Common PCB failures are mainly concentrated on components such as capacitors, resistors, inductors, diodes, transistors, MOSFETs, integrated chips (IC), and crystals. Some obvious damages can be visually detected, while others require the use of tools. Today, let’s learn how to troubleshoot PCB faults using a multimeter.
How Will You Diagnose a Faulty PCB By Visually?
For some printed circuit boards, we can check by our naked eyes. Here are some common ways to follow:
1. Check the condition of components
When you get a faulty PCB, first observe if there are any obvious component damages, such as burnt or swollen electrolytic capacitors, burnt resistors, and damaged power devices.
2. Inspect the soldering of the PCB
Check if the printed circuit board (PCB) is deformed or warped; if there are any loose or poorly soldered joints; if the copper cladding on the PCB is lifted, burnt, or blackened.
3. Examine the component plug-ins
Ensure the correct orientation of integrated circuits, diodes, and the PCB power transformer.
How to Check PCB with a Multimeter?
Before you start testing your PCB, ensure you have the right tools and environment. Here’s a checklist to get you started:
1. Safety First: Wear anti-static gloves and ensure you are working on an anti-static mat to prevent damage to the PCB.
2. Multimeter Selection: Choose a multimeter with the ability to measure voltage, resistance, and continuity. A digital multimeter is preferred for accuracy.
3. Visual Inspection: Examine the PCB for visible signs of damage such as burnt components, broken traces, or solder bridges.
4. Power Off the Board: Always test the PCB with the power off to avoid any electrical hazards and damage to the multimeter.
How Do You Test Individual Components on a PCB?
Testing individual components like resistors, capacitors, and diodes can pinpoint the exact failure. Here’s a general approach:
Diode
Transistor
MOSFET
Electrolytic Capacitors
How to Test Diodes?
1. Set the MF47-type multimeter to measure resistance.
2. Place the red and black probes on the two ends of the diode and read the value.
3. Swap the probes and measure again.
4. Judge based on the two measurements: the forward resistance of small power germanium diodes is 300-500Ω, silicon diodes are about 1kΩ or larger. The reverse resistance of germanium diodes is tens of kilo-ohms, and silicon diodes are above 500kΩ (values are much smaller for high-power diodes). A good diode has low forward resistance and high reverse resistance, and the larger the difference, the better.
5. If both forward and reverse resistances are very low, the diode is short-circuited; if both are very high or infinite, the diode is open-circuited and needs to be discarded.
How to Test Transistors?
1. Set the digital multimeter to the diode mode.
2. Measure the PN junction with the probes. If it conducts forward, the displayed value is the forward voltage drop of the PN junction.
3. Determine the collector and emitter: measure the forward voltage drop of the two PN junctions, the larger drop is the emitter (e), and the smaller drop is the collector (c). If the red probe is connected to the common terminal, the transistor is NPN type, and the common terminal is the base (b); if the black probe is connected to the common terminal, the transistor is PNP type, and the common terminal is the base (b).
4. For in-circuit testing, measure the forward and reverse resistance of the PN junction to determine if the transistor is damaged. If the branch resistance is larger than the forward resistance of the PN junction, there should be a clear difference between the forward and reverse resistances, otherwise, the PN junction is damaged.
The Way to Test MOSFETs?
1. Connect the black probe to the drain (D) and the red probe to the source (S), the resistance should be 500-600.
2. Without moving the black probe, touch the gate (G) with the red probe, then measure the source (S) again; it should conduct.
3. Connect the red probe to the drain (D), touch the gate (G) with the black probe, then measure the source (S); the resistance should be the same as the first measurement, indicating the MOSFET is working normally.
How to Test Electrolytic Capacitors?
1. Select the appropriate range on the MF47-type multimeter based on the capacitor’s capacity. Use R×1K range for capacitors below 47μF, and R×100 range for those above 47μF.
2. Connect the red probe to the negative lead and the black probe to the positive lead of the capacitor.
3. On initial contact, the multimeter needle will deflect right and then gradually return to the left until it stops at a certain position (close to infinity). This value is the capacitor’s forward leakage resistance; the larger the value, the better the capacitor’s performance.
4. Swap the probes and repeat the process. The measured value will be the reverse leakage resistance, slightly smaller than the forward leakage resistance.
5. If no charging phenomenon occurs (the needle doesn’t move), the capacitor is either open or short-circuited internally. If the resistance is very small or zero, the capacitor is leaky or has broken down and cannot be used.
This is the end of this article, if you want to know more about it, welcome to contact us.
hs code electronic (HS codes) for electronic products involve multiple categories and specific commodities, including but not limited to laptops, tablets, portable devices, phones, electronic watches, smartphones, electronic game consoles, electric toys, electronic cigarettes, etc. The HS codes for these commodities are as follows:
The HS code for laptops and tablets is 8471301000. The HS code for portable devices is 8471309000. The HS code for phones is 8517129000. The HS code for electronic watches is 9102190000. The HS code for smartphones is 8517130000. The HS code for electronic game consoles is 9504901000. The HS code for electric toys is 8501101000. The HS code for electronic cigarettes is 8516799000. The HS code for PCB (printed circuit board) is 8534001000. PCBs made of FR-4 material (i.e. silicon tetrachloride fiberglass board) are classified under HS code 8534.00.00 HS code for integrated circuit and microelectronic component parts is 8542900000 Electronic circuit boards: HS code is 8534.00.00 Capacitors: HS code is 8532.10.00 Resistors: HS code is 8533.10.00 Transistors: HS code is 8541.10.00 Integrated circuits: HS code is 8542.31.00 Connectors: HS code is 8536.69.00
These HS codes are the standards used by customs to classify and count goods in international trade. Each commodity has a specific HS code to facilitate customs management and statistics of imported and exported goods. Knowing these codes is very important for companies and individuals engaged in international trade, as it can help them declare goods correctly and avoid mistakes in tariffs or customs declarations.
How do I find an HS code?
You’ll often find HS codes on invoices and shipping documents around the world. HTS codes are like Schedule B numbers, but for importing goods into the United States instead. They’re also made up of 10 digits, and they help the US government to track imports and apply the right tariffs to different products.
HS code is a coding system consisting of six digits, each of which represents specific information in order to accurately define and classify goods. The following is the basic structure of HS code:
The first digit (chapter): represents the major category of goods, usually describing the general nature of the goods, such as raw materials, machinery and equipment, electronic products, etc.
The second digit (section): further subdivides the major category of the first digit to provide more specific information.
The third digit (subsection): continues to refine the classification of goods, usually including the materials and uses of goods.
The fourth digit (group): describes the specific characteristics and attributes of the goods.
The fifth digit (subgroup): provides more specific information related to the characteristics of the goods.
The sixth digit (item): the most specific code, used to identify specific goods.
What is the HS code for circuit boards?
he HS code for circuit boards is a standard international commodity code, the full name of which is “HS code for printed circuit boards”, which is part of the customs coding system. The coding system was formulated by the World Customs Organization (WCO) to uniformly identify the classification and classification of international goods.
The role of the HS code for circuit boards
The HS code for circuit boards is an important voucher in international trade, which can help customs to quickly and accurately count and classify imported or exported goods. At the same time, it is also an important basis for customs to determine tariff rates, levy import tariffs, supervise trade measures, and implement regional protectionist policies.
Classification of HS codes for circuit boards
According to WCO regulations, the HS code for circuit boards is divided into 16 chapters, Chapters 1 to 5 are industrial product codes, Chapters 6 to 14 are agricultural product codes, Chapter 15 is unlisted commodity codes, and Chapter 16 is supplementary codes for machinery and equipment. Among them, the HS code classification of circuit boards is in Chapter 85, which belongs to machinery and electrical equipment.
Application of HS code of circuit boards
HS code of circuit boards is one of the key points in international trade. Reasonable coding will have an important impact on trade costs and trade efficiency. When conducting import and export trade activities of circuit boards, relevant HS codes must be correctly declared, otherwise they may face customs control, return, fines and other consequences. Therefore, the correct understanding and application of HS code of circuit boards is of great significance to the commercial success of enterprises.
