During the manufacturing process of PCB, silkscreen is marking ink used to identify components during later assembly and troubleshooting processes. This can be placed on one or two sides (in yellow or white), depending on the board design and application. The silkscreen layer is the top layer of the PCB and serves as a reference indicator for placing components on the PCB. Screen printing is used to specify useful information on the PCB board, which can help users during the assembly. It is used to mark component values, part numbers, test points, polarity, etc. The problems related to the material of silkscreen are rarely occurred, except maybe some discoloration after high PCB reflow temperatures for RoHS compliant soldering. Silkscreen problems are always caused by the design of the PCB. If you want to order PCB product, please check and custom your order online. What is the importance of PCB silkscreen? In the past few years, the primary method of silkscreen referred to using a stencil to directly apply ink to the board surface. Nowadays, there are the two most common silkscreen PCB printing techniques, such as liquid photo imaging (LPI) and direct legend printing (DLP). Manual Screen-printing Manual screen-printing is done when the line widths are greater than 7 mil (0.007”) and the registration tolerance is 5 mil. For this method you require a stencil of the text and traces made of nylon. The ink is pushed through the stencil onto the laminate. Next the board is baked in a curing oven for the ink to cure. Liquid photo imaging (LPI): This method is used when the line widths are greater than 4 mil. Liquid Photo Imaging is quite similar to the process used for the application of solder mask. In this a liquid photo-imageable epoxy is coated on to the laminate and then exposed with UV light. After this the board is developed and cured. It is much more accurate than manual screening. Direct legend printing (DLP):DLP is the most accurate of all these processes but is more expensive. In this process an inkjet projector is used with acrylic ink that is applied onto the raw PCB directly from the CAD data. The ink is cured with UV light as it is printed. It should be noted though that the acrylic ink does not cure on boards with silver finishes. The application of PCB silkscreen is done during PCB fabrication, but it’s used for the PCB assembly process steps, which is mainly in referring to placing or mounting components. There are some silkscreen markings used to accurately place components as follows: Reference indicators - these identify the component types from the BOM. Pin 1 indicator - this indicates which pins connect to what pads of the footprint. Component outline – this, in conjunction with the landing pattern, indicates where the component should be placed. Polarity indicators – these provide the orientation of polarized components. For components with small numbers of pads or simple shapes, it may be acceptable for general placement to have the absence of the component outline. However, there still exists the possibility of asymmetrical placement, which may lead to problems during soldering, for example tombstoning. The absence of reference, pin 1 and polarity indicators may lead to incorrect component orientation or placement, which could have a negative effect on device functionality. What are tips for PCB silkscreen? As discussed earlier, using a silkscreen PCB layout is an important aspect of board design and not including it can cause serious problems for PCB assembly and testing. The silkscreen is also used for labeling, which may include manufacturer information, testing certifications, model or serial numbers. In order to be effective and useful, the silkscreen must have clearly readable text, provide sufficient image resolution and, most importantly, be accurate. Here are a few tips to help you ensure that your silkscreen PCB layout can be used for its important roles in PCB assembly, testing and identification: Tip 1: Only use fonts approved by your CM as some fonts, although easily created in software, are difficult to generate during board manufacture. Tip 2: Use white or black instead of other colors to provide the best contrast with your board’s solder mask color. Tip 3: Make sure to follow your CM’s clearance and dimension guidelines. This will ensure that your silkscreen items do not get covered by components and are easily visible. Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/26/2021 17:45
PCB files contain the application settings and data that are used by the software. The pcb file contains the necessary information on layers and other stuff related to the printed circuit board. The file contains information on every layer and routing on that layer. And it also contains information related to the top and bottom silk screens and hole sizes. For complete electronic product design, proper planning and designing are required. The digital software on the computer gives the flexibility to simulate the designed circuit. And omit the errors before it gets fabricate. But a deep understanding of the course and powerful software to make it simulation gives an error-free design. After finalizing the design, the appropriate selection of making components, the footprints of these components are available in the software. Also, it becomes part of the PCB file when making the final print—and finishing the wiring connection and optimal routing in the software based on the footprint of placed components on different layers and the surface of the board. The appropriate power points and signal traces plan is generated and digital software on the computer gives an output of a designed, printed circuit board. This designed circuit board is in the form of a Gerber file or a PCB file.If you want to order PCB product, please check and custom your order online. What are the common problems of a PCB file? Printed circuit boards are a crucial element for a wide variety of businesses, especially now in the digital age, when electronic technology is so important to many different fields. There is a significant range of different types of printed circuit boards as well, with different materials, shapes and sizes depending on the needs of a particular company or industry. PCB designers are constantly trying to find ways to develop circuit boards that are faster, stronger and