PCB designers must know 5 common mistakes

Whether manufacturing for a large multinational tech company or a small electronics company, PCB assembly can be riddled with numerous challenges. Effective assembly requires smooth collaboration between designers, fabricators and manufacturers in order to deliver a high quality circuit board to the market. Mistakes made in design can hold grave consequences to the whole organization, especially where the design failures result in substandard products reaching the market.

The mistakes can be both technical design flaws or operational flaws in the controls put in place in the assembly process. Below are the top five mistakes that you should look out for in PCB assembly:


1. Flex-Cracking
On the technical side, flex-cracking refers to excessive bending of the PCB under a ceramic chip capacitor. The ceramic chip capacitor cannot withstand excessive stress due to its brittle nature. For adequate electrical performance, some printed circuit boards will require large capacitors. Stress on the capacitor can result from accidental dropping or placement of excessive weight on it at any stage of PCB assembly. The type of ceramic chip capacitor that you use in the design stage should be able to handle the stress of assembly and it should not easily crack. You could respond to issues on flex-cracking by using a shorter capacitor or you could replace the capacitor with a smaller unit which has the same capacitance and voltage.

2. Failure to Adequately Gauge the Performance Environment
One of the most common mistake made by PCB designers is failing to cater for the environment in which the board will operate during the design stage. Some companies will exclude evaluation of the environment as a cost-cutting measure and designers may even be required to closely consider material costs in their designs.
Environmental factors such as: temperature, humidity and even forces such as G-force act on the PCB on a constant basis. If the materials used and the design specifications in terms of size and ability to handle these conditions are not adequate, the resulting circuit board will always fail. Depending on where it is placed, such failure could be catastrophic to the company.

3. Inadequate Communications
PCB assembly will often involve a number of participants. There is the designers, the fabricators and the Electronic Manufacturing Services (EMS) provider. It is often the case that the design-house outsources manufacturing to a different company for business reasons such as lower costs and economies of scale. The different participants need to be in constant communication for smooth delivery of quality products. Mistakes such as failure by the designers to send the preliminary component placement with the assembly house in the initial stages could greatly affect the delivery times. Each company schedules its work to create the most profits for their organization and communication ensures that none of the participants suffers from the other's policies.

4. Lack of Design Reviews
For companies that do not have well defined rules on the flow of work from initial product assemblyspecification, through design to delivery of the final product, there may be problems in design reviews. Whether the PCB is custom made for a particular client or for the mass market, having the client or your marketing personnel present during these reviews guarantees that the design does not veer away from what the client and the marketers had in mind when specifying the product. Design reviews should be incorporated as part of quality control procedures.

5. Lack of Design Back-ups
A very common mistake in any type of design work is failing to back-up the copies of your work. Imagine working for months on a new product and then loosing all your work due to a computer crashing. Every organization should implement data back-ups as part of the PCB assembly process. Even designers who work from home should back-up their copies on a spare drive to save themselves the trouble of having to redo the design from scratch. You could also explore safe online back-up options.

Bend requirements fall into three main categories as defined by IPC 2223C Design Standard

An essential element of a flex or rigid-flex printed circuit board (PCB) design is verification that the construction will meet your mechanical bend requirements. Exceeding the minimum flex bend radius requirements creates the opportunity to exceed the physical properties of the copper circuitry resulting in failed parts and long term reliability concerns.
When a flexible circuit board is bent, compressive forces are created at the inside of the bend and tensile forces are created at the outside.
flex-bend-capability.png
If these forces exceed the copper’s ductility limits, the traces will work harden - become embrittled, and lead to the formation of cracks.
Bend requirements fall into three main categories as defined by IPC 2223C Design Standard for Flex Printed Boards, all of which have its own requirements and limitations.
Flex to Install
Dynamic Flex
One Time Crease
For each category, the minimum flex & rigid-flex bend capabilities are calculated based on the deformation that the copper is subjected to and is related as a multiple of the finished flex thickness. The layer count is also a factor. If the flex circuit is 3-layers or greater, bonded designs are require for greater minimum bend radiuses.
Flex To Install
The flex circuit is bent to a required shape and installed in the final assembly. In this scenario the flex circuit is not subjected to any further significant bend requirements.
 Minimum bend radius:
1-2 layers = 6X
3 plus layers = 12X or greater
Dynamic Flex
The flex circuit is subjected to constant infinite repetitive bending as part of the operation of the final assembly.
 Limited to 1 - 2 layer designs:
1 layer preferred
Allows copper to reside on neutral axis of bend radius
 Minimum Bend radius:
Approximately 100X
One Time Crease
The flex circuit is bent/creased to the point of a zero bend radius and installed in the final assembly and not subjected to any further significant bend requirements. Creased fold is not to be opened.
Limited to 1–2 layer designs only:
1-layer preferred
Allows copper to reside on neutral axis of bend radius
Thin flex materials and copper weights required
PSA is typically added adjacent to crease area adhere the flex to itself and prevent any further manipulation of the creased circuit.
Take note that a lot of designs fall between the definitions of Flex to install and Dynamic Flex.
Semi Dynamic
The flex circuit is subjected to a number of bend cycles throughout its lifespan to allow for servicing or a predefined number of operational cycles. In this scenario, the bend radius and number of cycles should be carefully reviewed. Reduced flex thickness is also preferred to allow for sufficient safety margin and long term reliability.
Impact Of Electrical Design Requirements
Certain electrical design requirements result in a thicker flex design and in turn limit the minimum bend capabilities of the flex circuit.
Controlled Impedance:
Thicker flex core required to allow for correct dielectric spacing between signal layers and reference planes to meet specific impedance requirements.
Current Carrying:
May require thicker copper to meet current carrying requirements.
Wider trace widths preferred, if available room allows, as opposed to thicker copper.
Thicker copper requires thicker coverlay adhesive layers, to ensure full circuitry encapsulation, and further increases flex thickness.
EMI / RF Shielding:
Requires additional external layers to provide required level of shielding.
Layers may be either copper, silver ink or shield films.
Flex PCB Material Selection
A standard design practice is to minimize the thickness of the flex circuit as much as practical while meeting the electrical requirements of the design and not incurring unnecessary added material costs.
As a result the most common materials are as follows in order of preference:
Copper Weight: ½oz , 1oz
Flex Core Thickness: 1 mil, 2 mil, 3 mil
Coverlay Thickness: 1 mil, ½ mil
Flex cores are also available in two different construction types: Adhesive and Adhesiveless. Refers to method used to attach the copper to the polyimide core.
Adhesive utilize a layer of flexible adhesive to bond the copper to the polyimide core
Adhesiveless has the copper boned directly to the polyimide core
Higher cost material
Flex Circuit Constructions
Higher layer count designs may need to utilize an Un-bonded Air Gap construction. This construction technique configures the layers as separate independent pairs as opposed to a singular fully bonded unit. The thinner individual pairs provide a higher degree or flexibility.



