to describe the images of a printed circuit board (Signal, ground, power, solder mask, silk screen, and drilling layout plan, etc.). The Gerber format is the de-facto industry standard for printed circuit board image transfer. The Gerber format specification can be freely downloaded.
What is NC drill file?
THE NC DRILL FILE can be opened by Notepad. The NC drill file should have Tooling Size, and X Y info of the holes. An NC drill example is below: T define the hole size, X Y define the hole location. NC drill file can also define the NPTH holes; the best way is to generate a separate NC drill for NPTH holes (Non-plated holes).
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. Solder mask comes in different media depending upon the demands of the application. The lowest-cost solder mask is epoxy liquid that is silk screened through the pattern onto the PCB. Other types are the liquid image able solder mask (LPSM) inks and dry film image able solder mask (DFSM). LPSM can be silk screened or sprayed on the PCB, exposed to the pattern and developed to provide openings in the pattern for parts to be soldered to the copper pads. DFSM is vacuum laminated on the PCB then exposed and developed. All three processes go through a thermal cure of some type after the pattern is defined.
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.
PCB finishing
PCB Surface Finishes vary in price, availability, shelf life, reliability and assembly processing. While each finish has its own benefits, in most cases, the process, product or environment will dictate the surface finish that is best suited for the application. It is recommended that the end-user, designer or assembler work closely with their PCB supplier to select the best finish for the specific product design.
If need any more information on PCB, you could check and source from this website: http://www.wonderfulpcb.com Wonderful PCB Technology Co., Ltd is a professional PCB manufacturer for many years and could try best to help!
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Ms. Jodie Zhou
Wonderful PCB
T +86-755-86229518-807 | F  +86 755 2607 3529|  e  wonderful09@wonderfulpcb.com |
www.wonderfulpcb.com | Skype: wonderful-02   | MSN: wonderfulpcb06@hotmail.com
Welcome to our trading shows:
1. Booth:  L32, Expo Electronics 2013, Apr.10-12th in CROCUS EXPO, Moscow, Russia
2. Booth: 11J36, HK Global sources Apr.12-15th, 2013 Asia World-Expo, and Hong Kong 
3. Booth: 9J35, HK Global sources Oct.12-15th, 2013 Asia World-Expo, Hong Kong

FPC soldering Technology

Should adopt mandatory infrared reflow furnace hot air convection, so the temperature on the Flexible pcb can evenly changes, which reduce the generation of bad welding.If using a single side tape, because it only fix the four edges of FPC, because in the condition of hot deformation, the middle part of bonding pad tends to tilt, molten tin (under the high temperature of liquid tin) will flow to generate empty welding, soldering, tin beads, make the process defective rate is higher.

1) temperature curve test methods:
Due to the Heat absorptivity is different to the load board , difference type of components on FPC, the difference of their temperature rising speed after heated during reflow soldering, have different heat absorption, so carefully set reflow furnace temperature curve will bring great influence to welding quality. Relatively reliable method is, according to the plate spacing during actual production, put two sheet of the load board which with FPC in front and behind of the test board, at the same time, the FPC on the load board sticked with components, with high temperature solder wire to weld the test temperature probe onto the test points, at the same time use high temperature resistant tape to fix the probe wire onto the load board. Note that high temperature resistant tape can not cover the test point. Test point should be adopted the solder points which near the load board edges and the QFP pin, in this way the test result can better reflect the real situation.
2）Setting of the temperature curve：
During furnace temperature debugging, because the average warm to FPC is NG, thus it's best to adopt heating/insulation/reflow temperature curve method, so that each area’s parameter is easy to be control led, others, influence of heat shocks to FPC and other components will be smaller. Based on experience, the best temperature will be dispatched to the lower limit of solder paste technical requirements value, wind speed of furnace is generally adopt the minimum wind speed, chain of reflow furnace’s stability should be, can't have.

Conclusion: When doing SMD mounting on FPC, the top importance is to realize accurate positioning and fixation, the key for fixation if to make an appropriate load board, and the second importance is the prebaking, tin printing, mounting and reflow soldering to FPC. Difficulty to FPC soldering is obvious higher than to rigid PCB. so it is necessary to accurately set the process parameters,at the same time, strict production process control is also important, must ensure that operators strictly implement each regulation on SOP, engineer who track the line and IPQC should strengthen the inspection,  Discover the unusual situation of production line in time，with line engineers and IPQC inspection should be strengthened, timely discover the unusual situation of production line, analyze the reason and take the necessary measures so that can control the FPC SMT production line NG rate within scores of PPM.