more efficient. One thing all of these printed circuit boards and PCB designs have in common, however, is their reliance on quality Gerber files. Gerber files are the digital blueprints of your PCB, the layer-by-layer input for the PCB manufacturers that detail the manufacturing and fabricating process. Gerber files mistakes can be disastrous for a PCB manufacturer, leading to manufacturing errors and printed circuit boards that fail prematurely or do not work at an optimal level. Avoiding Gerber files problems so that these files are complete and accurate is critical to making sure each printed circuit board comes off the line able to perform according to specifications. Here are some of the most common Gerber file issues PCB manufacturers encounter and what they can do about them. Empty Gerber filesBelieve it or not, it is possible for the designer to create Gerber files with no information in them, or “zero-byte” files. Whoever is reading the file will not know if the file is completely extraneous or if there was information in it that was accidentally deleted. Designers must check each Gerber file to make sure it contains useful information before sending it on. Missing or incomplete filesThis is almost the opposite problem. Manufacturers need to know each specification related to the printed circuit board, from the size of the plated-through holes to the dimensions of the board. Any missing information will lead to a board that does not match the desired specifications. It’s important to make sure each necessary Gerber file is in place and accessible. Bad file labelingWhile not a catastrophic error, it is highly recommended that the designer name all Gerber files according to an established naming protocol the manufacturer understands. This way, the manufacturer can immediately find the Gerber file he or she needs without any confusion as to whether or not they have the right file. Too many aperture listsThe Gerber files should ideally have a single aperture list with all the details the manufacturer needs about the tools they require for each stage of fabrication. Multiple aperture lists create confusion, can slow down manufacturing and may increase the chances of error. Also look out for designers who create aperture lists in a different format than the Gerber files, which can lead to confusion as well. Composite layer design errorsIf the designer’s software creates composite layers while generating individual layer design specifications, it’s important that the images are combined in a way that creates one Gerber file for each layer, to avoid errors. Of all the potential problems you may have with your printed circuit boards, Gerber file mistakes are the most inexcusable. While most PCB design errors can be avoided with more careful and focused work, Gerber file errors are the easiest to avoid. Given that the consequences of Gerber file issues can be so expensive and so time-consuming, you simply cannot allow them to happen. A few ways to help you avoid Gerber files problems include: 1. Using a Gerber file viewer to check the Gerber files2. Printing a sample board to make sure the specs are correct3. Using high-definition CAD software4. Following best QA practices throughout the design processWanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/25/2021 17:46
It is indisputable that vias play an integral role in the PCB design and production process, but to what extent do you know about them? What are the various types of vias, and how do they vary from each other? Why do you need vias when designing a PCB? A via is a plated-through hole in a PCB that you can use to route a trace from your board's surface layer to the inner and other layers. It is essential to realize that you can drill PCB vias mechanically, and you can plate them to create electrical connections. Vias are vital in multi-layered boards, which are challenging to design and produce. They create routes for the sufficient flow of electrical and thermal current between the board's different layers. This article presents all the basics- not forgetting the via-production process, the primary types, and PCB design tips for vias.If you want to order PCB product, please check and custom your order online. What are the types of PCB vias? There are two primary categories of vias, depending on where they are in the PCB layers — the blind hole and the buried hole. In a blind hole, the hole penetrates the top or bottom layer of the board but stops before any of the internal layers. Blind holes are named as such because you cannot see through them when you hold a board up to the light. The process involved with blind-hole creation can be difficult because you must know when to stop drilling into the board. As such, many PCB manufacturers avoid hole plating of this type. Another type of via is the buried hole, which might appear through one or more internal layers. Since the buried hole is sandwiched between layers, it cannot be seen by the naked eye. For a multi-layer board to have a blind layer, the hole plating on the internal layer must be completed early on during PCB assembly, before the top and bottom layers are applied to the board. 1. Through-HoleThe most obvious type of via is the plating through-hole, which penetrates all the layers in a multi-layer board. Through-holes are typically larger than blind holes and buried holes and are also a lot easier to identify with the naked eye. When you hold a board up before the light, the light will pierce right through a plating through-hole. Through-holes are also easier to make because you can simply drill right through all the layers, unlike with blind holes, where you have to be careful how deep you make the hole. Through-hole technology has been around since the mid-20th century when it replaced point-to-point construction. Through-holes were most common between the 1950s and 1980s when nearly all the features found on a printed circuit board were attached to a through-hole. In the early days of through-hole technology, PCBs had their tracks printed only on the top side. As technology advanced, the printing appeared on both sides. Eventually, multi-layers boards came into use. At this point, through-holes were updated to plated through-holes to enable contacts between conductive layers. Today, plated through-holes are used to connect the different layers in a PCB. Through-holes are usually used to facilitate components with wire leads. Axial-leaded components are placed through these holes and used to connect across short spaces. 