How to Control Impedance of PCB with 7 Important Tips?

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. If you are looking for more professional knowledge about Impedance control of PCB, please check and read this passage for more information.Wanna know PCB knowledge? Check and read for more. What are the applications of PCB impedance control? Controlled Impedance should be considered for PCBs used in fast digital applications such as: · Telecommunications· Computing 100MHz and above· High Quality Analog Video· Signal Processing· RF Communication How to control dielectric of PCB impedance? The typical design considerations involved in the determination of the requirement for controlling the impedance are the strength of the signals involved, the susceptibility of the circuit to noise and signal distortion, the criticality of signal timing and the speed at which the signal’s source is attempting to force a change in voltage and/or current. 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 factors of PCB impedance control requirements? Many factors influence the stack-up design parameters and choices (such as impedance, physical structure, blind holes, and so on). The impedance of signal lines is affected by the stack-up structure characteristics. Change the stack-up parameters help attain target impedance. It is equally important to examine and balance other aspects in design that impact the stack-up. Consider the following: · The thicker the dielectric thickness, the higher the impedance· The smaller the dielectric constant, the greater the impedance· The thicker the copper weight, the lower the impedance· The impedance value will be higher if the dielectric constant is less· A greater inductance indicates a higher impedance· A higher capacitance indicates a lower impedance How to avoid the common problems of PCB impedance control? Here is a list of impedance-related notes we have seen that can also cause confusion or on-hold situations: Only one trace width can meet a particular impedance on any one layer. It is not sensible to expect, say, a 0.007” trace and a 0.005” trace to both solve for 50 Ohms on the same layer. Although this seems painfully obvious, we have seen instances where the requirements were called out in this manner. It does not work. Only one trace width or pair geometry can meet a particular target impedance per layer. If you have a dense 16-layer board, and your note reads: “All signal layers: 0.004” trace, 0.006” space to be 100 Ohms differential” please make sure that the specified geometry is present on ALL the signal layers. If it’s not, then clarify by specifying only the layers where the geometries exist. Searching through 8 or 10 dense signal layers with hundreds of seemingly parallel 0.004” traces in search of a few true differential pairs is tedious enough, but searching all those layers to discover that there are 0.004” / 0.006” pairs on just ONE of the internal layers wastes significant time. It is also necessary, once the weeding-through is completed, to document that impedance testing may be waived for layers not using those pairs. Otherwise an incoming inspector will reject the impedance report when the boards arrive, on the grounds that it is incomplete as defined by the drawing note. Therefore, it is important that you identify only those layers that actually use the specified trace geometries. If you supply a reference stack-up, it is good practice to also state clearly whether or not you permit adjustments to meet the impedance targets. Some drawings arrive with generic stack-ups included, which will not serve to meet the custom requirements of a controlled impedance PCB. If the notes do not make it clear that adjustments are permitted, then the fabricator has no choice but to stop the order and seek your permission to deviate from the supplied stack-up.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/17/2022 10:23

How to Process Best PCB BOM Management during Manufacturing?

There are three questions you need to be asking yourself when creating a BOM for your next project: The "when," the "what," and the "how." After discussing these topics with your selected staff and the client who has assigned the project to your organization, you can then proceed with your project. In this passage, we are going to provide you all the professional knowledge of PCB BOM. If you are curious about more information about PCB BOM, please check and read the content below.Wanna know PCB knowledge? Check and read for more. Why is BOM important? Anything that involves electronic products requires a lot of organization and operations when it comes to any materials. The purpose of a BOM is to make sure that everything involved in an electronic product project is operating smoothly. When this process is not organized correctly, a lot of unsavory things can happen. CostsThe creation of a proper BOM can reduce the costs involved in a project. Because there are many materials necessary when it comes to a project, much money goes into them. If a BOM is accurate and organized correctly, it can save a lot of money. One of the worst things that any manufacturer can do is rush to create a BOM. If the logistics list is in a hurry, two things can happen. First, insufficient material is ordered, and it will cost more money to get more materials contained, especially if time is of the essence, and you need the materials delivered quickly. The second thing that can happen is that you can get too many materials, it also means spending too much money. While it is true that you will possibly have surplus materials for the next project, the amount paid exceeds the necessary amount. Staffing and PersonnelOne thing related to cost is employees and people. Having staff to work on a project is something that should be directly determined by what is contained in the BOM. If you don't take the BOM seriously, it can affect employees to hire too many people. The staff members will not be compensated the way they like or also employ a few people, and their production will suffer from being overwhelmed and overworked. What is the 4 parts of BOM? There can be many types of information in a PCB BOM, but the parts must have a core set of elements to start with. Here is a list of some of the more core elements that you will see in a PCB BOM: Comment: Each part type on the Printed Circuit Board needs to have a unique identifier, or part number, listed as a comment in the bill of materials. Typically a company designated part number is used as the comment, but this is not a requirement. Vendor component part numbers or other designations can be used as instead. An example of a comment could be the company part number “27-0477-03”. Description: This is a basic description of the part. In the case of the comment 27-0477-03 listed above, the description could be “CAP 10uF 20% 6.3V”. Designator: Each of the individual components on the board will have its own unique reference designator. In the case of the 10uF capacitor, it could be “C27”. Footprint: This is the name of the physical CAD footprint used by the part. For instance, C27 could be using a CAD footprint named “CAP-1206”. How to fill a BOM? Regardless of the particular tool used, the creation of a BOM is divided into the following common steps: Creation of the initial version of the document, indicating on top the project name and any other useful information that allows immediate identification; Document organization, which identifies the users who can access it and their access rights (reading, writing, creation, cancellation, etc.). It is also necessary to activate the change tracking system and set up the physical repository (with backup functionality) that will host the file; Columns definition: each column of the spreadsheet must show on top the name that identifies the category, such as: name of the part, quantity, manufacturer, code, description and more (see Figure 1); Rows filling: for each element belonging to the BOM, a row must be added and properly filled. Since this information is crucial for the success of the project, the information entered must be accurate and consistent with the Gerber files of the PCB; Keep the BOM updated: once created, the file must be kept up to date, tracking every revision produced.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/17/2022 09:53

