What is PCB test and What is Tested?

August 28th, 2024

PCB test is a method of performing operational and functional tests on a circuit board and layout optimization. PCB test identifies any shorts, opens, incorrect component placement, or faulty components.

The purpose of PCB test and inspection is to check if the PCB meets the performance of a standard printed circuit board. It ensures that all PCB manufacturing processes are operating properly and without any defects as per the project specifications.

A PCB consists of different elements and components, each of which affects the overall performance of the electronic circuit. These components are analyzed in detail to ensure the quality of the PCB.

What is a PCB test?

PCB test is a technique that uses electronic testing instruments to detect the performance and quality of PCB (Printed Circuit Board) circuit boards. It is widely used in the electronics manufacturing industry to help manufacturers improve product quality and production efficiency.

The main purpose of PCB test is to ensure that all parts on the circuit board are properly connected and can still work properly under high voltage environments, while verifying whether the function of the circuit board is normal. Test methods include connectivity testing, withstand voltage testing, and functional testing, while inspection standards involve appearance inspection, size inspection, and performance inspection. In addition, PCB test also involves a series of professional techniques and methods, such as flying probe test, ICT test, FCT test, AOI test, etc., to ensure the electrical performance and structural integrity of the circuit board.

How to Test PCB?

PCB contains different components that affect the overall performance of electronic circuits. Tests are performed to check and optimize the status of these components using computerized machine software, simple electronic test equipment and tools, and even basic manual inspections.

1. Electrical test

2. Hole wall quality

3. Mechanical resistance test

4. Soldering quality

5. Cleanliness inspection, considering weather resistance, humidity and corrosion

6. Lamination, testing the ability of laminates to resist or heat peeling

Environmental testing is particularly necessary for PCBs used in humid environments.

What are the benefits of PCB test?

Error identification: The main benefit of PCB test is that it helps identify problems in PCBs. Whether the problem lies in functionality, manufacturability or other aspects, PCB test can identify problems in PCB design and layout.

Save time: Performing PCB test early helps save time in the long run by allowing designers to identify major issues during the prototyping phase. Comprehensive testing allows designers to quickly and easily identify the root cause of each issue and make adjustments so that they can move to production at a faster pace and reduce product lead times.

Reduce costs: PCB test avoids the waste of producing defective products by testing products using prototypes and small-scale components. By completing comprehensive testing early in the design process, designers can avoid the waste of producing defective PCBs, ensuring that the design is as perfect as possible before going into production.

Reduced returns: When PCB test is performed, the likelihood of selling defective products or products that do not meet performance standards is reduced, reducing the costs associated with refunding customers and handling defective goods.

Improved safety: Defective PCBs can cause fires, which can endanger people nearby. Pre-manufacturing testing also ensures that machines and workers are not damaged or injured due to poor design during the production process.

What are the types of PCB test?

1. In-circuit testing

In-circuit testing (ICT) is the most reliable type of PCB test available today. The high price reflects this – tens of thousands of dollars, although the cost depends on factors such as board and fixture size.

Also known as bed of nails testing, ICT fires and activates individual circuits on a board. In most cases, the test is designed to achieve 100% coverage, but actual coverage will be closer to 85-90%.

The test involves the use of fixed probes, whose layout matches the PCB design. The probes check the integrity of the soldered connections. A bed of nails tester simply pushes the board onto the probe bed to begin testing. Access points are pre-designed on the board to allow the ICT test probes to establish a connection with the circuit.

2. Flying probe testing

Flying probe testing is a tried and tested method that is cheaper than in-circuit testing. It is a non-powered test that checks for shorts, capacitance, inductance, diodes, and other problems.

The flying probe tester works by using needles connected to probes on an xy grid obtained from basic CAD. The ECM program coordinates to match the board and then runs the program connected to these test points.

In some cases, ICT makes flying probe testing unnecessary, but the PCB must be designed to fit the test fixture – which means a higher initial cost. ICT is faster and less error-prone than flying probe testing, and while flying probe testing may be cheaper initially, it may not actually be cost-effective for large orders. Finally, it is important to note that PCB flying probe testing does not power the board.

3. Automated Optical Inspection (AOl)

AOI is a contact-free visual inspection of printed circuit boards. AOI uses a camera and microscope to take photos of the PCB. The software then looks for inconsistencies between these photos and the board schematic. Technicians can thoroughly check each board and find any problems through this procedure.

The board is not powered during AOI, and it may not cover all part types. Due to these deficiencies, it should be used in conjunction with another test technology such as functional testing, flying probe testing, or ICT.

4. X-ray Inspection

As the name suggests, this type of test is essentially an inspection tool. It is also known as AXI. During this testing, X-ray technicians can detect defects early in the production process by carefully inspecting solder connections, internal traces, and barrels. Using X-ray inspection, invisible components can be inspected.

Due to the high density of SMT technology and the difficulty in locating connections in BGA and CSP (chip scale packages), more precise inspection techniques, such as those based on X-ray technology, are needed. Solder joints can be clearly seen in radiographs because they are made of materials with a higher atomic weight than other components on the board.

The main benefit of AXI technology is that it can identify every connection and solder joint, including those hidden by the package. In addition, solder joints can be inspected, highlighting any potential bubbles.

