Electronic devices in our normal life become more and more complex

Three assembly method of multilayer PCB board

If you have assembly some electronic products, you will find more small, smart device to have more complex assembly methods.
Most modern multilayer PCB boards use Surface Mount Technology (SMT), through-hole components, or a combination to form a hybrid SMT-through-hole component board.

Electronic devices in our normal life become more and more complex

Most modern HDTVs, computers, Servers, CNC devices, etc use high tech multilayer PCB boards.
These multilayer PCB boards can can contain 50 layers or so of interwoven copper metal traces and fiberglass.
If you have learn some multilayer PCB board, you may know it’s were diffcult to repair multilayer PCB board.

The theory of how to repair multilayer PCB boards

If you have learned some multilayer PCB manufacturer process, you may understand this part very easy.
The copper foil traces are connected using vials and blind vials which are embedded in the PCB board itself.
The villas are built up layer by layer using additive electroplating and or electroless plating systems.
Copper metal traces and pads are etched onto the surface of the board.
Once the etching, electroplating, and cleaning processes are finished a UV curable solder mask is then applied to the substrate or PCB surface.

Top 5 common problems of repair multilayer PCB board

Burnt PCB Traces

Burnt Components

Burnt PCB boards

Micro-crystalline fractures within RoHS compliant, solder joints (common on CPU’s and GPU’s)

Tin whiskers and gold whiskers

These boards can be repaired even when damage has occurred. PCB board failure can manifest itself in many different ways. Here are just a few.
Source:http://4mcpcb.com/top-5-common-problems-of-repair-multilayer-pcb-board.html

The advantages of Flex PCB

flex PCBs Defined

A Flex Circuit or Flex PCB is a patterned arrangement of printed circuitry and components that utilizes flexible based material with or without flexible coverlay. These flexible electronic assemblies may be fabricated using the same components used for rigid printed circuit boards, but allowing the board to conform to a desired shape (flex) during its application.

 flexible printed circuits were originally designed as a replacement for traditional wire harnesses. From early applications during World War II to the present, growth and proliferation for flex circuits and flexible printed circuit boards continues exponentially. A flexible circuit in its purest form is a vast array of conductors bonded to a thin dielectric film.

 Flexible PCB / FPCB Applications

FPCBs are used widely in everyday technology and electronics in addition to high-end, complex completed components. Two of the most prominent examples of flexible circuit usage is in modern portable electronics, devices, hard disk drives and desktop printers.

Flexible circuits are also used extensively in other applications and industries including:

In transportation they are extensively used due to their improved resistance to vibrations and movement.

 The advantages of Flex PCB

Flexibility during Installation
High Density Applications
Improved Airflow
Increased Heat Dissipation
Increased System Reliability
Point-to-Point Wire Replacement
Reliability and Durability
Repeatable Routings
Simplified Circuit Geometry
Package Size and Weight Reduction

Advantages of flex circuits You should know

Flex printed circuits can provide several obvious advantages over conventional ribbon cables in certain applications. For example, a flex circuit can span between a board and a connector on a bulkhead several inches away at a right angle in the same plane as the board. That’s not feasible with a ribbon cable.
Flex connections have mechanical advantages over conventional ribbon cables in various applications but in some cases, they also have better chemistry.
A flex circuit can be formed in complex shapes in three dimensions with branches to multiple connectors, which would be impossible to achieve with a ribbon cable. Moreover, flex circuits can be interfaced with rigid boards without the relatively tall and bulky connectors flat cables require, or in the case of rigid-flex construction, they can be integral with the boards and eliminate external connectors altogether. Furthermore, the conductor density of flex circuits can far exceed that of ribbon cables.
Flex Circuits’ Advantages
There are some subtle advantages of flex circuits versus conventional ribbon cables beyond the many clear distinctions. One of the materials commonly used for flex circuits, Kapton, has extremely low outgassing in ultra-high-vacuum environments, such as space. Though Kapton-insulated ribbon cables are available, they have a limited number of conductors and cannot be routed at angles in tight confines.
Ribbon cables insulated with Teflon and other plastic materials outgas fluorine or reactive compounds when subjected to high vacuums, which can attack electronics in closed containers if care is not taken to completely vent the gases.