How to Check PCB Soldering during the Manufacturing?

High reliability assembled PCB prototypes as well as novel surface mounted devices (SMD) and mixed systems must be assessed according to well defined qualification test plans. Such high reliability verification programmes are not limited to just evaluate the robustness, reliability and performance of the product but they also address the verification of tools, fabrication procedures and involved materials, as well as the confirmation of product integrity. For instance, “European Cooperation for Space Standardization” (ECSS) standards used in space programs In this passage, we are looking for more information about PCB soldering, if you are searching for more professional knowledge, please check and read the passage.Wanna know PCB knowledge? Check and read for more. What are the essential factors in PCB soldering? Solder Paste Printing technology primarily aims to solve problems concerning incompatibility of solder paste printing amount (filling amount and transferring amount of solder paste). Based on professional statistics, with PCBs correctly designed, 60% of PCBs for rework are caused as a result of bad solder paste printing. In solder paste printing, three important "S"s must be remembered: solder paste, stencil and scraper. If correct selections are made, excellent printing effect can be obtained. Quality of solder pasteAs a necessary material for reflow soldering, solder paste is a kind of paste solder evenly mixed by alloy powder and paste flux (rosin, diluents, stabilizer etc.) among which alloy powder is the key element to composition of solder joints. Flux is the critical material to eliminate surface oxidation, increase wettability and ensure quality of solder paste. In terms of quality, generally speaking, 80% to 90% of solder paste belongs to metal alloy while it accounts for 50% in terms of volume. Solder paste quality insurance comes primarily in two aspects: storage and application. Solder paste is usually stored between 0 and 10°C or stored according to requirement of manufacturers. Stencil designThe key function of stencil lies in uniform solder paste coating on PCB pad. Stencil is a must-be in printing technology and its quality directly influences quality of solder paste printing. Up to now, there are three methods to manufacture stencils: chemical corrosion, laser cutting and galvanoformung. Stencil design won't be ensured until the following aspects are fully considered and suitably dealt with. What are the features of soldering finished PCB? Although it is possible for anyone to throw down solder onto PCBs, whether you get classy solder joints or downright caveman quality ones is a different matter altogether. With components becoming smaller and more compact, the chances of soldering issues occurring have become higher. When soldering the PCB, try to make the finished product have the following characteristics: · The soldering surface is kept clean; · The solder joints must have sufficient mechanical strength to prevent the soldered parts from falling off or loose under vibration or impact; · The soldering must be reliable and ensure electrical conductivity This is not only a guarantee for the product’s function but also to prevent the product from being burned out by a short circuit. What are the preparations before of PCB DIP soldering? First Article InspectionWe will cross check and record all the supplied components’ quantity, item number, dimension, cathode direction, component silkscreen number, value, etc. Components outline processingSome components outline should be processed ahead of time because of their own design or for the PCB DIP soldering requirements and the whole PCB plan. Requests. The horizontal witch of the processed pins should be the same as the locating holes, the tolerance should be < 5%, the silkscreen upward. Components managementPreparation before DIP soldering: Every operator should follow team leader’s arrangement, prepare their WI content in their own station and receive all the components which match the WI completely. Put the received components into the part box and mark them well, including the defect parts if there is. Check if there is any cathode components, and compare with the WI picture, should be familiar with the part appearance and find out the pin position.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/16/2022 10:51

What is Solderability Test during Manufacturing to Guarantee the PCB Quality?