Summary
Flex PCB bend requirements and the ability of the flex materials and construction to meet those specifications is an important element of an effective design. Whether in a “Flex to Install” or a “Dynamic Flex” application, pushing flex materials beyond their physical property limits will result in failures and long term reliability issues.
For the majority of applications the industry has developed a wide range of design options, materials and construction methods that can be selectively applied to a design to cost effectively and reliably meet the bend requirements of flexible circuit boards. 

Top 3 characteristics of the aluminum PCB

LED heat dissipation problem is LED manufacturers the most difficult problem, but can be used aluminum plates, because of the high thermal conductivity of aluminum PCB, heat, and can effectively export the internal heat. Aluminum plate is a unique metal-based CCL, with good thermal conductivity, electrical insulation properties and machinability. We should try to be close to the aluminum base PCB design, reducing the thermal resistance potting segment generated.

First, the characteristics of the aluminum plate
1. The use of surface mount technology (SMT);
2. In the circuit design is very effective for the thermal diffusion process;
3. Reduce product operating temperature, increase power density and reliability, extend the life of the product, the smaller footprint, lower hardware and assembly costs;
5. Replace the fragile ceramic substrates, for better mechanical durability.

Second, the structure of aluminum plate
Aluminum clad circuit board material is a metal, copper foil, thermal insulation layer and the metal substrate composition, its structure is divided into three layers:
Circuit layer (i.e. line layer): the equivalent of the common PCB laminates, foil thickness loz line to 10oz.
Dielectric layer (i.e. insulation layer): Insulation layer is a layer of thermal insulation materials with low thermal resistance.
Base layer : a metal substrate, usually aluminum or copper can be selected. Aluminum clad and traditional epoxy glass cloth laminated panels.

Circuit layers (i.e. the copper foil) are usually formed after etching printed circuits, so that each member elements interconnected, under normal circumstances, the circuit layer requires a great current carrying capacity, and thus should be thicker foil, thickness 35μm ~ 280μm; thermal insulation layer is aluminum plate where the core technology, it is generally a special polymer made of special ceramic-filled structure, small resistance, viscoelastic performance, thermal aging has the ability to withstand the mechanical and thermal stresses.

High performance aluminum plate using a thermal insulation layer is of such technology, it has very good thermal conductivity and high strength electrical insulation properties; metal substrate is aluminum plate support member, is required to have high thermal conductivity, typically aluminum can also be used copper (including copper can provide better thermal conductivity), suitable for drilling, punching and cutting other conventional machining. PCB material has advantages compared to other materials incomparable. SMT surface mount power components for public art. No radiator, much smaller, excellent heat dissipation, good insulation properties and mechanical properties.

Third, the use of aluminum plate:
Purpose: Power Hybrid IC (HIC).
1. Audio equipment: input, output amplifier, balanced amplifiers, audio amplifiers, preamplifiers, power amplifiers, etc.
2. Power Supply: switching regulator(DC/AC converter,SW regulator and the like).
3. Communication electronic equipment: high-frequency amplifier circuit transmitters(filtering appliances).
4. Office automation equipment: motor drives.
5. Automotive: Electronic ignition regulator(power controller).
6. Computer: CPU board(floppy disk drive power devices).
7. Power Modules: Inverters(solid relay rectifier bridges).

South Korean scientists have made solar cells thin and flexible enough to be wrapped around a pencil

The idea of solar cells usually conjures the image of broad panels lying in the sun like scorched saltines. But in the latest probe into the physical limits of the technology, South Korean scientists have made solar cells thin and flexible enough to be wrapped around a pencil.

The new cells are more than 50 times thinner than human hairs and over 1,000 times thinner than most conventional solar cells. The cells were thinned down to the point where they could be wrapped around objects or fit the contours of unstructured materials like fabric. The researchers found the cells could wrap around a radius as small as 1.4 millimeters.


“Our photovoltaic is about 1 micrometer thick,” said Jongho Lee, an engineer who worked on the project at the Gwangju Institute of Science and Technology in South Korea. “The thinner cells are less fragile under bending,” experiencing only a fraction of the strain on solar cells many times thicker.

One of the problems with extremely thin solar cells is that they are more prone to energy loss than thicker versions. However, the new solar cell contains a metal electrode that reflects stray particles of sunlight back into the cell, increasing its overall efficiency.

In fact, the new solar cell, which consists of gallium arsenide semiconductor material, is actually more efficient than thicker cells. In laboratory tests, the prototype cell converted 15.2% of sunlight into electricity, while a 4-micrometer cell only achieved 14%. Normally, thicker cells inherently absorb more photons from sunlight.

The energy harvested by the prototype is meant to supplement the tiny batteries inside wearable devices, like smart watches or medical devices, extending their usually short battery lives. They could be integrated on the outside of fitness bands, for instance, enabling them to gather energy while users run on a sunny afternoon.

Other energy harvesting methods have strayed into the outlandish. Some devices attempt to generate electric current from human motions like running, walking, or tapping your fingers. Others filter out the energy from ambient wireless signals like Wi-Fi and millimeter waves.

In recent years, making new kinds of solar cells has become an admired pastime for scientists. Earlier this year, a team from the Massachusetts Institute of Technology made solar cells about two micrometers thick. The cells were actually light enough to be balanced on top of a soap bubble without popping it.

“It could be so light that you don’t even know it’s there, on your shirt or on your notebook,” said Vladimir Bulovic, an MIT professor that worked on the project. “These cells could simply be an add-on to existing structures.”

Bulovic’s project used vapor deposition to simultaneously grow all the layers of the solar cell, making it thinner and more flexible than possible with normal techniques. The South Korean scientists, on the other hand, used transfer printing to paint the solar cells directly onto a flexible substrate.

The cells were coated onto metal electrodes—a process recently outlined in the journal Applied Physics Letters. The scientists bonded the cells onto the electrodes by applying extreme pressure, using a material known as a photoresist to act as a temporary adhesive between the cell, metal, and substrate.

Once the solar cells were successfully bonded to the metal electrode, the scientists peeled away the photoresist to leave the finished device. Any permanent adhesive would have added to its thickness and weight, Gwangju’s Lee said.

Correction June 30, 2016: An earlier version of this article failed to include how efficient the flexible solar cells were. The cells built at the Gwangju Institute of Science and Technology were 15.2% efficient. The scientists found that their cells were more efficient than others made with the same material but four times thicker.

Modern high-tech PCBAs Testing process introduce

Modern high-tech PCBAs can potentially have 20,000–30,000 solder joints, requiring sophisticated automated inspection techniques to efficiently inspect results and provide process control feedback. But how do we control the efficiency and effectiveness of the test process itself?

