How to Prevent PCB Warpage with 9 Basic Important Tips?
How to distinguish the latitude and longitude? The rolling direction of the rolled prepreg is the warp direction, and the width direction is the weft direction; for the copper foil board, the long side is the weft direction, and the short side is the warp direction. If you are not sure, please check with the consumer or supplier. Do you know how to prevent the PCB warpage? If you are curious about the methods to prevent the PCB warpage, please check and read the content below for more information.Wanna know PCB knowledge? Check and read for more. What Are the Causes of PCB Warpage? In the automatic insert line, if the printing plate is not smooth, it will cause inaccurate positioning, and the components cannot be inserted into the hole and surface of the plate, and even break the automatic insert machine. The welded plates with the components are bent, and the component feet are difficult to be cut in order. The boards can’t fit into the case or the socket, so it’s equally annoying for an assembly plant to get stuck on the board. At present, the PCB has entered the era of surface mounting and chip mounting, and the assembly plant must be more and stricter. According to IPC – 6012, specification for the identification and performance of rigid PCB, the maximum permissible warp and twist for surface mounting of PCB is 0.75%, and other boards allow 1.5%. This is an improvement over IPC – RB – 276. Currently, the warping degree approved by each electronic assembly plant, whether double-sided or multilayer, is 1.6mm thick, usually 0.70~0.75%, and many SMT, BGA boards require 0.5%. Some electronics factories are agitating to increase the standard of warpage to 0.3% and test the warpage using gb4677.5-84 or ipc-tm-6220.127.116.11b. Put the printing plate on the platform to be checked, and insert the test pin into the place with the maximum warp. However, there are ways to detect warpage earlier. One of the ways is by using trace mapping technology, to predict warpage. This procedure is done by mapping the copper constituent. Observing this process makes it easier for the creator in arriving at the correct answer. How to prevent PCB warpage? 1. PCB warping is caused by design and manufacturing issues. The PCB with obtuse and concealed holes needs multiple layering. Most constructors need to be aware of this issue to be able to know what to do and how to do it. This is also one of the common causes of PCB warping. Sizes and shapes of the PCB can as well cause warping. Bigger and larger tabs on the panel structure can cause PCB warping. Also, if the plate you’ll be using isn’t smooth, it causes imperfect positioning. This can cause the construction plant to get stuck thereby causing PCB warping. 2. In addition, trying to make the PCB thicker than its normal weight can cause the PCB to warp. Sometimes the manufacturers don’t remember to de-stress after layering. This causes PCB to warp after manufacturing. In addition, using DFM check is a good technique used to detect possible PCB warping. When warping occurs in PCB it causes lots of damage that most times can’t be repaired. 3. Immediately warping is detected it should be addressed instantly. But if repair is not possible it can be discarded. Most times, when soldering, the solder machine may pick up solder and spread it all through the PCB. This can cause PCB warping. Another solution for avoiding PCB warping is by deducting the copper weight. 4. Pallet design during reflow: Thin PCBs require palletization during reflow. Rush PCB recommends the following design for the pallet: · Minimize the temperature difference between PCB and pallet· Minimize the clearance between PCB edge and pallet edge· Use low spring force for holding down the perimeter and corners of the PCB· Provide adequate support across the span of the pallet to prevent the PCB from sagging at elevated temperatures. 5. Boards are to be baked for a couple of hours above the tg temperature of the material during the fabrication process using heavy steel platens to protect the top and bottom of the stack. If the boards are secured properly during the baking process there should not be warping. Are the boards quick turn prototypes that are being processed too quickly for adequate curing? Another possibility is an unbalanced board design. An uneven inner layer ground plane design could be to blame. Not to mention the variability of laminate types and the affects that non uniform heating and cooling may have on the board. This is an issue you may want to communicate with your board supplier. Bottom line, boards should be cured properly at the board manufacturer prior to you receiving them. 6. Because in the PCB board making process, the substrate has to be subjected to heat and many chemical substances. For example, after the substrate is etched, it needs to be washed with water, dried and heated, and the thermal shock experienced by the hot air spraying tin is large. These processes may cause the PCB board to warp. Solution: Since stress is the main cause of substrate warpage, if the copper clad laminate is baked before the copper clad laminate is put into use, the role of the bake plate is to fully relax the stress of the substrate and help reduce the warpage of the substrate in the PBC making process. After the prepreg is laminated, the warp and weft shrinkage rates are different, and the warp and weft directions must be distinguished during blanking and lamination. Otherwise, it is easy to form the warpage of the waste board after lamination, and it is difficult to correct it even if the pressure is applied to the baking board. Many reasons for the warpage of the multilayer board are caused by the fact that the prepregs are not distinguished in the warp and weft directions during lamination. How to distinguish the latitude and longitude? The rolling direction of the rolled prepreg is the warp direction, and the width direction is the weft direction; for the copper foil board, the long side is the weft direction, and the short side is the warp direction. If you are not sure, please check with the consumer or supplier. During fabrication of a PCB, there is even distribution among all dielectric layers. However, it is the uneven distribution of copper layers that causes PCB warpage to occur. To prevent warpage, the designer must balance the copper pattern on each layer of the board with the circuit area. The designer must also equalize the component layout, the assembly distribution, and the thermal distribution to decrease warpage. Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/27/2024 16:21
What Are the Advantages of PCB Conformal Coating?
