5 Considerations of PCB CAF Failures for PCB Manufacturing Quality Control

The concerns with board reliability and the possibility of conductive anodic growth in printed circuit board assemblies have increased in the last few years. Original equipment manufacturers have increased the design density, and are concerned with field failures due to conductive growth. Do you know how to avoid PCB CAF failures? Are you going to learn more information of PCB CAF failures? In this passage, we are going to learn all the details of PCB CAF failures, if you are interested in it, please check and read the content for more.If you want to order PCB product, please check and custom your order online. 1. What is the historical basic of PCB CAF? CAF was first identified in 1976 by researchers at Bell Lab. The first studies involved tests of different coatings of UV-cured resins using FR-4 fine-line flexible printed circuits. Further failure-preventing variables were also studied, including the number of glass-reinforcement layers, cover coat and the thickness of the epoxy butter coat layer. Researchers found they could model time to failure on a log-normal plot and identified temperature, humidity and bias as factors that sped up the process. They also described four substrate-related failures. In 1979, researchers first used the term CAF to refer to these failures. The paper that first used it focused on how materials and conductor orientation related to CAF formation. That same year also saw the introduction of the two-stage model. Investigations into CAF has continued to this day, with researchers testing how humidity, temperature, bias, materials, conductor orientation and other factors influence its formation. Most of this research has focused on traditional laminates, such as FR-4, G-10, BT and MC-2. More recently, though, some have applied newer materials, namely CAF-resistant or halogen-free laminates, which typically have improved thermal properties.2. How to identify PCB CAF? 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. 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.3. What are the factors of PCB CAF? · Electrolyte – Water· Voltage bias – Force that drives the reaction· “Pathway” – A way for the ions to move from the anode to the cathode· The following factors accelerate CAF formation· Higher water content· Higher Voltage levels· Higher temperature (increases reaction rate of corrosion 4. What is CAF resistance in PCB? Conductive Anodic Filament (CAF) has been increasingly concerns on printed circuit boards in the last few years. The major factors are current trend toward smaller size, lighter weights, thinner and higher performances that the density of PCB shall be designed with more closely spacing conductors, much smaller pitches and single-ply dielectrics such as mobile telephones, notebook computer and camcorder. In the other hand, some electrical applications must be exposed in extreme environment. For example, the safe necessity of automotive like engine control and brake control system. There cannot occur electrical shorts phenomenon, so the insulation resistance of material becomes very importance. These factors are pushing the demand for anti-CAF materials. CAF is an electrochemical corrosion process that causes electrical shorts, when copper metal is dissolved at the anode and migrates to the cathode through the resin matrix/ glass fibers interface. CAF can occur between any two oppositely adjacent conductors when the conductors are in contact with the glass fibers. There are four ways that include hole-to-hole, line-to-line, hole-to-line and layer- to-layer. (See above diagram).5. What is CAF formation? ·Electrical-charge carriers, which enable the formation of an electrochemical cell. ·Water, which occurs due to humidity and moisture build-up and dissolves the ionic material, sustaining them in their mobile ionic state. ·An acid environment near conductors to enable corrosion at the anode.·A voltage bias, which is the force that drives the reaction.·A pathway for the ions to take as they move from the anode to the cathode. 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.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 10/29/2021 09:29

How to Make Vias in PCB through 7 Effective Methods for Beginners?