Solderability test on a printed circuit board is critical. If you fail to undertake some tests, then you are inviting trouble. There’s nothing riskier and expensive than rolling out faulty boards to the market. You can avoid such by only undertaking solderability tests. So what’s the importance of the PCB solderability test? Do you know the importance of PCB solderability test and how to process it? In this passage we are providing all the information of PCB solderability test, if you are searching for more knowledge of PCB solderability test please check and read the content below.Wanna know PCB knowledge? Check and read for more. What are the types of PCB solderability test? Three of the most common solderability testing formats are: · “Dip and look” method· The surface mount simulation test· Wetting balance analysis 1. DIP AND LOOKDip and look subjects the leads and terminations to up to 8 hours of steam conditioning, accelerating the aging process. (This is why skin doctors warn against saunas and hot showers!) Next, testers dip the components into solder using activated rosin flux. Finally, they’re inspected to ensure they meet requirements. 2. SURFACE MOUNT SIMULATION TESTThe surface mount simulation test is available for all surface mount technology (SMT) components, including ones that can’t use other types of PCB testing methods like dip and look. A specific solder paste is screen-printed onto a ceramic plate. The component then goes into the paste and is subjected to a convection reflow profile. 3. WETTING BALANCE ANALYSISWetting balance analysis also ages the components to measure the wetting forces. The testers plot the wetting force, starting at negative (nonwet). Solderability is measured as the amount of time it takes for wetting to occur. What is the equipment of PCB solderability test? The right tools and equipment are one of those factors which will see you staying relevant in a competitive environment. Without a doubt, one of the essential tools that you must have is the soldering iron. A soldering iron provides the heat source to melt the solder. But again, the soldering iron doesn’t need to be expensive as such. If you look around, you’ll find some that go for as little as $10. Besides the soldering iron, other tools that you may need during soldering include the following: Solder Flux The Solder Flux acts as a purifying agent, and it purifies the components while closing out extra air to prevent rust. The Solder Flux is one of the essential tools to have at hand when soldering. Manufacturers love it as it goes further to better the dripping individuality of the solder itself. Solder Paste Solder Paste joins various leads of chip packages to connection ends of boards. The solder paste appears like a gray putty-like substance. During soldering, the paste joins the multiple charges of chip packages to the connection ends on a PCB. Solder suckers Solder suckers also go by the name solder pumps. These mechanical vacuum pumps suck solder away from solder joints. They enable the removal of solder from a joint for components desoldering for rework. Wire cutters Even though they tend to be small, wire cutters are convenient tools. You can use the wire cutter to cut off long component legs. Also, you can use these wire cutters to strip the end of the wires. Wire cutters again go by names such as diagonal cutters, flush-cutters, clippers, electronic snippers, and more. Soldering iron tip cleaner Soldering tip cleaners are necessary during soldering. They are for cleaning iron tips from any old solder or carbon accumulation. If you want your soldering iron to last for long, then you’ll need soldering iron tip cleaners. Desoldering Wick Manufacturers use this to clean the leftovers of solder that remained behind during soldering. A desoldering wick is a finely braided copper wire. The copper wire has a rosin coating flux that can finely remove excess copper. Circuit board holder It is the perfect equipment for holding the PCB into place during soldering. Some refer to this equipment as a soldering helping hand and comes in handy when soldering adequate equipment. The circuit board holder fixes the objects at the required angles for soldering.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/16/2022 10:41

PCB Market Trends 2022: What Are the Tips for PCB Industry?