What is conformal coating and what is it used for? In short, conformal coating is a thin, transparent film that can be applied to the surface of a circuit board. This film contours to the PCB’s shape, protecting components from environmental conditions without impacting functionality. Conformal coatings will even increase the dielectric strength of a board allowing for reduced spacing between circuits in more compact and dense PCB layouts. In this passage, we are going to provide you everything about PCB conformal coating, please check and read the content below for more information.Wanna know PCB knowledge? Check and read for more. What are the types of conformal coating? Many types of conformal coating materials exist, including a range of specialty varieties. The most common of these conformal coatings are described below, along with their most prevalent applications: Urethane resin: Urethane resins (UR) or polyurethane resins are known for their excellent resistance to moisture, abrasion and chemical attacks. The downside of this material is that it is resistant to solvents, meaning it is difficult to remove and rework. Urethane resins are most commonly used in aerospace applications where components may be exposed to corrosive fuel vapors. Acrylic resin: Acrylic resins (AR) are acrylic polymers dissolved in a solvent. These substances require a simple drying process and are easy to rework. When complete, this type of coating provides good general protection against humidity and other environmental factors but poor protection from solvents and chemical vapors, making it most suitable for basic-level protection. The major upside of this material is the ease with which it can be removed and reworked, making it practical for repair operations. Epoxy resin: Epoxy resin (ER) coatings are compounds that create a hard layer with good humidity, abrasion and chemical resistance, with minimal permeability. Less flexible than other types of coatings, epoxy resins are difficult to remove and rework. Epoxy is the most common choice for PCBs that need to be coated completely and is often chosen for applications with low mechanical stress. Silicone resin: Silicone resin (SR) coatings provide excellent thermal, chemical, moisture and corrosion resistance while maintaining good flexibility. This type of coating is difficult to remove and offers poor abrasion resistance due to the surface’s rubbery texture. However, it makes up for this in offering good resilience against vibrational stress. Silicone resin conformal coatings are often chosen for electronics in outdoor environments that are exposed to broad temperature and moisture conditions. Parylene: Parylene (XY) coatings are applied through chemical vapor deposition. In this process, the parylene is heated to become a gas and put into a vacuum chamber to polymerize and turn into a thin film, which is placed over electronics. This film offers excellent dielectric strength and resistance to extreme temperatures, moisture and corrosive elements. However, it is also difficult to remove and rework, requiring abrasion techniques to remove. The specialized production process also makes replacing parylene coating more difficult than other methods. It’s often used in specialty applications. What Are the Advantages of PCB Conformal Coating? · Insulating properties allow a reduction in PCB conductor spacing of over 80%· Can help eliminate the need for complex, sophisticated enclosures· Light weight· Completely protect the assembly against chemical and corrosive attack· Eliminate potential performance degradation due to environmental hazards· Minimize environmental stress on a PCB assembly Printed Circuit Board (PCB) rework may be necessary for high-value boards. Conformal coatings should be removable with minimal to moderate effort and easily repairable off-line. Ease of rework and removal are directly linked to the resilience of a coating to specific factors in the operating environment. In general, solvent-based, non-cross-linked coatings will be relatively easy to remove with solvents. UV light-curable and cross-linked materials, with their enhanced environmental and chemical resistance, will be more challenging to remove. It’s important to consider the effect of the rework/removal method on solder masks, components, and assembly materials prior to choosing the appropriate method. The three most common techniques for removal are chemical, thermal, and mechanical. Chemical RemovalRemoving cured conformal coatings by chemical treatment requires immersion of the coated board or treating localized areas with the chemical stripping solution. Several companies manufacture materials that dissolve/ attack conformal coatings Thermal Heat RemovalTwo techniques are possible to remove a cured conformal coating depending upon the temperature sensitivity of the components located on the printed circuit board. 1) Heat the entire board to 150°C [300°F] and strip the coating once it softens (while still hot).2) Use a hot-air de-soldering tool or a solder gun to remove spot areas of the coating. Apply the heat source to the treated area and remove the coating as it softens. Exercise care not to damage heat-sensitive components or traces. These methods are useful when the surrounding area does contain heat-sensitive components since it directs the hot air to one spot. When heat sensitivity is not a factor, a heat gun capable of 200-230°C [400-450°F] may be used to heat the area. Mechanical RemovalScraping or cutting the conformal coating may be an option for some applications and is easier with thicker, more flexible coatings. Pressurized abrasive systems - like micro-abrasive blasting - are often used to safely remove cured coatings. The abrasive is easily separated from the surfaces without danger to the components or reworking process. This technique is fast, cost-effective, and environmentally clean. It also enables you to selectively remove the coating from a specific targeted area, while causing no damage to the surrounding components.Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/27/2024 16:11
What Are the Issues of PCB Signal Integrity?