2. Via-in-PadOne of today’s more popular designs for printed circuit boards involves the application of vias on ball grid array (BGA) pads, alternately known as via-in-pad. In the via-in-pad design, the vias are placed on the BGA pads of the PCB. The design has become popular because it makes it possible for manufacturers to minimize the amount of space required for vias. The via-in-pad design is especially convenient for routing because the holes connect straight to the layer that underlies the component, making it possible to route signals without the risk of going outside the perimeter of the device’s footprint. In a standard via layout, solder mask can be applied to stop the flow of solder into the via. With the via-in-pad design, you cannot leave the barrel free of filling because air could get trapped, causing out-gassing while the PCB is in production. Therefore, the vias need to be filled when placed on BGA pads. For the design to work, you must also have a flat planar surface, as this will make it possible to connect fine-pitch BGAs with little, if any, complications. 3. MicroviasIn PCB design, vias that are under 150 microns are known as microvias, which are used on many high density interconnect (HDI) boards. Designers prefer microvias because of the small size of the hole, which consumes far less space on the board than the holes that require more drilling. In a microvia, the layers are connected to one another with copper plating. Microvias are created in the shape of cones, which makes it easy for the via sides to be copper plated. A microvia can go through two adjacent layers but not any further. If a board design requires a via through multiple layers, multiple microvias would need to be stacked accordingly. From a manufacturing standpoint, creating stacked microvias can be a costly and time-consuming process. On boards that require one microvia over another, the most common design will feature two microvias. As far as stacking is concerned, the ultimate limit is four microvias. However, four microvias are rarely applied in PCB manufacturing because of the high costs. An alternative option to the stacked microvia is the staggered microvia, which is set up like a staircase where a second or third microvia is placed a step forward below the one above. As with stacked microvias, staggered microvias can be difficult and costly to produce on a multi-layer PCB. A microvia that connects two inner layers in a PCB is known as a buried microvia. For a buried microvia to be included in a PCB design, the layers that contain the holes must first be drilled before the outer layers are applied. With a buried microvia, you can connect two inner layers on a printed circuit board. The drilling can be accomplished with a mechanical tool or, alternately, with a laser. When you place a microvia on a PCB, it is crucial to pay attention to the aspect ratio of the hole size, otherwise, it might be impossible to plate the board properly. What is the importance of Via of PCB? If you have a simple circuit board, you may not need vias. But you need vias when you are dealing with a multi-layered board, as mentioned earlier. Vias will help you to establish an excellent component density in multi-layered boards.Besides, they also raise trace density in multi-layered boards as you can run them over and beneath each other in different directions. Vias allow the various traces to link with each other. In this case, they act as vertical connection factors. If you fail to incorporate vias into a multi-layered PCB routing process, you will end up placing your components densely. Lastly, you need vias to facilitate the transmission of signals and power between layers. If you do not want to use vias, you should route your PCB components on a single plane. Remember, surface mounted parts in a multi-layered PCB make it impossible to route components on a single plane.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/25/2021 17:24
PCB trace impedance
In printed circuit boards, wires and traces are typically formed from copper because it is the least-resistant element apart from silver. Impedance, unlike resistance, is based on frequency. All wires and traces will generate at least some impedance to current flowing from any driver. Usually you may have a fairly fast rise time for your signals for trace impedance to become a problem. Every trace has series inductance. It is distributed along the trace and is inversely related to the cross-sectional area of the trace. It is admittedly small, but it is non-zero. Therefore, for fast enough rise times, the impedance it offers can be significant. And in this passage, we will focus on the topic - PCB trace impedance, and if you are going to know the performance of PCB, please check the content below.If you want to order PCB product, please check and custom your order online. How trace impedance works? Every trace has a small, nearly indistinguishable series inductance distributed along the trace with an inverse relationship to the cross-section of the trace. As rise times increase, the resulting impedance becomes more noticeable. By the same token, each trace has capacitance distributed along the trace and the return path signal, which is a function of the width of the trace and the dielectric of the material between the signal return path and the trace. Once again, if rise times increase enough, the impedance generated as the current tries to flow through this capacitance can be significant. Your drivers read all traces as distributed LC circuits and your trace AC impedance comes from this distributed LC circuit. This is considered uncontrolled impedance. We make no effort to design the trace environment to account for this impedance, allowing the inductance and capacitance to vary as it will along the trace. Since the resultant impedance usually has no effect on operations, there is no need to waste time or money designing ways to control it. What is controlled impedance? But what if we are concerned about the effect of impedance on our operations? We can design a board where the trace looks like a transmission line, allowing us to avoid reflections by terminating it in its characteristic