As a basic work in international trade, HS code of circuit boards not only plays an important role in facilitating and smooth trade, saving costs and improving efficiency, but also is a key link in the import and export trade of circuit boards. Therefore, enterprises should attach great importance to the correct understanding and application of HS code of circuit boards, making it a powerful tool to promote the development of enterprises.
led ring light pcb leads the development of lighting industry with its innovative design, high efficiency and flexibility, bringing more intelligent and comfortable lighting experience to our life.
It is not only an integrated platform of electronic components, but also a perfect combination of modern technology and aesthetics, and is the focus of future lighting trends.
led ring light pcb, like a magic wand on the electronic stage, uses precise SMT technology to lightly attach LED components to it. Whether it is a warm small lamp for home decoration, efficient lighting in commercial space, or smart display inside the car, it is indispensable.
Its core structure includes efficient LED lamp beads, power cords that provide electricity, and intelligent controllers that adjust light effects, which together build an excellent lighting solution.
What Is led ring light pcb
Why use mcpcb for led ring light pcb
With the continuous development of LED technology, the heat generated by LEDs has gradually increased. The traditional FR4 printed circuit board (PCB) has been unable to meet the heat dissipation requirements due to its low thermal conductivity (only 0.36W/m.K). In order to solve this problem, the metal core printed circuit board (MCPCB) was proposed. It attaches the original printed circuit board to a metal with better thermal conductivity (such as aluminum and copper) to enhance the heat dissipation effect. The thermal conductivity efficiency of MCPCB is higher than that of traditional FR4 PCB, reaching 1W/m.K to 2.2W/m.K, which effectively improves the heat dissipation performance of LED PCB.
In addition, the use of MCPCB can also reduce the number of LEDs required to generate lighting, making it an ideal choice for street lights, automotive LED applications, and backlight unit applications. The use of metal substrates has practical advantages in heat dissipation, thermal conductivity, reliability, and electrical insulation, especially in harsh environments, and can also achieve reliable operation of LEDs. For example, using a metal substrate can reduce the LED junction temperature by 20-30°C, improve light output and enhance the overall performance of the product, ensure consistent UV light generation, and expand the possibilities of UV applications in various industries.
Unveiling the Components of LED PCBs
LED Chips: The heart of the LED PCB, these semiconductor chips emit light when current passes through them.
Substrate Material: The base layer of the PCB provides mechanical support and thermal conductivity.
Copper Traces: These conductive pathways connect the LEDs and other components, allowing current to flow through the circuit.
Solder Mask: A protective layer that covers the copper traces, safeguarding them from external factors and preventing short circuits.
Silkscreen: This layer contains markings and labels, providing important information about the PCB’s components and assembly.
Advantages of led ring light pcb?
Thermal performance advantages of metal substrate PCB
High thermal conductivity: The thermal conductivity of metal substrate PCB is much better than that of traditional plastic substrates such as FR4. It can effectively conduct the heat generated by components, reduce the operating temperature of components, and improve the reliability and life of circuit boards.
Good thermal stability: Metal substrate PCB can maintain good dimensional stability and electrical performance in high temperature environment, and is suitable for high temperature working environment.
Mechanical performance advantages of metal substrate PCB
High strength: Metal substrate PCB has high mechanical strength and rigidity, is not easy to deform and break, and can withstand large external forces and vibrations.
Good processability: Metal substrate PCB can be processed by conventional mechanical processing methods such as drilling and cutting, which is convenient for the production of circuit boards with complex shapes and sizes.
Electrical performance advantages of metal substrate PCB Excellent electrical insulation performance: Metal substrate PCB has a special insulation layer design to ensure good electrical insulation performance and avoid electrical short circuits between components.
Low impedance: The conductive layer of metal substrate PCB is made of metal material, which has low impedance, which is conducive to signal transmission and processing.
How does led ring light pcb dissipate heat?
The power device is mounted on the circuit layer. The heat generated by the device during operation is quickly transferred to the metal base layer through the insulating layer, and then the metal base layer transfers the heat to achieve heat dissipation of the device.
Compared with the traditional FR-4, the aluminum substrate can reduce the thermal resistance to the minimum, making the aluminum substrate have excellent thermal conductivity; compared with the thick film ceramic circuit, its mechanical properties are extremely good.
In the circuit design scheme, the heat diffusion is handled very effectively, thereby reducing the module operating temperature, extending the service life, and improving the power density and reliability; reducing the assembly of the heat sink and other hardware (including thermal interface materials), reducing the product volume, and reducing the hardware and assembly costs; combining the power circuit and the control circuit
How to make a LED light circuit board?
Step 1: Design Your LED PCB: Using PCB design software, create a schematic for your LED circuit and design the PCB layout, considering component placement and signal flow.
Step 2: Choose the Materials: Select a suitable substrate material and copper-clad board based on your project requirements.
Step 3: Transfer the Design: Print your PCB layout onto a special transfer paper and transfer it onto the copper-clad board using a heat press.
Step 4: Etch the Board: Immerse the board in an etching solution to remove the excess copper and reveal the copper traces.
Step 5: Drill Holes: Drill holes on the board to accommodate the LED chips and other components.
Step 6: Solder the Components: Carefully solder the LED chips and other components onto the board, ensuring secure connections.
Step 7: Test Your LED PCB: Connect your LED PCB to a power source and test the LEDs to ensure they light up correctly.
How to make a LED light circuit board?
Capabilities of led ring light pcb?
Item
Capabilities
Layer Count
1 – 10 Layers
Max Board Dimension
24*64″(610*1625mm)
Min Board Thickness
0.6mm
Max Board Thickness
4.0mm
Conductor Thickness
0.5oz – 10oz
Min Line Width/Line Space
4/4mil (0.10/0.10mm)
Min Hole Diameter
10mil (0.25mm)
Min Punch Hole Dia
0.12″ (3.0mm)
Min Hole Spacing
16mil (0.4mm)
Min PAD Ring(Single)
3mil (0.075mm)
PTH Wall Thickness
Normal: 0.59mil (15um); HDI: 0.48mil (12um)
Min Solder PAD Dia
14mil (0.35mm)
Min Soldermask Bridge
8mil (0.20mm)
Min BAG PAD Margin
5mil (0.125mm)
PTH/NPTH Dia Tolerance
PTH: ±3 mil (0.075mm); NPTH: ±2mil (0.05mm)
Hole Position Deviation
±3mil (0.075mm)
Outline Tolerance
CNC: ±6 mil (0.15mm); Die Punch: ±6 mil (0.1mm)
Max Aspect Ratio
10:01
Surface Treatment
ENIG, Flash Gold, Hard Gold Finger, Gold Plating(50mil), Gold finger,
Application in medical equipment The rapid progress of medicine is closely related to the rapid development of the electronics industry. Many medical devices are made of basic PCBs alone, such as pH meters, heart rate sensors, temperature measurements, electrocardiographs, electroencephalographs, MRIs, X-ray machines, CT scanners, blood pressure machines, blood sugar level measuring equipment, etc.
Application in industrial equipment PCBs are widely used in manufacturing, especially in industries with high-power mechanical equipment; these devices run on high power and require high current circuit drive. Such as arc welding, large servo motor drives, lead-acid battery chargers, clothing cotton machines, etc.
Application in lighting LED lights and high-intensity LEDs are mounted on PCBs based on aluminum substrates; aluminum has the property of absorbing heat and dissipating it in the air.
Application in the automotive and aerospace industries Flexible PCBs are lightweight but can withstand high vibrations. Because of their light weight, they can reduce the total weight of spacecraft; flexible PCBs can be adjusted even in narrow spaces. These flexible PCBs are used as connectors, interfaces, and can be assembled even in compact spaces
FAQs About led ring light pcb
What is the thermal conductivities and withstanding voltages of BT/FR4 layer and Dielectric layer? The SinkPAD conducts heat primarily through the copper base (400W/m.K), the withstanding voltages of Dielectric layer is around 4KV.
What is the placement accuracy for the SMT components? +/-0.05mm is our SMT accuracy tolerance. You are welcome to come to our SMT factory in Shenzhen China and Vietnam.
