The rapid development of the printed circuit PCB influences the LED industry. Some LEDs were soldered on PCB to created lighting electronic products. As we all know that LED will generate more heat compared with other electronic parts, which required the PCB to have a better ability for dissipating heat. For these special requirements, metal core PCB is frequently used on LED PCB, especially aluminum core PCB. This is because the aluminum PCB typically includes a thin layer of thermally conductive dielectric material that can transfer and dissipate the heat with much greater efficiency than a traditional rigid PCB. Now SMD packaging type is the most widely used packaging form in LED applications. In general, it’s limited for the light emitted from a single LED component. Multiple LED components would be used for single light fixture to make sufficient light. Like other semiconductor devices, PCB is the best method to electrically connect the LED components. And a PCB with LED components soldered is usually called as “LED PCB”. To help you understand why the LED lighting industry uses PCBs, we’ve outlined the nature of PCB base layers, the attractive qualities of aluminum PCBs and why they work well in the LED lighting industry.If you want to order PCB product, please check and custom your order online. What are the advantages of LED PCB? When it comes to the advantages of using LED PCB, well there are plenty of them and we are now going to mention a few so that you know about the application too. ．Light in Weight．No Dimension Issues．Efficient Low Power Consumption．Available In Different Sizes．Heat Dissipation Performance．Dust and Moisture resistant．May be used in silver flex membrane switches and copper flex membrane switches. How PCB influences LED industry? For many companies within the LED industry, aluminum PCBs are the new standard. This is because of the numerous benefits and features aluminum PCBs contain. Some of these benefits include the following: Less ExpensiveYou can find aluminum in mines across the world, making it easy to access and refine, especially compared to other metals. This abundance means aluminum is much less expensive than other rarer metals. As a result, manufacturing with aluminum is also less expensive, especially when it comes to aluminum PCBs. Aluminum-based circuit boards are also inexpensive when compared to other methods of heat transfer, such as heat sinks. While heat sinks may be slightly more effective at transferring heat than aluminum bases, they are much more expensive to add on to the PCB. Environmentally FriendlyMost of us know that aluminum soda cans are recyclable, and aluminum boards are no different. Aluminum PCBs are recyclable and non-toxic, which means disposing of them is relatively easy and environmentally sound. Improved DurabilityCompared to ceramic and fiberglass, aluminum is much sturdier. This strong, durable material is much more resistant to breakage, and can better handle the stresses of the manufacturing process. This also means that the end PCB is much more resistant to damage from everyday handling, especially in impact-prone environments. LightweightDespite how durable it is, aluminum is very lightweight. This means a PCB can have improved resilience without additional weight, an important factor in manufacturing. Not only this result in a lighter end product, but it makes shipping and handling of the circuit boards and end products much cheaper and easier to handle in large quantities. Better Heat TransferIn electronics, consistently high temperatures can cause serious damage, negatively affecting functionality. This makes heat transference one of the most important parts of a finished PCB. Heat transference is a term referring to how well thermal energy moves from one place to another. How effectively a material does his depends on the materials conduction, convection and radiation. Conduction refers to how easily a material will transfer thermal energy from one area to another, while convection is the transfer of thermal energy from a material to a fluid and radiation refers to the amount of thermal energy a material gives off. Aluminum has some of the best qualities for heat transfer, because it conducts thermal energy fairly easily, transferring it away from critical parts and minimizing thermal damage to the PCB. Comparatively, fiberglass is much less conductive. This difference results in PCB boards that are much more efficient at thermal energy transfer — in fact, aluminum-backed designs can be up to more efficient than fiberglass-backed designs by up to 10 times! Because of these qualities, specifically the incredible ability to dissipate heat, aluminum PCBs have become the new PCBs of choice within the LED lighting industry. This growing popularity within the LED industry is due to a few incredible capabilities and improvements upon LED PCB designs made possible with aluminum PCBs. These include: Increased LED DensityEach PCB design allows for a greater number of LEDs to mount onto it. Each of these LEDs produces heat, heating up the PCB more quickly. This can be a serious problem for the longevity of the LED lights, because each LED must stay within a strict range of temperatures in order to function properly. Traditional fiberglass-based designs have a cap on the density of lights per board, purely because the board can get too hot. This is because fiberglass transfers heat relatively slowly, causing the heat to build up. With aluminum boards however, more LEDs can function simultaneously without exceeding the specified temperature tolerance. This is because in an aluminum-core PCB, heat transfers quickly and efficiently, due to the high thermal conductivity of the material. Longer Operating TimeAs with most electronics, the longer you use them, the hotter they get. This can negatively impact the functionality of the system and alter its operation, especially in more complex systems. In the case of LEDs, the quality and color of the lights change depending on how hot they get, and operating at a hotter temperature reduces the overall lifespan of the LED.With aluminum LED PCBs, the improved heat transferring qualities of the material results in the LEDs operating at a lower temperature for a longer amount of time. This means aluminum PCB LEDs can operate for much longer before they finally fail.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 06/03/2021 18:02
PCB impedance control
Impedance measures the opposition of an electric circuit when alternating current is applied to it. It is the combination of the capacitance and the induction of an electric circuit at high frequency. Impedance is measured in Ohms, similarly to resistance. However, the two values should not be confused as resistance is a characteristic of direct current. When a signal passes from a conductor with given impedance to another of an identical impedance, the transmission is optimum. On the other hand, if the impedances are different, reflections and attenuation occur that deteriorate the signal. Impedance control consists in measuring the impedance of certain traces when the PCB is manufactured and making sure they are within the limits given by the designer. Even though it is expensive, this technique became widespread after the turn of the century due to the continuously increasing frequencies of electronic components. It features in the following products, for example: -Analogue and digital telecommunications-Video signal processing-Web boxes, TV, GPS, video games, digital cameras-Computers, tablets, mobile phones-Motor control modulesIf you want to order PCB product, please check and custom your order online. Why control impedance on PCBs? When a signal needs a specific impedance to operate properly, controlled impedance should be preferred. In high frequency