impedance. How does designing a controlled impedance circuit work? When we control impedance, we make sure the impedance is constant at each point along the trace rather than varying from point-to-point as in a normal uncontrolled impedance situation. To control impedance, we need to control three features of the circuit’s geometry: the width of the trace, the spacing between the signal return path and the signal trace and the dielectric coefficient of the material surrounding the trace. You may also want to address the trace’s thickness. For example, a coaxial cable is a controlled impedance transmission line. You can change these geometric features and still retain controlled impedance as long as you change other features as necessary so the relationship between these aspects does not change and impedance remains constant. How Do We Determine Trace Impedance? If we know the geometry of a trace and the properties of the material(s) surrounding it, how do we then calculate the trace’s impedance? In decades past we used various formulas for this. These formulas could be found in various application notes and industry standards, and they were “close enough” then to be suitable. But as requirements have become more precise, these older formulas are no longer considered reliable for the precision we now require. Our requirements became more difficult as we began to want formulas for edge-coupled differential traces, and there never have been reliable formulas for broadside-coupled differential traces. What is PCB trace impedance formula? To manufacture controlled impedance printed circuit boards, one must be able to measure impedance. The best way to calculate trace impedance is by using a trace impedance calculator. You can find trace impedance calculators online or in your CAD software. There are several parameters to consider when determining impedance, including: Trace widthTrace thicknessLaminate thicknessDielectric thicknessCopper weight Once you have calculated all relevant parameters, you can adjust the all of the above (typically the trace width) to arrive at the impedance you are looking for. Once you think you are at an acceptable impedance, you can test the board’s effectiveness using test coupons manufactured on the same panel at the same time, so you can get a good impedance rating without the challenges of accessing the traces on the actual board. The test coupon traces should be identical to the board traces in order to get an accurate test. Typically, the manufacturer will build test coupons on either end of the production panel so that by testing both coupons, you get a very reliable impedance reading without damaging the board. Testers measure impedance with a Time Domain Reflectometer (TDR) or a network analyzer. Impedance can be measured using a network analyzer, a laboratory Time Domain Reflectometer (TDR) or a controlled impedance test system that employs TDR techniques. An engineer with practice using controlled impedance test systems will run the impedance test to ensure high-quality results.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/24/2021 18:39
Text point in PCB
The PCB testing will determine how well they have been manufactured. In order for this testing to happen, the board must be prepared with specific elements that a test probe can access. These elements are called test points and their inclusion on PCB designs is very important. Let’s take a few minutes here to talk about the PCB test point and why it is so important to the success of the completed circuit board. A PCB test point is a small wire loop used for test probes on a PCB that contains surface-mount parts. During production, they enable the user to inject test signals or monitor the board’s circuitry. Test points come in a variety of materials, sizes and colors. With a test point, you can create an access area for your test probe. Many of these probes have J-hooks designed for older PCB styles that included leads. A PCB test point provides a place for the J-hook or has a sharp pointed end that touches a conductor on the board. Most surface-mount test points feature a phosphor bronze alloy, but they can also have more affordable silver plate coatings.If you want to order PCB product, please check and custom your order online. What are the different types of PCB test points? There are two main types of test points used on a printed circuit board. The first is an easily accessible point for a technician to access with hand-held testing equipment. To help with this, these points often have a post soldered into them for clipping on a test lead. These test points will be marked with a reference designator and usually the name of the net in silkscreen for easy reference, such as “GND.” The other type of test point is used primarily for automated test equipment. The automated test points on a circuit board are thru-hole pins, vias, or small landing pads of metal that are designed to accommodate the probes of automated test systems. There are three main test systems that will use these test points on the board: Bare board test: This is a test that is run after the circuit board has been fabricated to make sure that all of the nets in the board have electrical connectivity. In-circuit test: ICT is run after the board has been assembled. The board is positioned on the ICT fixture which is filled with probes for each individual net. These fixtures usually test the bottom of the board, but they can also test the top or both sides together if needed. Flying probe: Like ICT, this test is run after assembly on each net of the board by accessing the test points. Where it differs, however, is that the flying probe equipment uses two to six probes that move around to each test point instead of using stationary probes in a fixture like ICT does. Those are the different test points that will be included in a PCB design and what they are used for. Next, we will see why this testing is so important for circuit board manufacturing. Why test points are important for PCB manufacturing? Automated testing is essential for verifying the manufacturing of printed circuit boards. While a bare board test checks that the fabricated board has good connectivity, ICT and flying probe tests will verify the board assembly and solder connections. Here is how ICT and flying probe testing accomplish that: In-Circuit