A Kapton Flex Circuit
Sinclair Interplanetary incorporates a Kapton Class 3 flex circuit fabricated by Sierra Circuits in optical navigation devices the company manufactures for use in small satellites. The nine-conductor flex circuit links a D-type connector, which secures to the device enclosure, with pins on the rigid device board that carry telemetry data, commands, and power.
The flex circuit in this case is swaged to the pins on the six-layer rigid board, which is about the size of a credit card. It sweeps the conductors upward and at a right angle from the pins on route to the connector and ensures the connector is mechanically isolated from the board. The assembly can withstand more than 17.9 gRMS vibration. Sinclair Interplanetary star trackers are aboard several small satellites scheduled for launch in November and December 2013 for scientific and commercial missions.
Sinclair is one of several Sierra customers who manufacture components for small satellites or build the complete satellites. Small satellites—some of them little larger than a shoebox—can perform very complex missions rivaling those accomplished by spacecraft costing dozens of times more. Sierra Circuits also manufactures PCBs for companies that build those large spacecraft. Source: protoexpress

Multilayer Printed Circuit Board wireless application: Home Control Center

STEP1：HARDWARE WORK

In this part, we need to make an acrylic box as the picture below shows, this work is by my workmate Nosk, and he is an intelligent industry designer, you can download the drawings by click

STEP2: WIRING

I connect a Grove - Relay to GPIO_51, a Grove – Air quality sensor to A2 port and a Grove – Temperature sensor to A0 port on the Grove Base Cape for Beaglebone Cape.

STEP3: CONNECT TO YOUR BEAGLEBONE GREEN WIRELESS

First, we need to configure your BBGW connect to the internet. It’s very easy to do that by smart phone, you just need to connect to BBGW AP named “BeagleBonexxxx” using mobile phone as the picture below shows.

Then your mobile phone will open the login page automatically. Just select the SSID near you and input the password as shown in the picture below.

At last, The BBGW will show as below and get the local network IP, we can access the Beaglebone Green Wireless using the network IP via SSH. Now, the board is connect to the Internet and next we need to do some software network.

STEP4: SOFTWARE WORK

Since the software code is a little complex, I’ll show you the major technology point in this part, I run a web server on Beaglebone Green Wireless to manage the Grove Modules, view the Grove Sensor Values and using a Grove – Realy to control a table lamp or something else.

Step1：Install Flask
I use a flask web framework for this APP, Flask is a lightweight Python web framework based on Werkzeug, Jinja 2 and good intentions.

STEP5: THE RESULT

Open your web browser and input the Beaglebone Green Wireless local IP and the port is 8000, and you’ll see the web page as picture below shows.

This’s the home page, we can see the sensor data and control the Grove – Relay.

And this’s the about page, you can see the information of the SeeedStudio Beaglebone Green Wireless. Source: hackaday

PCBs are central to the effective operation of electronic devices.

In any manufacturing process, testing is a central element of the operation. Without robust testing processes, there is a risk of not identifying defects that could potentially cause products to fail, once they’re in the market. The long term outcome will be a poor reputation for your brand, and reduced customer confidence.

PCBs are central to the effective operation of electronic devices. To ensure the whole device works as planned, it is vital that they are comprehensively tested.  With PCB design, testing needs to be incorporated into each stage of the design process. There are specific test procedures that need to be conducted as part of the process.  Testing is more effective than identifying an error late in the development process or after the product has gone to market.

There are various tests for PCBs. The in-circuit test (ICT) method is a popular strategy for delivering fault diagnosis at a component level. It is cost effective, and helps identify issues with PCBs before they are integrated into larger units. ICT is a very accurate test process.

Specialist Automated Test Equipment (ATE) conducts a ‘manufacturing defect analysis’ (MDA). The testing validates each component on the PCB, and verifies passive control measurement, the orientation of diodes and transistors, and supply voltage. It also looks for open and short circuits. Tests can involve basic functional process validation as well as ‘vectorless’ test that check the PCB pins. Analogue and Digital measurements can be tested.