Trend forecasts for the early 2022s center on smaller and more flexible computing options. The push among PCB manufacturers to meet these demands has spurred certain trends within the market. Then what is the trend of PCB industry? If you are curious about PCB industry in 2022, please check and read the content below for more information.Wanna know PCB knowledge? Check and read for more. How COVID-19 affects PCB industry in 2022? COVID-19 can affect the global economy in three main ways: by directly affecting production and demand, by creating supply chain and market disruption, and by its financial impact on firms and financial markets. The outbreak of COVID-19 has brought effects on many aspects, like flight cancellations travel bans and quarantines restaurants closed all indoor events restricted over forty countries state of emergency declared massive slowing of the Printed Circuit Board (PCB) market volatility falling business confidence, growing panic among the population, and uncertainty about future. The scope of covers all the main system technologies that are currently being implemented within the global Printed Circuit Board (PCB) industry. Market values are supported the to puser (public and private) manufacturing of Printed Circuit Board (PCB) systems. Printed Circuit Board (PCB) market manufacturers place orders, once they receive work orders from Printed Circuit Board (PCB) market operators. Therefore, market numbers are derived fromthe topuser perspective, considering their (Printed Circuit Board (PCB) market operators) orders for the Printed Circuit Board (PCB) market. What is the review of PCB industry in 2021? The biggest highlight of the report is to provide companies in the industry with a strategic analysis of the impact of COVID-19. At the same time, this report analyzed the market of leading 20 countries and introduces the market potential of these countries. The Global Printed Circuit Board (PCB) market 2021 research provides a basic overview of the industry including definitions, classifications, applications and industry chain structure. The Global Printed Circuit Board (PCB) Market Share analysis is provided for the international markets including development trends, competitive landscape analysis, and key regions development status. Development policies and plans are discussed as well as manufacturing processes and cost structures are also analyzed. This report also states import/export consumption, supply and demand Figures, cost, price, revenue and gross margins. For each manufacturer covered, this report analyzes their Printed Circuit Board (PCB) manufacturing sites, capacity, production, ex-factory price, revenue and market share in global market. What are the main factors of the growth of PCB industry in 2022? The global PCB market is projected to experience a compound annual growth rate of 3.3% from 2021 to 2026. In 2020, it was valued at $70.92 billion and was expected to be worth $86.17 billion within five years. The market has seen significant growth in the recent years, mainly because of the high demand for consumer electronics. The use of circuit boards in connected automobiles has also enhanced the PCB industry growth. These vehicles are entirely connected with wired and wireless devices, facilitating smooth communication with other devices like smartphones. The autonomous technology enables drivers to unlock their cars, ignite climate regulation systems remotely, evaluate the status of their batteries, and monitor their vehicles from anywhere using smartphones. Besides, the high demand for consumer electronics like smartphones has boosted the industry’s growth. In the future, three-dimensional electronic products are projected to transform the way electrical systems are developed. These systems fashion three-dimensional PCBs by creating a substrate material in layer stacks, then incorporating a functional ink on top. Manufacturers then apply surface-mount techniques to form a complete system. Three-dimensional printed electronics can potentially offer significant production and technical advantages for PCB manufacturers and consumers, particularly when compared to two-dimensional circuit boards. With the onset of the coronavirus pandemic, the manufacturing of PCBs was affected by shipment restrictions and delays in Asian countries, particularly in China. PCB companies worldwide have not come up with significant adaptive changes to increase their manufacturing capacities, but low demand in China caused problems to the supply chain system. For example, a report from the Semiconductor Industry Association conducted in February showed potential long-term business effects in the rest of the world because of Covid-19. What are the applications of PCB industry in 2022? High Density Interconnect (HDI) PCBsIn our modern era, the use of advanced automation has become the new normal for people and businesses across the board. From aerospace applications and military communications to new improvements in medical diagnostic tools and wearable technology, the need for smaller parts with faster signal has increased – and therefore so has the demand for HDI pcbs. HDI pcbs provide reliable, high-speed signal and are smaller in size and lighter in weight than other pcbs. They also grant a cleaner circuit route with versatile routing options. Additionally, HDI pcbs provide smaller trace widths and better wiring density, allowing engineers to pack more function and power into a smaller space. They reduce the need for layering, which in turn lowers the cost of production. For these reasons, HDI pcbs are becoming crucial components in many products and applications. High Power BoardsThe demand for high power boards, especially those with 48V and higher, is increasing significantly. One reason for this trend is the growing prevalence of electric vehicles, in which voltages are often in the hundreds. Similarly, with new trends in sustainability there has been a higher need for solar panels, which operate at 24V or 28V. Internet of Things (IoT)One of the most notable trends this year has been the need for connectivity among all products – otherwise known as IoT. This coincides with a push for smart devices to become both smaller and more complex. It is only a matter of time before it is standard for pcb manufacturing to include IoT components. So, how will these requirements call for pcb design to change? Presently, any IoT device requires sensors, wireless connectivity, and power. For example, new IoT devices such as wearable smart watches are getting smaller, therefore needing tinier components that possess the same functionality. These devices are also getting ‘smarter,’ which will require fitting more components into a smaller space than ever before. We can’t forget to mention that consumers expect new IoT devices to sustain an even longer battery life, so pcb design must also ensure reliable power management. Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/16/2022 10:20

What is CAF PCB during Manufacturing with 5 Effective Tips?