Can the aluminum be made as the base of sinkpad MCPCB?
Actually, the sinkpad can only use copper as the base. As you can see the below manufacturing steps, the SinkPad will etch the copper base into convex platform with Copper Etching Solution, then hollow out the Double Layer FR4 PCB, and do lamination with the convex platform. However, regarding of current technical conditions, since aluminum or aluminum alloy cannot directly react with acid, the reaction process is too complex and difficult to control, which will increase the difficulty of etching the LED pad platform. Considering the scrap rate, the process of etching LED pad platform with aluminum is more complex and the overall cost is higher.
Can I plated copper in mcpcb via holes? Generally speaking, copper plating through holes requires hole rings, otherwise the copper in the hole wall will easily fall off.
In addition, if it is a copper substrate, through the hole first to resin plug before copper plating.
Otherwise there’s no chemical reaction between copper and copper. And if the copper layer is connected to each copper layer, it is easy to short circuit.
Are you UL certified led pcb manufacturer?
Yes, we are UL certified manufacturer, our UL is E475635. We have already passed UL certificated. Meanwhile, we are passed ISO9001, ISO13485 and IATF16949 certifications.
Our LED pcbs are manufactured under highly monitored by these quality system controls.
How does the conveity of sinkpad manufactured?
Actually the sinkpad can only use copper as the base.
As you can see the below manufacturing steps, the SinkPad will etch the copper base into convex platform with Copper Etching Solution, then hollow out the Double Layer FR4 PCB, and do lamination with the convex platform.However, regarding of current technical conditions, since aluminum or aluminum alloy cannot directly react with acid, the reaction process is too complex and difficult to control, which will increase the difficulty of etching.
Nowadays, PCBs became more and more important and you can see it in every electronic device. The PCB plays a critical role in our daily life. With circuit board, the device can power on and help to transmit signals, manage heat and perform electricity. A good PCB can help to improve the overall of your device. However, not all the PCBs are work good and within your expectable, you must know how to test it and ensure it enables a good performance. As an experienced PCB manufacturers in Asia, today we want to share with you how we test a PCB, and we try to use simple words to make you sense.
What is a printed circuit board?
Before knowing the methods of testing circuit board, let’s understand the definition of PCB. A PCB is a flat board made from insulating materials like fiber glasses with conductive pathways etched onto its surface. The pathways we called circuit or traces. These pathways connect different electronic components, so that they can communicate and function together. PCBs come in various materials, shapes and sizes, which always is customized to meet specific applications and performance requirements.
PCBs can be divided into different types according to substrate material used. They are – normal FR4 PCB, polyimide flexible PCB, metal core PCB, ceramic PCB, rogers PCB. Different has its own properties and advantages. The choice of materials and the design of the PCB significantly impact the performance and reliability of the final product. Understanding the materials used in PCBs is crucial for anyone involved in electronics, from hobbyists to professional engineers/designers.
Common PCB Circuit Board Issues
Though PCB has a strong construction, they are easy to be broken or failure since they always encounter a range of issues. These problems can stem from manufacturing defects, wear and tear, or improper handling. Identifying and diagnosing these issues promptly is crucial for maintaining the reliability and performance of electronic devices. Common issues we faced are including:
Open Circuits: These occur when a break in the circuits prevents current flow normally. Open circuits can result from physical damage or manufacturing errors.
Short Circuits: Due to improper soldering, unreasonable circuit design and other reasons, resulting in a short circuit between two or more points in the circuit that should not be connected. This can cause excessive current flow, potentially damaging components.
Grounding: The unreasonable design of ground area leads to interference signals on the grounding, which affects the normal operation of the circuit.
Signal: The signal circuit design is not reasonable, resulting in interference signals on the signal.
Component Failures: Individual components on a PCB can fail due to aging, overheating, or electrical stress breakdown. And incorrect orientation will lead to the failure of PCB.
Soldering Issues: Poor soldering can lead to weak connections, causing intermittent faults or complete circuit failure. This including the dents in the solder joints, this also can make the PCB failure.
Corrosion: PCB exposure to moisture and contaminants for a long time can cause corrosion, degrading the conductive pathways and component leads.
How to check a PCB?
In generally, there are four common ways to check whether if your PCB are good or failure.
1. Visual inspection
The easiest way is visual inspection. Through naked eye observation, check whether the solder joint on the PCB circuit board is firm, whether there is short circuit, open circuit and other phenomena. And look for burnt components, discolored areas, or broken traces, such as somewhere became black or be burned obviously. These are clear indicators of damage.
2. Use a multimeter
Multimeter is a common tool used for measuring PCB. Multimeter is versatility and it has multiplied modes. Select the appropriate mode on the multimeter, such as continuity, voltage, or resistance mode, depending on what you are testing. Before testing, make sure probes are in good condition and properly connected to the multimeter, with the red probe typically being positive and the black probe negative or ground. Click here to read What is the PCB flying probe test?
3. E-tester
E-tester is a good way to test short or open circuit when it is a mass production. If you just want to test one piece PCB, multimeter is much better.
4. Use oscilloscope
An oscilloscope is a powerful diagnostic tool used to observe the waveform of electrical signals in a circuit. Connect the oscilloscope probes to the test points on the PCB, it can capture the waveform. By observing the waveform, determine whether the circuit is working normally.
5. Use a thermal imager
A thermal imager also is a effective way to check the condition of PCB. It can capture the temperature distribution on the PCB. It helps identify areas with excessive heat, which can indicate potential issues.
How to Test a Circuit Board with a Multimeter Effectively?
Testing a circuit board with a multimeter is essential for diagnosing and fixing electronic issues. A multimeter can measure voltage, current, and resistance, helping you identify problems with the PCB. The main way to test a PCB with a multimeter is to measure voltage, resistance, and ground.
Measuring voltage
By measuring the voltage on the circuit board, can quickly test whether the circuit is working properly. Use the voltage gear of the multimeter, select the appropriate range, then measure the input and output of the power supply on the circuit board respectively, to check whether the voltage is within the normal range. If the voltage is abnormal, may indicate that the circuit is open or short.
Measuring resistance value
By measuring the resistance value on the circuit board, can detect whether the circuit is smooth. Use the resistance level of the multimeter, select the appropriate range, then measure the key nodes on the circuit board, check whether the resistance value is within the normal range. If the resistance value is abnormal, may indicate that the circuit is open or short.
Check the grounding
Grounding is critical to the proper operation of the circuit board. Use the multimeter’s ground test function, to check that key points on the board are properly grounded, this helps to spot potential electrical connection problems.
In addition, for industrial-grade PCB measurement, the use of higher-precision multimeters and special pens can improve the accuracy and efficiency of the measurement. For example, the Fluke 17B Max multimeter is equipped with an extra-pointed stylus, enables more accurate measurement of patch components and pins, and improves measurement fineness and accuracy.
Generally speaking, using a multimeter to test the PCB board needs to master the correct measurement methods and skills. At the same time according to the complexity of the circuit board to choose the appropriate measurement tools, to ensure the accuracy and efficiency of the test.
How to Tell if a Circuit Board is Bad?
Identifying a bad circuit board requires a combination of visual inspection and multimeter testing. Here are some signs and methods to determine if a PCB is faulty:
Visual Signs
Look for burnt components, discolored areas, or broken traces, such as somewhere became black or be burned obviously. These are clear indicators of damage.
Component Testing
Use the multimeter to test individual components. A component that doesn’t show the expected resistance or voltage is likely faulty.
Continuity Testin
Check for open circuits. Lack of continuity in a path indicates a broken trace or solder joint.
Short Circuit Detection
Identify any unintended connections between different paths. This can be done by checking for continuity where there should be none.
Functionality Testing
Test the circuit board in its intended application. If the device does not function correctly, there may be an issue with the PCB.
Why Choose Best Technology?
By reading this post, you may know how to test a PCB by multimeter already and other methods to identify them. Best Technology has engaging in the PCB manufacturing for more than 18 years, we have served over 2000+ customers all around the world. We have strong R&D team and equipped with advanced equipment to improve the yield and product quality.
