Environmental protection PCB material selection

WDF-PCB-D-25,double-sided,wonderfulpcb.com

Surface metal layer

The industry mostly use green solder "silver copper tin" formula HASL (Sn Ag - 3.9-95.5 0.6 Cn) instead of pewter, environmentally friendly lead-free PCB surface coating layer should have high wetting liquid, smaller thermal stress, high temperature is not easy oxidation features, facilitate lead-free SMT processing.In addition, flux, a synchronization is required to adopt green HASL is poor, and they have mutual fusibility with SMT solder.

Ink

Ink on the PCB leaving include: solder resist ink, printing ink, jack inks, ink composition with plank, mainly containing resin, bromine flame retardants and curing agent, at present many brand ink has do not contain harmful, such as Japan, taizhou, the new Korean ink the sun.The choice of ink must not only conform to the requirements of environmental protection, and to withstand environmental protection lead-free SMT long time high temperature for many times, not hierarchical discoloration, peeling, crack phenomenon.

Control of lead-free materials

The management of raw materials is very important one link in green PCB production, such as tin, so long as has the lead article tin was mistakenly add pure tin bath will lead to disastrous consequences, and indirect materials such as flux residues also nots allow to ignore, specific countermeasures include: (1) establishing that the encoding rules of the halogen free lead-free materials;(2) using color logo, on the inner and outer packing printed with "green" label to be approved by IQA.(3) in the warehouse and production site, to separate storage for environmentally friendly raw materials, production site personnel to add;(4) to realize "green qualified suppliers" certification program.
The choice of lead-free process and control: the selection of lead-free PCB surface coating layer process include: Ni/Au plating, chemical immersion Ni/Au, OSP (organic run-off protection agent) chemical tin Sn and chemical heavy silver Ag.

The import of lead-free process steps

CAM design

Environmental protection engineering design of PCB is basic aspects, lead-free process after the CAM should take into account the SMT process influence on the function of the PCB.
Graphic design examples (wiring, welding area shape)
1. prevent immersion flow insert parts left, red eye diameter welding area a little bit small.
2. Prevent immersion flow QFP bridging QFP tilt 45%.A dummy welding area.
3. To prevent the soft melting chip separation illuminates the basic in the past.To make the protective film: opening near it.
Prevent substrate warp

Technology development

Process of the development and management is important link in the production of environmental protection PCB, specific countermeasures including:

(1) environmental protection and environmental protection materials do not collinear or mixed line production, such as: enhancement and finished products to clean.
(2) in the MI process of paper, with environmental protection product operators, and sign the MI confirmed its, lead-free process remind now field operation department staff.
(3) environmental protection product production facilities, tooling, visual management, with prominent logo distinguish.
(4) ink has to withstand environmental protection lead-free SMT long time high temperature for many times, so the pretreatment, substrate drying is a very important link, the printing ink after spray tin or lead free HASL SMT, the possible defects of the ink on the side of hole stripping is mainly hole, floor water residue, high temperature when inflation and make the ink and copper layer separation.
(5) solder resist ink is not allowed to add rare ze agent, which can avoid high temperature circumstances hole ink residue solvent volatilization sharply inflation caused by the blasting hole.6 HASL Cu content in the tin bath to control below 0.85%.

reliability assessment

Therefore, environmental protection PCB products reliable test compared to the environmental protection PCB, but also improved the following experiments:

(1)Solderability test.(solderability test furnace with lead-free solder environmental requirements of SMT solder or HASL consistent)
(2)thermal shock test.Condition: - 40 ℃ / 85 ℃ / 85 ℃, no crack after 3000 times.
(3)the thermal cycle test.No crack, shrinkage cavity appear.
(4)constant temperature and humidity test.Condition: 60 ℃ 90-95% RH, 500 hours, under high temperature and high humidity for a long time do not produce metal products.

For more information, pls email: wonderful11@wonderfulpcb.com

Repairing printed circuit boards - tips by Exception PCB

PCBs, or printed circuit boards, have revolutionised the electronic industry; however they lack the robustness of the earlier, steel-chassis, hardwired equipment, driving them to be much easier to crack. Restoring a circuit board needs a particular level of analytical ability, along with the skill to handle each element in the correct way.

Without having a thorough knowledge of the way a circuit board works, experts from Exception PCB express that diagnosing the trouble will be a problem. For PCBs that are especially complex, you might also need an oscilloscope to discover signals at different points, so as to discover the section which is creating the problem. Once this component has been discovered, it will then have to be replaced. Here, Exception PCB provides you with a brief guide on how to do this.