When we have signal integrity issues in a PCB, it may not work as desired. It may work in an unreliable manner – works sometimes and sometimes not. It may work in the prototype stage, but often fail in volume production; it may work in the lab, but no reliably in the field; it worked in older production lots, but fails in new production lots, etc. Do you know signal integrity basics for PCB engineers? If you are looking for more information about signal integrity basics for PCB engineers, please check and read the content below in this passage.Wanna know PCB knowledge? Check and read for more. What Are the Issues of PCB Signal Integrity? PCB signal integrity issues mainly include signal reflection, crosstalk, signal delay, and timing errors. ReflectionWhen the signal is transmitted on the transmission line, when the characteristic impedance of the transmission line on the high-speed PCB does not match the source impedance or load impedance of the signal, the signal will be reflected, causing the signal waveform to overshoot, undershoot and the ringing phenomenon caused by it. Overshoot refers to the first peak (or bottom) of the signal transition. It is an additional voltage effect above the power supply level or below the reference ground level. Undershoot refers to the signal jump change to the next valley (or peak). Excessive overshoot voltage often impacts the device for a long period of time, causing damage to the device. Undershoot will reduce the noise margin. Ringing increases the time required for signal stabilization, which affects system timing. CrosstalkIn PCB, crosstalk refers to the undesired noise interference caused by the electromagnetic energy through the mutual capacitance and mutual inductance coupling to the adjacent transmission line when the signal propagates on the transmission line. It is caused by interaction of different structures of the electromagnetic field in the same area. Mutual capacitance causes coupling current, which is called capacitive crosstalk; while mutual inductance causes coupling voltage, which is called inductive crosstalk. On the PCB, crosstalk is related to trace length, signal line spacing, and the condition of the reference ground plane. Signal delay and timing error: The signal is transmitted at a limited speed on the wires of the PCB, and the signal is sent from the driver to the receiver, with a transmission delay in between. Excessive signal delays or mismatched signal delays can lead to timing errors and disrupted logic device functionality. What are the signal integrity issues in PCB? FrequencyAt low frequencies, you should not experience any major problems with signal integrity. However, with increasing signal speeds, you get higher frequencies, which can affect both the analog and digital properties of the system. You may experience reflections, ground bounce, crosstalk and ringing at higher frequencies, which can seriously damage the integrity of your signal. If you anticipate higher frequencies, you need to consider transmission line effects on the I/O signaling in your board design. SpeedNaturally, the relationship between speed and frequency is one you need to keep in mind. Lower speeds mean lower frequencies and fewer signal transmission problems, while faster speeds mean higher frequencies and the attendant problems that can come with them. LengthAnother issue to consider when it comes to transmission and signal integrity is the length of the transmission medium. The longer the transmission medium, the greater the chance there’s some type of signal loss. Fortunately, these and most other signal integrity issues can be counteracted by a quality design and by keeping some basic layout guidelines in mind when designing your printed circuit boards. What factors are responsible for signal integrity problems? Factors like characteristics of the signal, system impedance, propagation delays, attenuation, crosstalk, voltage fluctuations, and electromagnetic interference contribute to signal distortion resulting in signal integrity problems. Signal characteristics: Ideally, a digital signal is a square wave but practically, it takes some time for the signal to switch from one state to another. So, that is the reason, there is always a degree of signal distortion present. The rise time of the signal determines the maximum data transmission rate that is possible and is often measured by evaluating the signal knee frequency. The goal of the circuit designer is to realize a circuit with a flat response at all frequencies up to the knee frequency. Interconnect effects: Ideal interconnect only introduces a delay in the signal, but practically, it also changes the timing and amplitude of the signal. This deviation is called jitter and amplitude noise, respectively. Impedance: Changes in the impedance that a signal sees cause reflections, ringing, and distortion. The degree of interference intensifies with the increase in the signal frequencies associated with digital circuits. PCB trace branches, line stubs, connector pins, and vias all create impedance discontinuities. Propagation delay: Signals that travel different distances or through different mediums do not arrive at their destination at the same time. These discrepancies, called signal skew, cause signal sampling errors, particularly at high clock frequencies. Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/26/2024 16:01
What Are the Causes of Netlist in PCB Design?