What are the difficulties in PCB test?

Increasing complexity: PCB designs are becoming more complex, with higher component density and smaller size, which makes it more difficult to access test points and increases the risk of undetected defects.

Cost: High-end test equipment such as X-ray inspection systems can be expensive to purchase and maintain. Testing also increases production costs, especially when test failures require rework.

Accuracy: Although the test equipment is designed precisely, errors may still occur due to calibration problems, software errors or human errors.

Conclusion:

PCB test is very important to the quality of the product. It ensures that the PCB, which forms the backbone of all electronic devices, operates normally and meets the required quality standards, effectively avoiding the impact of poor products, improving the quality of the finished product, and preventing problems when the product is used.

BEST Technology has a complete set of PCB test equipment and has very complete testing standards to ensure that each PCB finished product has extremely high quality. Choosing us, you will not need to worry about any PCB quality issues.

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How to use solder flux?

August 27th, 2024

In the manufacturing process of printed circuit boards, it is very necessary to apply a proper amount of flux. The soldering pads, copper bars of components and the surface of solder paste are the places where flux should be applied, which can improve the firmness of the soldering points and the quality of printed circuit boards.

What is flux?

Flux: A chemical substance that can help and promote the soldering process in the soldering process, and at the same time has a protective effect and prevents oxidation reactions. Flux can be divided into solid, liquid and gas.

There are mainly several aspects such as “assisting heat conduction”, “removing oxides”, “reducing the surface tension of the material to be soldered”, “removing oil stains on the surface of the material to be soldered, increasing the soldering area”, and “preventing re-oxidation”. Among these aspects, the two most critical functions are: “removing oxides” and “reducing the surface tension of the material to be soldered”.

Do you apply flux before or after soldering?

Use flux before soldering printed circuit boards. ‌

During the soldering process of printed circuit boards, the main purpose of using flux is to improve soldering performance and help the metal avoid the formation of an oxide film that hinders solder wetting when heated, thereby promoting the formation of solder-metal alloys and avoiding the occurrence of cold soldering and false soldering.

Flux can be applied to the printed circuit board before soldering, or it can be used as part of the solder during the soldering process, such as solder paste or solder oil. When tinning the pins of components, rosin should be used as the flux, and if the printed circuit board is already coated with rosin solution, then no additional flux is required during soldering.

After using flux, make sure to wipe off the residual flux at the soldering site after soldering to avoid potential damage to electronic components and circuit boards.

In addition, the preparation work before soldering includes thoroughly cleaning the copper foil surface and then applying rosin water to protect the copper foil and help soldering. This step is performed before soldering to ensure the smooth progress of the soldering process. Therefore, the correct approach is to use flux before soldering printed circuit boards to ensure the quality and reliability of soldering.

How much flux to use when soldering?

When soldering printed circuit boards, the amount of flux used needs to be determined according to the specific soldering method and the type of flux. For wave soldering flux, when using brushing and foaming methods, the specific gravity of the flux should be controlled between 0.82-0.84 (specific gravity of liquid rosin flux stock solution).

During the soldering process, the specific gravity of the flux needs to be measured regularly. If the specific gravity is found to increase, it should be adjusted to the normal range with diluent in time, but the diluent should not be added too much to avoid affecting the soldering quality.

For the quantitative spraying method, the key is that the nozzle can control the spray volume. The nozzle should be cleaned frequently to ensure that the spray hole is not blocked. The spray pressure should be controlled at 0.2-0.3Mpa, the flux pressure should be controlled at 0.4±0.05Mpa, and the spray flow rate should be controlled at 20-35ml/min.

In addition, different types of flux formulas are also different. For example, rosin liquid can be made by mixing rosin blocks and alcohol in a ratio of 1:3. For the flux of printed circuit boards, you can directly use rosin water, and apply the prepared rosin water directly on the surface of the printed circuit board or the solder joints.

When using flux, you should also pay attention to the following points:

Put the bottle cap on immediately after use to prevent the flux from being in contact with air for a long time and causing oxidation reaction or absorbing water vapor in the air to cause the concentration to decrease.

Regularly replace the flux that has been stored for too long, because long-term storage will cause the flux composition to change and the activation performance to deteriorate, affecting the welding quality.

Clean it after welding, because the insulation performance of the flux will drop sharply at high temperature, and the residue may affect the heating components, and in severe cases may cause short circuits.

In summary, the amount of flux used in printed circuit board welding needs to be determined according to the specific welding method and flux type, and pay attention to the use and storage conditions of the flux to ensure welding quality and safety.

What happens if you use too much flux when soldering?

First, the main functions of flux include assisting heat conduction, removing oxides, reducing the surface tension of the material being soldered, removing oil stains on the surface of the material being soldered, increasing the soldering area, and preventing reoxidation.

However, excessive use of flux can lead to corrosion and electromigration. This is because improper use of flux, such as excessive use, can create more favorable conditions for potential chemical corrosion reactions.

In addition, if the flux used is not well controlled, resulting in excessive use of flux, more flux residue will be left, which creates more favorable conditions for potential chemical corrosion reactions.

Therefore, it is very important to control the amount of flux used to avoid negative effects on soldering quality and reliability.

What happens if I don’t use flux?