Many other factors are believed to accelerate the formation process including high temperatures, high humidity, repeated thermal cycles, high voltage gradient between anode and cathode, some soldering flux ingredients and more. Other problems, such as component failures and exceeding maximum operating temperatures might also contribute to a CAF-related failure. In this passage, we are going to learn more information about CAF PCB during manufacturing?Please check and read the content below in this article for more professional knowledge.Wanna know PCB knowledge? Check and read for more. How to identify the CAF PCB during manufacturing? Identifying CAF once it occurs is challenging, making it difficult to inspect and study. CAF often occurs in layers buried within PCBs. It also can appear alongside other contributing failure factors, making it hard to realize when CAF is a solely-responsible failure mode. You can, however, use various advanced testing methods to check for and characterize CAF formation and failure. These tests include IPC-standard electrical methods known as Surface Insulation Resistance (SIR) tests, which include: IPC Electrochemical Migration Testing: An IPC standard test to measure the resistance to the flow of current across the surface of a PCB substrate.Temperature-Humidity-Bias (T-H-B) Testing: A SIR test that takes into account the processing temperature, relative and aging humidity and voltage bias. You can also use various methods to image CAF formation on a PCB. These techniques include: · Scanning Electron Microscopy (SEM): This method involves the use of a primary electron beam gun that sends electrons toward the positively charged anode in a vacuum through electromagnetic lenses. You can operate this device in either secondary electron (SE) mode — which is ideal for surface-topography imaging — or backscattered electron (BSE) mode, which allows for atomic number contrast.· Energy Dispersive Spectroscopy (EDS): This incident electron beam can be used to identify elements such as copper, chlorine and bromine.· Focused Ion Beam (FIB): With this technique, you can magnify a surface at high resolution and then make a thin cross section to obtain a 3-D image.· Transmission Electron Microscopy (TEM): This system, which works similar to a light microscope, can identify material phases and determine the crystallographic structure.· X-Ray Photoelectron Spectroscopy (XPS): Sometimes referred to as electron spectroscopy for chemical analysis (ESCA), this method is a surface-analysis technique that can identify chemical compounds.· Fourier Transform Infrared Spectroscopy (FTIR): This technique analyzes organic constituents and creates a spectrum of intensity and wavelength readings.· Ion Chromatography: This process, which may be either anion or cation-exchange chromatography, separates ions and polar molecules. What are the reality problems of CAF PCB during manufacturing? There are many different measures you can take to minimize the risk of CAF failure. Researching into ways to avoid this problem is ongoing, but avoiding the conditions enabling CAF formation will help prevent it. Here are some of the factors to consider: Moisture and Humidity Because it requires an electrolyte, higher water content increases the chance of CAF failure. Increased humidity leads to higher moisture content, which decreases CAF performance. Processes That Lead to Acid Contamination Processes used during fabrication can introduce acid contaminations, which increases the likelihood of CAF formation. The use of some soldering fluxes and the introduction of acid residues during the plating process are examples of this. Bias and Voltage Since bias voltage is the force that drives the reaction, a high-voltage bias will significantly lower the chances of CAF formation. Higher voltages decrease CAF performance as well. Pre-Existing Defects Pre-existing defects such as fracturing, voids, wicking, contamination and misregistration can also create pathways for problematic filaments. You need to be careful when drilling holes so as not to cause damage to the board. Such damage can create these pathways by causing cracks, wicking and other defects. Drill speed, feed rate and other factors influence how likely these issues are to occur. Partial defects such as incomplete bridging between features can contribute as well. High temperatures like those from environmental temperature, repetitive thermal cycling and reflow with a high peak temperature create more stress on a board and increase the likelihood of damage as well CAF formation.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/15/2022 10:05