Test (ICT)ICT is a system that uses a test fixture that is prepared exclusively for a specific circuit board design as well as accompanying software that will be run on the test system. The fixture and software are created using the test point locations and other design data generated by the CAD database, and a probe will be used for each net on the design. While the main purpose of ICT is to verify the assembly of the board by testing each net for a good connection to its associated part pin, it can also be used to test the functionality of the board. ICT test fixtures and software are expensive and time-consuming to develop. The test fixtures are complex with thousands of probes in them and changes to a fixture for board revisions can also be very expensive. Once developed, though, the in-circuit test will test large amounts of circuit boards very quickly. For mass production, the benefits of speed and functional testing quickly offset the development time and costs of ICT. Flying Probe TestingThis system is also designed to verify the integrity of an assembled circuit board, but it does this very differently than ICT. Instead of a test fixture, there are only two to six probes that fly around accessing each test point on the board. Without the need to build an expensive test fixture, the flying probe system can be set up very quickly and inexpensively. Also, any changes to the board that require changes to the test system can be easily reprogrammed. The disadvantage of the flying probe is that it is very slow. Where ICT can test all of the points on the board almost instantaneously, the flying probe system has to maneuver its probes around to each individual test point. On a large board, this can take a very long time, and the ability to do functional testing is eliminated. However, for prototypes or low volume production runs, using the flying probe for testing can be very advantageous. Now that we’ve seen what test points are and how they are used, we’ll next look at how PCB CAD tools include them in the design.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/22/2021 17:15
Bare PCB board
In PCB terminology, the term “bare board” refers to the state of a PCB before it receives electronic components or through holes. A bare board consists of the PCB’s substrate, metal coating, conductive pathways and patterns. Some industry experts call a bare board a PCB and an assembled board a PCBA. The simplicity of the blank PCB gives plenty of freedom for engineers and designers to add components as needed. This blank slate provides flexibility and makes the bare PCB boards viable for mass production instead of making them unique for each order. These PCB boards require more design work than other wiring methods, but the assembly and manufacturing tend to be automated afterward. The automation makes PCB boards the cheapest and most efficient option. It truly becomes useful when the necessary components are added to it. Becoming a circuit board is the bare PCB board’s end goal and can be extremely versatile if matched with the right components.If you want to order PCB product, please check and custom your order online. Why Use Bare Board Testing? There are a number of reasons why it’s essential to test the bare boards before adding any additional components. Being the circuit board framework, the PCB board failing after installation can lead to many problems. While not common, the bare PCB board can already be defective before any components are added. The main issues that pop up are over-etchings, under-etchings, and holes. Even a minor flaw can result in a complete failure. The increasing demand for multi-layered PCB boards due to their increased component density is another reason to use bare board testing. Once a PCB has been put together into multiple layers, it becomes almost impossible to make repairs in case of failure. If the PCB board is the circuit board’s skeleton, then the components are the organs and muscles. Components can get expensive and are oftentimes delicate, so having a solid framework can prevent wasting high-end components in the long run. What are types of bard board testing? How do I know if my PCB is bad? You’ll need to test it in two different ways: electrical and resistance. Bare board testing considers both the isolation and continuity of the electrical connections. Isolation testing measures connections between two separate connections, while continuity testing checks to make sure there are no open points that could mess with the electrical current. The most commonly used is the electrical test, while the resistance test isn’t as common. Some companies use a combination of both instead of sticking with one over the other. The resistance test sends an electric current through the conductor to measure the resistance to the flow. Longer or thinner connections results in much more resistance than shorter or thicker ones. Large Manufacturer TestingA printed circuit board manufacturer will likely use the pinned fixture test, otherwise known as the “bed of nails.” This test uses spring-loaded pins to test every connective surface on the PCB board at once. The pinned fixture test is extremely efficient and only takes a handful of seconds to finish. The main downsides are the high expenses and the lack of flexibility. If a different PCB design is required, a whole new fixture and an array of pins are required. Small Manufacturer TestingWhat is bare PCB board testing like for smaller companies? They typically use the flying probe test. Two robotic arms with poles use a software program to test the board’s connections. It takes much longer to complete but is more affordable and flexible than the pinned fixture test. Switching to a different design is as simple as uploading new software. What are benefits of bare board testing? There are numerous benefits to bare board testing and no real disadvantages to doing so. This small extra step in the manufacturing process can save much heartache further down the line. The slight investment early on can save thousands of dollars in repair and replacement costs. Bare board testing helps to identify issues early on in the manufacturing process. Finding the issue early on means that it’s far easier to find the problem’s source and fix the problem at its roots. Catching an issue late in the process makes it much harder to find the source. Once the PCB board is covered in components, there’s no telling what would be responsible for an issue. Early testing helps remove a big piece from the equation for troubleshooting. The testing also ends up streamlining the entire process. If issues are caught and fixed in the prototyping stage, then the later production phases can move on unhindered.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/22/2021 17:08