If flux is not used on printed circuit boards, it may lead to reduced soldering quality, increased soldering difficulty, and affect the performance and reliability of the circuit.

1. Increased soldering difficulty: Without flux, the solder may be difficult to flow to the soldering point, resulting in loose soldering, prone to cold soldering or poor soldering.

2. Reduce welding quality: Without the help of flux, the soldering point may not be smooth enough, with burrs or unevenness, which may affect the normal operation of the circuit.

3. Affect circuit performance and reliability: Flux can reduce the resistance of the soldering point and improve the conductivity of the circuit. Without flux, the resistance of the soldering point may increase, affecting the performance and stability of the circuit.

In addition, the flux can also prevent oxidation to a certain extent, protect the soldering point from the influence of the external environment, thereby improving the life of the circuit. Therefore, in the soldering process of printed circuit boards, it is very important to use the soldering flux correctly.

What is an alternative to soldering flux?

Alternatives to printed circuit board soldering flux include no-clean soldering flux, special solder resist for printed circuit boards, water-based cleaning agents and dry ice cleaning technology. ‌

1. No-clean soldering flux is a new type of soldering flux that does not contain halide activators. It does not need to be cleaned after use, which can save investment in cleaning equipment and cleaning solvents, while reducing the emission of waste gas and wastewater, and the pollution to the environment is also reduced accordingly.

2. The main function of the ‌PCB solder mask‌ is to prevent “wiring” and short circuits during wave soldering and protect the PCB permanently. In addition, it can save solder, reduce the weight of the PCB, and reduce costs.

3. As a new type of cleaning medium, the ‌water-based cleaning agent‌ achieves cleaning through the wetting, dissolution, emulsification, saponification, chelation and other effects of the surfactants, emulsifiers, penetrants, etc.

4. The ‌dry ice cleaning technology‌ uses extremely low-temperature dry ice particles to spray onto the treated object under the action of compressed air, so that the dirt is rapidly frozen to brittleness and burst, and then vaporized to take away the dirt.

These substitutes have their own characteristics and are suitable for different application scenarios and technical requirements. When choosing, specific process requirements and cost-effectiveness must be considered.

What does rosin do when soldering?

In the process of printed circuit board soldering, rosin plays a vital role. It is mainly used as a flux to help the soldering process be smoother and more efficient. The role of rosin is reflected in the following aspects:

‌Removing oxide film‌: Rosin can remove the oxide film formed on the copper surface due to contact with air. These oxide films will prevent the tin from wetting the copper wire, thus affecting the quality of welding.

‌Preventing re-oxidation‌: Rosin can not only remove the oxide film, but also prevent the soldering surface from re-oxidizing during the welding process, which helps to maintain the stability and reliability of the welding point.

‌Isolating air‌: Under high temperature conditions of welding, rosin can isolate the air and prevent oxidation of the metal surface.

In summary, rosin plays an important role in the soldering process of printed circuit boards. Through its fluxing effect, it improves the quality and reliability of soldering and is one of the indispensable materials in electronic manufacturing‌.

Conclusion:

Flux is a key part of the soldering process. Without it, your solder will not flow smoothly through the joint and the solder will not adhere properly to the various components on the circuit board. High-quality flux is necessary to produce good solder joints.

BEST Technology is a professional PCB circuit board manufacturer with many years of experience in PCB circuit board welding. The circuit boards it produces are of extremely high quality. We have the most extensive experience to deal with all aspects of PCB welding issues.

Tags: flux, PCB, PCBA, SMT
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How to understand circuit diagrams?

August 27th, 2024

A circuit diagrams, also known as an electrical diagram, schematic diagram, or electronic schematic diagram, is a graphical representation of a simplified circuit. It is a visual tool for the design, construction, and maintenance of electrical and electronic equipment.

By utilizing images or standard symbols of different components, circuit diagrams can simplify the description of the components of a circuit and their interconnections. This enables electricians and technicians to easily understand the relative positions of components and their relationships in the circuit.

How to learn circuit diagram easily?

1. ‌Knowing electrical components‌: First, you need to understand common electrical components, such as AC contactors, push button switches, thermal relays, time relays, etc., and master their working principles and structures.

2. ‌Memorizing electrical symbols‌: Learn and memorize common electrical letters and graphic symbols, such as AC contactors (KM), intermediate relays (KA), etc.

3. ‌Basic theory learning‌: Have basic electrical basic knowledge, such as the relationship between the rotation direction of a three-phase asynchronous motor and the phase sequence of the power supply‌.

4. ‌Practical operation‌: If conditions permit, disassemble electrical components to familiarize yourself with their internal structure, or understand the internal structure and working principle through physical diagrams.

5. Practice step by step: Start with simple circuit diagrams and gradually try to analyze more complex circuit diagrams. Through continuous practice, you can gradually improve your ability to interpret circuit diagrams.

6. Use the principle of circuit simplification: Learn and apply the basic principles of circuit simplification, such as ignoring wire resistance, switch processing, etc.

7. Combine theory with practice: Apply theoretical knowledge to practice, for example, try to design your own circuit based on the learned electrical schematics, or design circuit diagrams according to actual needs.

Through the above steps and methods, you can learn and understand circuit diagrams more easily.

What are the 4 rules for drawing circuit diagrams?