applications, keeping impedance constant on the complete electronic board is essential to protect the transferred data from damage and to maintain the clarity of the signal. The longer the trace or the higher the frequency, the more adaptation is needed. Any lack of rigor at this stage can increase the switching time for an electronic device or circuit and cause unexpected errors. Uncontrolled impedance is difficult to analyze once the components are mounted on the circuit. Components have different tolerance capacities depending on their batch. Furthermore, their specifications are impacted by temperature variations which can lead to malfunctions. In such cases, replacing the component may seem to be the solution at first when, as a matter of fact, it is the unsuitable trace impedance that is the cause of the problem. This is why trace impedances and their tolerances must be checked early on in the PCB design. Designers must work hand in hand with the manufacturer to guarantee the compliance of component values. What are the main forms of PCB transmission lines? What is microstrip? Microstrip is a type of electrical transmission line which can be fabricated using printed circuit board technology, and is used to convey microwave-frequency signals. It consists of a conducting strip separated from a ground plane by a dielectric layer known as the substrate. Microwave components such as antennas, couplers, filters, power dividers etc. can be formed from microstrip, with the entire device existing as the pattern of metallization on the substrate. Microstrip is thus much less expensive than traditional waveguide technology, as well as being far lighter and more compact. Microstrip was developed by ITT laboratories as a competitor to stripline (first published by Grieg and Engelmann in the December 1952 IRE proceedings). The disadvantages of microstrip compared with waveguide are the generally lower power handling capacity, and higher losses. Also, unlike waveguide, microstrip is not enclosed, and is therefore susceptible to cross-talk and unintentional radiation. For the lowest cost, microstrip devices may be built on an ordinary FR-4 (standard PCB) substrate. However it is often found that the dielectric losses in FR4 are too high at microwave frequencies, and that the dielectric constant is not sufficiently tightly controlled. For these reasons, an alumina substrate is commonly used. On a smaller scale, microstrip transmission lines are also built into monolithic microwave integrated circuits. Microstrip lines are also used in high-speed digital PCB designs, where signals need to be routed from one part of the assembly to another with minimal distortion, and avoiding high cross-talk and radiation. Microstrip is one of many forms of planar transmission line, others include stripline and coplanar waveguide, and it is possible to integrate all of these on the same substrate. A differential microstrip—a balanced signal pair of microstrip lines—is often used for high-speed signals such as DDR2 SDRAM clocks, USB Hi-Speed data lines, PCI Express data lines, LVDS data lines, etc., often all on the same PCB. Most PCB design tools support such differential pairs. What is stripline? Stripline is the earliest form of planar transmission line. A stripline circuit uses a flat strip of metal which is sandwiched between two parallel ground planes. The insulating material of the substrate forms a dielectric. The width of the strip, the thickness of the substrate and the relative permittivity of the substrate determine the characteristic impedance of the strip which is a transmission line. As shown in the diagram, the central conductor need not be equally spaced between the ground planes. In the general case, the dielectric material may be different above and below the central conductor. To prevent the propagation of unwanted modes, the two ground planes must be shorted together. This is commonly achieved by a row of vias running parallel to the strip on each side. Like coaxial cable, stripline is non-dispersive, and has no cutoff frequency. Good isolation between adjacent traces can be achieved more easily than with microstrip. Stripline provides for enhanced noise immunity against the propagation of radiated RF emissions, at the expense of slower propagation speeds when compared to microstrip lines. The effective permittivity of striplines equals the relative permittivity of the dielectric substrate because of wave propagation only in the substrate. Hence striplines have higher effective permittivity in comparison to microstrip lines, which in turn reduces wave propagation speed.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 06/03/2021 17:55
ENIG finish PCB
ENIG (Electroless Nickel Immersion Gold) is surface plating that is applied over the copper pads on a Printed Circuit Board to protect them from corrosion and other abnormalities. Initially, the copper pad is covered by a Nickel (Ni) layer followed by a thin immersion Gold (Au) layer. ENIG provides good oxidation resistance, excellent surface planarity and allows for easy soldering which results in excellent electrical performance of the PCB board. When the surface finish is processing, there are metal or organic material optional. The surface finish you choose for your PCB will have a significant impact on its quality and usefulness within its parent part. The finish prevents the PCB’s copper layer from oxidizing, which would otherwise decrease its solder ability. Applying a finish protects the board from oxidizing before the components are added, ensuring that you can solder the additional elements as needed. Because the PCB’s electrical connections rely on adequate copper conductivity, it’s essential to prevent oxidation and adhere the components as necessary. And among several types of surface finishing, we are going to talk about ENIG. Check the content we provide below for more information.If you want to order PCB product, please check and custom your order online. What is ENIG? Despite the higher pricing of ENIG surface finishing, it has a high success rate for producing high-quality products. It holds up under multiple thermal cycles, showcases great solderability and is a suitable option for wire bonding. As the name suggests, it consists of two coating layers — nickel and gold. The nickel protects the base copper layer and enables secure attachment of electrical components, while the gold serves as an anti-corrosion measure for the nickel. ENIG can be used in situations where tight tolerances are required for PCB elements like plated holes, as HASL is not as effective for this. Like OSP, it offers excellent flatness and is ideal for fine pitch devices. Applying the ENIG coating requires nickel to be deposited onto a copper surface catalyzed with palladium. The immersion gold stage causes the gold to adhere to the nickel by way of a molecular exchange. ENIG is similar to OSP in its inclusion of micro-etching and rinsing between each stage — the process includes these steps: -Cleaning.-Micro-etching.-Pre-dipping.-Applying the activator.-Post-dipping.-Applying the electroless nickel.-Applying the immersion gold.