At Best Technology, we provide various PCB manufacturing, including metal core PCBs, ceramic PCBs, rigid-flex PCBs and some other special PCBs like HDI PCB, busbar PCB, heavy copper PCB. If you have similiar projects, you are welcome to contact us.
Heavy Copper Board does not have a set of definition per IPC. According to PCB industry, however, peopel generally use this name to identify a printed circuit board with copper conductors 3 oz/ft2 – 10 oz/ft2 in inner and/or outer layers. And Extreme heavy copper PCB refers to 20 oz/ft2 to 200 oz/ft2 printed circuit board.
Heavy copper normally used for a various products but not limited to: high power distribution, heat dissipation, planar transformers, power convertors, and so on.
Generally, the thick copper plate is about 3oz, and the larger current is 3oz~6oz. To achieve 15 ounces, the requirements for process and manufacturers are more stringent. Best provides 3-15oz 1-99 layers of PCB. It is a professional PCB manufacturer with 18 years of experience, providing one-stop PCB and PCBA services from design, manufacturing to after-sales.
Common copper foil thicknesses have the following options:
1 oz (35 μm): This is the most common and standard copper foil thickness, widely used in general electronic product manufacturing. It has good electrical and thermal conductivity.
2 oz (70 μm): This thickness of copper foil is usually used in circuits that require higher current carrying capacity, such as power amplifiers, high-power LEDs, etc.
0.5 oz (18 μm): This thinner copper foil thickness is suitable for some light and small electronic products, such as electronic watches, mobile phones, etc.
Other thicknesses: According to special needs, you can also choose copper foil of other thicknesses, such as 3 oz, 4 oz, etc.
What is copper foil
Copper foil is a cathodic electrolytic material, a thin, continuous metal foil deposited on the substrate layer of the circuit board, which serves as the conductor of the PCB. It is easy to adhere to the insulating layer, accept the printed protective layer, and form a circuit pattern after corrosion. The copper mirror test is a flux corrosion test, using a vacuum precipitation film on a glass plate. Copper foil is made of copper and a certain proportion of other metals. Copper foil generally has two types: 90 foil and 88 foil, that is, the copper content is 90% and 88%, and the size is 16*16cm.
How thick is the PCB copper foil
The commonly used international PCB copper foil thicknesses are: 35um, 50um, and 70um. Generally, the thickness of copper foil (copper cladding) of single-sided and double-sided PCB boards is about 35um (1.4mil), and the other specifications are 50um and 70um. The surface thickness of multilayer boards is generally 35um=1oz (1.4mil), and the inner layer is 17.5um (0.7mil). 70% of circuit boards use a copper foil thickness of 35um, which mainly depends on the purpose of the PCB and the voltage and current of the signal; in addition, for PCBs that need to pass large currents, some will use 70um copper thickness, 105um copper thickness, and rarely 140um, etc. The copper foil thickness is usually expressed in oz (ounces). 1oz refers to the thickness of 1oz of copper evenly covering an area of 1 square foot, which is about 1.4mil. It uses the weight per unit area to express the average thickness of the copper foil. Expressed in formula, that is, 1oz=28.35g/ FT2 (FT2 is square feet, 1 square foot = 0.09290304 square meters).
Different uses have different copper foil thicknesses,
Ordinary 0.5oz, 1oz
2oz, mostly used in consumer and communication products. Thick copper products above
3oz are mostly used for large currents, such as high-voltage products and power boards!
Copper foil thickness (track width) affects the current size. Although there is a formula that can directly calculate the current load capacity of copper foil, it is not so simple when actually designing the circuit. Therefore, safety should be fully considered when designing.
How thick is 2 oz of copper for PCB?
In the PCB industry, 1OZ means the thickness of 1OZ of copper evenly laid on an area of 1 square foot (FT2). It uses the weight per unit area to express the average thickness of the copper foil. Expressed in formula, 1OZ=28.35g/FT2 (FT2 is square feet, 1 square foot=0.09290304 square meters). First, we know that the density constant of copper and the conversion formula of related units are as follows: 1 cm = 10 mm; 1 mm = 1000 um 1 FT2≈929.0304cm2 According to the mass calculation formula m=ρ×V(volume)=ρ×S(area)×t(thickness), we know that the weight of copper foil divided by the density and area of copper is the thickness of copper foil! So, t=28.35÷929.0304÷8.9cm≈0.0034287cm=34.287um≈34.287÷25.4mil≈1.35mil Copper thickness 1.OZ(0.035mm) Copper thickness 1.5OZ(0.05mm) Copper thickness 2.OZ (0.07mm)
What are the materials of PCB board
FR-1——phenolic cotton paper, this base material is commonly known as bakelite (more economical than FR-2) FR-2——phenolic cotton paper FR-3——cotton paper, epoxy resin FR-4——glass cloth, epoxy resin FR-5——glass cloth, epoxy resin FR-6——matte glass, polyester G-10——glass cloth, epoxy resin CEM-1——cotton paper, epoxy resin (flame retardant) CEM-2——cotton paper, epoxy resin (non-flame retardant) CEM-3——glass cloth, epoxy resin CEM-4——glass cloth, epoxy resin CEM-5——glass cloth, polyester AIN——aluminum nitride SIC——silicon carbide
In our daily life, the electronics has been gradually infiltrated our lives. Between them, the PCB board plays an important role in it, and we must say, PCB is the foundational element of electronics. From the simplest gadgets to the most complex machinery, PCBs play a crucial role.
What is a PCB Board?
A printed circuit board (PCB) is an electronic that uses metal conductors to create electrical connections between components. Generally, a PCB is a flat, laminated composite made of non-conductive substrate materials with conductive pathways etched or printed onto it. These pathways, also known as traces, enable the electronic components mounted on the board to communicate with each other.
PCBs are designed to support and electrically connect various components such as resistors, capacitors, diodes, and integrated circuits. The intricate network of copper tracks forms circuits that dictate the device’s functionality. PCBs can range from simple single-sided boards used in basic electronics to complex multi-layered structures found in advanced applications.
Common PCB Structure
A PCB’s structure is composed of several key layers, each serving a distinct purpose. Here is a detailed breakdown of these layers:
Substrate (Base Material)
The substrate, usually made of fiberglass (FR4), provides the board with its rigidity and thickness. It is the foundational layer upon which all other materials are built.
Copper Layer
This conductive layer is typically made of copper foil. For single-sided PCBs, the copper layer is only on one side of the substrate, whereas double-sided and multi-layer PCBs have copper layers on both sides or between multiple layers of substrate.
Solder Mask
The solder mask is a protective layer applied over the copper traces to prevent oxidation and accidental short-circuiting. It insulates the copper traces and leaves the component pads exposed for soldering. The green color commonly associated with PCBs comes from this layer, though it can also be found in other colors like red, blue, black, and white.
Silkscreen
The silkscreen layer is used to add labels, symbols, logos, and other markings to the PCB. This layer helps in identifying component locations and orientations during assembly and troubleshooting.
Components and Connectors (PCBA)
Components such as resistors, capacitors, diodes, and integrated circuits are soldered onto the PCB. Connectors allow the PCB to interface with other boards, power supplies, and external devices.
How Many Types of PCB?
Single-Sided PCBs
These are the simplest types of PCBs, with copper on only one side of the board. You’ll find them in basic, low-cost electronics like calculators, radios, and power supplies. They’re easy to design and manufacture, which keeps costs down and makes them great for straightforward applications.
Double-Sided PCBs
These boards have copper layers on both sides, allowing for more complex circuits. They’re common in more sophisticated electronics like amplifiers, power monitoring systems, and HVAC systems. With increased circuit density and flexible design options, they can handle more complex tasks.
Multi-Layer PCBs
When you need to pack in a lot of circuits, multi-layer PCBs are the way to go. They consist of three or more layers of copper, separated by insulating layers. You’ll see these in high-tech devices like computers, servers, medical equipment, and aerospace electronics. They offer high circuit density, reduced size and weight, and better signal integrity.