The 4 rules for drawing circuit diagrams are:

1. Circuits or components should be arranged according to function and arranged in working order as much as possible. ‌

2. All electrical components should be represented by graphic symbols and text symbols that are unified by national standards. ‌

3. Different parts of the same electrical component (such as coils and their multiple contacts) are often not drawn together, but should be marked with the same text symbol.

4. In the circuit schematic, all contacts of the control appliance should be drawn in the “non-excitation” state.

These rules together ensure that the circuit diagram is clear, accurate and easy to understand, and provide an important reference for the design and maintenance of electronic equipment and systems.

How to get better at reading schematics?

Understand the basic composition and logic block diagram of the circuit: First, you need to understand the relationship between the various components in the schematic, such as power supply, reset, etc., and the connection relationship between the various devices on the motherboard.

Pay attention to details: When reading the schematic, you need to pay attention to details, such as the model of the components, the connection method, etc.

Do more exercises: Through a lot of reading and practice, you can become familiar with various circuit types and topics and gain more knowledge and experience from them.

Use relevant knowledge of analog circuits and circuit design: Having a deep understanding of the basic concepts and principles of analog circuits and circuit design can help better understand how the various parts in the schematic work together.

What are the components of common circuit schematics?

Power supply: The power supply provides electrical energy to the circuit in the form of voltage and current. Every functional electronic circuit requires a DC or AC power supply.

Switches: Switches can make or break connections in a circuit. They can also change the path that current flows.

Capacitors: Capacitors are passive electronic components that store electrical charge. There are two common types of capacitors: nonpolar capacitors and polar capacitors.

Diodes: A diode is a polarized device that allows current to flow in only one direction. Because it is polarized, it has a positive terminal (anode) and a negative terminal (cathode). The flat side of the triangle is the anode, and the line is the cathode.

Potentiometers and variable resistors: Both variable resistors and potentiometers have an arrow added to the standard resistor symbol. Variable resistors are still two-terminal devices, so the arrow just goes diagonally through the middle. Potentiometers are three-terminal devices, so the arrow becomes the third terminal (the wiper).

Resistors: The most basic circuit component and symbol, resistors on schematics are usually represented by a few jagged lines with two terminals extending outward. Schematics using international symbols may use a featureless rectangle instead of a wavy line.

What does a resistor do in a circuit?

Resistance (usually represented by “R”) is a physical quantity that indicates the magnitude of the resistance of a conductor to the current in physics.

The greater the resistance of a conductor, the greater the resistance of the conductor to the current. Different conductors generally have different resistances, which is a characteristic of the conductor itself. Moreover, the main functions of resistors in circuits include current shunting, current limiting, voltage division, biasing, filtering (used in combination with capacitors), impedance matching, and converting electrical energy into internal energy.

What is the simplest of all circuit diagrams?

The simplest of all circuit diagrams is the series circuit. ‌

The series circuit is one of the most basic circuit connection methods, consisting of components such as power supply, wires, switches, and electrical appliances. The characteristic of this circuit is that the path of current passing through each component is single, that is, the current flows out from the positive pole of the power supply, passes through each component and reaches the negative pole of the power supply.

The structure of the series circuit is simple and easy to understand and construct. Therefore, the series circuit is an important concept in the basic stage of circuit learning. In addition, the single path nature of the series circuit makes it the basis for understanding and analyzing complex circuits, laying the foundation for subsequent learning of more complex circuit structures such as parallel circuits and hybrid circuits.

Conclusion:

Circuit diagrams are an important tool in the field of electronics that provide a visual representation of circuits. These diagrams are essential for designing, troubleshooting, and understanding how electronic components are interconnected.

Whether you are a beginner or an experienced engineer, mastering the skill of reading circuit diagrams is the foundation for a successful career in electronics. It enables you to effectively design, troubleshoot, and understand electronic circuits. You can master this important skill by becoming familiar with common symbols, understanding circuit layouts, and practicing regularly.

Tags: circuit, circuit diagrams
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What are the types of PCB boards?

August 26th, 2024

PCB (Printed Circuit Board) boards can be classified according to their constituent materials and characteristics. PCBs are classified into single-sided boards, double-sided boards, and multi-layer boards according to board applications. They are classified into flexible PCB boards (flexible boards), rigid PCB boards, rigid-flexible PCB boards (rigid-flexible boards) according to materials, etc.

PCB is an important electronic component, a support for electronic components, and a provider of electrical connections for electronic components. Since it is made using electronic printing technology, it is also called a printed circuit board. PCB is simply a thin board with integrated circuits and other electronic components.

1. Single-sided board:

On the most basic printed circuit board, parts are concentrated on one side and wires are concentrated on the other side. Because wires only appear on one side, this type of printed circuit board is called a single-sided board. Because single-sided boards have many strict restrictions on designing circuits (because there is only one side, wiring cannot cross and must go around a separate path), early circuits used this type of circuit board.

2. Double-sided board

This type of circuit board has wiring on both sides. In order to connect the wires on both sides, there must be a proper circuit connection between the two sides. This connection between the circuits is called a guide hole. A guide hole is a small hole filled or coated with metal on a printed circuit board, which can be connected to the wires on both sides. Because the area of a double-sided board is doubled that of a single-sided board, and the wiring can be interlaced (can go around to the other side), double-sided boards can be used on more complex circuits than single-sided boards.

