The assembly of printed circuit board

After the printed circuit board (PCB) is completed, electronic components must be attached to form a functional printed circuit assembly, or PCA (sometimes called a "printed circuit board assembly" PCBA). In through-hole construction, component leads are inserted in holes. In surface-mount (SMT - surface mount technology) construction, the components are placed on pads or lands on the outer surfaces of the printed circuit board. In both kinds of construction, component leads are electrically and mechanically fixed to the board with a molten metal solder.

There are a variety of soldering techniques used to attach components to a PCB board. High volume production is usually done with SMT placement machine and bulk wave soldering or reflow ovens, but skilled technicians are able to solder very tiny parts (for instance 0201 packages which are 0.02 in. by 0.01 in.) by hand under a microscope, using tweezers and a fine tip soldering iron for small volume prototypes. Some parts may be extremely difficult to solder by hand, such as BGA packages.

Often, through-hole and surface-mount construction must be combined in a single assembly because some required components are available only in surface-mount packages, while others are available only in through-hole packages. Another reason to use both methods is that through-hole mounting can provide needed strength for components likely to endure physical stress, while components that are expected to go untouched will take up less space using surface-mount techniques.

After the board has been populated it may be tested in a variety of ways. Because of those test, printed circuit board may be designed with extra pads to make temporary connections. Sometimes these pads must be isolated with resistors. The in-circuit test may also exercise boundary scan test features of some components. In-circuit test systems may also be used to program nonvolatile memory components on the PCB board.

In boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the PCB board traces to test that the ICs are mounted correctly. Boundary scan testing requires that all the ICs to be tested use a standard test configuration procedure, the most common one being the Joint Test Action Group (JTAG) standard. The JTAG test architecture provides a means to test interconnects between integrated circuits on a board without using physical test probes. JTAG tool vendors provide various types of stimulus and sophisticated algorithms, not only to detect the failing nets, but also to isolate the faults to specific nets, devices, and pins.

When PCB board fail the test, technicians may desolder and replace failed components, a task known as rework.

Printed Circuit Board Words

PCB Protype, MOQ 1PCS, Delivery time fastest 1day

   CNC drilling, cutting edge, light painting, etching production process, only for less demanding customers, providing fast, cheap proofing services. No drilling metal plating, no character screen (single layer PCB can be printed in black silkscreen ), solder green oil, only suitable for the experiment, manual welding, can also be used to check for errors before production. Because no drilling metal plating, double panel vias problem Check "vias solution", or modify files, avoiding component pins and vias, shop may be able to modify the file, because vias can resolve threading welded at both ends, but if the pin element and vias, there may be elements blocked welding end less, so to avoid component pins and vias; pad line to be set a little rough, welding is best to use low-temperature solder (shop for sale ). Recommended not to do, of course, if a lot of your money, we do not oppose the demanding user is recommended to do the whole process. 16:30 hours before delivery traded at 22:00, 16:30, if the transaction had to be postponed until 22:00 the next day will delivery. Do not take different type in a panel.

Technical indicators are as follows:
Layers (maximum) 1-30
Panel type FR-4
The maximum size of 500mm X1100mm
Accuracy ± 0.2mm Dimensions
Thickness range of 0.40mm - 2.4mm
Thickness tolerances (t ≥ 0.8mm) ± 10%
Thickness tolerances (t <0.8mm) ± 10%
Media thickness 0.075mm - 5.00mm
The minimum width 6mil
Minimum spacing 6mil
35um thick outer layer of copper
Inner copper thickness 17um - 100um
Drilling aperture (ROP) 0.3mm - 6.35mm
Into the hole diameter (drilling) 0.3mm - 6.30mm
Diameter tolerance (ROP) 0.08mm
Diameter tolerance (ROP) 0.09mm
Thickness aperture ratio 8: 1
Solder type photographic ink
The minimum width of 0.1mm solder bridge

Sophie Deng
_______________________________________
Wonderful PCB Limited
NO.32A,Building NO.1, XianDaiC hengHuaTing,ChuangYeRoad|NanShan District,ShenZhen City 518054|  China  T +86-755-86229518-806 | F  +86 755 2607 3529|  e  wonderful08@wonderfulpcb.com |
w  www.wonderfulpcb.com  | Skype:wonderful-07   |                                                   
Welcome to our trading shows:
1.Booth: L32,Expo Electronic 2013,Apr.10-12th in CROCUS EXPO,Moscow,Russia
2.Booth: 11J36, HK Global sources  Apr.12-15th, 2013 Asia World-Expo, Hong Kong
3.Booth: 9J35, HK Global sources Oct.12-15th,2013 Asia World-Expo, Hong Kong
4.Booth: 70206, CES  2014  Jan,8th-11th in Las Vegas, USA