-Standard applications for an ENIG surface finish include: Complex surface components: Because of its flat surface, this finish type is a preferable choice for complex PCB components requiring smooth surfaces, like ball grid arrays (BGAs) or quad flat packages (QFPs). Wire bonding: ENIG finishes allow for minimal wire bonding for aluminum wires, although they are not compatible with gold. High reliability applications: You will often find ENIG surface finishes used for PCBs in industries such as aerospace, military, medical and high-end consumers. Its quality makes it suitable for applications where precision and durability are vital. What is ENIG black pad? There might not be any topic more controversial in the PCB industry than that of ENIG black pad. In simple terms, black pad refers to an inferior connection that occurs between the solder and nickel interface. While many professionals consider this phenomenon to be extremely rare — occurring by some estimates in less than one or two percent of ENIG PCBs — the fact that a black pad problem isn’t typically discovered until an assembly process commences makes it a costly error to discover and correct in the post-manufacture phase. Black pad is the result of the immersion gold and electroless nickel process. While it produces a highly solderable finish — ideal for applications where reliability and complex circuitry go hand-in-hand — the process can also create flawed joints that, when stressed, will break their connections. The resulting open circuits expose a layer of dark nickel that’s corroded — which gives this phenomenon its notable name “black pad.” According to recent research and industry reports, black pad is the result of an excessive level of phosphorous that’s a byproduct of the dissolution of nickel. Ultimately, as the result of consecutive reflow processes, a starting seven percent phosphorous level can easily climb to nine percent — or even higher. And the higher the level of phosphorous, the greater the risk of nickel corrosion is during the gold immersion/deposition process. What are the advantages of ENIG? -Flat surface, good for small SMD devices, -Reworking availability (>3 times reflow),-Excellent electrical conductivity, -Anti-oxidation & anti-rust,-Good heat dissipation,-Higher surface thicknessWanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 06/02/2021 17:45
A ground is a conducting body that acts as an arbitrary node of potential voltage and a common return for electric current. It is a point of zero reference or zero volts. The ground is the reference against which you base the signal. There are also special considerations when working in a mixed-signal analog and digital environment. Grounding can help to minimize noise when working with signals that have a wide dynamic range.If you want to order PCB product, please check and custom your order online. What are types of grounding? There are various types of nodes that get called grounds including floating grounds, virtual grounds and earth grounds. Floating grounds: These nodes are reference points in an isolated system and are not physically connected to the earth. Virtual grounds: These nodes can be found in a negative feedback circuit at the inverting terminal of an operational amplifier. When the non-inverting input is at zero volts, the feedback will make the inverting terminal match it in a stable circuit. The value is not a stable return for other circuits and is only held by feedback. AC grounds: These nodes have low-impedance DC values. This DC voltage is stable even when exposed to small disturbances. Because of its DC value, this node can’t be used as a proper ground, but because it is stable, it can be used as a reference point.Earth grounds: In a large electrical system, the earth’s ground is literally a connection to the ground. Every house, for example, has a copper pole that is stuck in the earth to deplete surplus currents. Chassis grounds: The electronics in a PCB cannot connect to the physical ground, but a chassis ground serves the same purpose. This ground is the connection of a safety wire from the AC mains to the product’s case or chassis. Because an earth ground and chassis ground serve the same function, these terms are often used interchangeably along with the term safety ground. When it comes to grounding a PCB, there is no one-size-fits-all approach. To determine the best way to ground a system, you need to understand the way the currents within it flow. There are, however, various methods to choose from and some tips for best grounding practices that apply across the majority of systems. To determine the approach that works for your board, you’ll need to ensure you understand the board’s design and may need to try several techniques. What are PCB grounding techniques? There are various techniques that one can use for grounding a PCB. The following are some of the most common approaches used today. 1. Ground PlaneOne common technique is to use a ground plane, which is a large piece of copper on a PCB. Typically, PCB manufacturers will cover all of the areas that don’t have a component or trace on them with the copper ground plane. In a two-layer board, the standard PCB ground plane rules indicate that the ground plane should be placed on the board’s bottom layer, while the components and signal traces are on the top layer. It is best to avoid creating a ring of conductive material formed by the ground plane, as this makes the ground plane more susceptible to electromagnetic interference (EMI). This conductive ring acts as an inductor, and an external magnetic field may cause an electric current called a ground loop. You may end up with a conductive ring if placing the ground plane over the whole bottom layer and then removing the parts that have electronic components. The ground plane is also often on both sides of the board. In some cases, the plane on the component side is kept at the supply voltage, and the plane on the other side of the board is grounded. The ground plane is connected to the ground pins of the components and connectors to keep the ground voltage at the same level through the whole PCB. 2. Ground Plane ViasIf there are ground planes on both sides of the PCB, they will be connected through vias at many different places on the board. These vias are holes that go through the board and connect the two sides to each other. They allow you to access the ground plane from anywhere you can fit in a via. Using vias can help you to avoid ground loops. They connect the components directly to the ground points, which connect through low impedance to all of the circuit’s other ground points. They also help to keep the length of return loops short. Pieces of copper, such as ground planes, may resonate at one-quarter of the wavelength of the frequency of the current which is flowing into it. Putting stitching vias around the ground plane at specific intervals can help to control this. 3. Connector GroundsAll of the connectors in a PCB should be connected to the ground. In connectors, all signal conducts must run in parallel. Because of this, you must separate connectors using ground pins. Each board will likely need more than one connector pin leading to the ground. Having just one pin may cause issues with impedance mismatch, which can cause oscillations. If the impedance of two connected conductors does not match, the current flowing between them may bounce back and forth. These oscillations can alter the performance of the system and cause it not to work as intended. The contact resistance of each pin of a connector is low but may rise over time. For this reason, it is ideal to use multiple ground pins. Connectors come in various pitches and can have different numbers of rows of pins. The pins of a connector may also be parallel to the PCB surface or at a right angle to it. 4. DecouplingPCBs contain one or more integrated circuit chips, which require power to operate. These chips have supply pins to connect them to an external power source. They also have ground pins, which connect them to the ground plane of the PCB. Between the supply and ground pins, there is a decoupling capacitor, which serves to smooth out oscillations in the voltage being supplied to the chip. The opposite end of the decoupling capacitor connects to the ground plane. One of the main reasons for the use of decoupling capacitors is related to functionality. A decoupling capacitor can act as a charge storage device. When the integrated circuit (IC) requires additional current, the decoupling capacitor can provide it through a low inductance path. Because of this, it is best to place decoupling capacitors close to the IC power pins. Another primary purpose is to reduce the noise put into the power and ground plane pairs and reduce EMI. Two main issues can cause this noise. One is a decoupling capacitor that does not provide adequate current resulting in the lowering of the voltage at the IC power pin temporarily. The other is an intentional current sent between the power and ground planes using a via with a fast-switching signal.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 06/01/2021 18:34