3. Multilayer board:

In order to increase the area that can be wired, multilayer boards use more single- or double-sided wiring boards. Multilayer boards use several double-sided boards, and put an insulating layer between each layer of boards and glue them firmly. The number of layers of the circuit board represents how many independent wiring layers there are, usually an even number of layers, and includes the two outermost layers.

4. Flexible PCB board

Flexible PCB board is a printed circuit board made of a flexible substrate. Its advantage is that it can be bent, which is convenient for the assembly of electrical components. Flexible circuit board, flexible PCB, flexible circuit and multi-function printed circuit are other names for these circuit boards. These printed circuit boards are made using the same components as rigid printed circuit boards. The main difference is that the circuit board is designed to bend to the desired shape throughout the application process. These PCBs are available in single-sided, double-sided, and multi-layer configurations. This helps reduce the complexity of unit assembly.

5. Rigid PCB Board

Rigid PCB is a circuit board that cannot be twisted or folded. The base material of the board is a rigid substrate, which gives the board rigidity and strength. They are composed of multiple layers, including substrate layers, copper layers, solder mask layers, and silk screen layers, which are bonded together by adhesives and heat. While some circuit boards are single-sided, double-sided, or multi-layered, rigid PCBs can be any of these as needed. However, once made, they cannot be modified or changed.

6. Rigid-Flex Board

Rigid-Flex Board is a hybrid circuit board that combines elements of flexible and rigid circuit boards to form a foldable or continuously bendable circuit board, which is usually molded into a curved shape or curve during the manufacturing process.

The flexible portion of the circuit board is often used for interconnections between rigid circuit boards, allowing narrower wires to take up less space, thereby reducing the size of the circuit board. Using flexible PCBs for interconnections often eliminates the need for bulky and heavy connectors, making rigid-flex boards lighter. The design of rigid-flex boards is slightly more complicated because these boards are 3D constructed, allowing the board to be folded or twisted to produce the shape required for the product.

7. High-frequency PCB board

High-frequency circuits refer to the overall circuit board design, not the other types of circuit board structures we described earlier. These PCBs are designed to conduct signals over 1 GHz.

High-frequency boards mostly use FR4-grade glass-reinforced epoxy boards, polyphenylene ether (PPO) resins, and Teflon, but Teflon has a low and stable Dk value, low dielectric loss, low hygroscopicity, and is slightly more expensive.

When designing high-frequency circuits, various factors must be considered, such as Dk value, dissipative loss, and dielectric thickness. The DK value of the substrate is an important factor to remember. Substrates with a higher probability of Dk value changes usually experience impedance changes, which affects the harmonics that make up the electrical signal, resulting in poor signal integrity.

8. Copper substrate

Copper substrate is a metal substrate with high thermal conductivity, suitable for high-frequency circuits and areas with large high and low temperature changes and heat dissipation and architectural decoration industries for precision communication equipment.

The copper substrate circuit layer requires a large current carrying capacity, and a thicker copper foil should be used, with a thickness of generally 35μm~280μm. The thermal conductive insulation layer is the core technology of the copper substrate. It is composed of core thermal conductive components and high molecular polymers, with low thermal resistance (0.15), excellent viscoelastic properties, resistance to thermal aging, and the ability to withstand mechanical and thermal stress.

The copper substrate metal base is the supporting member of the copper substrate, which is required to have high thermal conductivity. It is generally a copper plate, and a copper plate can also be used (where the copper plate can provide better thermal conductivity). It is suitable for conventional mechanical processing such as drilling, punching and cutting.

9. Aluminum-based PCB board

The design of aluminum-based PCB circuits is similar to that of copper-based PCBs, but the substrate material of aluminum-based PCBs is aluminum metal, rather than the standard glass fiber used in most circuits.

The aluminum layer is reinforced with the least heat-resistant insulation material, which means less heat is transferred from the insulation material to the backing. After applying the insulation layer, another layer of copper is required.

10. High Density Interconnect (HDI) PCB

Among the many types of PCBs, HDI PCB is a circuit with multiple interconnections that takes up very little space. HDI components are mounted close to each other, minimizing PCB space while maintaining high functionality. Boards containing 120-160 pins per square inch are classified as HDI PCBs.

HDI designs integrate dense device mounting and multi-purpose wiring. With the help of microvias, buried vias, and blind vias, compact circuits can be made, minimizing drilling to copper. For the electrical requirements of high-speed signals, HDI PCBs must have high-frequency conduction capabilities, impedance control, and minimal redundant radiation.

11. Thick Copper PCB

Thick copper PCB is also called heavy copper PCB. Basically, it contains more than 2 ounces of copper in the inner and outer layers of the board. Heavy copper transmitters significantly increase the overall thickness of the board; thick copper boards are known for supporting high currents, high temperatures, and cyclical thermal cycles.

12. High TG PCB

Among various types of PCBs, high Tg PCBs are circuit boards designed to work at high temperatures. Glass transition temperature (Tg) is an essential element of any epoxy resin. It is basically the temperature point at which the polymer changes from a hard glass substrate to a soft rubber substrate. The substrates used to make high Tg circuit boards must be flame retardant, which means that they soften instead of burning at the glass transition point (Tg).