There is a cost for setting up an ICT – usually around $10-13,000. This investment provides a ‘bed of nails’ fixture. Because of this relatively large one-off fee, the method is suited to high volume manufacturing, generally when the designs are stable.  While the initial cost is high, the ongoing cost for each unit is low. As a guide, a medium sized board can be tested in less than a minute, and at a cost per board of less than $1.50.



If there is a change to the PCB design, then new equipment will be required.  Therefore, it is important that the PCB has been designed to allow for the testing. Keeping configurations simple by separating all components from the test pads is an example of optimizing the layout. For example, keep all components on one side of the board while test pads are on the other. There are fixtures that will allow probing of both sides, but using these increases the cost and the time to debug.

There are technical requirements for an ICT. A 0.05” test pad for each net needs to be incorporated into the PCB design. Spacing is important, as using appropriate spacing allows for the use of robust, long lasting test pins. The pads need to be at least 0.125” from the edge of the PCB, and 0.1” apart from any other component and each other.  There needs to be space on the component side for the ‘pusher rods’ to be pressed down.

The test will be most effective when the board is provided in conjunction with a bill of materials, CAD and appropriate schematics. The data from the CAD will be used to generate the basic test program. This ensures that there is no manual interpretation of the board, but the information is sourced from the original design.

Debugging is achieved through using sample PCBs that are either populated or unpopulated. It includes ensuring that the PCB assemblies fit, physically, in their intended location.

The most effective way to reduce the cost of PCBs is to simplify the design of the PCBs

Abstract: With the development of modern technology, PCBs are widely used, and with the cost down of electronic equipment, everyone wants cheaper and cheaper prices. The heavy cost pressure can also be felt in the PCB industry. Of course when making the PCB boards, we can find a lot of ways to reduce the cost, like changing the base material, changing the material of solder mask... By using all these methods, the prices of printed circuit boards can be reduced by 10% to 50%. But there is no "free lunch". The reduced cost of PCBs may come at the expense of increasing the cost of assembling PCB, reducing the long-term reliability of the finished products. So it may increase the final cost of the equipment.

With our increased business in lately 10 years, a lot of customers ask us how to reduce the cost of their PCBs. In order to help our customers to know the PCBs better and give some guidelines on reducing the cost of PCBs, we will introduce the propriety of different PCB materials and important prosperity index of them. In this tech report and we also give some detailed information on the cost of PCBs. Hope we can answer some questions of our customers by this cost analysis, which including 3 part- Introduction of PCB Material, Cost Analysis of PCBs and Conclusion.

Part 1: Introduction of PCB Material

The materials used to make PCBs are very important. And because the price of different material can vary from 10% to 100%, so the price differences of PCBs made by different materials can be huge! But as we said before there is no "free lunch", usually low cost material come with low quality. In this section different PCB materials will be introduced.

1. Glass transition temperature Tg: A high Tg is very important for the PCBs to guard against barrel cracking and pad fracture during soldering operation

2. Coefficient of thermal expansion (Tce): SMD assembly process exposes the printed wiring assembly to more temperatur e shocks than typical through-hole process. At the same time, the increase in lead density cause the designer to use more and more 2 layers, making the board more susceptible to the problems concerned with the base materials ...Tce. This can be a particular problem with regard to Z-axis expansion of the material since this induces stress in the copper-plated holes, and becomes a reliability concern.

Dissipation factor: A measure index of the tendency of an insulating material to absorb some of the ac energy from electromagnetic field passing through it. Low values are important for RF application, but relatively unimportant for logical applications.

Electrical breakdown voltage DBV: The voltage per unite th ickness of an insulator at which an arc may develop through insulator.

Water absorption factor WA: The amount of water an insulating material may absorb when subjected to high relative humidity, expressed as a percent of total weight. Absorbed water increa ses relative dielectric constant as well as reduces Electrical breakdown voltage .