Take a look at your schematic and think for a moment. If you had to manually transfer the most vital information from your schematic into the more comprehensive PCB layout tool, what would be the most efficient way to do it? You might strip out all the visual elements of a schematic and just focus on transferring the connections between components. If a net is a connection between two components, a netlist is simply a list of the electrical connections that describe a circuit. If you are searching for more information about Netlist in PCB design, please check and read the content below for professional knowledge.Wanna know PCB knowledge? Check and read for more. What Are the Causes of Netlist in PCB Design? One might think that Gerber files are infallible and since the industry universally adopted RS274X and ODB++ as standard import formats, they are, in fact, nearly so. However, it is still possible for errors to occur. Features that are incorrectly described in the Gerber file header during importation will change the system’s interpretation of the desired electrical path leading to incorrect nets being defined in the Gerber-derived reference netlist. Corrupted features may include incorrect-sized pads or unfilled polygons. For example, occasionally a self-intersecting polygon will resolve incorrectly (usually because the Gerber file resolution is not fine enough). This can cause the polygon fill to leak through what the CAM program interprets as a keep-out that is not fully closed. What is intended to be a clearance then floods with copper, shorting the hole and the surrounding plane. Exporting your Gerber files with the highest possible resolution (2:6 if possible) or choosing line fill instead of polygons will help you to avoid this issue but supplying a netlist is still recommended. Operator setup errors can also cause the CAM program to misunderstand what it is looking at. The most common problem is a simple operator error when assigning the layer types immediately after importing the raw files. If a negative plane is assigned as positive, or vice-versa, the CAM system will see the reverse of what it is supposed to see. The resulting netlist will be incorrect. To explain: a layer with positive polarity appears in CAM as color = copper, black = absence of copper. A layer with negative polarity will be displayed the opposite way, with color = absence of copper, black = copper. When deriving the reference netlist, the CAM program interprets areas where copper is present as part of the board’s conductive path. If copper and absence of copper are reversed (because the operator has set the layer polarity incorrectly) then the CAM program will create a netlist that does not reflect the true design intent. What’s in a Schematic Netlist? Before going further, there are different types of netlists used in EDA software for IC design or PCB design. These netlists can define logic, connections between components, and hierarchical relationships. They are a powerful tool for summarizing the structure and functionality of your design. A netlist does not contain graphical information—this is contained in the schematic document itself. That being said, a schematic and its netlist go hand-in-hand; the netlist can be generated from a schematic, or schematics (flat or hierarchical) can be generated from netlists. With respect to the information in a PCB schematic, a netlist will contain multiple entries of data, in which each entry contains the following information: · Net label: the name you give to a particular net in your schematic· Reference designators: these designators are for the components connected on the net· Pin numbers: each component on a net will have some pins, thus the pin number for each component on the net will appear in the netlist· If you know how to read a schematic netlist, you can see how a circuit is translated into a SPICE netlist when preparing a simulation. You can also troubleshoot any errors that might be found in netlists from third-party libraries. What is a Netlist File? To answer the question of what is a Netlist file, there are a few basics to cover. For starters, ‘net’ is a term that describes a connection between two or more components. These components constitute the items on the circuit board. It can also refer to the association of capacitors, resistors, and transistors concerning analog simulation tools. Therefore, a Netlist is simply a textual catalog of components and the connections that go with them. Each Netlist has a preceding list of parts and their designations, PINs, and signal keywords for context and reference. Netlists are incredibly helpful during the testing process, even before starting any physical work on the PCB. They allow engineers to carry out these tests to locate any incorrect or missing connections. Netlists also provide nodes, instances, and might even show specific attributes of the components involved. With various structures, complexity, and multiple Netlist formats, no Netlist is the same, but they all play the same integral role in electronic design. Understanding how and why Netlists are beneficial can be advantageous when creating a PCB. Not only will it help identify errors, but making adjustments is a straightforward process.Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/26/2024 15:53
How to Meet the Requirements of PCB Layout Preparation?
When starting a new printed circuit board design, it’s sometimes easy to forget about the important design rules that will govern your project. There are some simple clearances that, if determined early in the design, will eliminate a lot of component shifting and re-routing later. So where can you get this information? If you are curious about more information about PCB layout design guidelines, please check and read the all the content below in this passage.Wanna know PCB knowledge? Check and read for more. How to Meet the Requirements of PCB Layout Preparation? There’s a huge demand in the PCBs market, but not just any boards but quality boards made under the right procedures. PCBs are manufactured once a layout is prepared to attract a huge market. Therefore, designers and manufacturers are under pressure to manufacture boards that promise to bring about desired functionality regularly. Plenty of PCB manufacturers lately, employ effective tools such as DFM software and PCB design tools to create the best layout plans. Such tools are effective as they bring about the best solutions for creating the best PCB layout. These and many other tools find use in a lot of PCB manufacturing firms since they are cost-effective and functional to PCB designers and manufacturers. To meet the demands of producing functional PCBs that deliver as desired, many manufacturers are heavily concentrating on having layout prepared first. This includes defining the board's outline, placing the parts together, creating connections between the parts, and exporting them for fabrication. PCB layout preparation matters in producing high-functioning PCBs, a reason why plenty of PCB manufacturers lately consider this matter seriously. What are PCB layout basics for engineers? Whether you are moving at a high speed or you're designing a high speed printed circuit board, good design practices help ensure your design will work as intended and can be manufactured at volume. In this guide, we've compiled some of the essential PCB layout guidelines that apply to most modern circuit boards. Specialty designs may need to follow additional board layout guidelines, but the PCB layout guidelines shown here are a good place to start for most designs. The guidelines shown here are focused