PCBs are the brains of all electronic devices. They are incredibly important to the functioning of society today. Everything from your Google Home to your computer to your key fob for your car has a circuit board. Because they are used in so many things, it is important that they comply with IPC standards. In this passage we will focus on the IPC PCB and if you are curious about our topic, please check the content below to get more information.If you want to order PCB product, please check and custom your order online. What is IPC standard? IPC is the trade association for the electronic interconnection industry. It provides industry standards for the assembly and protection of electronic equipment, as well as training, market research and public policy advocacy. IPC is a member-driven organization and has more than 3,000 member companies around the world. Its members include companies in all aspects of the global electronics industry, including designers, suppliers, board manufacturers, assembly companies and original equipment manufacturers. The organization got its start in 1957 as the Institute for Printed Circuits. It later changed its name to the Institute for Interconnecting and Packaging Electronic Circuits due to the expansion to packaging and electronic assemblies from bare boards. In 1999, it adopted the name IPC, with the tagline Association Connecting Electronics Industries. IPC has its headquarters in Bannockburn, Illinois, and has other offices around the United States and the world, including in India, China, Sweden and Russia. The American National Standards Institute (ANSI) has accredited IPC as a standard-developing organization. What are the IPC standards? They are the most widely recognized acceptability codes in the electronics industry. The organization publishes standards for nearly every phase of the electronic product development cycle, including design, purchasing, assembly, packaging and more. IPC currently has more than 300 active standards and more than 1,000 standards in its resource library. Electronic designers all around the world use these standards for everything from generic reference designs to more customized blueprints. Committees of volunteers from across the electronics industry draft, edit and vote on IPC standards. More than 3,000 industry professionals across the globe participate in this process. Committees can include people from around the world, as members can participate via in-person meetings, teleconference and email. The association provides validation services programs, including a standards gap analysis that helps organizations address manufacturing issues and determine what they need to do to reach compliance with standards. It maintains a qualified manufacturers list and qualified products to help you determine if a product complies with IPC standards. There are more than 110 IPC-licensed training centers around the world. The organization also offers online and multimedia education and training resources. It hosts educational events, as well as technical and management conferences, including IPC APEX EXPO, which is the largest electronics manufacturing industry exhibition in North America, and APEX South China. Additionally, the organization conducts market research and does work in government relations and environmental policy. IPC advocates for the electronics industry with regulators around the world. What is IPC PCB? Since IPC creates standards for the electrical and electronics industry, it also plays a crucial role in producing standards for PCBs. You can find IPC standards for PCB manufacturing at every stage of the PCB production process, including design and manufacturing. For example, at the beginning of a PCB’s creation, IPC plays a role in setting standards for file formats, PCB design software, design guides and electronic product documentation. These standards also affect the appropriate materials for PCB board assemblies, surface mount devices and surface finishes. Additionally, they play a role in testing and judging the acceptability of printed boards. IPC PCB standards also set requirements for soldering electrical and electronic work in PCBs. These soldering standards often relate to reflow and wave soldering, as well as solder splices. Companies also rely on them to see if their electrical and electronic assemblies are acceptable during manufacturing. IPC standards also cover cable and wire harness assemblies. Finally, they set acceptability standards for the manufacture, inspection and testing of electronic enclosures before the PCB is released as a final product. What Do IPC Classes Mean? IPC separates PCBs in electronics manufacturing into three different classes. These classes signal the quality of the PCB, with Class 1 being the lowest quality and Class 3 being the highest quality. Companies that produce electronics with PCBs should be aware of these different classes since they dictate the safety and performance specifications companies must meet in inspections and the quality standards that apply to the products. Learn more about how IPC defines the three classes of electronic products below: Class 1 – general electronic products: Class 1 products are for applications in which the primary requirement is the function of the completed IPC assembly. This class includes most typical everyday products and consumer electronics.Class 2 – dedicated service electronic products: Class 2 products must have high reliability and extended life. Uninterrupted service is preferable but not critical. The use environment of the product typically wouldn’t cause failures. Some examples of these products include microwaves and laptops.Class 3 – high-performance electronic products: Class 3 products must provide continued performance or performance on demand. There can be no equipment downtime, and the end-use environment may be exceptionally harsh. The equipment must function when required. This category includes critical systems such as life support systems. Class 3 PCBs are used in advanced medical equipment, clean technology and machine learning.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 06/01/2021 18:28