Vias are vital in multi-layered boards, which are challenging to design and produce. They create routes for the sufficient flow of electrical and thermal current between the board's different layers. In brief, vias are basically channels that vary in size and type. Are you a beginner for PCB manufacturing? If you are interested in the methods of making PCB vias, please check and read the content for more professional knowledge.If you want to order PCB product, please check and custom your order online. 1. How to route high-speed signal vias on PCB? Like signal traces, vias introduce inductance and capacitance to the circuit. In signals with lower frequencies, such characteristics are often negligible. However, placing vias on high-speed traces can alter the impedance and affect signal integrity. It’s advisable to avoid using vias on high-speed signals.2. How to pay attention to signal degradation of PCB via? You’ll also need to be wary of via stub, where a portion of the drilled via is unused. Via stubs exist when signals are routed from an outer layer to the middle layer, leaving the remaining section acting as an antenna. Via stubs may degrade the signal traveling on the trace itself. To prevent via stubs, back drilling is performed to remove the unused copper section on the via.3. How to plate vias on PCB? It is often desirable to perform additional treatments to the vias later in the production sequence to improve either thermal performance or assembly yield. These may include epoxy hole filling, secondary solder masking, or some combination of the two. These additional process steps are most often intended to eliminate assembly issues such as solder shorting between a component pad to a via pad or solder migrating down through the barrel of a via which has been drilled into a component soldering land. These problems lead to costly troubleshooting and rework. Fortunately, it is possible to eliminate most issues by specifying an appropriate via treatment. Tented vias have a non-conductive solder mask covering over the pad at both ends of the hole. Tenting was popular when dry film solder mask was in its prime, because dry film’s 0.004” thickness enabled it to tent even relatively large holes very reliably without much chance of breakdown. Today however, dry film mask is no longer used since its height causes difficulty with modern surface mount soldering.4. What are the limitations for multilayer PCB? Underwriter laboratories say that for supreme quality and reliability, you should not produce PCBs that need over three lamination steps. It means that you should not design vias such that they need more than three steps for assembly. This issue arises when you are dealing with PCBs having more than six layers. Figure 4 shows an example of a 10-layer PCB that would need two lamination steps. The first step, drill the buried holes and electroplate them from layers 3 to 8. In the second step, drill the blind holes and electroplate them on their layers and then laminate the rest of the layers. In the end, drill the through-hole vias and electroplate them, but this is not a lamination step. Hence, this PCB board only requires two lamination steps and three drilling steps.5. What are the 5 types of PCB via? Via A plated-through hole(PTH) for inner layer connection and not for inserting component leads or other reinforcing materials. Blind viaThe hole does not pass through the entire workpiece. The blind hole always has a specified depth, which usually does not exceed a certain ratio (aperture). The literal meaning of a “blind hole” is that it is not possible to see through the hole. For example, for a 6-layer board, the drilling is only from layer 1 to layer 4. This is called a blind hole. Buried viaBuried Via is a copper-plated hole that connects two or more internal layers of the board and is not accessible by the external layers. And it’s not possible to discover a buried viain a PCB because it is “buried” under the external layer surfaces of the board. For example, for a 6-layer board, the drilling only goes from layer 3 to layer 4; this is called buried via. Though viaThe through-holes extend from one outer layer of the PCB to another outer layer. Component holeThey are holes for fixing the components on the printed board and electrically connecting the conductive patterns.6. How to select vias for PCB? In ordinary PCB design, the parasitic capacitance and parasitic inductance of the via have little effect on the PCB design. For 1 to 4 layer PCB design, it is better to use 0.36mm/0.61mm/1.02mm (drilled hole/pad/power isolation area) via holes. Some signal wires with special requirements, such as power wires, ground wires, clock wires, etc., can choose 0.41mm/0.81mm/1.32mm hole. They can also choose other sizes of holes according to the actual conditions.7. What are the benefits of PCB via? Because PCBs have limited amounts of space, blind and buried vias can be a huge benefit. They allow you to keep the PCB small, which is essential when working with electronics. The use of vias frees up space on the surface of the board; that space can then be used for other functions. Vias are a relatively simple solution, but you will need to be aware that the addition of blind and buried vias will add to the cost of the board. Because there are many factors that go into getting the right PCBs with the correct blind and buried vias, it is important to work with a quality manufacturer.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 10/29/2021 09:22

Top 5 Important Elements of PCB Bare Board Manufacturing

In PCB terminology, the term bare board refers to the state of a PCB without any through-holes or electronic components. A bare board consists of manufacturing processes that are comprised of the PCB’s substrate, metal coating, conductive pathways and patterns. These pathways and patterns direct electricity which way to flow in the circuit. Are you curious about the knowledge about PCB bare board? In this passage, we are going to provide you all the details about PCB bare board. If you are going to learn more about PCB bare board, please check and read content below.If you want to order PCB product, please check and custom your order online. 1. What are the advantages of PCB bare board testing? Implementing bare board testing in the PCB design process can lead to: · Cost savings: Extensive testing in early design stages can help you save on the costs associated with faulty assembled PCBs.· Streamlined production: By identifying issues in the prototyping stage, you can save time in later phases of production.· Issue resolution: Bare board testing will help you identify potential issues early in production while narrowing down each problem’s source.2. What are the inspection types of PCB bare board? Notice that the visual inspection only works when inspecting a two-layer PCB. It is the testing of the printed circuit board. This could be done manually or using automated devices to help find any possible problem. However, in multi-layer PCBs, a visual inspection will not give you the desired results. As such, it may be necessary that you conduct an electrical test. Electrical TestHere you may have to choose between a universal grid and a flying probe. The universal grid requires that you use fixtures in conducting the test, while the universal grid does not require the use of institutions. The universal grid is also referred to as the bed of nails or clamshell test. Typically, a PCB test could either be capacitance or resistance. The capacitance test helps to detect opens and shorts. At the same time, the resistance test helps to measure the flow of current through traces. If you have traces of the same material, but one is two times longer than the other, the resistance of the longer one will be two times the resistance of the shorter one.3. What is the basic structure of PCB bare board? A bare board PCB (printed circuit boards) and the bare board testing play critical roles in PCB creation. Bare board, is the PCB before the electric components or through holes are placed on it. A bare board printed circuit boards comprise of: · Substrate· Metal Coating· Conductive Pathways Through a bare board layout, you could determine the placement of the components. In addition, the bare board testing can go a long way in ensuring that what you have is a reliable product. Our bare printed circuit boards also assist you in penalization, place your PCB on large boards, mounting and plating process. We understand the complexity of PCB bare board manufacturing. Our goal is to provide best product which can fit your needs and best customer service.4. What are the common defects of PCB bare board? Excessive or missing copperThe essential element used to make traces on a bare board PCB is copper. Copper is used based on the fact that it’s highly conductive, meaning that it can quickly transmit signals without losing some electricity along the way. However, either excessive or inadequate copper may cause defects on a bare board printed circuit board. Too much copper may bring about corrosion, while insufficient copper may bring about short-circuits to the board. Short circuit problemA short circuit is an electrical circuit problem that occurs when two or more wires that aren’t supposed to come into contact together touch each other. A short course may bring about very high currents that flow through the course. That’s not all. A short course also takes place the moment there’s a bypass of some electrical current. When it comes to the production of bare board printed circuit board production, short circuits are common problems that many designers face. However, to fix the problem, there’s a need to replace the wire. Otherwise, your bare board printed circuit boards won’t function as intended.5. How to select proper material for PCB bare board? The primary material used in bare printed circuit board manufacturing is of immense importance. It is essential to factor in vital aspects such as the performance of the chosen materials such as adhesion, temperature resistance, flexibility, tensile strength, dielectric strength, flexibility, thermal factors, and many other physical factors. The performance of a bare board printed circuit board depends on the material chosen to manufacture it. Some of the most common materials used in the fabrication of empty board printed circuit boards include the following: • FR-4 – FR-4 is a common material used in the manufacture of bare board PCBs. This material is made of a glass-reinforced epoxy laminate sheet. This material is water and flame resistant. • PTFE (Teflon) – this is a kind of plastic material that doesn’t provide any resistance. It is preferred based on its high speed. • Metal – traditional materials such as copper, iron, and aluminIum still find their way in bare PCB manufacturing. They are preferred based on the fact that they provide excellent mechanical durability.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 10/29/2021 09:06