Selecting a Test Strategy – The first step in selecting the proper test strategy for a particular PCB is defining the estimated fault spectrum. We use the PCOLA/SOQ method defined by Agilent to classify the most common types of defects. PCOLA (Presence, Correctness, Orientation, Live, Alignment) refer to attributes of the component. SOQ (Short, Open, Quality) refer to attributes of the solder joint. Together, they test structural integrity of the assembly.
 Optimum's EMS Handbook - Download Now
A Complementary Test strategy endeavors to test for each PCOLA/SOQ element just once on the most efficient test platform, where efficiency takes into consideration both runtime and programming time. In a high-mix environment we typically deploy automated optical inspection (AOI), automated x-ray inspection(AXI), and flying probe (FP). By endeavoring to minimize test element overlap, we minimize both programming and runtimes.

As PCBs become more complex and time-to-market pressures make the manufacturing process increasingly difficult, it’s important to look for any and all ways to drive down costs and raise productivity. Through the implementation of an appropriate complimentary test strategy, you will be able to lower your DPMO and create a system of quality control that will maximize the efficiency of your test strategy. Source: optimumdesign

Li-Fi connects through light, rectifying the security and congestion issues of Wi-Fi

Li-Fi connects through light, rectifying the security and congestion issues of Wi-Fi


Wi-Fi is not the only data transmission system out there. While it delivers data via radio waves, light fidelity (Li-Fi) technology, first introduced in 2011, connects data through light. Think of that LED lamp in your house, and then imagine if it became a wireless access point. With these possibilities in mind, it has been suggested that, when it is paired with Wi-Fi, Li-Fi could provide an ideal version of the Internet, weakening some common connectivity issues and balancing out the other’s capabilities.

Using common household LED lightbulbs to enable data transfer, Li-Fi is incredibly speedy, promising performance of up to 224 gigabits per second. A driver controls these lightbulbs and is capable of transmitting encoded data via this feature. All data is received through an optical sensor, at which point it is then decoded. Categorized under the Visible Light Communications (VLC) system, Li-Fi also requires a light source equipped with a signal processing unit and at least one device with a photodiode able to receive light signals.

University of Edinburgh professor Harald Haas, who founded the term Li-Fi, established the company pureLiFi to strive towards being “the world leader in Visible Light Communications technology.” pureLiFi studies have found that Li-Fi signals can be read as incidence light, meaning that the signal is picked up by a receiver when it’s reflected off surfaces and can allow mobile devices to connect to and use Li-Fi. However, Li-Fi connection on a mobile device has so far proven shaky when it comes to reliability, as the phone moving around disrupts the connection.

With the prospect of the Internet of Things drawing near, Li-Fi could still easily benefit these connective devices. It also provides advantages that Wi-Fi does not have – since it doesn’t use radio waves, Li-Fi doesn’t interfere with radio communication and, as a result, can be used during flights. After Haas had revealed that pureLiFi was testing with a “major aircraft manufacturer,” some commentators pointed out that the reading light above seats on a plane could be capable of streaming data. “The airlines are more interested because they save weight,” said Haas. “These seats are usually hard-wired with cables. And that also limits their flexibility. The airlines want to be able to change the seat spacing depending on what link they serve.”


Easy accessibility on airplanes is just one of the advantages Li-Fi could bring to users. Because radio frequencies are limited, many devices compete for bandwidth, causing network congestion. The frequencies of light waves are up to 10,000 times more plentiful than radio frequencies, opening up the Wi-Fi system for better usage. Wider usage of Li-Fi could also improve Internet security as data transmitted via Li-Fi can only be accessed where LED light illuminates. It also does not pass through walls or ceilings, making it safer than Wi-Fi’s radio waves.

While awareness of Li-Fi hasn’t hit its stride yet, there are inklings in the industry that the concept will soon be more incorporated into common devices. In November 2015, pureLiFi partnered with French lighting company Lucibel to work on Li-Fi-enabled products. Alleged reports even say that Apple may include Li-Fi capabilities into future iPhones, which would undoubtedly bring Li-Fi into mainstream conversation. Source: electronicproducts  

flexible circuit board material introduce

flexible circuit board material introduce
Soft board Function can be divided into four, respectively led Line (Lead Line), Printed Circuit (Printed Circuit), Connector, Connector and multi-functional integrated system (Integration of Function), application covers computer, computer peripheral auxiliary system, consumer minsheng electronics and automobile, etc.

COPPER Clad Laminater COPPER foil base plate (CCL)
CU (Copper foil) : condition and R.A. Copper foil
Cu Copper, Copper sheet is divided into RA, Rolled Annealed Copper and ED, Electrodeposited, both because of the different manufacturing principle, and characteristics are different, ED Copper manufacturing cost is low but fragile when doing Bend or Driver Copper surface body break easily.RA copper manufacturing cost but high flexible, so the FPC copper foil is given priority to with RA copper.
A (Adhesive), acrylic and thermosetting epoxy resin Adhesive
Rubber Adhesive for Acrylic Epoxy resin and Acrylic Mo Epoxy two big system.
PI (Kapton) : Polyimide (poly imide film)
PI for Polyimide abbreviations.In dupont Kapton, thickness unit is 1/1000 inch lmil.Features to be thin, high temperature resistance, strong resistance, good electrical insulation, FPC insulating layer are all brothers Kapton welding requirements.

Features:
Highly flexible, but solid wiring, according to the space limit change shape.High and low temperature resistance, resistance to burning.Folding without affecting the signal transfer function, can prevent electrostatic interference.
Chemical stability, stability and high reliability.
For the design of related products, can reduce assembly time and errors, and improve the service life of the products.
Application of product volume was reduced, significantly reduce weight, increase function, cost reduction.
Polyamide imide Resin, Polyimide Resin)
Polyamide imide resin is by oxygen layer and anhydrous pyromellitic acid reaction of polystyrene were represented by four acid imide, has five negative imide ring heat resistant resin known.
Polyamide imide resin is all high heat-resistant type one of the most widely USES in the polymer.It can cause such as polystyrene were four acid imide and other all sorts of inductor, at the same time also can make its function, so it is so versatile.Eps are four acid imide purposes though to it does not melt under large limitation, since the successful development as long as a little sacrifice its heat resistance can be made using solvent can make its melt or can melt forming polyamide imide, its USES widely up soon.
In printed circuit board with polyamide imide resin, heat resistance, pay attention to its formability and mechanical properties, dimensional stability, electrical properties, cost and other issues.So a lot of restrictions in the use.For these reasons, at present only a few addition polymerization type heat curing type polyamide imide is used for more than ten layers of multilayer printed circuit board.
The dosage of the future, however, believe that will continue to increase, the following table.In addition, flexible circuit board of the bottom of the protective film currently used are eps are still four acid imide.
Printed circuit board with conductors are thin foil of copper.Is the so-called copper foil.According to its process can be divided into electrolytic copper foil and rolled copper foil.