There are 6 major different materials, FR-1 FR-2, FR-3, FR-4 ,CEM-1, CEM-3 (except Isola FR406N, Rogers, Aluminum), used to make PCBs . They are introduced below:

A. FR-1 / FR-4

FR-1 is basically the same as FR-2. FR-1 has a higher TG of 130℃ instead of 1050℃ for FR-2. Some laminate manufacturers who produce FR-1 may not produce FR-2 since the cost and usage are similar and it is not cost effective for having both.

FR-3 is also basically FR-2. But instead of phenolic resin it uses an epoxy resin binder.

FR-4 (FR = Flame Retardent)is a glass fiber epoxy laminate. It is the most commonly used PCB material. 1.60 mm (0.062inch). FR-4 uses 8 layers glass fiber material. The maximum ambient temperature is between 120℃ and 130℃, depending on thickness.

In China FR-4 is the most widely used PCB base material, next is FR-1 then FR-2. But FR-1 and FR-2 are usually used for 1-layer PCBs because they are not good for passing through holes. FR-3 is not recommended to building multi-layer PCBs. FR-4 is the best selection. FR-4 is widely used because it is good to make from one-layer to multi-layer PCBs. With only FR-4, PCB companies can make all kinds of PCBs, which leaves the management and quality control much easier, and eventually it can reduce the cost!

B. CEM-3, CEM-1

CEM-3 (CEM = Composite Epoxy Material) is very similar to FR-4. Instead of woven glass fabric a "flies" type is used. CEM-3 has a milky white color and is very smooth. It is a complete replacement of FR-4. But it not popular in China, so it is not cost effective to use it.CEM-1 is a paper-based laminate with one layer of woven glass fabric. It is not suitable for Plated Through Hole, same as FR1-3. CEM-1 can only be used for one-layer PCB.

C. What’s the Conclusion?

From this analysis above it is obvious that FR-4 is the best selection to make PCBs. Some materials may be cheaper but it can only be used to make simple boards, and the reliability of the boards made by these materials is not good.

Part 2. Cost Analysis of PCBs

From the analysis in Part 1 it is clear that FR4 is the best cost-effective material for multi-layer PCBs and the reliability is the much better compared with other base materials. Then how to reduce the cost of the PCBs if we use FR4 material?

One simple way is to use cheaper and low- quality FR4 material. At the first sight this may be seemed as a good way if the board's quality is acceptable, but think twice before you make the final decision. High-quality FR4 material with a higher price is more stable and it will be much easier for you to control the quality of PCBs later, which is especially true in mass production. Big PCB manufactures usually only use high quality FR4 material, because it is easier to control the quality of their products. They reduce the cost by going really high volumes. The prices of high-quality FR4 at high volumes are not necessary higher than that of the low-quality FR4 at low volumes.

Then why do some companies still use lo w-quality FR4 material? The reason is that this kind of PCB manufactures is usually quite small and they can not go high quantities to reduce the cost. In order to survive in the market they get to reduce the cost. And for prototype it is a very effective way to reduce the cost by using low-quality FR4. Also quality control is not a problem in th is case. In addition big PCB manufacturers usually are not interested in making prototypes, so small PCB manufacturers can still make a living in the severe competition. In mass production some companies still use the low quality FR4 material, but the final price of the board they made are not necessary has a lower price, because their quality control cost will increase, and percentage of the qualified boards will also reduced.

Then if we use high quality FR4 material how can we reduce the cost? In the flowing paragraph we will give some datum to show how the final prices come out.



Pic 1) 2 Layers PCB Mass Production Cost Break Down (PCB size 4.13X4.19inch, 40m 2 /order)

1.Base Material(FR4) 2.Chemical Material 3.Drilling Fee 4.Plating and Finishing 5.Photo Etching 6.Solder mask and silk screen 7.testing and Shaping 8.Managing Cost 9 Profit

From the analysis shown in Fig 1 it is obvious that the highest cost in the mass production is plating and finishing 35%, next is FR4 material 15%, solder mask and silk screen 12%, test and shaping 12%.

So the most effective way to reduce the cost at mass production for 2-layer PCBs is to reduce the number of components and vias, to reduce the complexity of the PCB!