The higher the Tg value, the higher the temperature requirement during lamination. Under such conditions, the PCB will become hard and brittle, affecting the aperture size and related electrical properties. Standard boards will soften, deform and melt under such conditions, and their mechanical and electrical properties will be significantly reduced.

Standard FR-4 Tg is between 130-1400C, medium Tg is between 150-1600C, and high Tg is above 1700C. The higher the Tg value, the better the board’s heat, moisture and chemical resistance.

Conclusion:

PCB board types are updated and iterated with the rapid development of the industry, and various types of PCB boards have gradually evolved to cope with various application scenarios, adding corresponding materials according to the required performance. BEST Technology has various PCB types of manufacturing technology, which can meet your any type of PCB needs.

Tags: PCB, pcb design, pcb type
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What is the surface mount technology?

August 23rd, 2024

Surface mount technology (SMT) is a widely used surface assembly method in the electronic assembly industry. It mainly uses automated production equipment to directly solder surface mount components (SMD) to the pads on the surface of the printed circuit board (PCB). SMT has the advantages of high production efficiency, high space utilization, high density and miniaturization. However, it has high requirements for production equipment, processes and operating skills.

What is the surface mount technology process?

The process of surface mount technology (SMT) mainly includes the following steps:

1. Printed circuit board preparation: Before surface mounting, the printed circuit board needs to be prepared first, including cleaning the circuit board, removing the surface oxide layer, and applying solder paste.

2. Component mounting: Use appropriate equipment to accurately mount various electronic components on the printed circuit board.

3. Soldering: After the components are mounted, the solder paste is heated to melt it to form a reliable welding connection.

4. Inspection: After welding, use AOI for automatic inspection to ensure the correct mounting and welding quality of components.

5. Testing and debugging: Test and debug the mounted circuit board, and verify whether the function and performance of the circuit board meet the requirements through specific test equipment and procedures.

Each step needs to be carried out carefully to ensure that the mounted circuit board has good quality and reliability. In addition, surface mount technology is suitable for circuit board assembly, with the characteristics of compact structure and small size, and is widely used in the manufacture of electronic products.

What are the roles of surface mount?

The role of surface mount technology (SMT) is mainly reflected in improving the performance, reliability and production efficiency of electronic products, while reducing the volume and weight of products.

Surface mount technology (SMT) has the following significant effects:

Increase assembly density and reduce product volume: By using surface mount technology, the volume of electronic products can be reduced by 40%~60% and the weight can be reduced by 60%~80%.

‌Improve reliability: SMT has high reliability, low solder joint defect rate and strong vibration resistance.

Optimize high-frequency characteristics: SMT reduces electromagnetic and radio frequency interference and optimizes the high-frequency characteristics of the circuit.

Automated production: SMT is easy to automate, thereby improving production efficiency.

Enhanced compactness: Using small surface-mounted components can save a lot of space on the printed circuit board, and circuit assembly is easier to automate.

Adapt to a wide range of fields: As a new generation of electronic assembly technology, SMT has penetrated into various fields, including but not limited to computers, communication equipment, consumer electronics, etc.

In summary, surface mounting technology has significantly improved the comprehensive performance and production efficiency of modern electronic products by increasing assembly density, optimizing circuit performance, enhancing product reliability, and realizing automated production.

What is the advantage of surface mount?

The advantages of surface mounting mainly include:

High assembly density: Surface mounting technology (SMT) allows more electronic components to be installed in a limited space.

Small size and light weight of electronic products: By using SMT, smaller and lighter electronic products can be manufactured.

‌High reliability‌: SMT has a low solder joint defect rate, which improves the reliability of the product‌.

‌Easy to automate‌: SMT technology is very suitable for automated production and can greatly improve production efficiency‌.

‌Design flexibility‌: SMT allows different components to be used on the same circuit board, providing design flexibility‌.

‌EMC compliance‌: SMT technology helps meet electromagnetic compatibility (EMC) requirements and ensure the safety and performance of the equipment‌.

‌Selective soldering‌: SMT supports selective soldering, which increases the customizability of the product‌.

In addition, SMT technology is cost-effective because the packaging size of components is generally standardized and can be quickly and accurately installed using automated equipment, thereby reducing production costs‌. At the same time, SMT reduces human errors and improves product quality because the placement of components is very consistent, reducing errors or the need for rework.

What are the disadvantages of surface mount?

‌The disadvantages of surface mount technology (SMT) mainly include incompatibility with certain components, the possibility of soldering defects, and high equipment costs. ‌

‌Incompatibility with certain components‌: SMT technology is not suitable for all types of components.

‌Possibility of soldering defects‌: Although SMT technology reduces the need for drilling and shortens setup time, it is not a zero-defect soldering process. In actual applications, SMT may encounter various soldering defects.

‌Higher equipment cost‌: Although SMT technology can improve production efficiency and circuit density, it requires expensive special equipment and professional technicians.

In summary, although SMT technology has many advantages, such as reducing drilling, shortening setup time, and improving production efficiency, it also has some disadvantages, especially in terms of incompatibility with certain components, possible soldering defects, and high equipment costs.

What does SMD stand for in surface mount?