Function:
Stereo circuit connection between line hard printed circuit boards, movable type circuit, high density circuit.Commercial electronic equipment, car dashboard, printers, hard disk drive, diskette, fax machine, car mobile phone, general phones, laptops, etc.
High density thin printed circuit three-dimensional circuit camera, camera, cd-rom, hard disk, watches, etc
The connection of the connector board and low cost All kinds of electronic products
Multi-functional integrated system board and guide line and connector of the integration of computer, camera, medical instruments and equipment

It’s amazing how a few changes to your stackup design can ensure durability and manufacturability on your flex PCB board

Today, in what will be the first of many flex tips, we will be discussing optimal flex stackups and materials. One of our customers recently sent us a four-layer stackup that needed a little tweaking. We talked it over with our design engineers and came up with solutions and alternatives to all the issues at hand. It’s amazing how a few changes to your stackup design can ensure durability and manufacturability on your flex PCB board.
The Board:
This was a four-layer flex board with zif connectors requiring controlled impedance.
The high-speed zif connectors connected finger areas from the edge to the top of the board.
The Issues:
The board’s flex layers were located on the outside of the stackup, which increased the possibility of manufacturing problems and issues.
Making sure the board met the impedance requirements.

The Solution:
We embedded the flex layers in the center of the stackup. This protected the layers during the manufacturing process and ensured that the less-durable flex layers were not exposed to outer-layer plating. This is how most rigid-flex stackups are designed. When the flex layers are on the outside, panels are harder to handle and harder to process. This made the board more durable and easier to manufacture. It also allowed for better impedance and better control around the flex finger area.
Because the flex layer is a separate process, putting the flex layers inside allows flex manufacturers the ability to etch away from the design while protecting the flex layers. Putting the rigid material on the outside also allows us to manufacture what is essentially a rigid panel. The flex layers are also protected by our surface plating because it should brittle the material. The material used also played a large part in making this board rigid-flex instead of flex. Rigid AP material was used, allowing for better impedance and reliability. It was a much better option than the original FR-4 material. Source:Sierra

Use Flexible printed circuit board to maker a Flexible Wearable Electronic Skin Patch

Engineers at the University of California San Diego have developed a flexible wearable sensor that can accurately measure a person’s blood alcohol level from sweat and transmit the data wirelessly to a laptop, smartphone or other mobile device. The device can be worn on the skin and could be used by doctors and police officers for continuous, non-invasive and real-time monitoring of blood alcohol content.

The device consists of a temporary tattoo—which sticks to the skin, induces sweat and electrochemically detects the alcohol level—and a portable flexible electronic circuit board, which is connected to the tattoo by a magnet and can communicate the information to a mobile device via Bluetooth. The work, led by nanoengineering professor Joseph Wang and electrical engineering professor Patrick Mercier, both at UC San Diego, was published recently in the journal ACS Sensors.

“Lots of accidents on the road are caused by drunk driving. This technology provides an accurate, convenient and quick way to monitor alcohol consumption to help prevent people from driving while intoxicated,” Wang said. The device could be integrated with a car’s alcohol ignition interlocks, or friends could use it to check up on each other before handing over the car keys, he added.

“When you’re out at a party or at a bar, this sensor could send alerts to your phone to let you know how much you’ve been drinking,” said Jayoung Kim, a materials science and engineering PhD student in Wang’s group and one of the paper’s co-first authors.

Blood alcohol concentration is the most accurate indicator of a person’s alcohol level, but measuring it requires pricking a finger. Breathalyzers, which are the most commonly used devices to indirectly estimate blood alcohol concentration, are non-invasive, but they can give false readouts. For example, the alcohol level detected in a person’s breath right after taking a drink would typically appear higher than that person’s actual blood alcohol concentration. A person could also fool a breathalyzer into detecting a lower alcohol level by using mouthwash.

Recent research has shown that blood alcohol concentration can also be estimated by measuring alcohol levels in what’s called insensible sweat—perspiration that happens before it’s perceived as moisture on the skin. But this measurement can be up to two hours behind the actual blood alcohol reading. On the other hand, the alcohol level in sensible sweat—the sweat that’s typically seen—is a better real-time indicator of the blood alcohol concentration, but so far the systems that can measure this are neither portable nor fit for wearing on the body.

Now, UC San Diego researchers have developed an alcohol sensor that’s wearable, portable and could accurately monitor alcohol level in sweat within 15 minutes.

“What’s also innovative about this technology is that the wearer doesn’t need to be exercising or sweating already. The user can put on the patch and within a few minutes get a reading that’s well correlated to his or her blood alcohol concentration. Such a device hasn’t been available until now,” Mercier said.

How it works

Image

The alcohol sensor consists of a temporary tattoo (left) developed by the Wang lab and a flexible printed electronic circuit board (right) developed by the Mercier lab.

Wang and Mercier, the director and co-director, respectively, of the UC San Diego Center for Wearable Sensors, collaborated to develop the device. Wang’s group fabricated the tattoo, equipped with screen-printed electrodes and a small hydrogel patch containing pilocarpine, a drug that passes through the skin and induces sweat.

Mercier’s group developed the printed flexible electronic circuit board that powers the tattoo and can communicate wirelessly with a mobile device. His team also developed the magnetic connector that attaches the electronic circuit board to the tattoo, as well as the device’s phone app.

“This device can use a Bluetooth connection, which is something a breathalyzer can’t do. We’ve found a way to make the electronics portable and wireless, which are important for practical, real-life use,” said Somayeh Imani, an electrical engineering PhD student in Mercier’s lab and a co-first author on the paper.

The tattoo works first by releasing pilocarpine to induce sweat. Then, the sweat comes into contact with an electrode coated with alcohol oxidase, an enzyme that selectively reacts with alcohol to generate hydrogen peroxide, which is electrochemically detected. That information is sent to the electronic circuit board as electrical signals. The data are communicated wirelessly to a mobile device.

Putting the tattoo to the test

Researchers tested the alcohol sensor on 9 healthy volunteers who wore the tattoo on their arms before and after consuming an alcoholic beverage (either a bottle of beer or glass of red wine). The readouts accurately reflected the wearers’ blood alcohol concentrations.

The device also gave accurate readouts even after repeated bending and shaking. This shows that the sensor won’t be affected by the wearer’s movements, researchers said.

As a next step, the team is developing a device that could continuously monitor alcohol levels for 24 hours. Source:ucsd

How 3D printed technology effective to manufacturer assembly industry?

Although diverse 3D printing projects continue to capture the selective gaze of mainstream media, Andy Middleton, president – EMEA at Stratasys, lifts the lid on where the technology is making a more important and widespread impact.