Rigid PCBs
Made from solid, inflexible materials like fiberglass, rigid PCBs keep their shape and provide strong support for components. They’re durable and used in everything from simple toys to complex industrial equipment.
Flexible PCBs
These are made from flexible plastic materials like polyimide, allowing them to bend and flex. Perfect for wearable electronics, flexible displays, and compact devices where space is tight. They’re lightweight, can fit into small, irregular spaces, and can handle being bent repeatedly.
Rigid-Flex PCBs
Combining the best of both rigid and flexible PCBs, these are great for devices that need both stability and flexibility, like smartphones, cameras, and medical devices. They save space, reduce the need for connectors and interconnections, and improve reliability.
High-Frequency PCBs
Designed to operate at frequencies above 1 GHz, these are used in communication systems, microwave technology, and high-speed devices. They provide low signal loss and high performance, making them crucial for advanced communication technologies.
Ceramic PCBs
Using ceramic as the substrate material, these PCBs offer excellent thermal conductivity and stability. They’re perfect for high-power applications and environments with extreme temperatures, like LED lighting, power electronics, and aerospace systems. Ceramic PCBs ensure reliable performance in harsh conditions.
Metal Core PCBs
Featuring a metal core, usually aluminum or copper, these PCBs improve heat dissipation. They’re used in high-power applications where efficient thermal management is crucial, such as LED lighting, power supplies, and automotive electronics.
Special PCBs
Bus Bar PCBs
These integrate bus bars for high-current applications, ensuring efficient power distribution and minimal voltage drop. They’re used in heavy-duty power supplies, electric vehicles, and industrial machinery. Bus bar PCBs provide robust and reliable connections for high-power systems.
Heavy Copper PCBs
With thicker copper layers, typically 3 ounces per square foot or more, these PCBs can handle higher currents and enhance thermal management. They’re used in power distribution, automotive, and industrial applications where durability and performance are critical. Heavy copper PCBs ensure reliable operation under high-stress conditions.
HDI (High-Density Interconnect) PCBs
These feature finer lines and spaces, smaller vias, and higher connection pad density. They’re used in advanced electronics like smartphones, tablets, and medical devices where space and performance are paramount. HDI PCBs enable miniaturization and improved electrical performance.
Extra Thin PCBs
Designed with minimal thickness, these PCBs are perfect for fitting into compact and lightweight devices. You’ll find them in flexible displays, wearables, and miniaturized electronic gadgets. Extra thin PCBs allow for innovative design solutions and space-saving configurations.
RF (Radio Frequency) PCBs
Optimized for high-frequency signals, these are used in communication devices, antennas, and microwave applications. They’re designed to minimize signal loss and interference, ensuring optimal performance in wireless communication systems.
High Tg PCBs
These have a high glass transition temperature, making them suitable for high-temperature environments. Used in automotive, aerospace, and industrial applications, high Tg PCBs maintain structural integrity and performance at elevated temperatures.
Impedance Control PCBs
These are designed to maintain consistent impedance for high-speed signal transmission. They’re used in communication devices, high-speed digital circuits, and advanced computing systems. Impedance control PCBs ensure signal integrity and reduce signal loss and reflection.
Why Are PCB Boards So Expensive?
Material Quality
High-grade materials like FR4 (fiberglass), ceramics, and high-quality copper foil are used to ensure durability and performance. These materials are essential for withstanding environmental stress and ensuring reliable operation, but they are expensive. For example, ceramic substrates can cost up to 10 times more than standard FR4 materials due to their superior thermal conductivity and electrical properties.
Complexity of Design
Multi-layer PCBs and advanced designs such as HDI (High-Density Interconnect) boards require complex manufacturing processes. The process involves precise alignment of layers and sophisticated techniques like laser drilling for micro-vias. The added complexity increases the production costs significantly. For instance, a standard 4-layer PCB might cost $50 per square meter, while a 12-layer HDI PCB could cost over $200 per square meter.
Precision and Technology
Manufacturing high-precision PCBs involves advanced machinery for etching, drilling, and plating. This machinery requires significant investment, and the skilled labor needed to operate it adds to the cost. The precision required in the production process ensures that the PCBs meet exacting standards, crucial for high-performance applications. A single advanced PCB drilling machine can cost upwards of $500,000.
Volume of Production
Smaller production runs generally have higher costs per unit because the setup and tooling expenses are spread over fewer units. For example, a low-volume production run of 10 PCBs might cost $100 per board, whereas a high-volume run of 10,000 boards might reduce the cost to $10 per board due to economies of scale.
Testing and Quality Assurance
Rigorous testing, including electrical, thermal, and functional tests, ensures that the PCBs meet strict performance standards. This testing process is vital to ensure reliability, especially in critical applications like medical devices and aerospace. Quality assurance processes can add 20-30% to the overall production cost, but they are essential for maintaining high standards.
What is the Difference Between PCBA and PCB Board?
The terms PCB and PCBA are often used interchangeably, but they refer to different stages of the board’s life cycle. The PCB is the bare board itself, with no electronic components attached. It consists of a non-conductive substrate, copper traces, solder mask, and silkscreen. A PCB serves as the foundation for assembling electronic components.
On the other hand, a PCBA (Printed Circuit Board Assembly) is a PCB that has undergone the assembly process, where all necessary electronic components like resistors, capacitors, diodes, and integrated circuits are soldered onto the board. Essentially, a PCBA is a functional circuit board ready for use in electronic devices. The transition from a PCB to a PCBA involves component placement, soldering, and quality testing, transforming the bare board into an operational assembly. Below is a typical PCBA product for your reference.
What is PCB Board Common Use?
PCB boards are existing in everywhere what we live, for example, the global smartphone market, which relies heavily on PCBs, was valued at approximately $520 billion in 2020. Here are some common applications that PCB used in:
Automotive Industry
In the automotive sector, PCBs are used in engine control units, infotainment systems, and advanced driver-assistance systems (ADAS). These applications enhance vehicle performance, safety, and connectivity.
Medical Devices
PCBs are integral to medical devices such as diagnostic equipment, patient monitoring systems, and implantable devices. They ensure precise and reliable operation, which is critical for patient safety and effective treatment.
Industrial Applications
PCBs are used in control systems, machinery, and power distribution units in industrial settings. They provide robust and durable solutions capable of withstanding harsh conditions and continuous operation.
Telecommunications
In telecommunications, PCBs are essential in routers, switches, and communication devices, ensuring efficient and reliable data transmission. As the demand for faster and more reliable communication networks grows, so does the need for high-quality PCBs.
Why Are Circuit Boards Green?
The characteristic green color of most PCBs comes from the solder mask, a protective layer applied over the copper traces to prevent oxidation, short-circuiting, and to protect the board during soldering.
The green color is traditional, largely due to historical reasons and practical benefits. Green solder mask provides a good contrast against the white silkscreen and the shiny copper traces, making it easier for technicians to inspect and identify components during assembly and troubleshooting. Additionally, green solder mask was one of the first colors to be developed and standardized in the industry, leading to its widespread adoption. However, PCBs are not limited to green; they can also be found in other colors such as red, blue, black, and white, depending on the specific requirements and aesthetic preferences of the project. The choice of solder mask color does not affect the performance of the PCB, but green remains popular due to its well-established manufacturing process and visual advantages.
How to Get Started with Best Technology?
Here at Best Technology, we are experienced in designing all types of PCBs, including standard rigid PCBs, special PCBs, and irregular PCBs. We can design and develop PCBs according to customer specification and offer suggestions on the right materials for your project.
We provide the full series of PCB manufacturing, from the initial PCB design, PCB layout, to custom PCB fabricate, PCB assembly, box building and so forth. By the way, we have our own factory in Vietnam, that means we can ship out the PCBs directly from Vietnam.
Welcome to contact us when you want to get a quote!
FR4 is a commonly used material in the printed circuit boards (PCBs) manufacturing. If you’re in the electronics field, you’ve likely heard of it. It is the footstone of a circuit board, provides good mechanical strengthen and electrical insulation properties. Today, we will share informational about FR4 material, its types, advantages and alternatives. Keep reading if you are interested in.
What does FR4 stand for?