SMD stands for Surface Mounted Devices. ‌

SMD is a type of component in surface mount technology (SMT), which is characterized by small size, high power, stable performance, and easy automated assembly.

SMD packaging technology can maximize the space utilization on the circuit board, especially for the design of dense circuit boards. SMD packaging usually adopts metal oxide semiconductor (MOS) technology, and its packaging methods are diverse, including COB, QFN, LCC, BGA, etc.

In practical applications, the appearance inspection of SMD devices includes visual inspection or use of a magnifying glass to check whether the solder end or pin surface is oxidized or has contaminants, and to ensure that the nominal value, specification, model, accuracy, and external dimensions of the components are consistent with the product process requirements. To ensure the performance and reliability of the device.

The wide application of SMD technology not only improves the performance of electronic products, but also promotes the automation and efficiency improvement of the electronics manufacturing industry. It is an indispensable part of the modern electronics manufacturing industry, especially in applications that require high integration and high reliability.

What is the application of surface mount?

The application of surface mount technology is mainly reflected in improving production efficiency, reducing product volume and weight, and meeting the market demand for miniaturized, lightweight, and high-performance electronic products. This technology is mainly used to mount electronic components on printed circuit boards (PCBs) to achieve circuit connection and system integration.

Surface mount technology can replace traditional through-hole insertion technology, thereby improving product reliability and performance and reducing costs. The technology has a wide range of applications, including but not limited to consumer electronics, military cutting-edge electronics, and fire detectors, manual alarms, and various electronic modules.

In the manufacture of electronic products, surface mount technology has become a revolutionary change, dominating the development of electronic equipment and bringing about major changes in electronic products.

Conclusion:

Usually, the electronic products we use are designed by PCB plus various capacitors, resistors and other electronic components according to the designed circuit diagram, so most electrical appliances require various SMT (patch) processing technologies to process.

BEST Technology focuses on the procurement and processing of various electronic products and processing services for incoming materials, including but not limited to SMT patches, DIP plug-ins, welding, functional testing and maintenance, and assembly proofing and batch production. We can provide proofing, small batch and batch SMT mounting, and can also purchase electronic components and make PCBs.

Tags: PCB, PCBA, SMT, surface mount technology
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PCB Stack-up and Impedance Control Guidelines

August 23rd, 2024

When designing a PCB board, careful attention to stack-up and impedance control is essential for achieving optimal signal integrity and performance. The PCB stack-up refers to the arrangement of copper and insulating layers that make up the board. Impedance control, on the other hand, involves maintaining consistent electrical characteristics within signal traces, especially in high-speed circuits. This post provide a detailed guideline of PCB stack-up and impedance control for designers.

PCB Stack-up Parameter

Internal Copper Thickness After Processing

Base Foil	Min. After Processing
18um (1/2oz)	11.4um
35um (1oz)	24.9um
70um (2oz)	55.7um
105um (3oz)	86.6um
140um (4oz)	117.5um

External Copper Thickness After Plating

Base Foil	Min. Class 2	Min. Class 3
12um (3/8oz)	29.3um	34.3um
18um (1/2oz)	33.4um	38.4um
35um (1oz)	47.9um	52.9um
70um (2oz)	78.7um	83.7um
105um (3oz)	108.6um	113.6um
140um (4oz)	139.5um	144.5um

Common Prepreg (PP) Properties

Type	Thickness (mm)	Resin (%)
106	0.05	65
1080	0.075	65
2116	0.12	55
7628	0.2	46

Common Material List

Medium Tg	Shengyi S1000-H
	ITEQ IT-158
	Elite EMC-825
High Tg	Shengyi S1000-2M
	ITEQ IT-180A
	Elite EMS-827

Common Core Thickness

PCB Stack-up and Impedance Control Guidelines

Design Tips – Stack-up

1. Ensure the stack-up remains symmetric.

2. Typically, a foil build is recommended. Special core builds, like those with Rogers, are possible but less common.

3. For boards thicker than 1mm, the standard thickness tolerance is +/-10%. For 1mm boards, the standard tolerance is +/-0.1mm. Any board with a thickness ≤1mm requires approval from Best Tech.

4. The minimum dielectric thickness will be 90µm, according to IPC standards, unless otherwise specified by the FAB drawing and there are no micro vias.

5. Use a maximum of three sheets of prepreg to bond the layers.

6. While the stack-up used in production may differ slightly from the specified one, an Engineering Query (EQ) will be sent for confirmation.

7. Variations can occur due to factors like copper distribution and available materials.

8. Thicker copper foils require thicker dielectrics between layers, and the foil thickness after processing differs from the base foil thickness.

9. Additionally, variations in resin percentage for the same prepreg type can impact the final prepreg thickness.

10. When incorporating micro vias, consider the aspect ratio—recommended at 0.8:1 and advanced at 1:1—when selecting prepreg.

If you need special materials, thickness tolerances, or stack-ups, contact Best Technology for guidance. Below are some suggested stack-ups for different layers PCB.