5 Essential Aspects of PCB ICT Guidelines in PCB Manufacturing Process

There are three general areas for the board designer to be concerned about. First, it is necessary to determine what connections are needed from an electrical standpoint. Once this is determined, there are the mechanical concerns about how to provide areas for the probes to contact and how to align the board. Are you going to learn more about PCB ICT? In this passage, we will provide everything about PCB ICT, please check and read the content for more information.If you want to order PCB product, please check and custom your order online. 1. How to process location holes for PCB? In order that the connections can be made to the board, it is necessary to have accurate position or location holes that can be used to accurately locate the PCB onto the test fixture. In this way the PCB board can make accurate location onto any probes or connections required. Requirements for the tooling holes may include: · Three preferred but a minimum of two, on opposite diagonal corners· Tooling or location holes should not be plated to ensure their accuracy· Tooling or location holes should not be obscured and they should be free from components etc in the vicinity of the hole to enable any locating spigots on the test fixture to mate with the hole.· Location accuracy of the tooling or location holes should typically be within 0.05 mm, i.e. 0.002 inches, although with techniques changing all the time, check the requirements for the actual tester..2. What are the considerations before PCB ICT? The first step that a contract manufacturer will take when reviewing a design for test is to consult the customer test specification that has been provided. With this information, a test method can be developed to cover the specifications. Although the CM test engineers can create their own specification if necessary, it is a good practice for you to give your CM as much information as possible so the board is fully tested to the customer’s expectations. The CM will include marking up the schematic with test and connection points as part of their test review, as well as examining the layout. It is another good design practice to include specific test points in the schematic to help the CM with this preparation. The design review combined with the test methodology will help determine the type of fixture that is needed and if any modifications to the design are warranted to increase the effective fault coverage of the test procedures. All of this information is then incorporated into a test instruction (TI) document accompanied by descriptions, illustrations, and expectations for the test technicians to use during actual testing.3. What is the basic equipment for PCB ICT? 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.4. What is the standard ICT machine? In normal circumstances, this is the general test in this form of testing. However, they're standard because they offer elemental resistance, capacitance, and some device functionality.5. What are the benefits of PCB ICT? Although a costly fixture is required, ICT covers 100% testing so that all power and ground shorts are detected. · ICT testing does power up testing and eliminates customer debug needs to almost ZERO.· ICT does not take a very long time to perform, for example if flying probe takes 20 minutes or so, ICT for the same time might take a minute or so.· Checks and detects shorts, opens, missing components, wrong value components, wrong polarities, defective components and current leakages in the circuitry.· Highly reliable and comprehensive test catching all manufacturing defects, design faults, and flaws.· Testing platform is available in Windows as well as UNIX, thus making it slightly universal for most testing needs.· Test development interface and operating environment is based on standards for an open system with fast integration into an OEM customer’s existing processes.Wanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 10/28/2021 09:34