Anyone involved within the printed circuit board (PCB) industry understand that PCBs have copper finishes on their surface. If they are left unprotected then the copper will oxidize and deteriorate, making the circuit board unusable. The surface finish forms a critical interface between the component and the PCB. The finish has two essential functions, to protect the exposed copper circuitry and to provide a solderable surface when assembling (soldering) the components to the printed circuit board. Hot Air Solder Leveling (HASL) was once the tried and true method of deliver consistent assembly results. However, the ever-increasing circuit complexity and component density has stretched the capabilities of even horizontal solder levelling systems to their limits. As component pitches became finer and a need for a thin coating became greater, HASL represented a process limitation for PCB manufacturers. As an alternative to HASL, alternative coatings have been around for several years now, both electrolytic and immersion processes.If you want to order PCB product, please check and custom your order online. What is HASL? A HASL surface finish offers high-quality solderability and accommodates multiple thermal cycles while also being one of the more affordable options. It once served as the industry standard, although standards under the Restriction of Hazardous Substances (RoHS) have caused HASL to fall out of compliance. In turn, lead-free HASL has become the more acceptable option in terms of its environmental and health impacts. Although HASL has a long industry history and is well-known among engineers, lead-free HASL is safer to use and better fits the needs of directives like RoHS. HASL finishes are created by dipping the board into a tin and lead or tin and nickel solder and holding it there for some time. Once the PCB is removed, hot bursts of air called air knives remove the excess finish. HASL finishing allows for a large processing window, but various factors can affect its evenness and therefore its solderability. The angle of the air knives, the air pressure and the speed of the PCB board’s entry and removal from the solder all influence the finish’s quality. You’ll find HAL and lead-free HASL surface finishes used for applications such as: Electrical testing: HASL finishes provide automatic protection for the test pads and vias during electrical testing of the circuit boards.Hand soldering: HASL finishes are a suitable option for hand soldering processes, as the joints are easily formable.High-performance electronics: HASL is often a great choice for high-performance and high-reliability applications, like aerospace and military devices, because of its ability to form strong joints. What is the importance of HASL to PCB manufacturing? The surface finish you choose for your PCB will have a significant impact on its quality and usefulness within its parent part. The finish prevents the PCB’s copper layer from oxidizing, which would otherwise decrease its solderability. Applying a finish protects the board from oxidizing before the components are added, ensuring that you can solder the additional elements as needed. Because the PCB’s electrical connections rely on adequate copper conductivity, it’s essential to prevent oxidation and adhere the components as necessary. Selecting the appropriate finish will depend on various factors, such as the finishing process, the PCB’s design and the quality of the final result. Not all finish types are appropriate for every PCB. Below are a few characteristics to keep in mind when considering the different ones: 1. SolderabilityAvoiding soldering issues is essential to creating a PCB that will operate as intended. Smooth surfaces are necessary to ensure a connection that functions adequately within its given environment. Consider whether the surface finish can solder directly to the copper, such as in the case of immersion tin, or if it’s a layered technique, like ENIG. Good wire bonding is also crucial, considering that different metals require unique manufacturing techniques and behave differently even in the same environments. Wires may consist of materials like aluminum, gold and copper, with each surface finish type being compatible or incompatible with these elements. 2. Processing TimeThe processing window for a specific finish may be large or small — finishes like HASL have larger processing windows. How much time the process takes depends on how complex the assembly is. Some surface finishes, like OSP, have limited thermal cycles and can’t withstand numerous soldering processes. After a few cycles, it will disappear, and the PCB will lose its protection against oxidation. However, an OSP surface finish for a PCB can be reworked during fabrication. The same applies to immersion silver. ENIG is a more complex finishing process and takes longer to complete, which may make it better to use for PCB production lines that don’t need to output a large number of PCBs in a short time. 3. ReliabilityHow well will the chosen surface finish stand up to its environment? If your PCB will need to meet specific reliability requirements, you will want a finish that accommodates these. Although cost is only one component of the many other elements mentioned here, you should consider how high the cost of failure will be if the PCB’s finish doesn’t work as intended and fails to protect the surface. The IPC offers a set of standards under its TM-650 Test Methods Manual that details different ways to test PCBs for reliability and quality. These include techniques such as dimensional verification, chemical resistance, copper ductility and amount of signal loss. One test uses chemicals such as sulfuric acid and isopropanol to determine the effects these substances have on PCB dielectric materials. 4. CorrosionSome surface finishing types, like silver, can be more vulnerable to creep corrosion than others. This kind of corrosion can occur with essentially any type of finish you use, but it’s most common with immersion silver. As the corrosion of metal elements spreads along the PCB’s surface, it can cause short circuits due to interacting with neighboring features on the board. This issue has become more common as lead-free finishes have increased in widespread use, as lead was notably effective at providing resistance to corrosion. Creep corrosion is also more common in humid, sulfur-rich environments. Consider what kind of settings your PCBs will be exposed to before settling on any one surface finish. The environment may have a major hand in determining your products’ life cycles.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 06/01/2021 18:22
A PCB panel, also called a PCB array, is a single board consisting of multiple individual boards. Once assembled, the panel is then broken apart, or depanelized, into the individual PCBs during the breakout process. The benefit of the printed circuit board panelization process is a decrease in defects as automated assembly machines tend to encounter fewer problems during the assembly process. In addition, panelization also reduces cost by improving throughput. Successful PCB panelization requires multiple design specifications to work properly, including considerations surrounding panelization methods. In this passage, we’ll detail these panelization methods and their specific requirements more thoroughly.If you want to order PCB product, please check and custom your order online. What are the methods of PCB panelization? Multiple panelization methods exist, each with its own drawbacks and benefits. The design of the boards on the panel and the panel itself will often play a large role in which panelization method best suits the application. The most notable of these factors include: Design: The design of the board plays the largest part in determining the most appropriate panelization method. The amount of clearance between components and the edge of the board may make certain methods much less suitable than others, as does the presence of edge-hanging components. Components: The types of components used on the board are just as important as their placement. Particularly sensitive components and connectors may play a factor in the most appropriate breakout and panelization method. Materials: The materials used in a PCB may limit which type of panelization method is most appropriate, as some materials are more prone to splintering during the breakout process. Board thickness is also a factor, as particularly thin boards may be more likely to break during assembly, and thick boards may prove more problematic during the breakout process. These factors limit the choices available to any one application. In fact, many assembly companies may use a combination of methods on any one project to ensure the structural integrity of the array