in a few key areas that will help you with routing, manufacturability, basic signal integrity, and assembly: · Defining design rules with the goal of ensuring fabrication and assembly yield· Component placement, where the goal is to ensure solvability and ease of routing· Grouping components by type to prevent the need to route all over the board· Location of power and ground in the PCB stackup, including some points for mixed signal PCB layouts· Obeying mechanical constraints, such as connector locations and enclosure limitations What are routing guidelines for PCB layouts? Next up, connecting your signal traces to match the nets in your schematic. PCB layout best practices recommend that you always place short, direct traces between components when possible, although this may not always be practical in larger boards. If your component placement forces horizontal trace routing on one side of the board, then always route traces vertically on the opposite side. This is one of many important 2 layer PCB design rules. Printed circuit board design rules and PCB layout guidelines become more complex as the number of layers in your stackup increases. Your routing strategy will require alternating horizontal and vertical traces in alternating layers unless you separate each signal layer with a reference plane. In very complex boards for specialized applications, many of the commonly-touted PCB best practices may no longer apply, and you'll need to follow PCB design guidelines that are particular to your application. What are the challenges for nice PCB? Back when the devices on a board were simpler in nature, and only had one power and one ground connection, the noise tolerances were not as tight. You could easily control excessive noise with an extra capacitor. The switching speeds in those devices also didn’t create the same problems as the high speed devices of today do. With the processor chips today on large ball-grid array (BGA) packages, the power requirements are much more intense. There is hundreds of power and ground pins in these devices, and each device may require multiple supply voltages with some of those voltages going down to less than one volt. These pins are also pulling many amps of current for the processor to do its job, and to provide “clean” power requires a huge network of capacitors. What are certain guidelines for PCB layout? There are many ideas and guidelines that can be drawn up for the design and layout of a PCB. The list below covers a number of them. Obviously there are more, and the PCB design guidelines list below should not be thought of as a complete list. In order that the PCB design guidelines can be followed more easily, the guidelines are split into sections: · Board constraint design guidelines - those covering the initial constraints on the board· Overall layout design guidelines· Guidelines associated with the planes or layers· Track design guidelines· Thermal issues· Signal integrity and RF considerationsWanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/23/2024 14:51
What Is Process of Multilayer PCB Reverse Engineering?
PCB reverse engineering is a multilayered process that includes targeted PCB research, reverse analysis and PCB design technology reproduction. The process is also used to identify and obtain the design of a product’s functional and structural characteristics, as well as the processing flow. With this information, a company can produce products with similar functions and abilities — though businesses will make sure they’re not reproducing an exact replica of a reverse-engineered PCB. Do you know the basic knowledge of PCB reverse engineering? If you are looking for more information about PCB reverse engineering, please check and read the passage for more professional knowledge. Wanna know PCB knowledge? Check and read for more. What is the definition of PCB reverse engineering? Reverse engineering circuit boards can be a long process, but it’s well worth the payout. There are a few primary stages of reverse engineering PCBs that anyone who attempts to do it should follow. These steps include creating initial drawings, scans or photographs of PCBs that are then uploaded to the appropriate reverse-engineering software and programs. Once uploaded, users have to build the PCB’s layout and use that layout to create schematics. Reverse engineering is primarily utilized to determine and analyze the design principles behind a product. It’s especially useful when a company can’t easily find design information on a specific product. The most common method of reverse engineering a PCB involves disassembling a sample PCB and then analyzing it. From this analysis, a company will create documentation about the sample PCB, which various team members can review. This documentation will often include information about how the product is designed and how it operates. A company can then use the information they gather from a sample PCB to manufacture similar PCBs that may function better than their competitors’ offerings. Alongside reverse engineering’s ability to help companies analyze and outdo competitors’ products, it can also help businesses improve their own PCB offerings. For example, reverse engineering can help them enhance their boards’ functionality by spotting obsolete parts, security issues or poor designs. What Is Process of Multilayer PCB Reverse Engineering? · Assign reference designations to unmarked components before starting PCB reverse engineering.· Create a Component level BOM.· Design -Identify the system’s components and their interrelationships.· Components Placement & Mechanical.· XY locations of Connectors, LED, Switches etc.· Board mechanical Mounting holes & any special cuts on Boards, Board size etc.· Download datasheets, application notes, and architecture information.· Create net list.· Make the Schematic Drawing and PCB Layout. Why reverse engineer a PCB? There are several advantages of reverse engineering PCBs — many companies use these devices for various purposes. Reverse engineering can also help you produce more effective or less costly versions of a competitor’s PCBs. Learn more about the advantages of reverse engineering PCBs below: · Maintain crucial PCBs· Get information on PCBs without documentation· Reduce your reliance on experts· Identify weaknesses in a competitor’s designs What are the considerations of PCB reverse engineering? Basically figuring out how the PCB works without the original engineering documentation. You start by creating a schematic by identifying all the components on the board and then finding all of the interconnections. This gives you a schematic which allows you to figure out how the board works. It sound easy but on complex boards in can be extremely time consuming and is frequently made more difficult by the use of complex custom chips. You can actually reverse engineer the actual chips as well, but this is even more specialized and requires a lot of specialized equipment. One of the common uses for reverse engineering is do determine if competitors are using your patents, hardware or Ontellectual property to make their competing products, but there are other malign reasons. Government security agencies do this kind of thing as well to gain insights into other countries weapons susystems, for example. There are specialist companies that perform this kind of work for a fee. If you are right and a competitor is illegally using your patents you may get a financial settlement that will cover your costs, but that is not guaranteed.Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/23/2024 14:42
How to Design PCB Creepage with Standards?