As outlined by Exception PCB, with the majority of passive (and occasionally active) components, a similar, as opposed to an exact copy of the broken element can be used as a replacement. You will find, for example, several unique versions of voltage regulators available, and one version can easily be swapped for another in a PCB. However, broken active components that have a very specific function (for example, audio amplifier chips) must be replaced with an exact copy.

After you have acquired the right replacement, you'll have to place the PCB on a flat surface for the fix. Exception flexible PCB says that you might use tape to stick the board on both sides to the surface, to ensure that it doesn't move whilst you are carrying out the replacement. Pull the damaged component off the board very delicately, using tweezers. Next, switch on your soldering iron and set it to about 400 degrees Celsius.

Take some copper wire and put it on the pads of the PCB where the component was, and use the soldering iron to heat it. Wonderful pcb that any surplus solder remaining on these pads could be absorbed by the copper. Get in line the leads of the replacement component with the board's pads, taking a look at to make sure that the element is aligned as it needs to be. Then, use the soldering iron and the solder to join the leads with the corresponding pads on the board.

PCB Repair

As we know, PCB Is customized product. Manufacturers produce PCBs based on customer’s Gerber Design. No matter how good electronic contract manufacturers become at producing ever-smaller and more complex circuit boards, every now and then, a defect  will be produced. In batch production, maybe it will not be a major issue. Due to it’s common when a certain small percentage of loss is expected. However, in a small order even sample order, what if the circuit board is unique? In this case, you could be looking at huge costs to recreate it, or even larger costs if you move forward anyway. To resolve these fails, it uses a PCB repair service.

PCB Repair Process:

1. Repair

When a component which was working has failed and you don’t know why, commonly this is the most common reason you might need to use repair service. Luckily, electronics experts can analyze both the original schematics and the resulting board to discover the underlying problem. Often, it's something as simple as a single broken bit of circuit wiring or a single failed component that can be fixed for far less than it would cost to recreate the board.

2. Rework

Sometimes, it's the initial design that's flawed. A capacitor cannot handle the charge it needs, or a particular computer chip proves to be incompatible with the board. In this case, PCB board repair services can take a look at the original design specs, compare them to the finished product, and uncover which component(s) are causing the issue.
From there, it's a relatively simple matter to find suitable replacements which can meet your original specifications.

3. Modification

Or, perhaps your PCB works, but just not quite up to par. Perhaps it fails to meet a necessary requirement, such as FCC feedback shielding standards. If this is the problem, much as with rework efforts, your PCB repair service can take the working design and improve on it so it meets your needs.

4. The Protection Process

Finally, there is the highly important process of making sure all of those components can work in extreme conditions. A special type of coating is either done by dipping the components into a solution or spraying them, allowing the coating to protect the entire board from extreme heat, cold, possible corrosion or leakage, and even helps prevent shortages should condensation accumulate.

Concluded, as the development of PCB repairmen, the defects of PCB are decreasing in the finished production. Of course, it may cost some more time to find out these problems and repair them. But all we do are for better quality and better functions of PCB.

China Circuit Board Analysis

The report firstly introduced Printed circuit board(PCB) basic information included Printed circuit board(PCB) definition classification application industry chain structure industry overview; international market analysis, China domestic market analysis, Macroeconomic environment and economic situation analysis, Printed circuit boards(PCB) industry policy and plan, Printed circuit board(PCB) product specification, manufacturing process, cost structure etc. then statistics Global and China key manufacturers Printed circuit board(PCB) capacity production cost price profit production value gross margin etc information, and Global and China Printed circuit board(PCB) capacity production market share supply demand shortage import export consumption etc data statistics, and Printed circuit board(PCB) 2009-2014 capacity production price cost profit production value gross margin etc information.

Nowadays, the high technology products such as cells, LED lights, TVs release new product kind often. With the high technology improves, there will come out new product time to time. Most of high technology products concerns about the electric products, which will lead to the bigger request for the PCB products. In general, I think PCB is a promising product.

The demand for smart phones and touch screen tablets are the major drivers of this industry. Another significant driver for this industry is the demand for products with features that are more advanced and that offer greater convenience. The frequent technological changes occurring in the electronic market, together with the demand for new products, are among additional industry drivers.

China has become the country that enjoys the largest circuit board output value and the fastest growth speed, and also the main driving force to promote the development of the global PCB industry. In 2012, there were 791 PCB enterprises with above designated scale in China with the market scale exceeded CNY 250 billion.