while still mitigating issues during the breakout process. There are three panelization techniques in use today, though only two are commonly practiced. They are: What is V-Score panelization? This common method of panelization separates individual PCBs with V-shaped grooves. These grooves remove approximately a third of the board’s thickness from the top and bottom of the board with an angled blade. A machine is commonly used to finish the breakout process, considering the remaining third of the board between the grooves is surprisingly strong, and hand-breaking can put stress on the PCB and surrounding components. What is tab routing panelization? PCB arrays that can’t feasibly use a V-groove method will instead use a tab routing method. With this method, PCBs are pre-cut from the array and held in place on the board with perforated tabs. Three to five holes are often used in these perforation patterns. This method is often beneficial for its ability to support designs with edge-hanging components. It can also be broken by hand instead of with tools. What is solid tab panelization? Arrays can be designed with solid tabs between each board, improving overall strength. However, the depaneling method for this type of panel requires either a depaneling router, a laser-cutting machine or a hook-shaped blade tool. The router can result in dust and vibration, while the laser-cutter is extremely expensive and ineffective on boards over 1mm thick. The hook-bladed option is less expensive but inefficient and prone to blade rotation. This method tends to be less common than the other two. V-Score and Tab Routing are the preferred panelization methods for most applications. The most important thing for PCB designers understands which of the two methods is best for their application. The next step is to design their array for maximal strength and breakout success. Many prefer the V-groove panelization method when possible for its efficiency and reduction in surface stress. Depaneling machines for this type of array are also relatively inexpensive and cost-efficient. Even better, they’re portable and require minimal maintenance. Though the method tends to result in rougher board edges, this is rarely a concern for applications where V-groove panelization is used. However, while V-groove panelization is preferable for various applications, it is rather restrictive in terms of panel design. For example, V-groove panelization is not ideal for designs where components are placed too close to or hang over an edge. They also introduce various manufacturing concerns that must be considered during the design process, such as: Clearance: To ensure components are not affected during the cutting process, a clearance of 0.05 inches must be maintained between components and any V-grooves. Taller components may need to be placed further away to ensure the cutter doesn’t interfere with them. For example, surface-mounted multilayer ceramic chip capacitors must be kept at least 1/8 inches away from the score line. Components with larger connection areas should also be placed further away from the groove, as the stress of depanelization can fracture solder joints if they’re placed too close to the V-groove. Jump-Scoring: V-grooves can reduce the structural integrity of a PCB array, causing the leading and trailing edges to sag when run through a wave-solder machine. This can cause the array to warp or get caught in the wave-solder machine. To strengthen an array and prevent these issues, designers can add jump scoring to the leading and trailing edges of the array. This can be accomplished by including a ½ inch breakaway edge on the leading and trailing array edges and running the V-groove approximately halfway through these edges. Just instruct depaneling operators to remove these breakaway edges before separating the boards.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/28/2021 17:41
Packing a PCB is more than just a decorative affair. Although PCBs appear as hulking slabs of copper and fiberglass, they are deceptively delicate. They cry out for protection. During shipping, packages can be subjected to all manner of crushing, shaking, tossing and dropping among many other forms of physical damage. Damage is not always visible to the naked eye but can be just as fatal. If you’ve also arranged for your PCBs to be populated for you, your package will be extra vulnerable to electrostatic damage or moisture penetration. As the last step of manufacturing, we will lead you to learn the details about PCB package.If you want to order PCB product, please check and custom your order online. What is anti-static packaging? Electrostatic discharge (ESD) is the rapid transfer of electrostatic charge between bodies of different electrical potential when they come into contact with each other. ESD is one of the major causes of component failure. Although some components are robust enough to resist damage from ESD, parts like integrated circuits and semiconductors can be permanently damaged from just a small jump in current. With the size of integrated circuits getting smaller, this means that devices have become more susceptible to damage by ESD. Examples of components sensitive to ESD include MOSFETs, as they have a very high impedance, which makes charge dissipation more difficult. And even if components do not fail immediately, ESD can gradually cripple the functionality of devices down the road. Thus, if you have components highly sensitive to ESD, it’s reassuring to know that the packaging isn’t doing any harm. In addition, electrostatic adsorption of dust will reduce the insulation resistance of the component (shorten the life). The heat generated by the electrostatic discharge electric field or current can damage the component . One of the most basic means of protection against ESD during shipping is the use of anti-static bubble wrap. Besides acting as a cushion against all the tossing involved in the shipping process, unlike regular bubble wrap, it will not generate electrostatic charge and helps dissipate it away. The anti-static bubble wrap is recognizable from its distinctive pink color, due to the anti-static coating applied. ESD bags or pink poly are anti-static bags used for storing electronic components prone to ESD damage, much like anti-static bubble wrap. Made of polyethylene, it doesn’t generate ESD and can contain a layer of bubble wrap for extra cushioning against physical shock. Pink foam is also widely used for the same purpose. Another type and more superior form of ESD protection is the use of conductive anti-static bags. You can tell these from regular anti-static bags, or dissipative anti-static bags, as they have a shiny metallic layer often with a Ziploc style seal. These do well for long term storage, shipping and handling since they actively shield against charges. Hence they are also known as shielding bags. Therefore, the contents are effectively protected from any external charges and are vital in protecting bare components like MOSFETs. What is moisture-proof packaging? Moisture in the air can damage the electronic components on the PCB in many ways. For example, a small water spot accidentally traverses the trace on the circuit board and may cause a short circuit. Or electronic equipment may corrode the traces on the circuit board due to moisture. When used in outdoor applications, one of the most common causes of PCB degradation is due to moisture. In the field, your board will likely be enclosed in a suitable waterproof housing, but even before they are installed, the boards could be exposed to moisture during shipment. Even bare PCB boards can be adversely affected by moisture. If your PCBs are going to be traveling long periods at via sea freight, or through areas with a humid climate, pay attention to the moisture-proof