PCB gold finger
Gold Fingers are the gold plated narrow connectors found on the edge of printed circuit boards to enable connections between multiple boards. And they aim at connecting the secondary circuit board to the motherboard of a computer. Because the alloy has a great conductivity, gold is used in the connecting points along the board. They are made from flesh gold, the hardest form of gold available and work for a long time with superior conductivity. The thickness of gold fingers usually ranges from 3 to 50 microns. Gold is chosen for these fingers as it has the highest corrosion resistance and electrical conductivity after Copper and Silver. Sometimes, Gold is combined with Cobalt and Nickel to increase the resistance of the fingers for wear and tear. PCBs are connected/disconnected from each other multiple times. So these connection points (fingers) need to be able to handle some wear and tear. In this passage, we will provide the knowledge of the gold finger in PCB manufacturing process. Please check the content below for more.If you want to order PCB product, please check and custom your order online. What is gold finger? Gold fingers are the gold-plated columns that you see along the connecting edges of printed circuit boards (PCBs). The purpose of gold fingers is to connect a secondary PCB to the motherboard of a computer. PCB gold fingers are also used in various other devices that communicate via digital signals, such as smartphones and smartwatches. Gold is used for the connecting points along a PCB because of the alloy’s superior conductivity. There are two types of gold applicable to the PCB gold finger plating process: Electroless Nickel Immersion Gold (ENIG): This gold is more cost-effective and easier to solder than electroplated gold, but its soft, thin (typically 2-5u” composition renders ENIG unsuitable for the abrasive effects of circuit board insertion and removal. Electroplated Hard gold: This gold is solid (hard) and thick (typically 30u”), thus more ideal for the abrasive effects of constant PCB usage. Gold fingers make it possible for different circuit boards to communicate with one another. From the power source to the device or equipment, signals must pass between several contacts for a given command to be enacted. Once you press a command, the signal will pass between one or more circuit boards before it is read. For example, if you press a remote command on a mobile device, the signal will be sent from the PCB-enabled device in your hand to the near or distant machine, which in turn receives the signal with its own circuit board. The process involved in the plating of gold fingers involves a number of meticulous steps. This ensures each circuit board rolling off the production line is properly equipped to conduct signals free of error. The standards involved in the plating process also helps to ensure a perfect fit between the gold fingers on each circuit board with the corresponding slots on a given motherboard. To ensure that all of these fingers and slots fit hand-in-glove, each PCB must pass a series of inspections and defect tests. If the gold plating on a circuit board lacks smoothness or does not adequately adhere to the surface, the results will not be sufficient for commercial release. For PCB gold fingers to come together, the plating process must be carried out in steps where the surrounding details of the board are completed first. When the time comes to plate the fingers, nickel is applied over the copper. Then, the surface finish is applied last. Once everything has set, the board is inspected under a magnifying lens and subjected to adhesion tests. How are gold fingers applied? Gold fingers can be used for many various things. And they use depending on the designer’s purpose. There are some common applications of gold fingers as the follows: 1. Provide an interconnection point for transferring network data;2. Connect external components to the PCB prototype; 3. A place for attaching specialized adapters or daughter boards;4. Serve as an audio adapter What are the specifications of gold finger? There are some standards you need to follow for the gold fingers so that it can work correctly during the plating process of gold finger. As well as the PCB design need to take into account the areas where is necessary to proper finger length and alignment. The rules can be used for the gold finger design as the follows no matter what the size or the purpose of the circuit board: 1. Plated through hole should far away from the gold fingers;2. There should be kept at a distance between gold fingers and solder mask or screen printing;3. Gold fingers should always keep the opposite direction from the middle of the board. Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/21/2021 17:25
PCB, also known as etched wiring board, is a structure used to connect and support electronic components through conductive pathways. These pathways are etched from copper sheets that are laminated into a substrate that does not conduct the signal. Understanding the different types of laminate for a printed circuit board is crucial for the design and development process your PCB manufacturer will go through. The type of laminate you choose will determine the stability and overall performance of your PCB. The laminate of the PCB is what holds the layers together. Traditionally, there are four layers that make up the board: Substrate, Copper, Soldermask, and Silkscreen (from bottom to top). The laminates are developed by curing under pressure and temperatures of cloth using thermoset resin to create the final piece of uniform thickness. When you see a type of laminate written out, it typically will look like this: FR-4 (with FR-4 being the most common material used). These numbers and letters are the characteristics of the laminate produced. Some of the important characteristics include: fire retardant, dielectric constant, loss