Ask a random selection of the general public about where 3D printing – or additive manufacturing – is making its biggest impact and the answers will likely be varied.

Opinions might range from chocolate printing to the building of entire houses, to the still unchartered territory of human organ printing. Even a good number of those who have some understanding of the technology will still cite prototyping as the mainstay of its capabilities.

This is perhaps due in part to the broader news coverage, opting to highlight what are deemed the more ‘interesting’ of examples. Typically, these don’t accurately reflect the true nature or extent of 3D printing’s potential and its impact.

The truth is that, having been around for 30 years, the technology has evolved incredibly, no longer confining itself to solely offering a faster, more cost-effective method of prototyping.

Although still a significant area of use, 3D printing has developed to offer a much wider proposition to the industrial manufacturing world – particularly within sectors such as automotive, aerospace and engineering.

The factory of the future – right here and right now

For manufacturing applications, we’re seeing a tremendous uptake of 3D printing in two areas – augmented manufacturing, and alternative manufacturing.



This doesn’t just apply to individual businesses, but for manufacturing as a whole, which in turn creates a positive knock-on effect with the potential to affect economies.

Augmented manufacturing – disrupting manufacturing processes

Used to position; hold; protect, and organise components and sub-assemblies during the manufacturing process, tools like jigs, fixtures and guides are virtually invisible when production is running smoothly, but their importance becomes evident when problems arise.

As a result, to avoid production halts or product defects, new tools must be rapidly designed, manufactured and deployed to maintain workflow. The downside is that they are typically fabricated from metal, wood or plastic in small quantities using a manual or semi-automated process, with the result that each tool takes between one and four weeks to design and build.

Using Stratasys additive manufacturing technology, Volvo Trucks has reduced turnaround times on certain clamps, jigs and supports from 36 days to just two days
Using Stratasys additive manufacturing technology, Volvo Trucks has reduced turnaround times on certain clamps, jigs and supports from 36 days to just two days – image courtesy of Stratasys.
Furthermore, with elaborate or intricate tools sometimes requiring several cycles of design, prototyping and evaluation to attain the required performance, it’s easy to see that this can be a costly area of manufacturing from both a monetary and time perspective.

The use of 3D printing for such applications relieves the strain that would otherwise rack up costs and manufacturing lead-times and provides a fast and accurate method of producing these manufacturing tools. Using Fused Deposition Modelling (FDM) 3D printing technology, the traditional fabrication process is substantially simplified, such that tool-making becomes less expensive and time consuming.

Immediate and real benefits for industry

The immediate and real benefits for manufacturers are instant improvements in productivity, efficiency and quality.


Among the assembly tools 3D printed by Opel with its Stratasys FDM 3D Printers are those used to position the roof onto vehicles – image courtesy of Stratasys.
Indeed, those companies deploying it within their operations aren’t simply replacing machinery, they are redesigning their entire production lines to make the work more efficient; accurate; fast; simple, and profitable.

In certain cases, some of our own customers have reported lead time reductions and cost savings of 90% or more. A good example is German automotive company, Opel, which 3D prints a range of manufacturing and assembly tools to advance the production of its iconic ‘Adam’ hatchback car.

A similar scenario is taking place at Volvo Trucks’ engine production facility in Lyon, France. Here, Stratasys additive manufacturing technology is employed to produce different durable – yet lightweight – clamps, jigs, supports and even ergonomically-designed tool holders that ensure a more organised working environment for operators.

A better alternative


The continued evolution of 3D printing will continue to come from applications where it offers a more efficient process to traditional manufacturing. For example, for the production of low volume quantities or on-demand parts that improve supply chain workflows.

The acknowledged holy grail of 3D printing – alternative manufacturing – has established itself as a genuine substitute to challenge traditional methods of production – something we continue to see demonstrated by our customers.

This is underscored by major aerospace giant, Airbus, which uses more than 1,000 end-use flight-ready parts in place of traditionally manufactured parts in its A350 XWB aircraft programme.

By using our additive manufacturing technology, the company is able to reduce supply chain risk by rapidly manufacture strong, lighter weight parts almost on-demand and increase supply chain flexibility – thereby substantially reducing production time and manufacturing costs.

Boldly going where no 3D printed parts have gone before

Meanwhile, our partnership with rocket manufacturer, United Launch Alliance (ULA), has seen our FDM 3D printing technology used to produce 3D printed parts in place of metal parts on the company’s Atlas V rocket, which was launched into space earlier this year.

Using 3D printing, ULA consolidated part count from 140 to 16 parts for one complex assembly, significantly reducing installation time and resulting in a 57% part-cost reduction. According to ULA, switching to manufacture components using 3D printing has contributed to annual savings of up to US$1m.

Despite having turned a corner, the manufacturing sectors of many Western countries are still bearing the brunt of recent challenging economic climes. The fortunes and indeed long term success of individual companies will play a huge role in safeguarding the sector’s continued passage into calmer waters.

Looking ahead, I believe that the positive impact of 3D printing within manufacturing and the way in which an increasing number of companies are adopting this efficiency-driving, cost-reducing technology will be instrumental to supporting this.Source:themanufacturer

Flex PCB design experts recommend Seven FPC drawing requirement guideline

This post will discuss some FPC drawing requirements.
And our flex PCB experts also give their suggestions in FPC design.
Go deep to read about Flex PCB design experts recommends Seven FPC drawing requirement guideline.




1. The Basics
First and foremost, there are several board elements that must be included in your design. These include:
Layer count
Finished board thickness
PCB materials used
Surface finish
These may seem like obvious requirements, but they occasionally go overlooked. When that happens, the PCB manufacturer will need to follow up for clarification, delaying turnaround time.

2. A Drill Symbol Chart
The drill symbol chart indicates all of the finished hole sizes, as well as the hole size tolerance, for your circuit board design. The standard finished hole size is +/- .003," but this is never assumed, so this measurement must be stated on your design drawing.
"The dimensional drawing should define the rigid to flex interfaces."

3. Dimensional Drawing
The dimensional drawing identifies a number of critical measurements for the PCB design. Notably, the dimensional drawing should define the rigid to flex interfaces, noting where these two types of material meet. While the typical outline tolerance is +/- .010", it is imperative for the designer to determine and clearly state whether this meets their specific needs. If a pallet or array is needed for the design, a dimensional view is also required.

4. Board Construction and Layer Order
This documentation differentiates between layers comprised of rigid material and layers containing flexible material, such as copper weights. Without these drawings, the PCB manufacturer will need to follow up with the customer, delaying turnaround time.