properties of the packaging. Your boards should be in a sealed moisture barrier bag, with a little bag of desiccant. Desiccant is a drying agent packed in a porous pouch, to enable moisture to go through the pouch and be absorbed by the desiccant. The purpose of the desiccant is to absorb any moisture from the air left inside the bag after it has been sealed, and also any moisture that penetrates the bag. The desiccant remains dry even after it is fully saturated with water vapor. What is anti-vibration packaging? Due to the possibility of rigorous handling during shipment, PCBs can be subjected to shock or flex damage if insufficient anti-vibration packaging is used. This can lead to shock or flexing of a PCB. To prevent that from happening, sufficient padding should be used to limit movement within the outer packaging and protect vulnerable areas such as exposed pins.packaging technology can be subdivided into the following categories:1. Compressed packagingPack fragile items with elastic materials for reinforcement, so that the energy from vibration or impact can be absorbed and guided to the strongest part of the contents. When the elastic material is shock-proof, it can effectively absorb energy, disperse external force, and effectively protect the contents. 2. Floating packagingIt is basically the same as the compression packaging method. The difference is that the elastic material used is a small pad, which can be displaced and flowed, so that it can effectively fill the gap of the directly stressed part and disperse the impact of the contents. 3. Wrap packageVarious types of sheets are used to wrap a single piece of content into the outer packing box. This method is mostly used for shockproof packaging of small items. 4. Mold box packagingThe system uses the model to make the material into a mold box with the same shape as the product, and uses it to package the product to achieve the shockproof effect. This method is mostly used in the packaging of small, lightweight products. 5. In-situ foam packagingFill the foam material between the contents and the outer packing box.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/28/2021 17:34
There are many components in kinds of electronic equipments these days. Rather than using traditional components with wire leads like those that may be used for home construction and kits, these components are mounted onto the surface of the boards and many are minute in size. This technology is known as Surface Mount Technology, SMT and SMT components. Virtually all today's equipment that is manufactured commercially uses surface mount technology, SMT, because it offers significant advantages during PCB manufacture, and in view of the size the use of SMT components enables far more electronics to be packed into a much smaller space. In addition to the size, surface mount technology allows automated PCB assembly and soldering to be used, and this brings significant improvements in reliability as well as enormous savings in cost.If you want to order PCB product, please check and custom your order online.What are the advantages of SMT? More Compact Devices and Increased Design FlexibilityOne of the most significant benefits of surface-mount technology is how it supports more compact devices and increases design flexibility. This is because the higher density of the board allows the PCB to take up less space while still providing the same capabilities as a traditional printed circuit board. As electronic devices get smaller, and the demand for these smaller devices increases, PCBs must also get smaller — surface-mount technology enables this. Manufacturers, designers, and engineers need to keep up with these trends. Implementing SMT methods to your printed circuit board manufacturing process will lead to more flexibility in design and lighter products. Creating a more lightweight product can expand the possibilities for innovation, reduce shipping costs, and limit the amount of power required to charge and use the device. Easier AssemblyWith surface-mount technology, you eliminate an entire step in the manufacturing and assembly process. Since you don’t have to connect through-holes by utilizing SMT, the assembly process will be quicker — boards become easier to design, assembly by the manufacturer goes faster, and products get to market quicker. An easy and efficient assembly process alleviates the number of potential mistakes in producing printed circuit boards. Lower CostsIt’s not rocket science — when printed circuit boards are smaller, and assembly is easier, costs will be reduced, especially if you partner with the right electronics manufacturer. With SMT, there are fewer materials to be used, fewer steps in the assembly process, and a better chance to design the next hot electronic device. What are the disadvantages of SMT? While the benefits of surface-mount technology are profound, there are also disadvantages to note. First off, the smaller boards and limited lead space make repairs on products created with surface-mount technology difficult. Printed circuit boards can be as little as 0.2” x 0.2”, leaving no room for tools to get close and make repairs. Having the ability to repair boards and components is important because, without this ability, you’ll likely have to remanufacture, which is costly. Another common disadvantage to note of surface-mount technology is that this method cannot be used on electronics that have components that produce high amounts of electric heat. This is because the component’s heating can melt the solder, making the printed circuit board useless. However, the benefits of SMT strongly outweigh the disadvantages in most instances. Conclusion Before deciding whether to adopt surface-mount technology for your printed circuit boards, it’s important to first determine the requirements needed to produce an end-product successfully. Once you have determined your needs, design a prototype for testing purposes before beginning mass production. Utilizing SMT will enable you to create smaller devices and simpler designs with quicker assembly and lower costs. Consider implementing this method in your PCB manufacturing process to get a step ahead of the competition.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/27/2021 17:46
There are several factors will influence the manufacturing process, performance and quality. And among all the factors, temperature as a very important element, affects the safety, reliability and performance of PCB. High temperatures can quickly lead to malfunctions and permanent damage. The physical shape of a PCB is made up of traces, holes, layers, through holes, and solders masks. Each of these things can be affected by PCB temperature. A snowball effect of problems can occur if PCB temperatures rise linearly. If unchecked, this will negatively affect the performance of the PCB. In this passage we will focus on the topic – all about the PCB temperature, and if you are going to get into the knowledge of it, please follow us and read the content below.If you want to order PCB product, please check and custom your order online. What are common causes of PCB’s high heat? There are several causes that lead to the high heat of PCB: 1. Component Malfunction Causing DissipationOne common cause of high heat in a PCB is that one component within the PCB malfunctions and dissipates, failing to generate the amount of power it typically produces. When this happens, the surrounding components have to generate more power to compensate. Generating more power leads to the risk of overheating. 2. Through-Hole InterferenceThrough-hole components and heat-sink components are the components of the PCB that supply power. They generate heat and dissipate it into the air. If a heat sink is soldered incorrectly, or if a different component of the PCB is interfering with the through-hole, the other components will generate more heat than usual to compensate. This scenario also leads to a risk of overheating. 