What Are the Considerations of ICT in PCB Manufacturing？

Upfront cost is the payment made in advance to the manufacturers before the testing and inspection starts. Unit cost is an expenditure incurred to produce, store, and sell one department unit of a particular product or service. Cost is also inclusive of the maintenance you'll need to make on the PCB once in a while. An instance, even if your products design changes, you may only need a program change. In ICTs, however, you will need a new fixture and components. If you are going to learn more about ICT in PCB manufacturing, please check and read this passage.Wanna know PCB knowledge? Check and read for more. What are the advantages of ICT? ICT has some significant advantages that have been the reason manufacturers opt for it for centuries. They include: · In contrast to the AOI and flying probe testers, it can test the ball grid array assemblies (BGAs). · Straightforward interpretation: the ICT system quickly locates the faultiness and presents it to you in a matter of minutes. You may not need professionally skilled personnel to proceed with the interpretation. · Fast/ Time-effective: it roughly takes 1 minute in comparison to a flying probe tester that may take about 25 minutes. Being short is in regards to contacting all the board’s test points at once. · Easy program generation: an ICT tester is effortlessly programmed. In that, you can take files from the PCB outline to make the essential program. · It can test functionality as well as assembly defects as ICT systems can handle complex testing methods. · Cost-effective: The high speed helps in quick recovering of the expense of setting up the fixture and program. It is especially true when considering boards that you assemble in large volumes. · ICT platforms: The testing platform for ICT is available in both Windows and UNIX OS, making it universal. · The testing can carry out several tests without applying power to the Device Under Test (DUT). It ensures a safe test and protects the board from any damage. What are the basic concepts of ICT in-circuit test? In circuit test equipment provides a useful and efficient form of printed circuit board test by measuring each component in turn to check that it is in place and of the correct value. As most faults on a board arise out of the manufacturing process and usually consist of short circuits, open circuits or wrong components, this form of testing catches most of the problems on a board. These can easily be checked using simple measurements or resistance, capacitance, and sometimes inductance between two points on the circuit board. Even when ICs fail, one of the major reasons is static damage, and this normally manifests itself in the areas of the IC close to the connections to the outside world, and these failures can be detected relatively easily using in-circuit test techniques. Some in-circuit tester are able to test some of the functionality of some integrated circuits, and in this way give a high degree of confidence in the build and probability of operation of the board. Naturally an in-circuit test does not give a test of the functionality of a board, but if it has been designed correctly, and then assembled correctly, it should work. In-circuit test equipment consists of a number of elements: In circuit tester: The in circuit test system consists of a matrix of drivers and sensors that are used to set up and perform the measurements. There may be 1000 or more of these driver sensor points. These are normally taken to a large connector conveniently located on the system Fixture: The in-circuit test system connector interfaces with the second part of the tester - the fixture. In view of the variety of boards this will be designed specifically for a particular board, and acts as an interface between the board and the in circuit tester. It takes the connections for the driver sensor points and routes them directly to the relevant points on the board using a "bed of nails". Software: Software is written for each board type that can be tested. It instructs the test system what tests to perform, between what points and details of the pass / fail criteria.These three elements for the major parts of any in-circuit test system. The tester will be used for a variety of boards, while the fixture and software will be board or assembly specific. In circuit test system are normally relatively expensive items of equipment. They are typically sued on high volume production lines. The fixture and programme generation costs mean that they are not viable for small runs of less than 250 to 1000 items. A cost analysis should be undertaken to ensure that the cost of generating the fixture and programme is viable.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/15/2022 09:56

What Factors Did the Technician Considered in Etching the PCB？

The etching process is one of the major steps in the final processing of printed circuit boards (PCBs). This process removes excess copper so as to reveal the desired circuit patterns. In the PCB etching process, all copper is removed except the circuitry that is protected by the tin plating that was applied during the previous treatment in PCB manufacturing. The tin is then stripped and the copper is cleaned and the newly prepared circuit is ready to move on to the next step in manufacturing. Are you curious about etching the PCB? If you are curious about more information about etching the PCB, please check and read the content below for more professional knowledge.What are the main types of etching the PCB? PCB etching is the process of removing copper from a circuit board layer that is not protected by the hardened photoresist by immersing it in a chemical solution. The etching used by industrial circuit board fabricators is broken into two different processes: acidic etching and alkaline. Acidic etchingAcidic etching is used for removing copper from internal layers in standard rigid FR-4 circuit boards due to its precision and less aggressive action. The acidic process won’t react with the photoresist and will produce less of an undercut in the metal it etches. The trade-off, however, is that acidic etching will take longer than other methods. Alkaline etchingAlkaline etching is used for the outer layers of the circuit board, where a quicker process is more to maintain the uniformity of the remaining copper. Alkaline is more active than acidic and requires careful monitoring to ensure its accuracy. The acidic and alkaline etching processes are ideal because they have a high etching rate at a relatively low operational cost and effectively etch many different metal materials. PCB fabricators must precisely maintain their etching processes to guard against exposure to hazardous liquids and fumes and prevent any chance of water contamination. Now, let’s see how this etching is used in the fabrication of printed circuit boards. What are the advantages and disadvantages of etching the PCB? Advantages of wet PCB etching · The most important advantage of wet PCB etching is that it can be conducted in a normal atmospheric environment.· High etching rate· Low operational cost· High selectivity: wet etching can be used to etch off a wide range of materials.· Ease of equipment maintenance Disadvantages of wet PCB etching · Inadequate power to etch traces <1μm.· High use of chemicals· Creating a significant amount of hazardous chemical waste· The risk of wafer contamination· Chemical hazards· Direct exposure to liquids· Direct and indirect exposure to fumes What are the types of chemical solution used in PCB etching? The etch rate is stable. It is particularly suitable for producing the correct topography and cleanliness for hot air levelling. It is non foaming and sprayable. 150 MG copper etchantIt is a proven etchant, specially designed for etching copper in the manufacturing of printed circuit boards during mass production. MG Etchant chemicals are based on ammoniac compounds in highly selected proportions. It can be used in spray or immersion application. 1932 Nickel cleanerIt is an aquoues solution of acidic chemical components used to restore the solderability of nickel plated and nickel alloy surfaces. Tarnish can be removed by immersing the part for 15-20 seconds at room temperature. Immersion time can be reduced if the solution is warmed up to 74°C . After treatment the part should be thoroughly cleaned through hot water spray, followed by cold or hot water immersion. 6401 Solder stripperIt is an acid based stripper designed to be used for stripping tin, tin / lead and lead from PCBs. It is extremely economical and will hold in excess of 15 oz. per gal. without replenishment. It contains a unique stabilizer, copper inhibitor system which reduces base metal etching during stripping. 6810 Resist stripperIt is a concentrated alkaline solution formulated specially to remove alkaline soluble dry films and silk screen printing inks from printed circuits boards. It contains no organic solvents and can be used in dip tanks and spray equipment. 8200 De-foamerIt is an alkaline, non-silicon de-foamer (foam suppressant) used in conjunction with all alkaline resist stripper and developer solutions. It is recommended for use in conveyorised spray machines. It operates over a wide temperature range, which allows it to be used where necessary to control excessive foamingWanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/15/2022 09:33