factor, tensile strength, shear strength, glass transition temperature, and how much thickness changes with temperature (the Z-axis expansion coefficient).If you want to order PCB product, please check and custom your order online. What are the types of PCB laminate? The following list is comprised of the different types of PCB laminates and the PCB materials needed, starting with the most common ones. The designation of a laminate comes from the resin used. FR-4What makes FR-4 the most commonly used laminate is how it performs across all characteristics. This material has a good strength-to-weight ratio, is flame resistant, which improves its reliability, and when there is an increased temperature, the material’s mechanical, electrical, and physical properties stay maintained. High-Performance FR-4You would use a high-performance FR-4 laminate when dealing with multi-layered PCBs. It has a high-reliability level due to the increased TG and is more suitable for high-frequency circuits because of its low dielectric properties. High Tg EpoxyFor multilayer PCBs, the High Tg Epoxy is most suitable. The Tg is the vitrification temperature, similar to the melting point. The higher the number, the more rigid the board will be. A material with a high TG (over 170o C) has better heat, moisture, and chemical resistance, as well as better stability. BT EpoxyMost suitable for lead-free PCBs, the BT Epoxy laminate is known for having outstanding thermal, mechanical, and electrical properties. This laminate is commonly used for multilayer PCBs. It will also maintain bond strength at high temperatures. PolyimideThis type of laminate produces extreme environmental stability. You would use the Polyimide laminate when working with high-density, flexible, rigid-flex circuit boards, and multilayer PCBs. It also produces high levels of thermal, chemical, and mechanical properties. A polyimide laminate is ideal for advanced applications, including military, aerospace, automotive, and consumer electronics. Copper Clad (CCL)The Copper Clad laminate is made up of a glass fiber or wood pulp paper as the reinforcing material. You would typically use a CCL laminate for high-voltage circuits based on specific aspects, including appearance, size, electrical, physical, chemical, and environmental performance. TeflonThe most commonly used material in high frequency applications. Teflon materials come in many different options, the easier materials to use in manufacturing are teflons with woven glass. There are several challenges with manufacturing teflon PCBs that causes issues with a conventional board shop. What factors need to be considered during PCB laminates? Now that you know the commonly used PCB laminates. Among the aforementioned types, which one should to choose to assemble the PCB? There are several factors to consider. A few of them include: Dielectric constantLoss factorThermal conductivityTransition temperatureCoefficient of thermal expansion (CTE)Electrical performanceAbility to operate in varying thermal environmentsWanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/20/2021 17:37
PCB layering, or stackups, is simply a way to get multiple printed circuit boards in the same device by stacking them on top of each other while making sure there is a predefined mutual connection among them. These multilayer PCBs, which can multiply speed and functionality in a device, consists of at least three conductive layers, with the bottom layer synthesized with the insulation board. While PCB stacking can confer a lot of advantages, including a reduction in impedance mismatch and signal cross-talk problems, there are also challenges that come with a printed circuit board layer stack. In this passage, we will talking about all about PCB stackup, please check the content below for more details. If you want to order PCB product, please check and custom your order online.What is purpose of PCB stackups? A PCB stackup refers to the arrangement of copper and insulating layers that make up a PCB. These layers are arranged in a way to get multiple printed circuit boards on the same device. At their most basic, multilayer PCBs consist of at least three conductive layers. The bottom layer is synthesized with the insulation board, and each circuit board layer is connected to the next. While PCB layering creates a more complex and space-saving board, PCB stackups also offer the following advantages: Maximize functionality: Multilayer PCBs can multiply the speed and functionality in the device, making for a more functional board. Minimize vulnerability: Layer stacks can help protect internal layers from external noise, making it less vulnerable to damaging exterior forces. Reduce radiation: Well-designed PCB layer stacks can help you minimize radiation from your device, especially in high-speed layouts. It is important to note, however, that poor designs with impedance mismatches can easily result in greater EMI radiation than a normal PCB. Decrease costs: Good layer PCB stack-ups can also help achieve lower-cost manufacturing by placing multiple circuits onto a single board. One board means streamlined manufacturing for the board, the part the board will be used in and the packaging for the complete setup.On top of these benefits, PCB stackups also reduce impedance mismatch and signal cross-talk problems. All these advantages make it highly desirable to make PCB stackups. What are common types of PCB stackups? Each type of board is described in more detail below, along with the conditions under which they are often used. Each type of board is described in more detail below, along with the conditions under which they are often used. 2-LayerOften called double-sided PCBs, 2-layer PCBs are probably the most common types of multilayer PCBs as they can accommodate interconnects on both sides. These PCBs consist of three material layers, two of which are functional: Signal layer: This top layer consists of copper with an approximate thickness of 0.0014 (1 oz.) inches to 0.0021 inches (2 oz.).Laminate core: The laminate core separates the top and bottom copper layers, keeping them isolated. Vias create connections between the sides of the board.Bottom layer: This second layer of copper is similar to the signal layer with an approximate thickness of 0.0014 inches (1 oz.) to 0.0021 inches (2 oz.).These PCBs are inexpensive and relatively easy to produce, which is why they are often favored over the more expensive 4-, 6-, 8-, and 10-layer and up designs. They are also highly functional as there are no propagation delays, and they tend to have fewer potential design issues compared to other stackup options. 