3. Surface-Mount Device DistanceSurface-mount devices (SMDs) connect to the PCB in the same way through-hole components do. They allow for a smoother flow of current through the through-hole and heat-sink components. But the through-hole components and the SMDs must be positioned at the correct distance from one another. If they are too far away, the current will have farther to travel. The extra time it takes the current to travel can cause the receiving components stay cool for too long. When that happens, other components may overheat to compensate. 4. High-Frequency CircuitsHigh temperatures are particularly likely in applications that make use of high-frequency circuits. The reason is that the generation of more power naturally produces more heat. Radio-frequency circuits, for example, represent a fast-growing sector in PCB engineering. These circuits are highly complex but have many useful applications, from wireless security in medical and industrial products to smart phones. These high-frequency circuits tend to generate tremendous amounts of heat, so special design techniques are necessary for these types of PCBs. 5. Lead-Free SolderAs a whole, the PCB industry is moving toward the restriction of hazardous substances (RoHS). RoHS PCBs use lead-free solder, and lead-free solder requires high temperatures so it can flow freely. How to prevent high temperature of PCB? 1. Heat SinksA PCB is basically a heat-generating factory because of all the heat-producing components it contains. The PCB needs some way to dissipate all that thermal energy. Generally, the answer involves heat sinks. Heat sinks dissipate the heat safely so it will not build up and damage the board. 2. FansMost electronic devices contain fans for cooling, and part of the purpose of those fans is to help cool PCBs. Cooling fans disperse heat out of electronic devices while letting cool air in, helping to prevent overheating and extend the PCB’s lifespan and performance. 3. Considering Materials and ComponentsChoosing heat-resistant materials is one of the most effective strategies for reducing heat in a PCB. For example, heavy copper PCBs constructed with thick copper plates make excellent choices for their durability and ability to withstand high temperatures. They handle higher levels of currents, resist higher temperatures for longer amounts of time and provide for stronger connection points than standard PCBs. For these reasons, they are particularly useful in automotive, aviation, heavy machinery and power converter applications and other heavy-duty environments. Many PCBs contain FR-4, which, though it is useful as a flame retardant, cannot tolerate extremely high temperatures. Knowing that a PCB contains FR-4 in its construction can allow engineers to design circuits that will not generate more heat than the material can withstand. Materials such as RF materials — used in radio-frequency circuits — and polyamide are also sensitive to high temperatures. Polytetrafluoroethylene (PTFE) is extremely common in RF boards, but it can smear under the heat of drilling, and the smear is very difficult to remove. These materials are not as common in PCBs as FR-4, but engineers should use caution in their designs if they are working with these materials as well. Making use of a high-temperature laminate in these situations is highly recommended. 4. Increasing Plate Thickness and WidthIn PCBs, thicker plates tend to conduct heat less effectively than thinner ones. They require more power to reach high temperatures, so with the right engineering, they can help reduce the risk of overheating, warping and disruption. 5. Applying LaminatesApplying laminates is another way to prevent damage from high temperatures. High-temperature PCB laminates can prevent overheating by offering heat protection for the PCB’s components. High-temperature laminates should have the following protective properties: Glass transition temperature (TG): Glass transition temperature refers to the temperature at which polymers shift thermodynamically from rigid to soft. High-TG PCBs offer superior protection. Time to delamination: High heat can delaminate a PCB laminate over time. The best laminates will take a long time to become delaminated at high temperatures. Moisture absorption: PCB laminates should have dependable, protective moisture-absorption capabilities. If the PCB will operate in an air-controlled environment like a laboratory, moisture absorption may not be a high priority. But if the PCB will operate in an environment where it may become exposed to the elements, adequate moisture-absorption capabilities are critical. Decomposition temperature (TD): Decomposition temperature refers to the temperature at which 5% of the laminate’s mass is lost because of decomposition. A high decomposition temperature offers superior protection. Z-axis expansion: Z-axis expansion refers to the expansion of the material along the z-axis as a percentage of the coefficient of thermal expansion. Lower z-axis expansion also offers superior protection. 6. Aligning CTEsThe coefficient of thermal expansion (CTE) measures how much a material expands when exposed to high temperatures. In PCB design, it’s ideal for the dielectric layers to have a similar CTE to that of the copper layers. That way, if the layers expand, they do so in a uniform way that leads to minimal damage. In a multilayer stack, if CTEs are not aligned, the layers will expand at radically different rates, which can cause warping and disruption. If this uneven expansion occurs during PCB assembly, the misalignments can also cause serious problems for drilling. Choosing PCB materials with lower CTEs helps prevent overheating. For example, PTFE filled with woven glass or microglass fibers has excellent electrical characteristics, but it also has a high CTE. So this material is a poor choice when thermal toughness is a top priority. On the other hand, PTFE filled with ceramic has a lower CTE and performs much better at high temperatures, though it loses a little in electrical characteristics. 7. Maintaining Adequate SpacingDetermining component spacing on a PCB can be a tricky process. When board components are too close together, crosstalk may result — that is, different components may begin interacting with each other in undesirable ways. These unwanted interactions lead to something known as the skin effect. When the skin effect occurs, trace resistances increase, leading to resistive losses and adding heat to the circuit. The skin effect is particularly common with high-frequency PCBs, so engineers must take extra care with component spacing to keep the boards from overheating. 8. Integrating Heat Pipes CorrectlyHeat pipes in a PCB can help disperse heat as well. The liquid in the pipes can absorb heat and prevent it from damaging the components of the board. 9. Maximizing RTI and MOTRelative thermal index (RTI) and maximum operating temperature (MOT) are two relevant measurements engineers should pay careful attention to in the design of PCBs. RTI indicates the highest temperature that a material can handle without undergoing changes to its properties or a reduction in its performance. MOT refers to the highest temperature that a particular circuit board configuration can withstand without undergoing changes to its properties or diminution of its performance. Engineers should keep both these measurements in mind in the design of PCBs and choose materials and circuit components with robust heat resistance as determined by these metrics.Wanna know PCB knowledge? Check and read for more.
PCB Glossary ⋅ 05/26/2021 17:50
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