Oversea PCB assembly service

Regardless of how large, small, old, or new a business is, every company is faced with some problems along the way. When it comes to certain issues like a lack of time and resources, many businesses make the decision to overcome their difficulties by outsourcing some of their work. This is especially true of electronics companies. In order for your business to focus on research, marketing, and sales, you may need to take advantage of the design and assembly solutions offered by a reputable contract manufacturer. Doing so can improve efficiency, speed up production times, and minimize your costs, all while allowing you to provide a stellar product to your customers. For you to be able to enjoy these benefits, though, you need to know what you should expect from your contract manufacturing service. Here's a breakdown of what you should look for:
In order to have all of your needs met, you need to take the time to find an outsource company that's able to provide multiple solutions. Some businesses may only offer design help, while others focus strictly on manufacture. It's simpler and more efficient to work with a business that handles both, and will continue to support you with board repair after the PCBs have been produced. This ensures that you will be taken care of from the very start to the very end of each project.
Does your business have a niche client base or very specific, industry-related requirements for your board design and production? If so, it's in your best interest to find a contract PCBA manufacturer that is familiar with your particular market space and can offer expertise and proficiency in those areas.
This one is a biggie. In order for you to provide electronics devices that are efficient, effective, and safe for customer use, your contract manufacturing service absolutely must adhere to industry regulations and standards. Keep in mind that many foreign-based services do not follow the same standards that we do in the United States, and therefore may generate a board that does not comply. Furthermore, the use of counterfeit parts could not only prevent the board from functioning properly, but could also reduce the safety of the finished product. For best results, it's smart to narrow your search for design and assembly solutions to companies that operate in the U.S. and that have a solid reputation for acting with professionalism and integrity.
Without advanced design and assembly equipment that is well-maintained and cared for, how can you possibly expect for your boards to be up to par? Don't hesitate to ask about upkeep routines.
To make your customers happy and to keep your business up and running, you need to know that your contract design and manufacturing service will be able to work quickly to fulfill your needs. While you want design specs and product assembly to occur in a timely manner, though, you don't want to compromise accuracy. Your outsource company should work like a well-oiled machine, with the experience, skill, and ability to work speedily and without mistakes.
Will your contracted service provider leave you high and dry after the order has been fulfilled? Some electronics companies have learned the hard way that there are businesses out there who will keep the original designs to themselves, preventing internal troubleshooting or repairs on boards. The best outsource vendors will continue to work with you after production, offering complete fulfillment services. Seek out a company that has a repair-and-return depot. Troubleshooting and correcting minor PCB issues is far more cost-efficient than simply being required to fully replace the board.
Get the design and assembly solutions that you need to thrive today. By knowing what you should expect from a contract service, you can confidently develop a strong partnership with your outsource company and become a better, more successful business.
If you need expert PCB service, feel free to contact wonderful02@wonderfulpcb.com.

PCB market demand analysis

1, The rapid growth of production capacity in Asia, industry development trend of high quality manufacturers
Before 2000, 70% global PCB of value mainly is in Europe, America, Japan, Korea and other countries. Over the past decade, the rapid shift to Asia, so that PCB production capacity in Asia to grow rapidly. Asia, especially China has become the world's largest producer of electronic products, the downstream machine manufacturers need to make China the world's largest PCB production areas. 2008-2009 affected by the global economic crisis, there are many companies or because of the small production scale, low-tech, or the lack of market forecasts, but was forced to shut down. Since 2010, with the full recovery of the global electronic information industry, PCB overall demand growth, especially in the high-end product demand increased significantly, which is the domestic PCB manufacturer, especially the financial crisis experienced manufacturer of high quality test provides a broad space for development.
2, The downstream market demand for multi-wide, to accelerate the pace of industry transformation and upgrading
With the increasingly diverse needs of the downstream market, PCB products become even broader with the range of applications, including aerospace, military, automotive, home appliances, computers and mobile phones, and other fields, covering more and more areas, technical requirements are high, especially consumer electronic equipment and systems and entertainment applications development developed too fast, and showed a shorter life cycle characteristics, PCB is expected to pull off the favorable conditions in the new round of growth. Only to accelerate the pace of transformation and upgrading can we meet the growing needs of the market changes .

CES 2015: The future of wearable technology

CES 2015: The future of wearable technology
Flexible devices for clothing, virtual-reality contact lenses and tools to help hearing impediments are some of the futuristic use cases for rapidly emerging wearables.