FR4 stands for “Flame Retardant 4”, also called FR-4 Epoxy Glass Cloth by PCB manufacturers. It is not a material name, but a material grade, so there are many types of FR-4 grade materials used in general circuit boards. But most are composites made with so-called Tera-Function epoxy resins plus fillers and glass fibers. FR4 is made from woven glass-reinforced epoxy resin. The typical composition of FR4 includes approximately 60% glass fabric and 40% epoxy resin by weight.
This composite material is known for its high mechanical strength and flame-retardant properties. The “4” in FR4 signifies the level of flame retardancy. It means the material is resistant to catching fire, which is critical in preventing electrical fires in electronic devices.
What are the classifications of FR4 materials?
FR4 materials are classified based on various properties and specifications to cater to different applications and requirements. These classifications help in selecting the right type of FR4 material for specific PCB needs. Here are the primary classifications of FR4 materials:
1. Standard FR4
Standard FR4 is the most commonly used classification. It offers a good balance of electrical insulation, mechanical strength, flame retardancy, and cost-effectiveness. Standard FR4 materials have a glass transition temperature (Tg) typically around 130°C to 140°C. They are suitable for general-purpose PCBs used in consumer electronics, industrial controls, and telecommunications equipment.
2. High Tg FR4
High Tg FR4 materials are designed for applications requiring higher thermal performance. These materials have a higher glass transition temperature, usually above 170°C. High Tg FR4 is used in applications where the PCB is exposed to higher temperatures, such as automotive electronics, aerospace, and high-power devices. The increased Tg provides better stability and performance at elevated temperatures. This is the high Tg FR4 PCB that we made before.
3. Low Dk FR4
Low Dk (Dielectric Constant) FR4 materials are used in high-frequency applications where signal integrity is crucial. So, we called it as “High-frequency FR4”. These materials have a lower dielectric constant, which reduces signal loss and improves signal transmission. Low Dk FR4 is often used in RF and microwave circuits, where maintaining signal integrity is essential.
4. High CTI FR4
High CTI (Comparative Tracking Index) FR4 materials have an improved resistance to electrical tracking. These materials are used in applications where the PCB is exposed to high voltages and harsh environments. High CTI FR4 provides better insulation and reduces the risk of electrical failure due to tracking.
5. Halogen-Free FR4
Halogen-free FR4 materials are designed to meet environmental and safety requirements by eliminating halogens. Which can be harmful if released during PCB manufacturing or disposal. These materials are used in applications where reducing environmental impact is a priority. Halogen-free FR4 offers similar performance to standard FR4 but without the use of halogenated flame retardants.
Benefits of using FR4 as PCB material
Excellent Electrical Insulation
High Mechanical Strength
Flame Retardancy
Moisture Resistance
Cost-Effectiveness
Thermal Stability
Ease of Fabrication
Properties of FR4 material
Property
Parameter
Vertical flexural strength
Normal State: E-1/150, 150±5℃≥340Mpa
Parallel layer impact strength
≥230KJ/m
Insulation resistance after water immersion (d-24/23)
≥5.0×108Ω
Vertical electrical strength
≥14.2MV/m
Parallel layer breakdown
≥40KV
Relative Dielectric Constant (50hz)
≤5.5
Relative Dielectric Constant (1mhz)
≤5.5
Dielectric Loss Factor (50hz)
≤0.04
Dielectric Loss Factor (1mhz)
≤0.04
Water Absorption (D-24/23, 1.6mm Thickness)
≤19mg
Density
1.70-1.90g/cm³
Flammability
FV0
What is the Difference Between IMS and FR4 PCB?
IMS (Insulated Metal Substrate) and FR4 PCBs serve different purposes. IMS PCBs are designed for applications requiring efficient heat dissipation. They have a metal base layer that helps manage heat more effectively than FR4. This makes IMS ideal for high-power applications like LED lighting.
On the other hand, FR4 PCBs are used in general electronic applications due to their balance of performance and cost. While IMS excels in thermal management, FR4 is preferred for its electrical properties and versatility.
What is the Cost of FR4 PCB Per Square Inch?
The cost of an FR4 PCB can vary based on several factors. These include the board’s thickness, the number of layers, and the complexity of the design. On average, the cost per square inch of FR4 PCB ranges from $0.10 to $0.50. However, this is a rough estimate. For a precise quote, it’s best to contact PCB manufacturers with your specific requirements. If you are searching for a PCB supplier, Best Technology is here to waiting for you.
Why is Rogers Better Than FR4 Material?
Rogers material is often considered superior to FR4 in high-frequency applications. Here are some key reasons why Rogers might be chosen over FR4.
Lower Dielectric Loss
Higher Thermal Conductivity
Improved Dimensional Stability
Consistent Dielectric Constant
Superior Performance in High-Frequency Applications
Compliance with Stringent Industry Standards
What Material is Similar to FR4?
Several materials are similar to FR4 and can be used as alternatives. One such material is CEM-1, which is also a composite material made from epoxy and fiberglass. It offers good mechanical strength and electrical properties but is less flame retardant than FR4.
Another alternative is polyimide, known for its excellent thermal stability and flexibility. It is often used in applications requiring high-temperature resistance. However, polyimide is more expensive than FR4. For specific applications, materials like PTFE (Teflon) can also be considered, especially in high-frequency applications.
FAQs
1. Can FR4 be used in high-temperature applications?
FR4 can withstand moderate temperatures, but for high-temperature applications, materials like polyimide are preferred.
2. Is FR4 environmentally friendly?
FR4 is not biodegradable but can be recycled to some extent. Proper disposal and recycling methods should be followed.
3. How does the thickness of FR4 affect PCB performance?
The thickness of FR4 can impact the board’s mechanical strength and thermal dissipation. Thicker boards offer more durability but may also increase the cost.
4. Are there any disadvantages to using FR4?
FR4 has limitations in high-frequency and high-temperature applications. It is also less effective in thermal management compared to materials like IMS.
5. Can FR4 PCBs be used in flexible circuits?
FR4 is rigid and not suitable for flexible circuits. For flexible applications, materials like polyimide are used. But recently, Best Technology developed a new product called “semi-flexible FR4 PCB”, its flex area is made by FR4 material.
Is FR4 RoHS Compliant?
Yes, FR4 is RoHS compliant. This means that it meets the regulations set by the European Union to limit the use of specific hazardous materials found in electrical and electronic products.
What is FR4 Tg?
The glass transition temperature (Tg) of FR4 is a critical property that indicates the temperature at which the material transitions from a hard, glassy state to a soft, rubbery state.
Best Technology excels not only in PCB and assembly manufacturing, but also in offering top-quality PCB design services. Our professional engineering team is ready to support your innovation across various industries, including communications, healthcare, industrial, and consumer electronics. We welcome all the questions or inquiries from you.
If you are familiar with SMT or PCB assembly process, you may know BOM file. It is an important element in the SMT process. Creating BOM is a crucial step in the manufacturing process, especially for PCBs. A BOM serves as a comprehensive list of all the parts, components, and materials needed to build your product. It ensures that everyone involved in the production process is on the same page, reducing the risk of errors and delays. Today, Best Technology would like to introduce BOM and giving you a guide to create a BOM file step by step.
What is a Bill of Materials (BOM)?
A Bill of Materials (BOM) is a detailed list of all the parts, components, and materials needed to manufacture a product. In PCB manufacturing, a BOM outlines every item required to assemble a PCB, including quantities, part numbers, and descriptions. It serves as a guide to ensure that the manufacturing process runs smoothly and that no crucial components are missing.
Types of Bill of Materials
There are several types of BOMs used in different stages of production. Each type serves a specific purpose and provides unique details to streamline processes and ensure accuracy. Here are the primary types of BOMs:
Engineering BOM
This type of BOM is creating during the design phase. It lists all the parts and components designed by the engineering team, including specifications and relationships as intended in the final product. And of course, it mainly used by design engineers to communicate the product structure and details to manufacturing teams.
Manufacturing BOM (Formal)
It is a formal BOM files that used in the assembly phase. Different with engineering BOM, it includes additional details necessary for manufacturing, such as packaging, handling instructions and assembly details. And some special instructions.