2-layer PCBs without solder mask and silkscreen will reduce the cost by around 12%. If less expensive material is used for solder mask and silkscreen, the price can be reduced around 5%.

Pic 2) 4-Layer PCBs Mass Production Cost Break Down (PCB size 7.08X6.65inch, 40m 2 / order)
1.Base Material(FR4) 2.Chemical Material 3.Internal Layers 4.Drill Fee 5.Plating and Finishing 6.Photo Etch 7.Solder mask and silk screen 8.testing and Shaping 9.Management Cost 10. Profit

From the cost breakdown of the 4-layer PCBs, the cost becomes more complex than 2-layer PCBs. This time the material cost is the highest (25%), next is internal layers (20%), then plating and finishing (17%).

But 20%+17% is still much higher than 25%, so again to reduce the complexity of the PCBs is the most effective way to reduce the cost!

And since using low-quality FR4 in mass production of multi-layer PCBs will increase the managing cost, the final price is not necessarily reduced. The safest way is to change to cheaper solder mask and silk screen material, and the cost can be reduced by around 3%.

Cost of other multi-Layer PCBs such as 6-Layers, 8-Layers...... have similar result.


Part 3. Conclusions

The cost of a 2-layer and 4-layer PCBs are analyzed. From the datum we get from our PCB line, it is obvious that the most effective way to reduce the cost of PCBs is to simplify the design of the PCBs such as reducing the number of vias and components. The safest way to reduce the cost is to get ride of the solder mask and silk screen, by which the cost can be reduced by 5% to 10%.

Reducing the cost by using low quality FR-4 material is very effective for prototypes, but in mass production the managing cost will increase, which is especially true in the mass production of multi-layer PCBs. In addition because low quality FR4 usually has lower Tg and higher Tce, the cost to assemble the PCBs may increase. So even the cost of the PCBs is reduced, the price for the final products may not be reduced.

To accurately analyze the cost of the PCBs and its relationship with the cost of final products is a very complex task; a lot of analyses will be needed. This tech report just gives our customers some guidelines and suggestions when they want to reduce the cost of their products, and we hope this report can answer most questions of our customers on reducing the cost of PCBs.

Flying probe test Introduce

Why Flying Probe?

Flying probe test is particularly valuable for:

Electronic assemblies with many components or densely placed components
Products that that require high reliability
Testing prototype boards and low-volume production runs on designs that are in flux and need to be quickly re-spun
Situations where fast turnaround is required on test programs and test results
When you contact us about your needs for electronic test services, PCB assembly, or other electronics manufacturing requirements, we will advise you about the best test options for your product. Source:ocmmanufacturing

rigid-flex PCB designs may be expensive to fabricate, but they can save costs during system assembly