What is Package in PCB Design with 5 Essential Tips for Customers？

Many PCB design software packages are available, ranging from software that can be downloaded for free to high end tool suites costing tens of thousands of dollars. But which is best for your application? Are you going to learn package in PCB? If you are interested in package in PCB, please check and read the content for more information.If you want to order PCB product, please check and custom your order online. 1. What is material composition of Package in PCB Design? The performance of an IC package relies largely on its chemical, electrical and material makeup. Despite their functional differences, lead-frame and laminate packages both rely heavily on material composition. Lead-frame packages, the prevailing format, use silver or gold wire-bond finishes, attached with a spot-plating method. That makes the process simpler and more affordable. On ceramic packages, Alloy 42 is a widely used metal type because it works with the underlying material. On plastic packages, the copper lead frame is preferable because it safeguards the solder joint and offers conductivity. Due to policies in certain territories, the material is also one of the critical factors on surface mount plastic packages. Because of revisions in European standards, the lead finish has been a matter of intense scrutiny on next-level packaging assembly. The aim has been to find viable replacements for tin-lead solders, which are easily applied and have been a longtime staple throughout the industry. However, manufacturers have yet to unify around a single solution, due in part to the widespread competition among suppliers. The lead issue is unlikely to resolve itself for some time to come.2. How to select package for PCB? In its simplest form, SMD package selection may be thought of as identifying a device that meets your functionality requirements while fitting within any space restrictions or limitations your design may have. However, you should also incorporate rules and guidelines for your board’s fabrication and PCB assembly; this is best done by including your contract manufacturer (CM) early in the design process. By collaborating with your CM before and during the prototyping process, you can utilize SMD package selection options that may reduce board turnaround time and cost. One option that will simplify the board fabrication and PCB assembly of your design, while providing easier access for functional testing, is using larger component packages. In addition, you can also use a non-form factor or a larger board than required by the production design. Besides this relaxation of size restraint options, you may also want to use less-complex vias to the extent possible. This is not a recommendation to change the number of layers in the stackup, but instead to use pitch spacing that is easier to fabricate, for example from ball grid array (BGA) and chip scale packages (CSPs).3. What are the required materials for PCB package? The lead frame materials are the dominant IC package materials. Hence, engineers use them mostly for wire-bondable finishes and wire-bond interconnected die. And a perfect example is gold or silver. These finishes get plated in the inner bond-land area via a spot-plating method. By doing so, you’ll be saving a ton of cost. And it’s because noble metals don’t join to encapsulants with ease. It’s because three factors establish the foundation of a package. And they are: · Chemical properties· Physical properties· Electrical properties4. What are the packages for ceramic PCB? Income or Alloy 42 is a common choice for ceramic packages. Why? It’s because there’s a linkage between the alloys and CTE. The close match is a crucial feature because of the ceramic’s brittleness. But, the low CTE could have a harmful effect. And it’s worse if you install the final assemblage of surface mounted devices. However, the size of the CTE plays a significant role. And we can link everything to the mismatch of most common PCB substrates. We must also note that lower CTE metals have an excellent reputation to work well as lead frames. And they work perfectly for plastic DIP-type and ceramic packages. However, copper lead frame materials are usually an ideal choice for surface mount plastic packages. And it’s because they have the capacity and compliance to secure solder joints.5. What are the benefits of PCB package? PoP technology is being widely applied by OEMs owing to its impressively advantages: • Flexibility - Stacking structure of PoP provides OEMs such multiple selections of stacking that they are able to modify functions of their products at ease. For example, they are allowed to modify low-memory chip into high-memory chip to cater to newly-coming demands without need to change circuit board design of motherboard. • Overall size reduction• Shrinking overall cost• Reducing motherboard complexity• Improving logistics management• Enhancing technology reuse levelWanna know PCB knowledge? Check and read for more.

PCB Knowledge ⋅ 10/28/2021 09:26

5 Main Factors during SMT PCB Assembly Process

The majority of the surface mount technology (SMT) parts on a PCB will be assembled with automated pick-and-place equipment. To prepare for that, the raw boards and the components must be prepared for production. This begins with both being validated by the CM’s inspection teams. Once that is complete, the boards will then be prepared for assembly using this process: PCB Instant Quote .my-button { display: inline-block; padding: 10px 50px; font-size: 16px; text-align: center; text-decoration: none; background-color: blue; color: #fffff0; border: none; border-radius: 5px; font-weight: bold; cursor: pointer; box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.3); transition: background-color 0.3s ease, transform 0.3s ease; } .my-button:hover { background-color: #C23C30; transform: scale(1.05); } And if you are going learn the knowledge of SMT PCB assembly, please check and read the content for more detailed information below. 1. What are the preparations before SMT PCB assembly? A few preparatory steps have to happen before real PCBA process even begins. This helps PCB manufacturers assess the functionality of a PCB design, and primarily includes a DFM check. Most companies specializing in PCB assembly need the design file of the PCB to start out, along with any other design notes and specific requirements. This is so the PCB assembly company can check the PCB file for any issues that may affect the PCB's functionality or manufacturability. This is a design for manufacturability check, or DFM check, for short. The DFM check looks at all the design specifications of a PCB. Specifically, this check looks for any missing, redundant or potentially problematic features. Any of these issues may severely and negatively influence the functionality of the final project. For example, one common PCB design flaw is leaving too little spacing between PCB components. This can result in shorts and other malfunctions. 2. How to solder the paste for SMT PCB assembly? Applying soldering paste is one of the first steps in the SMT assembly process. Soldering paste is "printed" on the boards using the silk-screen method. Depending on the design of the board, different stainless-steel stencils for "printing" the paste onto the board and various product-specific pastes are used. Using a laser cut stainless-steel stencil custom made for the project, the soldering paste to be applied only to the areas where components will be soldered. After the soldering paste is on the boards, a 2D-soldering paste inspection is performed to ensure that the paste is evenly and correctly applied. Once the accuracy of the soldering paste application has been confirmed, the boards are transferred to the SMT assembly line, where the components will be soldered. 3. How to make DFM check for SMT PCB assembly? Once a turnkey order is released to Bittele’s production team, their very first task is the validate the design through a thorough DFM / DFA Check process. These checks include verification of consistency across different design documents (i.e. BoM, Gerbers, Centroid, etc.), part spacing, footprint accuracy, and clear orientation markings. The main objective of this procedure is to minimize as much as possible the potential for design errors to affect the finished product, which acts to protect Bittele’s clients against the additional time and cost involved with board-level rework. Clients should watch for emails from Bittele’s production team over course of the first one or two days after placing an order. If any issues or discrepancies are detected during this initial check, the production coordinator for the order in question will reach out to the client directly for resolution. Generally, an itemized report will be sent for response, and the order will be placed on hold pending full confirmation, so it is important to reply to these questions as soon as possible in order to avoid delays. 4. What is the process of SMT? Here we divided the complete SMT soldering process into 10 steps: · Printing · Adhesive Dispense · Component Placement · Pre-Reflow Automated Optical Inspection (AOI) · Reflow Soldering · Post-Reflow Automated Optical Inspection (AOI) · Conformal Coating · Final Inspection and Functional Test · Washing & Drying · Packaging & Shipping 5. What are the uses of SMT? SMT assembly was born as a way to create a better, more powerful electronic product. One look around your office or living room will show you several common surface mount technology applications. Basically, turn to surface mount PCB assembly whenever you need a product that’s: · Smaller · Lighter · Faster · More powerful While through-hole is still used in certain applications or even certain locations on a board, SMT assembly has largely taken over