Printed circuit boards that conduct high voltages can be victimized by an electrostatic discharge between exposed metal if that metal is too close together. This discharge can potentially cause damage to the board and its components, and it is important for PCB designers to observe proper spacing between metal conductors on the board. Conductor spacing on a circuit board is measured in two ways—creepage and clearance: In this passage, we are providing all the details information of creepage distance in PCB. If you are curious about creepage distance in PCB, please check and read the content below for more professional knowledge.Wanna know PCB knowledge? Check and read for more. How to calculate PCB creepage distance? The measurement of clearance depends on factors such as the applied voltage, air pollution, and temperature variations. Additionally, humidity decides the breakdown voltage of air and affects the likelihood of arcing. On the other hand, along with board material and environment conditions, moisture, and contamination due to particulate accumulation shorten the creepage distance. Designers are unable to solve issues related to clearance at PCB layout design stage since the measured distance is along the air pathway (line of sight). Component placement will likely reduce errors occurring during spacing. However, key factors, such as the usage of insulating materials and the adoption of double-sided assembly, play a critical role while determining PCB component spacing requirements. Insulating materials acts as a sheet barrier between the high-voltage nodes. They also sleeve or cover overexposed high-voltage leads. There is a high proportion of PCB components belonging to the surface-mounted category, allowing designers to place circuits as per the requirement of clearance on opposite sides of the board. It is also important to maintain clearance from the bounding surface and through-hole connection points present on the board. Nodes within the same high-voltage circuits at the same potential do not require increased clearance or creepage. However, low-voltage circuits have to meet clearance requirements in relation to high-voltage circuits. Few international standards have suggested the use of conformal coating for limiting issues related to the clearance. The conformal coating is applied as per the design requirement. Minimum creepage distance can solve tracking failures. Avoiding the conductive path along the insulator surface limits tracking failures. Several factors affecting creepage and clearance include: · Working voltage· Pollution degree· Insulation· Type of circuit What are the PCB creepage standards? For those of us who don’t want to learn about the importance of creepage and clearance from direct experience, there are a few standards to help us. Primarily you should look into IEC 60601 and IPC 2221. These two standards detail spacing between conductors for different voltages and scenarios. Sometimes there will be gray areas where the standards won’t tell you exactly how to solve a problem or layout your conductors. Although, your CM’s DFM rules will ensure manufacturability you should have your boards tested to ensure the safety requirements for creepage and clearance are met. The most well-known testing service is Underwriter’s Laboratory (UL), which will validate your boards, give your customers confidence, and provide you with protection against a related contingency. At the end of the day, it’s important for you to know the principles of design for creepage and clearance so you can ensure your board is compliant. How to Design PCB Creepage with Standards? Once you have the spacing requirements the board will need for proper creepage and clearance, the next step is to set these values up in your PCB layout system’s design rules. Rules and constraints can be set up for metal to metal clearances, whether it is between traces, pads, copper pours, or any combination of the three. You will also want to set up the correct spacing for your component footprints, especially those larger parts that are conducting a lot of voltage. In some cases, you can even set up unique keep-out clearances around specific footprints to account for heat sinks and other unusual configurations. All of these rules will help you to maintain the necessary spacing between high voltage components that you need. When you are placing the components in the layout, make sure to consider all aspects of the parts as you place them. This will include any metal conductors, such as heat sinks, that may overhang the part, especially if you aren’t able to set up a unique keep-out zone around it. During layout, you will also want to ensure that any edits or changes to the component placement don’t end up violating spacing that you have already carefully set up between the parts. Even rotating a component 90 degrees can cause an unusually shaped part to violate a voltage clearance. Here are a couple of other techniques to consider during layout for spacing: To help maintain the right amount of clearance spacing, try locating high voltage components on one side of the board and low voltage parts on the other. In some cases, high voltage parts may not have as stringent spacing rules between them as they do to low voltage parts. Creepage will require another solution, as putting parts on the other side of the board won’t give you the separation you need through the surface of the board. Instead, you may want to install insulating barriers or cut grooves or slots into the board. The change in the contour of the board will increase the distance over the surface that the voltage has to travel, giving you the creepage separation you need.Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/22/2024 16:20
What Are the Rules PCB Ground Plane?