5. Notes
Along with the flex PCB drawings themselves, you'll need to present accompanying notes when submitting your circuit board design. These notes should encompass a broad range of specific details. For example, your notes should state:
Class, wiring type, and installation use requirements
Electrical test requirements
Packaging and shipping needs
The notes should also include specific design requirements, but that point deserves its own section.
The more detailed your notes, the better.The more detailed your notes, the better.

6. Specific Design Requirements
In many cases, particularly when it comes to prototypes in areas like the Internet of Things, you'll have unique PCB design requirements that do not fit into any of the above categories. In order to maximize quickturn benefits, these need to be presented as part of the design drawings early in the design process. Communication between designers and fabrication houses before designing begins and throughout the manufacturing process will speed the process even more, allowing for no confusion or delays.

7. Flexibility
This last drawing requirement isn't what you think. We're not focused on the flexibility of the PCB, but rather the design itself.
Writing for Engineering.com, Kagan Pittman noted that it impossible for engineers and designers to accurately predict all of the potential ways that a circuit board design could go awry.
Sometimes, designers will refuse to alter their designs, even when the PCB fabrication partner offers manufacturability or reliability suggestions. Industry expert Al Wright told Pittman about one such instance he ran into where the client, instead of adapting, went to another manufacturer. As a result, the PCB produced was completely faulty. If you're not sure whether the suggestions made will be applicable to your design, ask the fab house to elaborate on the potential issue.
The purpose of these drawing requirements is to help you make the most of your partnership with a PCB manufacturer. If you've chosen an industry-leading PCB firm to work with, then you should absolutely take advantage of the expertise and guidance they offer. That means you need to be flexible and open to suggestions.Source:Sierra

Different design consideration that influences manufacturing and cost as well as electrical and mechanical performance

For many years the demand for polyimide and PTFE materials was very low, very specialized, confined in the case of polyimides almost exclusively to high-temperature or high-voltage applications and in the case of the PTFE laminates, such as the Rogers duroids, microwave circuits. Designers increasingly are turning to those laminates, perhaps for good reasons based on the thermal or electrical attributes listed in data sheets, but without regard to certain manufacturing characteristics that set them apart from the fabrication processes for conventional FR4. Many of those manufacturing characteristics are not apparent from data sheets.
Wise designers consult manufacturers before developing hybrid stackups, because combining laminates with dissimilar mechanical properties can complicate fabrication and therefore bear on cost, especially with respect to yield. By the time a design is ready to prototype, it’s often too late and too expensive to recast in a way that would achieve the design objectives yet be easier to build. My company, which is devoted to prototype manufacture and up to medium scale production, often takes on challenging projects that might have been better architected had the designers reached out to us at the stackup stage.
Not Covered in Data Sheets
Let me focus on one aspect of hybrid builds brought to mind by a recent conversation with the engineer who supervises drilling operations here. “The problem is,” he emphasizes, “there can be very different feed and speed requirements for drilling one material compared to another.” Several designs we recently built involved three, four, even five different materials. For example, we had a project with two different polyimide materials, FR4, and flex material combined. The in-feed setting for the drills (how quickly they descend) and their spindle speed for drilling the polyimides is completely different than the in-feed and spindle speed for the flex material. Polyimide laminates are hard materials that fracture easily. Therefore, they must be drilled at a relatively low in-feed rate and a high spindle speed. Flex material is just the opposite, requiring a high in-feed rate and a slow spindle speed, because the slower the in-feed and the higher the spindle speed, the more heat that will be generated.
“It’s difficult when those materials are combined, because the polyimide can’t be drilled using the flex parameters, or vice versa, or the boards will be compromised,” the engineer points out. “The softer the material—the duroids and flex materials are about the same–the easier it is to drill, but the more susceptible it is to heat, so if you also have a harder material in combination to drill, it’s easy to distort the softer material if you go in at too high an in-feed. The drill can essentially pull the material out of the hole wall and then the material snaps back but not all the way, so one of the things you would see is that for no apparent reason there’s what appears to be negative etchback in the hole wall of the softer material.” What we are doing in such rigid-flex cases is “peck” drilling. We control the machines to drill a just certain distance and then withdraw the drills to let them cool, and then drill further. We are guided by the drilling characteristics of the most-sensitive materials.
ENEPIG—short for electroless nickel, electroless palladium, immersion gold—is a somewhat more expensive surface finish that has nearly universal advantages.
Unlike the duroids, Rogers 4000 materials have drilling characteristics that are relatively close to FR4. Some defects can result because the 4000 materials must be drilled more slowly and generate more heat. There is a tendency for the interconnects to smear a little bit in the holes—so-called nailheading—though that’s typically not cause for rejecting a board. Slowing down the feed rate for a given material in a stack runs the risk of causing some defects in the region of the hole where that material is located. Polyimides and the ceramic-filled materials have slower in-feed rates and higher spindle speeds because they are hard, and therefore less material is removed per revolution of the drill. The combination of feed rate and drill speed is sometimes referred to as chip load. A harder material necessitates a lower chip load; that is, a lower feed rate and a higher spindle speed. When you have a combination of materials, you have to adjust the drilling parameters to meet the requirements for the hardest material, or distortion inside the hole can result and that can interfere with plating the hole. But when you have two materials with very different drilling parameters, the settings are a compromise.
For manufacturers, there’s yet another consideration besides chip load and that’s drill hit count; the sharper the drill, the fewer the issues that will be encountered. For FR4 the drill hit count typically is around 800 but for a hard material, drills have to be changed after 400 or so hits, and that affects project cost.
Still another consideration internal to manufacturers is which of three entry materials will be used on top of the board stack for drilling support. There’s a coated aluminum material that’s best for drilling small holes; there’s an aluminum material with a paper core that’s used for most other drilling needs; and there’s phenolic material, which provides the most surface support and would usually be used when a soft material, such as a Rogers duroid, is the top layer of a board, but the phenolic material is the worst of the three entry materials for drilling accuracy. The phenolic entry material is hard and drills can skate when they start. If the drill diameters involved are not less than 10 mils, accuracy is not compromised by the phenolic material. If the drill diameters are much smaller, the coated aluminum material must be used or the drills will snap. However, in most cases, the amount of burring, the amount of debris in such small holes as a result of using the coated aluminum material is negligible.
There is considerable work among laminate suppliers to provide alternatives to polyimide and PTFE materials whose manufacturing characteristics are closer to those of FR4.
Switching Gears
Let me turn to a different design consideration that influences manufacturing and cost as well as electrical and mechanical performance: surface finish. For example, if HASL [hot-air solder leveling] is selected, the PCB design must not include any fine-pitch components because a HASL surface finish will be to too uneven to ensure uniform contact bonds for such parts. Immersion silver or immersion gold finishes are better alternatives if devices with tight contact pitches are involved. The immersion gold finish is called ENIG (electroless nickel, immersion gold).
Immersion silver does not require a layer of nickel underneath as does the immersion gold finish. The nickel is used as a barrier layer to prevent copper migration into the gold over time, which can result in increased contact resistance if boards are left unassembled too long. Both immersion silver and ENIG result in even surfaces that are much flatter than can be obtained with HASL; moreover, both are more electrically conductive. The overall thickness of the immersion silver finish can be held to tighter tolerance than that for ENIG, so silver is preferred if there are press-fit connectors in the design. However, silver tarnishes quickly and assembly must therefore be completed soon after board fabrication. ENIG is the better choice for designs with very fine traces. ENIG is also better for thin boards because it is a relatively low-temperature process.
Both electrolytic soft gold, which would be a choice for designs that involve wire bonds in assembly, and electrolytic hard gold, which also supports wirebonding and has advantages for sliding contacts, have a downsides. To accomplish either finish requires the addition of buss bars on panels to electrically interconnect the copper features during the plating process, which afterward must be severed from the PCB circuits. Moreover, copper can remain exposed on trace sidewalls.
ENEPIG—short for electroless nickel, electroless palladium, immersion gold—is a somewhat more expensive surface finish that has nearly universal advantages. Nonetheless, my advice regarding surface finishes jibes with my advice regarding hybrid stackups: Consult your prospective manufacturer at the outset of your project, to make sure you don’t become invested too deeply to improve your design decisions.Sourse:Sierra