PCB Knowledge ⋅ 10/28/2021 09:15

How to Identify Multilayer PCB with 5 Essential Tips for Beginners?

These types of PCBs offer a range of benefits. One of the most common reasons for using the multilayer PCB is the size. Because of the layered design, it means that the PCB will be smaller than other printed circuit boards but still have the same level of functionality. Most people today want their electronics to be smaller, while still being powerful. The multilayer PCB allows for this. These types of boards also happen to weigh less, which helps to reduce the overall weight of the gadgets in which they are used. However, the size is certainly not the only benefit. PCB Instant Quote .my-button { display: inline-block; padding: 10px 50px; font-size: 16px; text-align: center; text-decoration: none; background-color: blue; color: #fffff0; border: none; border-radius: 5px; font-weight: bold; cursor: pointer; box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.3); transition: background-color 0.3s ease, transform 0.3s ease; } .my-button:hover { background-color: #C23C30; transform: scale(1.05); } In this passage, we are going to provide you the methods to identify the multilayer PCB. If you are going to learn the professional knowledge, please check and read the content for more. 1. What are the advantages of multilayer PCB? · Useful for more complex projects – Complex circuitry requires a multilayer PCB. Complex projects that need advanced equipment must-have tools with multilayer PCBs in them. Luckily enough, this is an easy thing for multilayer boards. · High quality. – Unlike single and double-layered PCBs, multilayer boards require intense planning and production. Therefore, it means that they are of the highest quality compared to other boards. · Increased power. – Based on increased circuit density that is characteristic of multilayer PCBs, this means that they are more powerful. Additionally, they run at very high speeds bringing about enhanced performance in equipment. · Higher durability – Multilayer PCBs are highly durable, partly due to their stack up. · Smaller in size and lighter in weight – More layers in a board mean thicker, hence durable. With more layers, such panels can effectively function in harsh conditions. · Single connection point. – If you use several PCB components, you would need several connection points. But this isn't the case with multilayer PCBs. Their design is to work with a single point of contact. With such, the system becomes simple, and the weight also reduces. 2. What are the types of multilayer PCB? Single-layer PCBs – It is one in which copper layer [thin] coating is on only one side of the board. On the other hand are connections of electrical components connected electrically. Double layer PCBs – In this type of PCB, a thin layer of copper coating is on either side of the board. Drilled holes connect circuits of both parties. Multi-layered PCBs – It is a series of 3 or more double-layered PCBs. Insulation is between each PCB. They are in place through powerful glue. Rigid PCBs – These PCBs use rigid substrate, which does not twist. It comes in a single layer, double layer as well as multi-layer PCB. Flexible PCBs – These PCBs use flexible substrate material. It also comes in a single layer, double layer as well as multi-layer PCB. 3. What are the condiferations of multilayer PCB? When considering how to determine PCB layers stackup, the best practices is to prioritize signal integrity. Signal integrity occurs when RF current generation is avoided with careful organization of the layers. RF currents are generated through unwanted impedances built in the material giving opportunity to generate common-mode currents. Common-mode currents are the primary source of RF energy. RF energy gets into the power distribution network or emits into free space as noise. Noise presents itself as reflections, ringing, or crosstalk. The PCB layer stackup may be designed to incorporate features useful to maintaining signal integrity. Maximum capacitive decoupling in the power distribution network is achieved by placing power planes directly adjacent to ground planes in the layer stackup (see figure above). Signal planes should always have a ground plane adjacent in the PCB stackup. Including a ground plane next to each signal plane enhances flux cancellation and removes noise. Minimizing spacing between conductive layers increases flux cancellation. 4. How to determine multilayer PCB through inspection? Determine the number of PCB layers by inspecting the via holes or blind vias. The principle is mainly based on the use of the via hole technology in the circuit connection of the multilayer circuit board. We're able to determine the number of PCB layers, by identifying the vias. On the single-sided PCB boards, the parts are concentrated on one side and the pins are concentrated on the other side. If a multilayer PCB is to be used, it is necessary to punch holes in the board so that the component pins can pass through the board to the other side, we can see that the pins of the parts are welded to the other side. However, currently more complex buried via technology is used in the circuit board manufacturing; this type of vias is only used to connect couples of inner layers, and invisible on the PCB surfaces. So determining circuit board layers count by inspecting vias is easy-use but also limited. 5. How to determine multilayer PCB with other methods? For novices, it might be a little bit difficult identifying a multilayer board. So, how do you tell that your board has more than a single layer? Read below to understand: · Observe the PCB edge. – If you want to know whether your PCB is multilayered or not easily, observe its boundaries. The advantage of a multilayered PCB is slightly thicker. · View the copper surface under the flash. – The copper surface under the second layer in multilayer PCBs is thicker than those you can find in single-layered PCBs. · Use intense light to analyze the inner layer – If you use a bright light, you'll see if your board has some inner layers. · Observe the traces and paths. – The trails and tracks of single-layered PCBs differ from multilayer PCBs. For multilayer PCBs, you'll most definitely spot return signal paths.