A straight line is not always the shortest route between two points in electronic products: Thanks to rigid-flex PCB architecture, circuits can be folded onto themselves with 180º bends—superimposed at minimum height—thereby shrinking product dimensions. Moreover, rigid-flex construction conserves the board territory that cable connectors would otherwise consume, improves system reliability by eliminating connector solder junctions, tightens impedance control, and greatly increases the number of potential paths for board I/O compared to coaxial flat cables. Furthermore, if a product has moving sections with electronics embedded, rigid-flex construction is the ticket.
Rigid-flex PCB designs may be expensive to fabricate, but they can save costs during system assembly.
Credit rigid-flex architecture for the existence of smartphones and other pocket-sized electronic wonders. There’s simply no alternative for stuffing that much functionality into such a small space. However, to realize the advantages of rigid-flex construction (including lightweight assemblies) certain design constraints apply specifically to the flex layers in a stackup. Do not attempt your first (or second, or third) rigid-flex design before you consult your prototype manufacturer.
Using Flex in Rigid-Flex Assembly
Unlike a conventional PCB stackup, foil construction cannot be used for flex layers. The flex layers in a rigid-flex assembly are built from unreinforced base substrates typically consisting of polyimide dielectric film, clad with rolled annealed copper. The rolled copper is much more flexible than the copper used for rigid boards, but it cannot be plated without becoming brittle. Therefore, the clad base material is first drilled, holes are selectively plated, then the traces and pads are etched. Bondply, a layer of polyimide film with adhesive coating on both sides, isolates that conductor layer from the next, and so forth. A cover layer of adhesive polyimide film insulates and protects the top and bottom surfaces of the flex stack along the ribbon that extends between rigid board sections.
Flex materials are elastic under all circumstances, including processing. During the final lamination of the rigid-flex stack, they are less dimensionally stable than the rigid core and prepreg materials that sandwich them. Hole to copper clearance must be greater than the minimum possible with a rigid-only stackup, ideally at least 10 mils. Vias must be farther from the edge of the rigid area adjoining the flex ribbon than the minimum distance in rigid-only stacks, preferably at least 50 mils from the edge, but certainly no less than 30 mils. This rule is the one most violated in rigid-flex designs.
Seek guidance to develop your stackup and design rules. Differing coefficients of thermal expansion among the flex base material, adhesives, prepreg, and rigid cores requires a very careful balance of thicknesses, especially for impedance-controlled designs. There can be many layers of flex in a rigid-flex design, depending on the bend radius of the ribbon portion and whether it will remain stationary after assembly. Flex layer count must be limited in dynamic applications. Consult your manufacturer. If more than four flex layers are required, bonding adhesive must be absent in the sections that are designed to bend. The bend radius should be no less than 12 times greater than the circuit thickness.
Effectively Using Trace Routing
Trace routing in the ribbon area should be curved, not angled, to increase peel strength. This recommendation is opposite the routing practice for rigid boards. To increase ribbon flexibility, planes should be cross-hatched; however, the cross-hatch complicates impedance control. Again, a careful balance is required. In some applications, a wide, solid strip under critical traces suffices. Traces on different layers should be staggered vertically, not placed atop each other, to increase ribbon flexibility.
Annular rings should be as large as possible in flex-only regions to reduce the risk of peeling, and the transition from the annular ring to the trace should be teardrop-shaped for the same reason. Adding tabs or anchors (Figure 1) also helps to prevent peeling.
Solid Rigid Flex Design Eases System AssemblyTraces should always be perpendicular to the fold in the flex areas that will be bending. Where flex ribbons have sharp interior corners, tear stops should be added. Copper can be incorporated during layout at the elbow of those corners for reinforcement or polyimide stiffeners can be specified for the inside corner radii. The stiffeners can be laminated when the cover-coat is bonded and are the preferred method to prevent tears. The best strategy is to avoid using sharp corners in a flex design.
A very basic checklist for rigid-flex designs includes these routing considerations:
Stagger flex traces vertically layer to layer
Turns should be gradual
Vias should be no closer to the edge of the rigid board than 30 mils at the flex transition
Minimize flex layers
Remember, rigid-flex PCB designs may be expensive to fabricate, but they can save costs during system assembly. Such architecture often is the only way to squeeze the required product functions within the target package volume. The earlier you consult a PCB manufacturer during the planning stages, the better your board.Source:sierra

In Production PCB manufacture there is always the risk of solder joint defects

It has been estimated that over half of all such defects are the result of improper solder paste printing. There are variations based on the print volume. For smaller volume printing, good solder paste printing practices can be acceptable. For larger printing volumes, it will be worthwhile considering using solder paste inspection (SPI).

When you think of the processes involved, surface mount assembly is complex. It relies on solder paste for connecting the leads on the integrated chip to the correct points on the board. The process involves using the stencil to print the paste onto the chip. This is then melted, resulting in a fused connection. There are crucial aspects of the process – the volume of solder used is vital in ensuring an effective fusing, as is the alignment. The complexity of achieving this has increased for two reasons – the density of components has increased in PCBs over time; and the SMT production often involves solder paste that is hidden from view.

Because of the technical issues involved, the solder printing process is responsible for the majority of assembly defects. As an example, if too much solder paste used; OR if too little is used, there is a risk of unreliable joints, leading to the risk of failure. Because of these risks, SPI was developed. It provides a tool that allows manufacturers to monitor the volume and alignment of solder paste, and can be integrated into manufacturer’s quality management systems.

