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

Printed Circuit Board

A printed circuit board, or PCB, is a self-contained module of interconnected electronic components found in devices ranging from common beepers, or pagers, and radios to sophisticated radar and computer systems. The circuits are formed by a thin layer of conducting material deposited, or "printed," on the surface of an insulating board known as the substrate. Individual electronic components are placed on the surface of the substrate and soldered to the interconnecting circuits. Contact fingers along one or more edges of the substrate act as connectors to other PCBs or to external electrical devices such as on-off switches. A printed circuit board may have circuits that perform a single function, such as a signal amplifier, or multiple functions.

There are three major types of printed circuit board construction: single-sided, double-sided, and multi-layered. Single-sided boards have the components on one side of the substrate. When the number of components becomes too much for a single-sided board, a double-sided board may be used. Electrical connections between the circuits on each side are made by drilling holes through the substrate in appropriate locations and plating the inside of the holes with a conducting material. The third type, a multi-layered board, has a substrate made up of layers of printed circuits separated by layers of insulation. The components on the surface connect through plated holes drilled down to the appropriate circuit layer. This greatly simplifies the circuit pattern.

Components on a printed circuit board are electrically connected to the circuits by two different methods: the older "through hole technology" and the newer "surface mount technology." With through hole technology, each component has thin wires, or leads, which are pushed through small holes in the substrate and soldered to connection pads in the circuits on the opposite side. Gravity and friction between the leads and the sides of the holes keeps the components in place until they are soldered. With surface mount technology, stubby J-shaped or L-shaped legs on each component contact the printed circuits directly. A solder paste consisting of glue, flux, and solder are applied at the point of contact to hold the components in place until the solder is melted, or "reflowed," in an oven to make the final connection. Although surface mount technology requires greater care in the placement of the components, it eliminates the time-consuming drilling process and the space-consuming connection pads inherent with through hole technology. Both technologies are used today.

Two other types of circuit assemblies are related to the printed circuit board. An integrated circuit, sometimes called an IC or microchip, performs similar functions to a printed circuit board except the IC contains many more circuits and components that are electrochemically "grown" in place on the surface of a very small chip of silicon. A hybrid circuit, as the name implies, looks like a printed circuit board, but contains some components that are grown onto the surface of the substrate rather than being placed on the surface and soldered.

Wonderful PCB (HK) Limited, with over 15 years experience of producing PCB, fabricates printed circuit boards for customers in many industries worldwide, including communications/telecom/IT, medical electronics, consumer electronics (mobile phones, computers, LED lighting, etc.), and the automobile industry. We supply high-precision, high-density, double-sided and multilayer custom PCBs and PCBA services for customers in many countries.

About PCB manufacturer

1.Drilling and electroplating
If production is a multilayer PCB, and containing buried hole or blind hole, each layer board must be bored with first plating before bonding. If you don't pass this step, then can't connect each other.
After by machine equipment according to the requirements of drilling borehole Kong Bi inside must go Through electroplating (Plated Through Hole technology, Plated - Through - Hole technology, PTH).After Kong Bi internal make metal processing, can make the internal lines of each layer can be connected to each other. Before starting the electroplating, must first clear hole of sundry. This is because the resin epoxy compound after heating will produce some chemical change, and it can cover internal PCB layer, so need to clear out. Remove and electroplating movements will be completed in the chemical process.

2. Multilayer PCB pressing
each single layer must be pressing to make sandwich plate. Pressing action including adding insulation between the layers, and fastened to each other. If there is through several layers of guide hole, then each layer must be repeated. A multilayer wiring on the outside of the two sides, is often only after a multilayer pressing processing.

3. Treatment resistance welding layer, surface screen printing and gold finger plating
Next resistance welding paint coverage on the outermost wiring, so the wiring will not come into contact with the outside plating parts. Screen printing surface is printed on it, to mark the location of the various parts, it will not be able to cover at any wiring or gold finger, otherwise may reduce solder ability or the stability of the current connection. Gold finger parts usually gold plating, which, when inserted into the expansion slot to ensure high quality of the current connection.

4. Test
to test whether there is a short circuit or open circuit PCB can use optical or electronic means testing. Optical methods using scanning to find out the defects of each layer, electronic testing is usually with fly needle detector (Flying Probe) to check all the connections. Electronic testing in search of short circuit or open circuit is precise, but the optical test cans more easily detected incorrect gaps between the conductors.

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.