PCB Knowledge ⋅ 10/27/2021 09:30

What is Vapor Phase Reflow during PCB Manufacturing Process?

The vapor layer transfers heat to the PCB and associated components as the assembly sits within it. The heat transfer rate is high, achieves good wetting, and requires much less power input. The process produces very little temperature difference between components of different thermal mass on the PCB. This makes the process very suitable for densely populated PCBs. PCB Instant Quote .my-button { display: inline-block; padding: 10px 50px; font-size: 16px; text-align: center; text-decoration: none; background-color: blue; color: #fffff0; border: none; border-radius: 5px; font-weight: bold; cursor: pointer; box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.3); transition: background-color 0.3s ease, transform 0.3s ease; } .my-button:hover { background-color: #C23C30; transform: scale(1.05); } If you are going to learn the vapor phase reflow during PCB manufacturing process, please check and read the content below for more professional knowledge. What is the structure of vapor phase reflow? The base liquid layer refers to the chemical that provides the vapor you need for soldering. Without the smoke, the soldering can’t occur. When choosing the ideal base liquid, designers and assemblers use a variety of factors, including: · The boiling temperature of the liquid · The liquid’s environmental impact · How corrosive the vapor is Remember, you will immerse the PCB board at the temperature that the liquid boils. That’s why you need a predefined value for the boiling temperature of the base fluid. Of course, you can still manipulate the pressure within the phase chamber of the vapor or opt to operate at ambient air pressure. Be sure to use the correct chemical composition to don’t end up with too high temperatures to destroy components. You also want to make sure that the temperatures aren’t too low to melt the solder enough. It is also crucial that the resulting vapor is non-reactive. This way, no oxidation can cause defective joints. What is the process of vapor phase reflow? Regardless of the solder paste, you utilize, you'll ultimately need to configure both the reflow process and the solder. The aim is to reduce voiding and ensure there's enough wetting. That's why you need to assess the process as a whole instead of looking at each element separately. In general, the vapor phase reflow process requires more investment than other solutions. These solutions include the convection oven reflow process. This investment includes what you spend on the system initially and the fluids you'll need to invest in during operations. In vapor phase reflow, you use Perfluoropolyether Fluorinated Fluids or Golden. The liquids' thermal stability makes them suitable for PCB reflows. These liquids also have a wide operating temperature range, which is excellent for the vapor phase reflow process. The vapor process's reflow process involves heating gold plating. The aim is to provide the necessary temperature to wet the circuit board. This process is especially perfect for PCBs with a wide range of chip sizes. That's because there are minimal temperature fluctuations between components with different thermal mass. Why to process vapor phase reflow during PCB manufacturing? In our search for a Surface Mount Device (SMD) Reflow System that would not require constant profiling every time we ran a new job, Newbury Electronics was reintroduced to Vapor Phase Reflow machines. We wanted to improve the efficiency of our SMD process as the current set up was causing delays and production bottlenecks, and Vapor Phase ovens have proven to be the best investment to eliminate these hold ups. What are the advantages of vapor phase reflow? Vapor Phase Reflow is a great method for SMD PCBAs. The process window is far wider than that for HACR and there is no risk of overheating components. It is a reliable method for small runs of PCBAs where you need to get it right for the first time and offers 100% repeatability for low and high mass boards. As a result, it has become a favorite machine of ours at Newbury Electronics. What are the applications of vapor phase reflow? Medical devices Not only here in the United States, but also many European companies are increasingly using gas reflux for medical device boards. The main driving reason is that gas phase backflow helps reduce Tin Whiskers. There are many experimental data proving that gas phase backflow can greatly reduce Tin Whiskers, both with lead and lead-free welding materials. The electronic products of medical devices are generally used for a relatively long time, and many products are 3 types of products concerning life and close human contact; therefore, he pays more attention to tin whisker, which takes time to form. If you search for "Vapor Reflow + Tin Whisker", there should be many articles online. Large thick boards In ordinary reflux furnaces, large thick boards are prone to uneven heating and problems resulting from large differences between the highest and lowest temperature points. For example board is thick, board face and board bottom temperature difference is big, and make board surface expands first and bend (board becomes warped). In a gas reflux furnace, the uniform heating of the entire boards can greatly reduce many of these problems caused by temperature differences or uneven heating.