The SPI process uses pictures taken from angle cameras that accurately measure the alignment and volume of solder paste. The pictures are then interpreted using software to provide key data about the printing process. The results help identify any potential errors that can then be addressed and corrected before assembly. SPI works to rapidly identify issues with volume or alignment of the solder. As a result, using SPI can improve the print quality and the yield, helping ensure efficient production of PCBs. The process also minimizes the potential of costs due to re-working of faults.

SPI was originally developed as a two dimensional tool, but has developed from 2D to 3D. The third dimension measures the height of the solder paste, enabling the equipment to accurately measure the volume that is being laid onto the board in the printing process. When 3D SPI is used in conjunction with Automated Optical Inspection, quality control can be ensured for both the placement of components and the associated placement of the solder print.

A sign of a good manufacturer is one who can provide PCBs on time, and defect-free. Manufacturers who integrate 3D SPI and Automated Optical Inspection have systems to ensure they can deliver your PCBs in line with your specifications. It will always be worth your while ensuring that you choose your manufacturer on this basis.Sourse:rushpcb

The priority is to change standard subtractive manufacturing of PCBs that is labour intensive

As part of the growing demand for hi-tech products, leading PCB maker HTD Circuits has unveiled a new range of multilayer PCB.

According to the MD, top PCB manufacturers are adding value added products to the industry. The new PCBs have 1 to 24 layers and narrow tolerances with vias that are hidden or blind, high frequency, aluminum made and higher copper thickness.

More technology advancements are happening in design to improve processing services that address the latest size and power constraints, he said.

To keep up with the innovation, new generation products have high-density interconnect (HDI) with an aim to boost innovation in techniques and processes in manufacturing as a standard practice.

He said HDI processing interconnects and PCBs will be more efficient. Mainstreaming of HDI processing techniques in multilayer PCB production incorporates a higher number of smaller components and permits more signal traffic in smaller geometries.

The MD said PCB fabrication will have high-precision laser drilling for microvias to ensure dense electrical connectivity between various layers.

He said carbon dioxide lasers will be further innovated for longer wavelength in penetrating the glass fibers and for suitable modification in additional oxide treatment on copper.

Also, in making laminates, many layers of copper tracks are being used as they determine the layers needed for routing complicated circuitry.

The MD said on premium PCB manufacturing will be supplemented by a new scale in Flex and Rigid PCB prototyping. More production facilities are being opened to obtain premium quality for narrow tolerance PCBs.

The fabrication facilities will have the most current PCB production resources with inspection equipment. The full complement of fast turnaround PCB fabrication services providing will aim low run proto-type PCBs and high run PCBs.

He said the aim is to have PCB fabrication done without process defects and have adequate system for corrective actions.

Manufacturing errors will be zero and will be addressed through internal systems in areas like imaging, protective coatings, drilling, surface prep, etching chemistries, lamination, final finishes, etc.

The hardware and software in electronic devices are evolving fast and prototyping has to keep pace with the challenge to avoid costly delays during PCB development.

The MD said the next move will be to add 3D printing in the production of PCBs for saving time, costs and boost innovation.

The priority is to change standard subtractive manufacturing of PCBs that is labour intensive. The time on complex prototypes running into too many days need to be curbed.

The copper thickness used in a flexible circuit board needs to be carefully selected

The copper thickness used in a flexible circuit board needs to be carefully selected in order to meet both the electrical and mechanical bend requirements of specific flex circuit design. Copper weight for a flex PCB is both the stiffest and most critical component.

Copper Weight Recommendations
It is recommended to use the thinnest copper weight in your flexible circuit design that meets the proper electrical requirements in order to improve the flexibility and reliability of the flex circuit.

Flexible Circuits used in Medical Device
Small Flexible Circuit Boards Used in a Medical Device


Base Copper
0.33 oz. - 0.00046" (0.012mm) ED Copper
0.5 oz. - 0.0007" (0.018mm) RA Copper
1 oz. - 0.0014" (0.036mm) RA Copper
2 oz. - 0.0028" (0.071mm) RA Copper
RA = Rolled Annealed
ED = Electro-Deposited

Most Common Copper Weights
The two most common flex PCB copper weights are ½oz and 1oz however thinner copper weights are available. 2oz and greater copper weights are also available when manufacturing flexible PCB's but may not allow the required flexibility needed for the particular application that they will be used in. Using 2oz and greater copper weights in your flex circuit could create additional design and manufacturing challenges.