"We should not be trying to make tech wearable, but rather make wearable things technology-enabled," according to Mike Bell, the vice president and general manager of Intel’s new devices group.
Speaking in Las Vegas today on a CES 2015 panel about the growth of wearables, Bell discussed the challenges manufacturers and brands in the space must overcome to break into the mainstream.
He said a "cellphone on the wrist" [the smartwatch has become the poster child for wearables] is not what people want, and wearable tech will start moving into items like jewellery and watches.
Wearable tech gets its share of bad press for a wide range of reasons, including its failure to look good and demonstrate utility for consumers. Reports have shown that current devices, such as fitness trackers, are often abandoned several months after use.
Despite the challenges the category faces, the panellists were bullish on wearable tech’s future, confident the devices are not a technology fad.
Christopher Glode, the general manager at Under Armour Connected Fitness, said: "The market valuation of wearables is not really relative to the amount of hype they get, but real markets are being created around wearables now.
"Sensors are getting smaller, batteries are lasting longer and the technology is evolving very, very quickly, piggybacking on smartphones, which means more things are possible now."
Bell added that wearable devices are more accepted these days because of the rise of smartphones, legitimising the need for consumers to have a device with them all the time.
But wearables will not replace smartphones any time soon, the panel argued.
"The phone will become even more important as a hub for experience," Glode said.
Carmichael Roberts, a partner at North Bridge, the venture capitalists, said that wearable tech would continue to innovate in the direction of something "invisible, seamless, comfortable and very personal," blurring the boundary between humans and computers.
"People won’t think about it, like they don’t think about having tattoos on their skin, like a stamp or a sticker," he said.
Limor Schafman, the founder and chief executive of GlobeShift, said the major future developments in the wearables space would be in flexible wearables that can become part of clothing, contact lenses with virtual reality and technology to help people with hearing impairments.
"There is no limit to the imagination of what is possible," Schafman said. "What is fascinating is that the technology is here. Now, what do we do with it?"
This story has been taken from http://www.wonderfulpcb.com/news.html
This article was first published on http://www.wonderfulpcb.com/

Solder mask

Solder mask or solder stop mask or solder resist is a thin lacquer-like layer of polymer that is usually applied to the copper traces of a printed circuit board (PCB) for protection against oxidation and to prevent solder bridges from forming between closely spaced solder pads. A solder bridge is an unintended electrical connection between two conductors by means of a small blob of solder. PCBs use solder masks to prevent this from happening. Solder mask is not always used for hand soldered assemblies, but is essential for mass-produced boards that are soldered automatically using reflow or solder bath techniques. Once applied, openings must be made in the solder mask wherever components are soldered, which is accomplished using photolithography.[1] Solder mask is traditionally green but is now available in many colors.
Solder mask comes in different media depending upon the demands of the application. The lowest-cost solder mask is epoxy liquid that is silkscreened through the pattern onto the PCB. Other types are the liquid photoimageable solder mask (LPSM) inks and dry film photoimageable solder mask (DFSM). LPSM can be silkscreened 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.
In electronic design automation, the solder mask is treated as a layer of the printed circuit boards, and is described as a Gerber file like any other layer, such as the copper and silkscreen layers.

PCB Assembly Introduction

There are two process for manufacturer to do PCB assembly.
Below picture show controle base plate(PCBA) exist everywhere in our house appliances.
Process of PCB assembly fabrication
(1) . Traditional DIP process
(2) . SMT process

Here first is the introduction of the process of DIP today.
1 . Traditional DIP process to PCB assembly means inserting the parts which with leg into the PTH hole of PCB.
2 . And then pass the PCB through tin soldering machine, to reach the purpose of soldering tin.                              

The structure of tin soldering machine

The structure of flux tank


The function of foamed pipe in flux tank
1. To air through the tiny holes on the foam tube body, causing numerous of air bubbles, with the number of air bubbles to cleave with flux, by metal accumulation, contact from the bottom of the base board and achieve the function of the flux coating, and then extra flux be strike off by air knife, and make flux distributed uniformly at the bottom of the base plate.

Method of flux coating
1. Bubble type flux coating
2. Wave type flux coating
3. Spray type flux coating

Hello I also would like to make simple introduction on flux which is used for assembly

A. The function of Flux
1. Remove the oxide on the surface of part and substrate
2.Reduce the surface tension of the solder and promote the flow of the solder
3.To protect the surface of the metal, avoid it to be oxidized under the environment of high temperature.

B. The main ingredients of flux
1.Rosin: it is refined from the grease of pine tree.
2.surfactant : Because of the gentle characteristics of rosin, it is not easy to remove the oxide, thus must add surfactant in order to enhance its effect.
3. Solvent: Dissolve and blend solid state material like rosin and surfactant, general multi-purpose isopropyl alcohol or ethylene glycol.
4. In addition, there are interface active agent, foaming agent and other ingredients

C. Variety of flux.
(1) Rosin flux :
1. R grade : Inactive rosin flux
2 . RMA : Weak activity rosin flux
3 . RA : Strong activity of rosin flux
4 . RSA : Super Strong activity of rosin flux

(2) Synthesis of active flux : This kind of flux is developed by DUPONT company, it’s advantage is can make the residue which caused after soldering can become liquid state, easily for cleaning.
Based on activity, it can be divided into:
SR–No active synthetic flux
SMAR – Weak active synthetic flux
SSAR – Strong active synthetic flux
SAR – Super strong active synthetic flux

(3). Water-soluble flux: The flux of organic acids, performs best help on welding, but must pay attention to the cleaning situation of the base board of welding after washing. If there’s residues, it will cause corrosion of substrate material, military and aerospace industry are banning the use of water-soluble flux process of substrate

(4). Disposable flux
Rosin kind improved flux: solid content 5-20%, residues will not cause corrosion to the base plate.