What is PCB Wave Soldering and What Is the Function?

In the market, you will encounter many kinds of wave soldering machines. You can buy lead wave solder machines or lead-free wave solder machines. It is all up to you. However, the main principles and fundamental parts of all of these machines are alike. A conveyor is an essential part that is used during this process. It takes printed circuit boards via various zones. Are you going to learn more information about PCB wave soldering? If you are looking for more information about PCB wave soldering, please check and read the content below in this passage.Wanna know PCB knowledge? Check and read for more. What are the common problems of PCB wave soldering? Wave soldering is a large-scale soldering process by which electronic components are soldered to a printed circuit board (PCB) to form an electronic assembly. The name is derived from the use of waves of molten solder to attach metal components to the PCB. The process uses a tank to hold a quantity of molten solder; the components are inserted into or placed on the PCB and the loaded PCB is passed across a pumped wave or waterfall of solder. The solder wets the exposed metallic areas of the board (those not protected with solder mask, a protective coating that prevents the solder from bridging between connections), creating a reliable mechanical and electrical connection. The process is much faster and can create a higher quality product than manual soldering of components. Wave soldering is used for both through-hole printed circuit assemblies, and surface mount. In the latter case, the components are glued by the placement equipment onto the printed circuit board surface before being run through the molten solder wave. What is the preparation of PCB wave soldering? In order that a electronics printed circuit board may be successfully processing using a wave soldering machine, it is necessary that it is designed and manufactured in the correct manner. Solder resist layer: The first is standard practice when designing boards these days. A solder resist or solder mask layer is included in the PCB design, and this adds a layer of "varnish" like material to the board to which the solder will not adhere. Only those areas where the solder is required are left exposed. This solder resist is most commonly green on colour.Pad spacing: The second main precaution is to ensure that there is sufficient spacing between the solder pads requiring soldering. If they are too close then there is the possibility that the solder may bridge the two pads causing a short circuit. In view of the way that wave soldering works, where the solder wave is caused by the solder flowing out of the reservoir tank, and the board passes over it, the spacing requirements are dependent upon the direction of the board relative to the solder flow. Pads that are spaced apart in the direction of the solder flow should have a greater spacing than those that are spaced at right angles to the solder flow. This is because it is much easier for solder bridges to occur in the direction of the solder flow. What are the defects of PCB wave soldering? Insufficient hole fill is a problem that occurs on printed circuit boards with pre-drilled holes for components to be mounted onto the board. Essentially, insufficient hole fill occurs when an inadequate amount of solder has filled the holes drilled for the components, meaning solder won’t stick to the circuit board once it cools. There are several reasons for insufficient hole fill: The flux was applied incorrectly and did not penetrate through the board, meaning the solder was not activated and could not bind the components properly.The temperature of the top side of the board isn’t high enough to turn solder molten so it can rise through the holes. There was not enough of the board in the wave of the solder. If not enough of the board makes contact with the wave, too little solder is pushed up into the through-holes.The best way to fix these issues is to run through another series of pre-solder checks. Check the type of flux you’re using, and make sure there’s a sufficient volume of it to cover the entire PCB. This step will also help with the second problem: insufficient pre-heat. Older flows to heat, the solder won’t flow as well if your PCB’s through-holes aren’t at the correct temperatureSince solder flows to heat, the solder won’t flow as well if your PCB’s through-holes aren’t at the correct temperature. While the “right” temperature depends on your company’s operating standards, the general rule of thumb is between 300 and 340 degrees Fahrenheit, or roughly 150 to 170 degrees Celsius. The whole assembly needs to reach this temperature before the board makes contact with the wave. If you’re not sure whether your through-holes are reaching the correct temperature, take a profile of the wave-solder process — it should look either exactly alike or very similar to your board’s reflow processes.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/14/2022 09:57

How to Reflow PCB during the Manufacturing Process in Factory?