PCB Knowledge ⋅ 10/27/2021 09:24

What Is CNC Milling Used for PCB Manufacturing Process?

Depending on various factors, some milling machines will be more appropriate than others. The complexity of the CNC milling process will be dependent on the design of the final part. The more structurally important and high-end the part or product is, the more complex the design may need to be. For example, for intricate designs that require high precision, such as medical parts or aerospace components, a more complex machine may need to be used. PCB Instant Quote .my-button { display: inline-block; padding: 10px 50px; font-size: 16px; text-align: center; text-decoration: none; background-color: blue; color: #fffff0; border: none; border-radius: 5px; font-weight: bold; cursor: pointer; box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.3); transition: background-color 0.3s ease, transform 0.3s ease; } .my-button:hover { background-color: #C23C30; transform: scale(1.05); } In this passage, you can get everything about CNC milling in PCB manufacturing. If you are interested in CNC milling in PCB manufacturing, please check and read the content below for more information What are the advantages of CNC milling for PCB manufacturing process? High quality and precision is guaranteed The very nature of CNC Machining as a process leaves very little room for error and high levels of accuracy and precision. This is because it operates from a computer led program, inputting 3D designs that have been developed via CAD (Computer-Aided Design). All operations are launched via a machine interface. CNC Machined Parts Acid Etched aluminium CNC Milling allows for high production output. The level at which CNC Machines operate means they are capable of high levels of production due to the automated processes involved. Should a part need to be produced in high volume, with every part meeting the same level of consistency in terms of quality and finish, CNC Milling, is a trusted and popular option. It is particularly easy to program and operate a 3-axis machine, achieving high accuracy at a low cost. CNC Milling is a less labour intensive process Using a CNC Milling Machine significantly reduces the amount of labour involved in the production process. At full capacity, the tools used in a CNC Milling machine can spin at thousands of RPM (revolutions per minute), resulting in high production output, while also being a time-saving expense. No manual processes could achieve a similar output. It’s worth noting that the simpler the design is, the less human intervention is needed. For example, if there was a complicated design that required the blank to be moved in the process, this would involve machinists to ensure the process was completed safely and securely. How to process the CNC milling for PCB? Like most conventional mechanical CNC machining processes, the CNC milling process utilizes computerized controls to operate and manipulate machine tools which cut and shape stock material. In addition, the process follows the same basic production stages which all CNC machining processes do, including: · Designing a CAD model · Converting the CAD model into a CNC program · Setting up the CNC milling machine · Executing the milling operation The CNC milling process begins with the creation of a 2D or 3D CAD part design. Then the completed design is exported to a CNC-compatible file format and converted by CAM software into a CNC machine program which dictates the actions of the machine and the movements of the tooling across the workpiece. Before the operator runs the CNC program, they prepare the CNC milling machine by affixing the workpiece to the machine’s work surface or workholding device, and attaching the milling tools to the machine spindle. The CNC milling process employs horizontal or vertical CNC-enabled milling machines—depending on the specifications and requirements of the milling application—and rotating multi-point (i.e., multi-toothed) cutting tools, such as mills and drills. When the machine is ready, the operator launches the program via the machine interface prompting the machine to execute the milling operation. How to select CNC milling machine for PCB? The most widely used variety of CNC machine, CNC milling tools perform a machining process much like both drilling and cutting. At its most basic, milling uses rotary cutters to remove the necessary excess material from a workpiece as it is fed into the milling tool. It’s a popular industrial solution due to the detailed sizes and shapes that milling can accommodate. The rotating cylindrical cutter in a CNC milling machine can move along multiple axes to create unique shapes, slots, holes, and details in a part. Most machines operate on three to five axes, allowing the most advanced tools to perform sophisticated machining with extremely complex geometries. In fact, today’s most intricate CNC projects would be practically impossible to produce with manual tooling. Modern CNC milling machines are assembled as both horizontal and vertical machining centers, and can create precision components from plastics, ceramics, and composite materials, in addition to metals. They come equipped with technical features such as automatic tool changers, tool carousels and magazines, coolant systems, and enclosures. What are the working principles of CNC milling for PCB manufacturing process? Machines are controlled numerically in CNC, where a software program is assigned to manage an entity. The language used in CNC machining is known as G-code, and it is used to monitor the different behaviors of an interconnected system, such as velocity, flow rate, and cooperation. CNC machining, in essence, allows you to pre-program the speed and location of machine tool functions and operate them in routine, predetermined cycles through software, all with no input from human operators. Because of these capacities, the process has been embraced in the manufacturing industry, and it is essential in the areas of metal and plastic processing. A CNC Milling Machine is a machine that uses a spinning cylindrical cutter to drive along several axes and cut slots, gaps, and information in material to produce a vehicle or mechanical component. Modern CNC milling machines may be configured as horizontal or vertical machining hubs. Plastics, ceramics, and composite materials, in addition to metals, can be used to make components. Remote tool changers, tool carousels and magazines, coolant devices, and enclosures are among the technical features that keep machines working smoothly without human intervention. The CNC milling process is used in the vast majority of tangible goods of global industrial production in some way or another. Although it only directly produces a limited percentage of components, it is the most popular way of creating tooling, so it is impossible to eliminate. CNC milling operations nearly all come into play in the course of getting new goods to life, and it’s a good idea to be familiar with the CNC milling process.

