#pcboard

🔥 Get the best deals on 3BHE022287R0101 ABB Full Wave Communication Control Measurement! High quality, reliable performance, and unbeatable prices. Limited stock – order now!🚀

Printed circuit boards come in different materials known as substrate, including copper-clad laminate or CCL. PCB substrates are either organic or inorganic, depending on their properties. The organic substrates come up in different materials known as the reinforced board, such as glass felt, fiberglass, fiber paper, fiber cloth, and so on.

PCB fabricators impregnate thereinforcing materials with an adhesive called resin, making it dry, and then cover it with copper foil athigh pressure and temperature. Such a substrate is CCL or copper-clad laminate that resides on either one or both sides of the board. So, CCL is either single-sided or double-sided.

Rigid PCB has a rigid CCL with a substrate, such as

·         Resin epoxy FR4

·         PTFE

·         Aluminum or copper

·         Ceramic

These materials help make different types of PCBs, including single, double, and multilayer PCBs.

Printed circuit boards come up in different colors of which a green solder mask is the most common one. You will see most circuit boards with green solder masks. But, the industry is getting innovative due to changing technologies, so designers try new colors to make printed circuit boards.

PCB Solder Mask

Before getting into PCB colors, you should know what the solder mask is? The printed circuit board has different layers, and the top layer is the solder mask, whereas the bottom layer is the copper foil. The purpose of the solder mask is to cover the bottom layer from getting polluted or oxidized. The main material of solder masks is often the insulating resin which is printed on the circuit board’s unsoldered areas. The resin protects the board from heat, moisture, and any kind of damage.

FR4 is a blend of fiberglass and epoxy resin, and manufacturers also call it a composite material. It resists flame and is highly used for PCBs as a substrate or base layer. FR4 circuit boards are now used instead of G10 boards due to their properties.

 FR is also a great electrical insulator because it is completely water-resistant which means it does not absorb a little drop of water. Such qualities mechanically make it very strong and it maintains its qualities in all kinds of weather, including humid, hot, and dry weather.

Properties of FR4

FR4 is an inflammable material, and it is UL94V-0 compliant which means it does not spread fire, instead, itstops fire the moment the material starts burning.It has bromine that resists fire and does not absorb water as described above.

Moreover,the glass transition temperature is very high ranging from 115 to 2000 degrees Celsius, depending on the type of the resin and manufacturing method.Mostly such PCBs FR4 lies between the two layers of copper laminates.

Types of FR4 Material

FR4 material has different types, such as:

Standard FR4: Its heat resistance goes up to140-a50 degrees Celsius.

High CTI FR4: The index of this type of FR4 goes beyond 600V.

High TG FR4: It has a high-glass transition value, such as 180 degrees Celsius.

FR4 without copper: This type of FR4 is suitable for insulating plates, and it can support the circuit board.

Printed circuit boards come up in different colors of which a green solder mask is the most common one. You will see most circuit boards with green solder masks. But, the industry is getting innovative due to changing technologies, so designers try new colors to make printed circuit boards.

PCB Solder Mask

Before getting into PCB colors, you should know what the solder mask is? The printed circuit board has different layers, and the top layer is the solder mask, whereas the bottom layer is the copper foil. The purpose of the solder mask is to cover the bottom layer from getting polluted or oxidized. The main material of solder masks is often the insulating resin which is printed on the circuit board’s unsoldered areas. The resin protects the board from heat, moisture, and any kind of damage.

PCB is a printed circuit board that helps connect different electrical components. The board is a combination of laminated material, and the copper foil laid on a non-conductive substrate.

A PCB is the main part of any electronic device, so it has to be perfect. It should have functional components and microelectronics circuits to perform well. Development of PCB goes through different processes that you should know well. PCB manufacturing has 4 stages, including design, manufacturing, PCB assembly, and PCB testing.

First Stage- Design

PCB design involves different steps, such as schematic design, layout planning, the placement of the components, routing, and manufacturing files.