Sales BOM
Sales BOM is used by sales teams and includes information relevant to the sales process, such as pricing and availability. It helps in providing accurate quotes, managing customer expectations, and handling sales orders efficiently.
What Should Include in an Effective Bill of Materials?
An effective BOM should be detailed, accurate, and easy to understand. It should include all the details of components and indicated revisions. As a 18 years expertise in PCBA production, we summarized the key elements that should be included in the BOM.
Component details
It should include all the components and their detailed information, such as names, part numbers (PN), and descriptions for each part.
Quantity (QTY)
The exact quantity of each component required for the product. Accurate quantities can prevent shortages and overstocking.
Foot print
It is the package of each component, helping to ensure the correction of part.
Reference Designators
Unique identifiers that match each component to its specific location on the product layout. These are essential for assembly and troubleshooting.
Manufacturer Information
Manufacturer information, including the manufacturer name of components and manufacturer part number. It helps to ensure correct parts are sourced. And convenient for alternative part sourcing if it is shortage.
Supplier information (Optional)
It means the name of the supplier or distributor. The part number used by the supplier, which may differ from the manufacturer’s part number.
Assembly instructions
Any special notes for assembly such as DNF remark, and version control to track revisions should also be included. Additionally, cost information helps in budgeting, and lifecycle status information helps plan for component availability and avoid discontinued parts.
How to Make a PCB Bill of Materials (BOM)?
Creating a PCB BOM is a systematic process that involves compiling all the necessary information about each component required for the assembly of the PCB. Here’s a detailed guide on how to create a PCB BOM:
Open a Blank Spreadsheet
Use software like Microsoft Excel or Google Sheets to start with a blank spreadsheet. They are common to use, offering flexibility and ease of use for creating and managing BOMs.
Define Columns
Set up your spreadsheet with appropriate column headers. Common headers include:
Part Number
Component Name
Quantity
Reference Designator
Manufacturer
Manufacturer Part Number
Supplier
Supplier Part Number
Description
Package Type
Cost
Notes
Input Data
Enter the required details for each component under the appropriate headers. Please be make sure that all information is accurate and complete. This may involve referencing design files, datasheets, and supplier catalogs. If it is incorrect, then it needs a lot of time to find out and revise the errors, resulting in schedule delay.
Use Formulas
Utilize Excel formulas to automate calculations, such as summing total quantities or calculating costs. This helps in reducing manual errors and saves time.
Format for Clarity
Use cell formatting options to highlight important information and ensure the spreadsheet is easy to read. For example, you can use bold text for column headers, color coding for different component types, and borders to separate sections.
Include Version Control
Add a version control section to your BOM to track revisions and updates. This can be a simple row at the top or bottom of the spreadsheet, indicating the version number, date of revision, and a brief description of changes.
(BOM file reference)
Save and Update
Save your BOM and update it regularly to reflect any changes in the design or component availability. Regular updates ensure that the BOM remains accurate and up-to-date, preventing issues during production.
Review and Verify
Have multiple team members review the BOM for accuracy. Cross-check all component details, quantities, and part numbers against the design files. Verification helps catch errors early and ensures the BOM is reliable.
Communicate with Suppliers:
Maintain open communication with suppliers to confirm component details and availability. This ensures that you can source the correct parts and avoid delays in the production process.
How Can I Optimize My BOM for PCB Assembly?
Sometimes, a simple BOM is not good to process PCB assembly process, and manufacturers may need to spend a lot of time to optimize it, make into convenient for manufacturing. If you are a layman, here are some steps to help you in optimizing your BOM file.
First, it’s a good idea to standardize components where possible. Using standard parts that are readily available from multiple suppliers can simplify procurement and reduce costs. This approach minimizes the risk of shortages and ensures you can get parts quickly and affordably. Also, make sure all entries in your BOM are clear and concise to avoid confusion during assembly. Double-checking part numbers and quantities against design files is crucial to prevent errors that could lead to rework or delays.
Building strong relationships with your suppliers is another key factor. Good communication with suppliers helps ensure reliable component availability and keeps you informed about any changes in lead times or part availability. Regularly updating your BOM to reflect any design changes or component availability issues is essential. Keeping your BOM current and accurate prevents last-minute surprises during assembly.
What Common Mistakes Should I Avoid When Creating a PCB BOM?
Avoiding common mistakes in BOM creation can save time and reduce errors. Here are some pitfalls to watch out for:
Incomplete information – ensure all necessary details are included for each component.
Incorrect quantities – double-check quantities to avoid shortages or excess inventory.
Outdated data – keep the BOM updated with the latest design changes and component information.
Ambiguous descriptions – provide clear and precise descriptions to prevent confusion.
Lack of version information – implement version control to track changes and ensure the correct BOM version is used.
Creating an effective and accurate PCB BOM is essential for smooth manufacturing and assembly. By following best practices and using the right tools, you can ensure your BOM is comprehensive, clear, and up-to-date, ultimately leading to a successful PCB production process.
Best Technology is an expert in SMT and PCB assembly, we have more than 18 years in this industry, that can offer you a best experience of PCBA solution. In our facotry, we have advanced equipment like full auto pick and place machine, online dual AOI, X-ray, 3D SPI, nitride reflow oven and three-proof paint machine. So that we can ensure the fast lead time and high quality of your PCBA products. Reach us to get a instant quote!
In the world of printed circuit boards (PCBs), understanding material properties is crucial. One such property is Tg, or glass transition temperature. For FR4 PCBs, knowing what Tg means can significantly impact design and performance. In this blog, we’ll explore what Tg is, how it’s measured, its importance, and other related questions.
What Does Tg Mean in PCB Manufacturing?
Tg stands for glass transition temperature. It refers to the temperature at which a polymer material, such as the resin in a PCB substrate, transitions from a hard, glassy state to a softer, rubbery state.
For the circuit board, the Tg value reflects the highest temperature it can withstand. When the temperature exceeds Tg values, the molecular structure of the circuit board material will be changed, lead to changes in its physical properties. Such as mechanical strength, size stability, adhesive, water imbibition, thermal expansion, etc. Therefore, the level of TG value of the PCB directly affects the stability and high temperature resistance of the circuit board.
In the high temperature environment, if the TG value of the circuit board is too low, it is easy to cause PCB deformation, fracture, cracking and other problems, affecting the reliability and life of the printed circuit board. If the TG value of the circuit board is too high, the PCB is easy to become hard and brittle, affecting the processability and flexibility of the circuit board.
How is Tg Measured in FR4 Materials?
Accurate measurement of Tg is crucial for ensuring the performance and reliability of FR4 PCBs. Knowing the exact Tg helps in selecting the appropriate material for specific applications, particularly those involving high temperatures and thermal cycling. Using materials with a Tg well above the operating temperature ensures the PCB will maintain its mechanical and electrical properties under expected conditions.
The primary method for measuring Tg in FR4 materials is by differential scanning calorimetry (DSC). It involves heating a small sample of the material at a controlled rate, typically between 10°C to 20°C/min. As the sample heats, the DSC measures the heat flow into the material and records it as a thermogram. The Tg is identified as the temperature where there is a noticeable change in heat capacity, appearing as a step or inflection point on the thermogram. DSC is widely used because it provides precise and reliable Tg measurements.
Additionally, Dynamic Mechanical Analysis (DMA) and Thermomechanical Analysis (TMA) also can be used to measure the Tg value.
Why is Glass Transition Temperature Critical in PCBs?
Glass transition temperature is critical because it affects the thermal and mechanical properties of the PCB. If a PCB operates near or above its Tg, it can experience issues like delamination, warping, and electrical failure. Here are some benefits of Tg.
Thermal stability
One of the main reasons is its role in determining thermal stability. During operation, PCBs are subjected to varying temperatures due to power dissipation from electronic components and environmental conditions. Make sure the Tg of the PCB material is well above the maximum operating temperature, it helps maintain mechanical stability and reliable performance under thermal stress.