PCB Knowledge ⋅ 10/27/2021 09:16

Top 6 Main Features of PCB Substrate Material Properties

If your goal is to design a suitable circuit, you also need to consider how rough the copper foil surface will be. Roughing will ensure that the conductors have peel strength and that bonding of the substrate material and the copper foil is optimal. The standard roughness nowadays is set to around 5μm. PCB Instant Quote .my-button { display: inline-block; padding: 10px 50px; font-size: 16px; text-align: center; text-decoration: none; background-color: blue; color: #fffff0; border: none; border-radius: 5px; font-weight: bold; cursor: pointer; box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.3); transition: background-color 0.3s ease, transform 0.3s ease; } .my-button:hover { background-color: #C23C30; transform: scale(1.05); } In this passage, you could learn 7 main features about PCB Substrate. If you are interested in PCB substrate, please check and read the content below for more information. What are the types of PCB substrate? Once upon a time, the choice in radio frequency/microwave circuit-board materials was a simple choice of: · Hard, or rigid circuit material · Soft, or flexible circuit material You now have more to choose from. With the boom in electronics, circuit materials are now available for specific applications, such as antennas, or even frequency ranges, e.g. millimeter-wave frequencies. Still, the base substrate for most PCB materials tends to fall into the same categories as before: hard/rigid or soft/flexible. What are the 6 main features about PCB substrate? 1. Mechanical properties of copper tube and the matrix resin adhesion (peel strength) and mechanical strength (e.g., flexural strength), impact resistance, dimensional stability, flexibility, heat distortion resistance, the base processing (punching, drilling performance) and the like. 2. Electrical characteristics of insulation resistance, resistance to the electric field strength (voltage resistance), the dielectric properties (dielectric constant, dielectric loss factor Wei, etc.), ion migration resistance, resistance to leakage and trace quality copper resistance. 3. The physical characteristics of thermal expansion coefficient (CTE), flammability (flame retardant), a base that is generally warped by the degree of flatness (bow and twist), moisture absorption. 4. Chemical properties. Heat resistance, breaking glass transition temperature (Tg), weldability, resistance to chemicals capacity (acid, alkali and solvent resistance) and the like. 5. Environmental resistance. Fungus resistance, moisture resistance, cooking, resistance to thermal shock properties. 6. Green living substrates suitable for RoHS Directive inauspicious lead and other harmful substances halogen chapter though - .. Some high reliability requirements of the product is not currently required · main lead solder must be used, but from the perspective of environmental protection jealous consideration. When conditions are ripe to make the use of non-polluting or less polluting materials. What are the properties of PCB substrate? This material allows a minimum amount of electricity from the circuit. Because there exists an insulating layer between two conducting layers. For example, FR-4 is the most common sort of dielectric substantial. You must consider its properties before choosing it for your circuit board. Here are the 4 most important properties of dielectric material: Thermal Properties Let’s consider the thermal properties of the substrate material: A temperature range in which a glassy or rigid state of the PCB substrate becomes a softened or deformable state. The properties of the material return its original states after cooling down. You can express this temperature range in the Tg unit. And, you need to measure this temperature in degrees Celsius. Electrical properties Relative Permittivity of Dielectric Constant (Dk or Er) It is very important to consider the dielectric constant of material for checking impedance considerations and signal integrity. Both are remarkable factors of high-frequency electrical performance. The range of Er is between 2.5 and 4.5 in most PCB substrate material. Chemical Properties Flammability Specs – UL94 It is a plastics flammability standard for classifying plastic from the lowest flame-retardant to the highest one. So it is very helpful for plastic material appliances testing. Underwriters Laboratories (UL) defines this standard. Here are some essential requirements of this standard: · Mechanical Properties · Peel Strength It denotes the bond strength between the dielectric material and copper conductor. The unit to express the peel strength is pounds of force per linear inch. You can denote it as PLI. · Thermal Stress: After floating the sample on solder for 10s at 288 ºC. · Elevated Temperature: After exposing the sample to the fluid at 125 ºC. Or, you can expose that to hot air. · Exposure to Process Chemicals: After exposing the sample to a series of chemical and thermal processes.

PCB Knowledge ⋅ 10/26/2021 09:28