The automotive PCB has brought widespread changes in the automobile industry in the last few years

PCBs are electronic circuits boards created for mounting electronic components on board. The board itself is nonconductive for creating connections between the components.

The circuit patterns are designed and developed by either adding to or subtracting from the circuit boards. The conductive circuit is copper, nickel, aluminium, chrome, and even some other metals are used. There are three basic varieties of printed circuit boards: single-sided, double-sided, and multi-layered. 

The automotive PCB has brought widespread changes in the automobile industry in the last few years. They can be used to provide highly reliable and long-lasting services at a reasonable and yet, at a highly competitive rate. They find application in many passenger vehicles, trucks, trailers, subassemblies and dealer support systems.

The automotive PCB finds its application in power relays, electronic mirror controls, ECL/ECU control modules, antilock brake systems, onboard radar, digital displays, and interior LED lighting system and so on.

These days, some modern facilities and accessories are present in the vehicles such as televisions which the passengers can view. To make this possible, a number of PCBs is used in these vehicles. Also, the advanced security features such as the anti-lock brake systems and ECU systems make use of different kinds of PCBs.

Moreover, today’s cars come with GPS navigation systems today. For this, some exclusive PCBs are required.

The automotive PCBs benefit the vehicles in the following ways:

Boosting the Performance of the System: With the use of these PCBs, the Automobiles become stronger and faster.

Driveability: The response of the vehicle to the driver inputs is also enhanced.

 It also helps in Powertrain Development, Motor Sport, and Modal Analysis.

Not only the automobile industry, but there are also many electronic devices that make use of PCBs. In the recent times, the burgeoning demand of PCB encourages an emerging market in the domain of electronic components. There are various companies in this vast world that specialize in manufacturing and supplying PCBs.

But China has almost gained a monopoly in the domain of PCB manufacturing. There are many PCB factories in China that manufacture superior quality PCBs, to serve the purpose of thousands of users. If you are looking for a professionally designed PCB for your business or project, look no further than the PCB factories in China. They will make customized PCBs to meet all your requirements. They provide services specifically for domestic and foreign cutting-edge enterprises and research institutes.

The PCBs manufactured in China are expressly distinctive components with state-of-the-art features that catalyze the diverse mechanisms of electronic devices. The component has immense scope for further innovation which will sufficiently revamp the electronics industry.

Flex circuit can be formed in complex shapes

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.
Sourse:Sierra Circuits

Through-Hole Mounting (THM) Vs. Surface Mounting (SMT)

Semiconductor packaging is constantly evolving. There are increased demands for increased functionality, added utility, and smaller sizes. There are two main methods when mounting components on a PCB. These are Through-Hole Mounting (THM) and Surface Mounting (SMT).

Through-hole mounting involves leads being placed into holes that have been drilled into the PCB board. The technology was the only process used until Surface Mounting was developed in the 1960s, but became common during the 1980s. With the advent of SMT, it was widely presumed that THM would be phased out. However, manufacturers still make THM PCBs, as there are clients who still prefer, or require boards that use the older board design. The main reason is that THM boards have greater reliability.

The reasons for increased reliability are evident. SMT components are secured to the board by solder. THM components are secured by leads running through the board. The result is that the THM boards can hold up in more stressful environments. As a result, boards used in military or aerospace situations often specify THM boards, as the conditions they are used in may include very high or very low temperatures, or rapid acceleration.

There are other reasons that THM boards continue to be used. A common use of THM boards is in prototype testing, as the board structure allows for manual adjustments. Not all components are available for surface mount situations. And in some instances, THM components are less expensive than the equivalent SMT component.

However, the benefit of lower cost components needs to be balanced with the higher cost of preparing the THM. The THM board needs to have holes drilled, which can be an expensive process, as well as being time consuming.

Another issue with THM boards is layering. Drilled holes must pass through all layers of the PCB. Therefore, routing on multilayer boards is more challenging for THM.

Manufacturing of THM is a more complex process. SMT soldering is completed using reflow ovens, while THM requires hand-soldering, and needs soldering on both sides of the board. SMT rarely requires soldering on both sides of the board. As a result, components can only be placed at the rate of hundreds per hour, so manufacture is relatively slow compared to SMT boards.

In contrast, SMT has components mounted directly onto the surface of the PCB. Virtually all components are now manufactured using SMT. The process is considerably more cost effective for most requirements. The component leads in THM are replaced by vias, which are small components designed to allow a conductive connection between layers. SMT allows used of components such as BGAs that allow for shorter leads and more interconnection pins. They can deliver higher speed processing.

SMT PCBs are generally smaller and have a higher component density. They have more ‘real estate’ to work with. Components can be installed very quickly, at rates of thousands of placements per hour. The solder joints are more reliable; and through programming with appropriate quality controls, can be completed quickly and efficiently.

In summary, in most circumstances, SMT will provide a more cost effective and more reliable board, and be suitable for high production runs. In contrast, THM boards have become a specialist product, providing a valuable tool in specific situations such as high temperatures, or situations that may involve mechanical stress.