Some other PCB concepts to explore

Soldermask – If I had to guess what you think of when I say “PCB” I would bet that it is probably something green. Did you know that PCB’s are not this color as a result of what material is used? This is in fact another layer that is applied to the board after manufacturing. The purpose is to keep solder paste from spreading where it shouldn’t be, but it also has the effect of giving the board a definite style.
Fiducials – These are special markings on your board that allow a pick-and-place automated assembly machine to calibrate itself. Fiducials are usually just a circle where the soldermask has not been applied with copper circle in the middle. This makes the point appear fairly reflective.
Silkscreen – This is also another layer of the PCB added after fabrication. Silkscreen is used to provide visual cues to the user, document board information, identify proper component placement, or for branding. There are conflicting suggestions on proper usage of silkscreen and I will address this in part 2.
Copper fill - Deciding whether to use a ground/power plane in your design will be an important decision to make during the design stage. The most common reasons for using a copper fill are to suppress noise on the ground circuitry, dissipate heat from a particularly active device, or because someone told you that was the way to do it.
That’s enough of learning what goes into PCBs though, let’s discuss how to get started on your design.

Following will be continued in next chapter.

Shirley Xia
Oversea sales
www.wonderfulpcb.com

FPC Assembly

Nowadays, technology is already very mature to rigid Printed circuit board, however, many problem may be faced by operator during SMT to FPC.
1 False soldering, short soldering,Tin beads.
2.The Reason is due to the hardness of  raw material of FPC(Flexible printed circuit) caused, FPC is out of shape when meet the hot air and high temperature in reflew machine. Lead the wave shape to Flexible pcb, and the slop to FPC pads, then cause the flow of molten tin (liquid tin under high temperature), which cause False soldering, short soldering,Tin beads.(The main reason is the hardness of FPC). So if make the hardness of FPC into the same situation as rigid printed circuit board, and all soldering problem to FPC can be solved. The condition is you should know the SMT process to PCB. And then improve the hardness of Flexible Printed circuit into with the same hardness as rigid PCB, and then FPC SMT can be realized. And some problem, like no fix hole, no mark point, or the FPC is over long, which are the fault of designer, and it is also hard to be solved even to rigid PCB SMT. And NG rate can be only reduced based on personal experience or device independence.

According to above comment, the main solution is to improve the hardness of FPC the same as hardness of rigid PCB.

B. How to realize stable soldering to FPC
How to get the stable FPC (flexible circuit board) to the rigid PCB welding effects depends on the degree of hardness.
Methods: using jigs(carrier, handling plate) to make FPC perform as rigid board during SMT.

Below is the instruction of Magnetic reflow soldering tray
The material
1. Choose imported alloy material: good flatness, stable performance under high temperature
2. High temperature resistant magnet (300 degrees) to ensure permanent magnet during reflow soldering process.
3.The special steel, with magnetic treatment and good elasticity, and no deformation under high temperature.
4.Performance
(1) Because the flatness to FPC surface cause from the steel pressure l, it can reduce the flow of solder tin during reflow, which can ensure the good quality of soldering and reduce the NG soldering at meanwhile.
(2) Ensure the life of tray when choosing tray material.   
(3) Easy and convenient operation with high stability. 
(4) Heat insulation, prevent the FPC from deformation
There’s no special requirement to the composition of solder paste of FPC, the size of the tin ball particles and the amount of metal content, etc will be subject to if there is narrow space of IC pins on FPC, BUT FPC has high performance requirements to the solder paste printing, solder paste should has good thixotropy, solder paste should be able to easily be printed , demoulding and can be firmly adhere to the surface of FPC, there will be no mold release lead the hole in stencil filled with tin or such as collapse after printing.

     Because FPC fixed on the pallet before SMT,  and the FPC with high temperature heat-resistant pressure-sensitive adhesive tapes for purpose of location, which make its planar inconsistencies, thus FPC printing surface is unlikely to be as smooth as rigid PCB and the same consistent on thickness and hardness, so operator should not use a metal scraper, and should use the polyurethane scraper which with hardness of 80-90 degree.

 Solder paste printing machine is best to be with the best optical positioning system, otherwise will have great influence to printing quality, FPC although fixed on the load board, however, there always be small space between FPC and the load board, this is the biggest difference as rigid PCB board, thus the equipment parameters’s setting will also has great influence to the printing effect.

    Printing stations is also the key location to prevent FPC from being smudgy, need to wear glove then can go ahead for operation, at meanwhile,  workstation should be kept clean, stencil should be frequently wiped to be clean, to prevent the solder paste to pollute the gold fingers and gold plated key button. 

Control of FPC SMT

According to the properties of the products, components quantity and efficiency of mounting, it is OK to adopt high-speed placement machine for SMT. Because every piece of FPC has positioning with fiducial MARK, therefore, there’s no big difference on surface mounting technology between FPC SMD mounting and rigid PCB SMD mounting. It is important to note that although the FPC are fixed on the load board, but its surface can’t be the same flatness like rigid PCB board surface, local space must  exist between FPC and load board, so, the height of suction nozzle’s dropping, compression of blowing should be exactly setted.  On other side, most bare FPC performance as panel; format, and the rate of good finished product relatively low, so it if normal that there’re part of pieces with not good quality, which request recognition function on BAD MARK to SMT machine, otherwise, when mounting FPC panel with the status of not all pieces are good, will show low efficiency.