As mentioned already, an infrared lamp is used to heat the air and melt the solder in the reflow soldering technique. The board is passed through a tunnel or reflow oven where it is heated in a controlled manner. In this, you apply the solder paste only over the areas (contact pads) where you want to assemble the electronic components. In this passage, if you are looking for more information about reflow PCB, please check and read the content below for professional knowledge.Wanna know PCB knowledge? Check and read for more. What the considerations are of reflow PCB? Reflow soldering is the most popular and widely used method of connecting surface mount technology (SMT) components to a printed circuit board (PCB) . The process is focusing on creating acceptable solder joints by pre-heated components, which provides the opportunity to melt the solder without causing damage by overheating. In order to create an appropriate reflow profile, thermocouples are connected to a simple assembly (often using high-temperature solder), in different locations to measure the range of temperatures across the printed circuit board. Proheat- During this phase of the process the printed circuit board, components and solder are heated to a specific dwell or soak temperature, with the main aspect, which is not to be heated too quickly (usually no more than +2 degrees a second). Fast heating could cause component defects such as solder paste slattering or cracks. Soak- This is the part of the project in which it ensured that the components have reached the required temperature before entering the next reflow stage. The soaks last no more than 60 to 120 seconds, depending on the type of assembly. Reflow- In this general stage, the temperature in the oven is increased above the melting point of the solder paste, forming it into liquid. The time in which the solder is held above the melting point temperature is important to ensure that the "wetting" occurs between the printed board and the components. The time is about 30 to 60 seconds and it should not exceed to avoid the creation of brittle solder joints. Another thing that you should know is that the peak of the temperature has to be strictly controlled as many of the components could fail if they are exposed to excessive heat. On the other hand, it is important for the temperature to be high enough in order to achieve the desired results. If the reflow profile provides insufficient heat, it will result in bad solder joints which is one of the most common defects. Cooling- It is not healthy to heat the assembly fast, here would be the same. Make sure to never cool down the assembly too rapidly as it could lead to malfunctions. The recommendation here is to keep the rate of cooling above 3 degrees a second. What are the basic solder components? After the printing of a circuit board, the first step in reflow soldering is the application of the solder to the board. The paste must be applied only to the relevant areas of the circuit board. In this stage, accuracy is key. For this reason, a paste mask is essential when applying solder. The paste mask is a stencil to be placed on the PCB. (You can read more about the solder paste printing process here) It indicates the areas for solder application. Some mass production systems utilize both a solder mask and paste machine for a more automated process. After the direct application of solder to the specified areas of the board, it is time to put the components in place. This requires the use of a pick and place machine. The technology removes the need for a laborious and lengthy manual process. Pick and place machines allow for rapid, highly precise application of the electrical components to the circuit board in a repeatable process. Following placement, the natural adhesive of the solder paste temporarily holds the components in place. This allows for the secure transfer of the components to the oven. Reflow soldering VS wave soldering How do you know which type of soldering to use and when? It may depend on a variety of factors, such as pad shapes, the amount of time you have, component orientations, type of printed circuit board and more. In some ways, wave soldering is more complex. Issues like board temperature and time the board spends in the solder wave need careful monitoring. Failure to create the right wave soldering environment is much more likely to lead to board defects. You don’t need to be nearly as concerned about controlling the environment when you’re utilizing reflow soldering to fabricate your printed circuit boards. However, even with that being the case, wave soldering tends to be faster and cheaper than reflow soldering. In more than a few cases, it’s the only practical way to solder a board. Reflow soldering is typically used in smaller-scale manufacturing products that don’t require a method amenable to fast, cheap mass production. Keep in mind that you may be able to use both reflow soldering and wave soldering for certain situations. You might reflow solder parts on one side and then wave solder them on the other. Also, you can always manually solder or hand solder PCB components, but this will rarely be a good approach if you have access to one of the mechanical methods of soldering. Manual soldering would only be an alternative to reflow soldering, but reflow soldering is still far superior.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 02/14/2022 09:46