Mechanical Strength
The Tg value also affects the mechanical strength and durability of the PCB. Below the Tg, the material is rigid and can withstand mechanical stress without significant deformation. This rigidity is essential for maintaining the structural integrity of the PCB, especially during assembly processes like soldering, where the board is subjected to mechanical and thermal stresses.
Thermal Management
Thermal management is very important to electronics, especially for those miniaturized electronic devices. If the PCB itself has good thermal management, then designers no need to install heatsink or coolers. Materials with higher Tg values exhibit lower coefficients of thermal expansion (CTE), meaning less expansion and contraction with temperature changes.
Application-specific requirements
Different applications have varying thermal and mechanical requirements. High-performance computing, automotive, aerospace, and industrial electronics often operate in environments with high temperatures and thermal cycling. For these applications, using PCB materials with appropriate Tg values is crucial.
What is the Typical Tg Value for Standard FR4 PCBs?
Standard FR4 materials generally have Tg values in the range of 130°C to 140°C. For high-performance applications, materials with higher Tg values are necessary. The table below lists some common high Tg materials used in PCB manufacturing, along with their Tg values and characteristics.
Material
Tg Value (°C)
Characteristics
Applications
ISOLA IS410
180
Excellent thermal and mechanical properties
High-reliability applications
Nanya NP-175
175
High thermal stability, good mechanical strength
Automotive, industrial electronics
Shengyi S1000H
170
Cost-effective, widely used
Consumer electronics, industrial applications
Ventec VT-47
170
High Tg and low CTE
High-density interconnect (HDI) PCBs
Rogers 4350B
280
Extremely high Tg, excellent thermal stability
RF and microwave applications
(Common used high Tg materials)
Can You Explain the Difference Between Tg and Td in PCBs?
Tg and Td (decomposition temperature) are two different thermal properties. Unlike the reversible physical change associated with Tg, decomposition is an irreversible chemical process. At Td, the polymer chains in the material break down, leading to a loss of structural integrity and release of volatile compounds. Key points about Td include:
1. Chemical Stability
Td represents the upper thermal limit of a material’s chemical stability. Exceeding Td results in the breakdown of the polymer structure, rendering the material unsuitable for further use.
2. Material Selection
Knowing the Td helps in selecting materials for high-temperature applications. A material’s Td should be well above the maximum operating temperature to prevent degradation.
3. Safety and Reliability
Operating a PCB above its Td can result in catastrophic failure, including charring, delamination, and loss of electrical performance. The operating temperature remains below Td is critical for safety and reliability.
How Do You Choose the Right Tg Value for Your PCB Design?
Choosing the right Tg value depends on the operating environment and thermal demands of your application. Consider factors such as the maximum operating temperature, the thermal cycling the PCB will undergo, and the mechanical stresses it will face. Consulting with material suppliers and using simulation tools can help make an informed decision. According to our 18 years experience in PCB, we summarized a recommend Tg value for each application. Hope this is useful for you guys.
Consumer electronics
If your PCB will be used in standard consumer electronics, just like smartphones and tablets, a Tg value of around 130°C to 140°C is typically sufficient. These devices generally do not encounter extreme temperatures or thermal cycling.
Automotive applications
Automotive PCBs are always exposed to high temperatures and significant thermal cycling. A Tg value of 170°C or higher is recommended to ensure reliability and performance under the hood. So, Rogers material is good for this kind of PCB.
Aerospace and defense
Applications in aerospace and defense require materials that can withstand extreme temperatures and harsh environments. High Tg materials with values of 180°C or more are often used to meet these stringent requirements.
Industrial Electronics
Industrial environments can vary widely, but generally, high Tg materials are preferred due to the exposure to high temperatures and mechanical stress. A Tg value of at least 150°C to 170°C is advisable.
Best Technology is a well-known PCB and PCBA assembly provider in Asia and Vietnam. We have a large facility for handling low-medium to mass production PCBs, and supporting for various kinds of custom PCBs. Some special PCBs are available here, like bus bar PCB for new energy vehicles, heavy copper PCB for high power and high current PCBs, ceramic PCBs for harsh environments, extra thin PCB, RF PCB, microwaves PCB, IC substrate PCB and so on.
For more information, please do not hesitate to contact us.
Ceramic PCB is a type of emerging PCB in the recent years, they are known for their high thermal conductivity and low expansion coefficient. Except this, it has numerous advantages that normal FR4 PCB can not achieved. And even for metal core PCB (MCPCB). Today, we are going to introduce their characteristics in detail.
1. High thermal conductivity
The core metal content of ceramic circuit boards is as high as 96-98%, which makes them have extremely high thermal conductivity. Compared with ordinary FR4 circuit boards, the thermal conductivity of ceramic circuit boards can reach 170-230 W/mK, while the thermal conductivity of FR4 boards is usually only 0.3-0.4 W/mK. Higher thermal conductivity allows for more efficient heat dissipation, avoiding the problem of damage to electronic components due to overheating. This is particularly important in high-power applications, such as LEDs and power semiconductors.
2. Low thermal expansion coefficient
Ceramic materials have a very low coefficient of thermal expansion (CTE), usually between 6-8 ppm/°C. In contrast, FR4 material has around 14-16 ppm/°C CTE. This means that ceramic materials hardly expand or contract when temperature changes. The low thermal expansion coefficient improves the reliability of the circuit board, reduces the influence of the thermal cycle on the circuit board structure and the connection of electronic components. Especially suitable for use in the environment with frequent temperature changes.
3. High surface hardness
The surface hardness of ceramic materials is up to 9 Mohs, which is harder than aluminum oxide and silicon. It means ceramic PCB has more wear-resistant, scratch resistant, and not easy to damage. It enables to run stably for a long time even in harsh physical environments, extending the service life of the board. That is why ceramic PCB is always recommended to use in military.
4. High compressive strength
The compressive strength of the ceramic circuit board can reach 450-500 MPa, which can withstand large mechanical pressure without deformation or rupture. This characteristic makes them excellent in applications that require them to withstand mechanical stress, such as industrial automation and aerospace.
5. High dielectric strength
Ceramic PCB has very high dielectric strength, usually between 15-25 kV/mm. And it can withstand higher electric fields without electrical breakdown.
6. Ability to withstand higher temperatures
Ceramic circuit boards can operate at temperatures up to 1000°C without degradation or damage. While FR4 circuit boards typically operate at an upper limit of 140-170°C. Ceramic circuit boards are suitable for electronic devices in high temperature environments, such as electric vehicles and high-power lasers.
7. High breakdown voltage
The high breakdown voltage of the ceramic circuit board can reach 20-35 kV, ensuring reliable operation under high voltage conditions. It is well suitable for use in high-voltage power supplies and power electronic equipment, providing higher safety.
8. Does not absorb water
The water absorption of ceramic materials is usually less than 0.1%, while the water absorption of FR4 materials is 0.1-0.2%. The non-water absorbing feature prevents performance degradation and damage caused by water absorption in a humid environment. It is ideal for Marine, medical, and other applications that require moisture resistance.
9. Low loss at high frequency
In high-frequency applications, the dielectric loss Angle tangent (Df) of ceramic circuit boards is usually between 0.0001-0.001, while the loss Angle tangent of FR4 materials is 0.02-0.03. Low loss ensures signal integrity and transmission efficiency, which is suitable for communication equipment and high-frequency electronic equipment.
10. Resistance to cosmic rays
Ceramic materials can resist the impact of cosmic rays, will not be degraded or damaged by rays. They are suitable for satellite electronic equipment, ensuring the stability and reliability of the circuit board in a high radiation environment.
11. No organic ingredients
Ceramic circuit boards do not contain organic components, so they have high chemical stability, are not susceptible to chemical corrosion and decomposition. They are good choice to use in harsh chemical environments.
12. High-density assembly
Ceramic circuit boards support high-density assembly with line/pitch resolution of 20 microns. This allows them to be adapted to more complex and refined circuit designs, suitable for microelectronics and high-precision applications.
Best Technology provides professional one-stop ceramic PCB design and manufacturing service all around the world. We welcome all the friends and partners from domestic and abroad to visit our ceramic circuit board workshop.