PCB schematic design: It is a blueprint of PC design that shows all PCB components with symbols. The schematic design is always according to the technical requirements of the user.

Layout planning: After the schematic design, you have to develop the layout of a PCB that includes physical components’ models, the shape of the PCB, and the structure of a PCB.

Placement of components: It involves planning the placement of various components. You decide on the PCB layers according to your requirements. The right placement of the components ensures a flawless board, decreasing the production cost.

First of all, the designer places the fixed components in the layout, including switches and connectors.

Then, the critical components are placed, such as memory chips, microprocessors, as well as power supplies.

Then the supporting components of the PCB are placed, like inductors, capacitors,  and resistors.

In the end, the decoupling capacitors and terminating resistors are placed.

Routing: Once the components are placed, you have to connect all components through trace routing. There are four ways to do so, such as manual routing, auto-interactive routing, semi-automatic, and batch-auto routing. You can choose any method according to your Printed Circuit Board and budget.

Design: In this stage, you have to plan for the number of board layers, dimension of the board, and types of components. You can use a special app in this case, such as EDA or electronic design automation. The designer often adopts the SMT instead of a through-hole technology, depending on your requirements.Once the design is over, you can export the design files to CAD or Gerber format.

Preparation of manufacturing files: This is the last stage of design where the designer exports the Gerber files for manufacturing. The manufacturer needs these files to develop a printed circuit board.

 Stage 2-Manufacturing of Circuit Board

Once the manufacturer receives all design drawings, he starts making PCB. It involves different stages as described below:

Design Imaging: The manufacturer uses a plotter to convert the PCB design files into filmslike they resemble the photo negatives of the schematic design. The printer uses black and clear inks for inner and outer layers. Copper traces and circuits are shown with black ink, whereas the non-conductive parts are shown with clearink.

Printing of Inner Layers on Copper: It is the initial stage of PCB manufacturing. The engineer uses a substrate material to make a laminated board. Like, epoxy resin or fiberglasses are common in this case. The design of the PCB is printed on the board, and then his pre-bondscopper on a board’s both sides. After that comes the etching of copper, and then the board is protected through a photo-sensitive film.

Ultraviolet Light: the manufacturer then exposes the resist-covered PCB to UV light to strengthen the photo-reactive material. Then the board is cleaned with an alkaline solution to get rid of unnecessary copper particles. The expert checks the board to remove any errors and then goes to the next stage. The main aim of UV blasting is to develop a PCB Board according to the schematic drawing.

Inner layer’s etching: copper’s inner layer needs chemical etching for removal. The process of photoresist prevents the essential copper from etching. The board size determines the amount of the solution and etching time which is less for small boards but more for large boards.

Some other manufacturing processes include:

·         Alignment of layers

·         Optical testing

·         Layer pressing and lamination

·         Drilling

·         Plating of PCB

·         Imaging of external layer

·         Etching of external layer

·         Solder mask

·         Silk screening

·         PCB finishing

·         Testing

·         Profiling

·         Quality testing

·         Packaging of PCB

·         Shipping of PCB

 Stage 3-PCB Assembly

The assembly of a PCB involves four stages, such as soldering, placement of components, solder pasting, and testing. Let’s review them in detail.

Solder Pasting: It is like t-shirt screening, as it involves solder paste stenciling. The stencil is made of stainless steel and it’s very thin. You have to use the stencil to apply the paste in areas where different components will be installed. In this process, flux is used for melting the paste to help it bond to the PCB.

Placementofthe Components: Once you are done with the solder paste, you need a pick and place the tool for the components. Generally, it is SMT or surface mount technology where components are placed on the PCB surface. Initially, it used to be a manual process and assemblers used tweezers to pick and place different components on the board. However, new technology has made this process automated due to robotics and it’s more precise and consistent.