One 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. Do you know the methods about ground plane PCB? If you are curious about the professional knowledge about ground plane PCB, please check and read the content in this passage.Wanna know PCB knowledge? Check and read for more. What is PCB plane capacitor? This is not a major benefit, and it applies only to ground planes that are adjacent to a power plane. I think it’s still worth mentioning, though. A ground plane separated from a power plane by a thin dielectric sounds a lot like a parallel-plate capacitor, and that’s exactly what it is. This structure adds a bit of distributed power-supply capacitance to your entire circuit board, though it certainly isn’t going to replace your decoupling capacitors. A solid ground plane provides some degree of protection against electromagnetic interference (both radiated and received). I wouldn’t rely on a ground plane to solve all of your EMI problems, especially if you have components on both sides of the board; a carefully designed conductive enclosure would be more effective. Nonetheless, every little bit helps, and if you’re concerned about EMI then you have one more reason to incorporate a ground plane into your layout. Why Is the PCB Ground Plane Important? The ground plane on a printed circuit board is typically a large area of metal connected to the circuit ground. This area of metal is sometimes only a small portion of the board, or in a multi-layer design it may be one entire board layer. Depending on the needs of the design, it may even occupy multiple layers. The ground plane serves three important purposes in a printed circuit board: Voltage return: Most every component on the PCB will connect to a power net, and then the return voltage will come back through the ground net. On boards with only one or two layers, ground nets usually have to be routed using wider traces. By devoting an entire layer to the ground plane in a multi-layer board however, it simplifies connecting each component to the ground net. Signal return: Regular signals also need to return, and with high speed designs it is very important that they have a clear return path on the ground plane. Without this clear return path these signals can generate a lot of interference for the rest of the PCB. Reduce noise and interference: As signal speeds increase, there are more digital circuits switching states. This creates noise pulses through the ground circuit that may affect other parts of the circuit. A ground plane with its large conducting area helps reduce the amount of this disturbance because it has lower impedance than if the ground net is routed through a trace. What Are the Rules PCB Ground Plane? Maybe you’ve designed a digital device with some variance in your ground and data can still move safely around. However, consider something like a high-reliability medical system. If that device gets zapped with a high-voltage ESD charge, you better hope you properly designed your ground. In sensitive electronic designs such as these, proper grounding can mean the difference between life and death. Leave nothing unattachedNothing should remain unattached on your PCB layout. If there’s an open space on your board, fill it with copper and vias to connect with your ground plane. This will create a structured path for all of your signals to efficiently get to ground. Never slice up your ground layerMost engineers working on four layer boards will have a dedicated ground layer. This works great as long as you don’t route traces on this layer. Once you do, you’ve effectively created a ground current loop. Keep your ground layer whole at all times. Grounding before routingA poorly designed ground puts your entire device at risk. The same can’t be said for messing up a single signal. Be sure to properly design your ground first before doing any routing. This will serve as the foundation for your entire routing process. Know where your currents are goingMany designers only think about where their signal is traveling to, but every signal has a return path to take through ground. Both the sending and return path of your signal will have the same current which can affect power stability and ground bounce. You can use Kirchhoff’s Current Law to understand how current will travel through your circuit.Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/22/2024 16:05
How to Prepare before PCB Prototyping?
Before you begin the PCB prototyping process, make sure that prototyping is right for your needs. While it is beneficial for many projects, it's not necessary for every type. If you decide to create a prototype, you'll need some basic information about your project to get started. Electronic design businesses can benefit from faster turnaround time, as the manufacturing process for a PCB is far less labor-intensive than traditional circuit boards. Do you want to know the methods of PCB prototype? Please check and read the content below for more information in this passage.Wanna know PCB knowledge? Check and read for more. How to Prepare before PCB Prototyping? A prototype printed circuit board is an essential step in the design process of an electrical item. Printed circuit boards use conductive tracks to connect components. Printed circuit boards have lower manufacturing costs that traditional circuit boards. Because they are printed, there is no need for a complex wiring process. Deciding If You Need a Prototype Prototypes are ideal for when you want to test your design or perform a quality check of your board. You should use a prototype any time you use a new design for a new project. If you've already successfully produced an electronic product with that board, you may not need a prototype. If you make any design changes or create an entirely new PCB design or product, however, you should order a prototype. Through our rapid prototyping service, we can build test boards with no more than eight layers and provide quality standard IPC1 boards using standard RF-4 material. For prototypes, we can fulfill orders of 5 to 100 pieces and offer a build time of four to five business days. Once you have approved your prototype, you can order a full production of boards with more layers and different materials in greater quantities. What Are the Common PCB Manufacturing Challenges？ Electronics and PCB manufacturing is presently facing several challenges together with opportunities. Along with the need to control costs, the PCB manufacturing services will have to focus on finding ways of capitalizing on current trends. This may include integrating technologies outside their primary areas of expertise, while meeting demands from customers for highly efficient manufacturing processes that are also eco-friendly. The biggest trends and challenges in the electronics manufacturing industries are likely to be: Manufacturing is different from designing The design of your PCB might look good on paper or a computer screen - but it can be an entirely different story when it comes to manufacturing it. For example, there may not be sufficient tolerances between tracks on the board, which later on in the process could result in the circuit shorting out. Or perhaps the design includes a number of components positioned closely together, each with a different thermal mass. Achieving a quality solder joint on each of these components without heat damaging the rest of the circuit board requires expert process engineering skills. If you are manufacturing a double-sided PCB, there are other factors to consider. Adopting this approach can allow you to fit more components into a limited space or to keep down costs. However, you will need to ensure that, where possible, your largest components are all placed on one side of the board and that this side is passed through the oven second. Otherwise, you risk these components falling off the board. You can use glue to hold down particularly difficult parts, but this requires additional manual work. Insure the multilayer PCB stackup Multilayer printed circuit boards are those boards that contain more than a single layer counts, hence the need for stack-up. Stack-up is the arrangement of insulating and copper layers to make a printed circuit board before the PCB layout design. When it comes to the manufacture of multilayer printed circuit boards, challenges come in when it comes to pressing the insulating and copper layers together. A majority of multilayer printed circuit board manufacturers tend to encounter difficulties when it comes to pressing multilayer printed circuit board components together. How to use PCB prototype board? Perf BoardPerf boards are one of the available types of prototype boards. This category is also known as the “Pad per hole” design, where each hole has its own conductor pad made from copper with it. With this setup, you can test connections by running solder between individual pads. Additionally, you can also run wires between pads on a perfboard as well. StripboardLike the other common type of prototype PCB, stripboards also have the individual hole set up. Instead of each perforation having a single conductor pad, strips of copper run parallel under the length of the board to connect the holes—hence the name. These strips substitute as wires, and you can also break connections as well. PlanningEven if you know how to use a PCB prototype board, you don’t want to drive straight into building one. While protoboards are way less costly than a printed circuit board, they still have more permanent configurations. Before you get started putting components into place, you should spend some time on the planning stage to give yourself the best results. A straightforward way to get started is to use a board-planning application on your computer. Software like this gives you a choice to visualize circuits before putting any components down. Be aware that some programs are suitable for working with both perf and stripboard, while others only work well with one type, so plan your protoboard purchases accordingly.Wanna know PCB knowledge? 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PCB Knowledge ⋅ 02/21/2024 16:31
What Is the Importance of PCB Error Analysis?