 In 2013, as the cost of copper declining, the upstream industry like copper clad laminate manufacturers can directly benefit from the decrease of cost of copper. For downstream industry like circuit board manufacturers, can also reap a little less profit from it. But the increasing cost of components will directly influence PCBA industries. Therefore, the prospect of the whole circuit board industries may not be defined as flourishing or not up to now.

According to “Information Industry Science and Technology Development “11th Five-Year” Plan and Long-term Planning Framework in 2020”, circuit board (especially multi-layer, flexible, flexible-rigid and environment-friendly circuit board technology) is one of the key fields in China’s electronics information industry over the next 5 to 15 years.

Printed circuit board industry in China mainland will maintain rapid growth in the next three years. The rapid development of the domestic 3G industry as well as the rise of electronic terminals such as smart phones, tablet PCs, green base station, will have a strong pulling effect on circuit board, driving the growth of circuit board industry. In 2016, the output value will reach USD 48 billion in China, accounting for 49.4% of the global circuit board output value.

Prototype PCB Necessity and Benefits(2)----Wonderful PCB (hk) Limited

These printed circuit boards prototypes are checked in all critical conditions as everything must be checked and every problem must be solved before the production. Again, the leads and traces are re-measured so that it meets the required thickness. The VIAS and holes need individual programming for each board and their making process is also sophisticated. The tolerances and electrical signals are tested even after the addition of the surface components.
When all the components are added and it is made as the specification, it is finally tested for several times for the required result. The board must also be able to provide proper reliability and effectiveness. In this time, the board is tested without planting it in the environment it is made for. And all steps are recorded. 
And when it meets the standard quality, it is sent for production. But if any wrong occurs, it is tested again and sent for further solution. Even sometimes the whole design is changed for the failure in tests.
The prototype is made by the companies to check their products and inventions before manufacturing. And thus it helps a great deal in the development of PCB.

Introduction on flux and Tin paste for PCB assembly

FLUX
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 PCBA manufacturer.
(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.

Low content of solid flux: solid content at 5%,  disposable flux disposable because its residue in the residues of substrate could not cause corrosion of substrate, but solid content in about 5% of the flux its residue is too much less than the flux with solid content of 5-20%, so if product with high requirements on cleanliness and appearance, you must use the solid content at 5% disposable flux.

TIN PASTE
(5). VOC-FREE disposable flux :
Does not contain volatile organic solvents of disposable flux, the above all flux contain volatile organic solvent, the solvent flammable (dangerous). Not easy to control (quality) is volatile harmful to human body and the environment (toxic), in order to avoid such problems, so developed the pure water as the solvent of disposable flux.
(1).The main ingredients of Tin solder paste
Tin powder: Can realize the electrical conduction between parts and base board, and can joint the parts and boards.
Flux: compromise the tin powder and other solid substance into paste.
Its main ingredients are as follows:
A.Solvent : mix all flux element into homogeneous liquid thickens.
B. Flux : can prevent the PCB board surface to be oxide again after welding, and can pack the surfactant to improve the SIR, to enhance the trustworthiness of the base board.
C. Thixotropic Agent: avoid separation of powder and flux, and improve the printability of tin and protect tin from collapse.
D.Active agent: The main function is to eliminate the solder joints and lead oxide substrate, common active agent is: organic ammonia hydrochloride, ammonia, organic acids, etc. 

(2). Kinds of Tin Paste
1 . Water type of Tin paste: Use water to clean the flux residue on PCB board                    Water temperature 50 – 60 degree,
water pressure 2 – 3 kg / cm 2 ,
Water low: 11 – 15 l / min
2 . Resin type of Tin paste:
a . Use solvent ( CFC or HCFC Cleaner ) to clean the flux residue on PCB board.
b . Because resin kind substance does not dissolve in water, using saponification agent to make it become the material which can be soluble in water,  then use it to clean the flux residues on board.
c . Semi-wash, use EC – 7R Axarel 32 to clean the flux residue on PCB board.
3 . Free wash kinds Tin Paste : no need to be cleaned after soldering.



Ms Grace Zhang
________________________________
Oversea sales
Wonderful PCB
A Floor 6, Nanyuan Fengye Mansion, Nanshan Avenue, Nanshan District, Shenzhen City 518054, China

T +86-755-86229518-809 | F  +86 755 2607 3529|  e  wonderful16@wonderfulpcb.com |
w  www.wonderfulpcb.com  | Skype:wonderful16 | MSN: wonderful16@hotmail.com