Soldering of PCB: After the placement of components, you have to place the PCB on a conveyor belt to help a board move to a reflow oven that heats the board. The heating helps melt the solder paste, and bond the components on the board permanently. However, if the board has more components other than SMDs, it would need a through-hole insertion that involves more advanced soldering.

Testing of PCB Quality: Sometimes, the components are misplaced during reflow when the PCB is moving. This issue may cause a poor connection, or no connection at all, or the parts are not well-connected. So, you need to inspect the PCB to ensure a flawless function. A PCB can fail this test even if it passed other tests, and a failed PCB goes to scrap or you have to recycle it with all essential processes until you get a flawless circuit board.

 Stage4-PCB Testing

Manufacturers use different methods for PCB testing to ensure that it will function correctly. These methods include in-circuit, optical inspection, flying probe, turn-in, x-ray, anda functional test.

In-Circuit: It is also known as ICT, or you can call it the bed-of-nails inspection. In this method, PCB is pressed on the bed of probes. It is highly accurate because it checks all components of a PCB. You can also test the BGAs with this method. Moreover, it also tests the solder integrity of the bottom-terminated components.

However, this test is expensive and time-consuming. Moreover, it does not test the non-electrical parts and connectors.

AOI, Automated Optical Inspection: This testing method involves a visual inspection of the board. It is done with the help of HD cameras, LED lights, UV, and high-level infrared. The test is contact-free and helps check poor solder joints or missing parts. It also tests the smt assembly issues and it’s very accurate.

However, it only inspects the preprogrammed errors and can’t check defects regarding glue or sealing.

Flying Probe Test: It involves probes that help test the upper and lower surface of a PCB. This PCB testing method is cost-effective, consumes less time, is easy to do, and is compatible with many applications of PCB assembly. However, it is slower than other testing methods and not ideal for complex testing.

Burn-In Test:  In this test, PCB is exposed to a high temperature to see if it works well. It ensures a lifetime product and enhances the brand because of an effective end product.

However, this test is costly and can affect a PCB by damaging its components. Moreover, it can be less reliable due to voltage scaling.

Inspecting Through X-Ray: It involves an x-ray machine that inspects a PCB. It thoroughly checks soldering which is hard to detect with AOI. The x-ray inspection is ideal for thick or multilayered PCBs. It also detects the voids or bubbles and can also check the components under a shield.

However, it needs expensive x-ray machinesand can cause hazards in the workplace.

Functional Test ofPCB: It involves functional testers that you connect to the edge connector. It creates an electronic environment for which a PCB is made. It inspects the functional errors and identifies the analog issues. It also checks issues with digital circuitry.

However, it is very costly and needs high-end tools, which are too expensive. It needs a proper understanding of the working atmosphere of the DUT.

Final Thoughts

The development of a PCB involves different processes, including design, printing, assembling, and testing. Each stage is further divided into different parts, and you have to understand all stages to create a flawless PCB.

The board is a combination of laminated material, and the copper foil laid on a non-conductive substrate. A PCB is the main part of any electronic device, so it has to be perfect.

Would like to know more about the design or pcb assembly services stages? Email us at [email protected]

A microwave circuit refers to any electrical or electronic device which operates on microwaves or uses microwaves for its operation. Some examples include radar systems, satellite dishes, cell phone towers, and TV antennas among others. Such circuits are designed to operate at specific frequencies or bandwidths so that they do not interfere with each other.

A microwave is an electromagnetic wave of frequency between 1GHz and 30GHz. It falls under the band B, C, D, and E in IEEE standards. Microwaves occupy a large part of the entire RF spectrum as compared to other frequencies. The global demand for communication devices such as routers, DSL, and mobile phones has increased significantly due to technological advancements such as internet connectivity being provided by these devices and advancements in technology by small-sized electronic components that can operate at high frequencies. As a result, there is an increase in demand for microwave circuit design services.

Microwave PCBs have to meet certain requirements that have not changed even though the designs have.