4-LayerIn terms of PCB stackups, 4-layer PCBs are the second most common option in multilayer boards. These PCBs have four layers to route electrical signals. These layers are sandwiched together, with a top and bottom layer on the outside and two inner layers contained between them. The top and bottom layers are where components and routing are placed. The inner layers, however, cannot make outside connections, so they are often used as power planes or for signal routing, which helps enhance the quality of trace signals and reduces EMI emissions. It is not recommended to make the inner layers signal layers — if you need four signal layers, it is recommended to look into a 6-layer board. While more expensive to prototype and produce than 2-layer PCBs, 4-layer PCBs provide greater functionality overall. With thoughtful design, they can also provide excellent signal integrity and EMC capabilities. 6-LayerA 6-layer PCB is functionally a 4-layer PCB with two additional signal layers. In total, 6-layer stackups include four routing layers — two internal and two outer — and two internal planes for grounding and power. The design described above is the most common, as it balances high-speed signaling with EMI control. The design achieves this by running high-speed signals through the two buried layers while running low-speed signals through the surface layers. However, this design isn’t effective for all applications. High-speed designs, for example, keep ground and power planes next to each other. Designs made for low EMI emissions, on the other hand, have extra ground planes to help with shielding. If you are wondering what design variation will best work for your application, always work closely with your PCB designer and supplier to determine the best options. 8-LayerThe 8-layer PCB stackup offers even more options than the 6-layer board by adding two more layers for either routing or performance. It is also the first board listed that can achieve all five objectives for multilayer PCB design.Typical 8-layer PCB stackups feature the power and ground layers in the center, offering good capacitance between layers as well as a separation between the second and third signal planes to protect signal integrity. Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/20/2021 17:30
Rigid PCB, as a kind of PCB, is the largest number in PCB manufacturing process. It is made of solid substrate material, which can effectively prevent the distortion of the circuit board. Rigid circuit boards are very popular largely due to their low cost. In conventional electronics, and particularly in consumer electronics, with greater space availability, manufacturers can save significantly by using rigid circuit boards. Perhaps the most common rigid PCB is the computer motherboard. The motherboard is a multi-layer PCB designed to distribute power from the power supply while allowing communication between all components of the computer, such as CPU, GPU, and RAM. Rigid PCB can be used in any position where the PCB itself needs to be set to a shape and maintained during the remaining life of the equipment. Rigid PCBs can be anything from simple single-layer PCBs to eight or ten-layer multi-layer PCBs. In this passage, we will talk about the knowledge of rigid PCB and please check the content below for more information.If you want to order PCB product, please check and custom your order online.How is rigid PCB manufactured? Rigid PCB is made up of different layers that are joined together using adhesive and heat, providing a solid shape to board material. Following layers are used to develop a rigid PCB. Substrate Layer - rigid PCB materialSubstrate layer, also referred base material, is made of fiber glass. The FR4 is mostly used as a substrate material which a most common fiber glass that provides rigidity and stiffness to the board. Phenilcs and epoxies are also used as a base material but they are not as good as FR4, however, they are less expensive and feature unique bad smell. Decomposition temperature of phenolics is too low that results in delamination of the layer if solder is placed for long duration of time. Copper LayerOn the top of substrate layer, there resides a copper foil which is laminated on the board with the help of added amount heat and adhesive. In common use, both sides of the board are laminated with copper, however, some cheap electronics come with only one layer of copper material on the board. Different boards come with different thickness which is described in ounces per square foot. Solder Mask LayerSolder Mask Layer houses above the copper layer. This layer is added on the board to add insulation on the copper layer in order to avoid any damage in case any conduction material is touched with the copper layer. Silkscreen LayerSilkscreen layer is located above solder mask layer. It is used to add characters or symbol on the board that provide better understanding of the board. White color is mostly used for silkscreen but other colors are also available including grey, red black and yellow. What are factors that affect the cost of rigid PCB? There are three main factors that impact the cost of rigid-flex PCB: Materials: The raw materials used to manufacture rigid-flex PCBs tend to cost more than traditional PCB materials. While these boards use common materials such as copper foil, they also incorporate no flow prepregs, flexible copper-clad laminates and thicker polyimide films.Assembly: Because there are separate components and complex steps required, the assembly process costs more.Manufacturing yield: To manufacture rigid-flex boards, specialized equipment and software tools are needed, which impacts the final cost. How to reduce the cost of rigid PCB? There are various ways to lower the cost of your rigid-flex PCB, including:Minimize the amount of circuit layersChoose materials carefullyReduce the thickness of the materialsSimplify the configurationTailor the design processWanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/19/2021 18:05
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