Conclusion
When designing a flexible printed circuit board, it is always the best practice to make sure your design meets current IPC standards in regards to specific flexible materials, circuit design, performance, and assembly processes involved in manufacturing flexible circuits.
Sorse:epectec

87 percent quick turn PCB designers have made those 7 mistakes

Printed circuit boards play a major role in determining the success or failure of any quickturn project. There are many factors—and therefore many potential mistakes—that PCB layout engineers and other professionals have to avoid to enjoy the benefits of quickturn PCBs.
Here are seven of the most common, critical mistakes for PCB layout engineers to avoid through the design process and beyond in order to achieve fast time to market.
1. Ignoring PCB Fabrication Companies' Reputations
"If a firm doesn't have a reputation for quick turnaround times, then it isn't going to deliver."
This first mistake is also one of the broadest. Without a doubt, the PCB manufacturing partnership will significantly impact whether a company can fulfill quick turnaround times. When choosing a PCB partner, make sure you know the PCB shop’s reputations. The fact of the matter is that if a firm doesn't have a reputation for quick turnaround times, then it isn't going to deliver in this area. If quickturn PCBs are a priority, you need to look for a vendor that has clearly made speed a priority on their end as well.
2. Overlooking PCB Fabrication Companies' Capabilities
Another major mistake is assuming that a given PCB fabrication company will be able to provide precisely the services your design requires. Again, no two PCB manufacturers are the same. If you don't ensure their capabilities can address your PCB design requirements, you’ll run into delays that could diminish their turnaround time. Or worst case scenario, they’ll be unable to manufacture the board to your specifications.
This is especially important if your PCB design requires any unique processes. Regardless of your board’s complexity, you should reach out to the manufacturer to discuss capabilities and optimal speed.
3. Disregarding Prototype vs. Volume Issues
We covered this topic in greater depth previously. Suffice to say any company that assumes prototype and large-volume production speeds will be unable to achieve quick turnaround time for their PCBs.
4. Overlooking the Importance of Manufacturer Support
Even seemingly simple PCB designs may run into complications that can potentially prevent quick turnaround times. You can minimize this risk by developing a manufacturing partnership with a PCB fabrication firm that offers in-depth and always-available support. More specifically, the manufacturer should have expert engineers on staff who can work closely with clients to identify design problems early on, before they cause any delays.
You need a PCB manufacturing partner that can always provide help.You need a PCB manufacturing partner that can always provide help.
5. Unnecessarily Incorporating Multiple Laminations
Moving from the bigger-picture issues to the more granular, this misstep is easy to overlook. Every board lam cycle requires the same amount of time and processes as the fabricating an entirely new board. With each lamination cycle, the board must go through every fabrication step, which can easily add two days to the total turnaround time, or even more.
This doesn't mean that multiple laminations aren't ever necessary, of course. But the process is inherently going to conflict with quick turn efforts, and as such should be used sparingly in quickturn designs.
6. Adding Via-in-Pads
Similarly, via-in-pads are a feature which, when unnecessarily included, undermine quickturn. There are certainly benefits to using via-in-pads. Most notably, the process can potentially keep heat out from under components or conserve space. However, adding via-in-pads can add a day or more to the total PCB turnaround time, and should only be done deliberately if quickturn is a priority. Check with your fab house to see if via-in-pads are required, or if there are any workarounds
7. Lacking Clarity for Your Notes
Finally, you need to be sure that any notes you include on your fabrication drawing are completely clear. This may seem obvious, but it's an extremely common mistake that can seriously delay PCB delivery. If your PCB fabrication partner cannot fully understand the design, the manufacturer will need to reconnect with the designer for clarification, and that back-and-forth can delay the delivery date. Make sure notes are thorough to avoid this complication and speed up PCB delivery.
sourse:protoexpress