To start your checklist, start at the foundation of your PCB design and work your way through it. Some fundamental tasks must be done first to complete a successful layout, and you want to be sure to account for them. In fact, many PCB design departments will have multiple design reviews with different checklists for each review. What are errors in PCB manufacturing? If you are curious about errors in PCB manufacturing, please check and read the content below for more information in this passage.Wanna know PCB knowledge? Check and read for more. What Are the Main Errors in PCB Manufacturing? Temperature & Moisture PCBs are affected by temperature, both in storage, and when they are installed in components. Extreme temperatures or large temperature fluctuations may cause components or joints to break or fail. Many people take the maximum or minimum safe temperature into consideration, without thinking about the fluctuations in temperature that may occur either during operation or in storage. Exposure to moisture, both during the manufacturing process and in storage, can cause shorts to occur and may lead to defects in components. Humidity in the air, as well as the moisture content in the solder can wreak havoc on printed circuit boards, causing corrosion. Plating Hole Defects Holes carry electricity from one side of the board to the other. Plating of the hole wall during manufacture. During this, If the copper deposition is incorrect, it will create plating voids, leaving gaps in the wall with no copper coating. It could happen due to air bubbles, contamination in the holes, contaminated materials, and other similar reasons. You can prevent this from happening by following the manufacturer’s direction and cleaning the equipment as instructed. Soldering Defects The bulk of printed circuit board defects can be traced back to a soldering issue. Soldering is a technical skill that becomes even more difficult when dealing with the extremely small components on a printed circuit board. Some of the most common soldering defects include: Open joints, sometimes called “dry joints,” occur when the solder doesn’t bond correctly with the point of contact, typically the pad. Occasionally, open joints are caused by using too much solder, which causes the component to lift. Shifts occur when the printed circuit board or component is not aligned correctly during the soldering process. Shifts can result in open joints, shorts, and crossed signal lines. Short circuits, often referred to simply as “shorts,” most often occur due to a soldering error called solder bridging. What Is the Importance of PCB Error Analysis? As smart phones, tablets, and wearable devices have become smaller, thinner, and more functional, PCBs and components continue to be even smaller, denser, and more layered. In the automotive industry, research and development of technologies such as automatic brakes and autonomous driving has promoted computerized control of important components. Such control then expects PCBs and electronic components to have high durability and reliability so as to withstand long-term stress caused by driving, accelerating, and stopping. Terminals and devices now have an important role in various daily situations, and cars require a high degree of safety. Any failures and defects of important components that are computerized in such products can lead to serious trouble or accidents. To evaluate the durability and reliability of PCBs and electronic components, reliability evaluation tests, including acceleration tests, have become increasingly important. In addition to such tests, using microscopes to identify defects and failure causes is more important than ever. What are the basics of avoid PCB error? To start your checklist, start at the foundation of your PCB design and work your way through it. Some fundamental tasks must be done first to complete a successful layout, and you want to be sure to account for them. In fact, many PCB design departments will have multiple design reviews with different checklists for each review. These could include a pre-layout review, a component placement review, and a critical routing review, for example. All of these elements are included here and you can decide how best to organize the list, or lists, for your workflow: Schematic· Complete: Has the circuitry been completed in the schematic? It is a good idea to review the schematic prior to the layout to ensure that any missing circuitry is caught before the physical layout is started.· Checked: Have all of the schematic design rule checks (DRCs) been run and any errors cleaned up?· Ready for layout: Have all of the components been updated to their latest library versions? Many board designs have been ruined because the schematic still contained preliminary library parts instead of their final versions. Board outline· Correct documentation: Do you have the latest board information to work with? This would include mechanical dimensions, as well as connector and other mechanical part locations.· Available data files: If you are working with mechanical CAD data that will be used in your PCB layout tools, are those 3D files ready and up to date?· Board layer stackup: Do you have board layer stackup finalized with the correct configuration and materials? This is important for good signal integrity and manufacturability.Wanna know PCB knowledge? Check and read for more.
PCB Knowledge ⋅ 02/21/2024 15:47
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