Resour:rushpcb

best balance of performance and board cost

Since the turn of the 21st century, there has been intensive research toward the development of embedded optical channels for transporting high-speed digital signals within printed circuit boards. I suspect that an alternative to copper traces might be commercially viable by 2035 or sooner, depending on the development of semiconductor devices with integrated photonics to transmit and receive signals through those channels.
Finding the low-loss material that will provide the best balance of performance and board cost for a given application is more complicated than simply comparing laminate data sheets and prices.
The development of embedded optical waveguides and integrated photonics is driven largely by the capacity demands (as well as the power consumption) of high-performance routers and network switches, whose backplanes may span more than 20 inches. Signal attenuation resulting from dielectric and conductor losses is a major concern for designers of those backplanes, as are signal reflections caused by impedance variations resulting from shifts in the dielectric constant of laminates with frequency. Signal propagation delay, which is governed mostly by laminate dielectric constant, and trace crosstalk are also spurring the development of optical channels.
Optical channels would be immune from noise, virtually loss-less, and electrically independent of surrounding material. They would be the conduit for high-speed signals, while copper traces elsewhere in the boards would comprise the remainder of circuits. However, creating those channels involves changes throughout the entire infrastructure of electronics manufacturing, including semiconductor materials and fabrication processes, IC and PCB design tools, and IC packaging technology, beyond the development of optical materials compatible with high-volume, panel-based PCB manufacturing processes. That will take time.
Meanwhile, PCB materials with stable Df values on the order of 0.003 up to at least 10 GHz are necessary to meet channel loss budgets in such current high-speed digital applications as network line cards for 40-Gbit/s and faster data rates. Various materials, some of them widely used in RF applications, have Df values low enough to satisfy the loss budgets of high-speed signal paths on 40-Gbit/s Ethernet line cards, for example, within safe margin. These materials cost more than regular FR-4 laminates, so hybrid stackups are common that dedicate high-speed nets to low-loss layers and less-critical circuits to layers of FR-4 for economy.
 A Suitable Low-loss Material
Finding the low-loss material that will provide the best balance of performance and board cost for a given application is more complicated than simply comparing laminate data sheets and prices. Data sheets do not reveal which materials involve relatively more or unusual processing steps during PCB fabrication, which can raise manufacturing cost. Consider Rogers 4350B and Panasonic Megtron 6, which have similar low Df and Dk values, have been used extensively in RF applications, and are increasingly being used for high-speed digital products. Both are based on hydrocarbon resins; the Rogers resin has a ceramic filler. Neither laminate is available clad with quarter-ounce copper. The thinnest foil available for the Rogers material is half-ounce, and for Megtron 6, one-third-ounce. Both materials are available with low-profile foils to prevent signal reflections at high frequencies. The Rogers core material is essentially perfectly flat and repeatable, aiding impedance control; the Panasonic material slightly less so. The Rogers material is at least twice as expensive as Megtron 6.
Rogers offers three prepreg choices for bonding the 4350B laminates: a 4-mil prepreg that is available in two glass styles and one that is 3.6-mils thick with one glass style. Rogers discourages etchback of the material, advises against using a single layer of prepreg in high-layer-count, single-lamination stackups,and recommends cap construction. Manufacturers have to adjust the lamination cycle for fabricating boards when the Rogers material is involved because of the restriction on using a single layer of prepreg. The Rogers prepregs for the 4350B cores require higher pressure for proper lamination than do the Panasonic prepregs,which process no differently than conventional FR-4 materials.
Eight laminate thicknesses are available. Megtron 6 laminates come in 18 thicknesses, complemented by a wide range of prepreg thicknesses and glass styles, including various tightly woven, so-called flat-glass styles to avoid impedance variation caused by fiber-weave effect. Resin evenly coats the surface of those tight weaves. Three different percentages of resin content can be selected for several of the Megtron 6 prepreg glass styles. The most significant contrast betweem the Rogers material and the Panasonic material is that Megtron 6 laminates the same as conventional FR-4 materials; no incompatible pressures, temperature, movement, or cure time are involved.
What is the upshot of the differences between Rogers 4350B and Panasonic Megtron 6, beyond their raw material costs, considering that their electrical properties are alike? The most significant contrast is that Megtron 6 laminates the same as conventional FR-4 materials; no incompatible pressures, temperature, movement, or cure time are involved. Hybrid boards can be built in a single lamination with inner layers of relatively inexpensive FR-4 materials and an outer layer or layers of Megtron 6, using foil construction or cap construction. Moreover, the wider selection of Megtron 6 core and prepreg thicknesses and resin content eases stackup development and impedance control.
Many PCBs have been built using Rogers 4350B material for very high-speed digital circuits. It is a proven choice from a functional perspective, and a highly predictable material from a manufacturing perspective, with well-established fabrication protocols. Though its use is routine, it is somewhat more complicated to process than Megtron 6. The fact that fabrication complexity and yield have an inverse relationship is worth recognizing at the outset of design. Manufacturing yield may not be a concern if you only need a few boards, but that is certainly not the case for volume production.
from:Sierra Circuits

Each PCB supplier will have a strong area of specialization

The Printed circuit board (PCB) market is vast and varied with wider segmentation. User applications, components, materials define the segments generally.

Most people have heard about leading companies in PCB industry such as Samsung EM, Sumitomo Denko PC, Gold Circuit, Nanya PCB, and SEMCO.

These are global companies yet so many well to do companies are operating in national and local levels.

For end users looking to buy mass production pcb, do carry out a background research of different suppliers to know the exact capabilities and price points at which they pay for the services.

The user industries in PCBs are as varied as electronics, auto, and computers. The PCBs are extensively used in consumer electronics such as TVs, digital cameras, and MP3 players.

PCBs are an indispensable part in all consumer and commercial electronic devices. If you take the case of computers and electronic devices such as PCs, they are everywhere-- motherboards, RAM, and network interface cards.

The key drivers of the market are electronic industry and the ongoing advancements that are pushing the industry limits.

The growth prospects of PCB market are high and the market is divisible into seven segments: Aerospace, Defense, Automotive, Communication, Computing, Consumer Electronics, Medical, Instrumentation, Industrial etc.

The rising demand of precious metals and rare earth metals are also driving the expansion of PCBs. Functionally, PCBs are used in electrically connecting components through conductive paths.

Among the advanced hitech industries, PCBs have use in commercial electronic equipment such as aerospace and defense electronic products, healthcare equipment, and communications routers.

According to Market research, the Global PCB market has been growing 13 percent over the period between 2014 and 2016.

In getting suppliers avoid the temptation of choosing for low prices and focus on quality so that prices match the quality of the products.

Each PCB supplier will have a strong area of specialization. There is multilayer circuitsPCB production, requiring ample time in manufacturing plates. If any haste is shown in production it will hurt the quality of the final product. The period of production also depends on technology used.

For example, some companies take 4 to 10 days to make a dual platen sample and carefully consider each factor to ensure that the tight quality standards.

Low quality products are cheap but they are not cost effective and not all durable. If used, they will require more repair and maintenance.

To sum up, in finalizing a supplier, go by merit and focus on reliable products of high quality.