Impedance Parameters Needed for Calculation

Symbol	Feature
H1, H2, H3..	Dielectric thickness between copper layers after pressing
Er1	Dielectric constant of prepreg or core used between copper layers.
W1	The bottom width od impedance lines, which is the customer required impedance trace width.
W2	The top width of impedance lines.
S1	The space between two differential impedance traces.
T1	Finished copper thickness, which is different with our normal definition.
C1	Solder mask thickness on material.
C2	Solder mask thickness on copper.
C3	Solder mask thickness on material between traces (C1 = C3).
CEr	Dielectric constant of solder mask. Normally use 3.4 to calculate.

Tolerance of Impedance Control

Type of Impedance	Common Requested Value	Tolerance of Impedance Control
Type of Impedance	Common Requested Value	General	Moderate	Advanced
Single/Single Coplanar	40Ω/510Ω/75Ω	+/-10%	+/-8%	+/-5%
Differential/Differential Coplanar	90Ω/100Ω/120Ω	+/-10%	+/-8%	+/-5%

Relationship between Parameters and Impedance Value

Parameters Modification		Effect on Impedance Value
Parameters	Increase/Reduce	Impacts on impedance	Impedance value increase/reduced
H (dielectric thickness)	Increase	Big	Increase
W (trace width)	Increase	Big	Reduced
S (trace space)	Increase	Big	Increase
T (copper thickness)	Increase	Low	Reduced
C (solder mask thickness)	Increase	Low	Reduced

Design tips – Impedance

When signal speeds exceed 2 GHz and timing is critical, consider using better materials such as medium, high, or ultra-high-speed options, along with flat glass styles. To ensure a reliable lamination process and prevent resin starvation, allow the factory to select the number of prepregs, prepreg styles, and resin content in the stack-up.

Key factors influencing impedance signal losses include:

1. Line Length: Signal losses are directly proportional to the line length—shorter lines result in fewer losses, while longer lines lead to greater losses.

2. Dielectric Loss: These losses can be minimized by selecting appropriate materials.

3. Copper Loss: This includes losses from the cross-sectional area (affected by stack-up design) and surface roughness, which can be reduced through material selection and proper stack-up configuration.

If you require impedance tolerances tighter than +/-10%, discuss your design possibilities with the Best Technology team.

When designing rigid-flex boards, note that separate calculations are necessary for both the rigid and flex sections of the same signal. Manufacturers will adjust the thickness and dielectric constant of the solder mask based on their solder mask properties and printing method. Variations in resin content for the same prepreg type can also affect impedance. For assistance with impedance calculations, contact Best Technology for support.

Checklist of Necessary Information for Impedance Calculations

1. Specify the type, value, and tolerance of impedance control.

2. Ensure you define the width and space of impedance traces, as well as the layers where these traces will be present, along with the layers to be considered as reference points.

3. Identify the type of material and final board thickness, and provide a reference stack-up for the design.

4. Confirm the finished copper thickness on external and internal layers, and note if any special type of solder mask is required.

5. Always request Best Technology’s stack-up before starting the routing design.

Tags: pcb design, pcb stackup
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What is a 3A masterpiece? Why is Black Myth Wukong so popular?

August 23rd, 2024

In the field of games, domestic games have always been labeled as “low-quality” and “imitation”, and the emergence of “Black Myth Wukong” has undoubtedly dropped an atomic bomb on the entire game industry, attracting Chinese people to applaud. It will leave a strong mark in the history of games. Since the first trailer was launched, industry peers and players have high expectations for Black Myth, and it has even been dubbed the “light of domestic games”.

What is a 3A masterpiece?

3A masterpieces usually refer to games with high development costs (a lot of money), long development cycles (a lot of time), and high resource consumption (a lot of resources). These games generally have high quality, large development teams, high development budgets, high visual and auditory effects, perfect combination of art and technology, and outstanding ease of use.

3A games represent the pinnacle of production quality, top technology and huge market influence. They are not only entertainment products, but also the perfect combination of technology, art and business. 3A games not only define the highest standards of the industry, but also become the golden benchmark in the minds of global players.

What are the classic 3A masterpieces?

1. Red Dead Redemption 2

The graphics of Red Dead Redemption 2 have reached a very high level in the past and even now. Its game graphics not only show us a real and shocking Western world, but also bring us a brand new experience.

In terms of image quality, it can be said to be top-level. From modeling to scenes and weapons, it is very realistic, and the detailed textures are also very rich, which makes the light in the entire game environment very beautiful, and it can also give players an immersive feeling.

2. Assassin’s Creed: Revolution

This is a high-quality action-adventure game. Players can experience the real style of Paris in the game, and can also choose different professions to unlock different abilities.

The overall picture effect of the game is very good, and the picture quality is also at a very high level. “Assassin’s Creed: Revolution” not only has a very good 3D visual experience, but also has an extremely powerful open world. This world is full of excitement and thrills, and it is a good game.

3. Call of Duty Series

The image quality of “Call of Duty” is relatively top-notch among 3A masterpieces. This is a high-quality 3D game, and the gameplay is very simple, that is, the player controls a special forces soldier to collect resources and ammunition on the battlefield, and use various types of weapons to defeat the enemy.

In addition, it contains not only single-player campaigns, but also cooperative campaigns, multiplayer cooperative campaigns and other types of campaign gameplay. “Call of Duty” also has a very rich map scene, a variety of terrains, weapons, ammunition and other resources and many other elements to provide players with richer content, more gameplay, etc.!

4. Forza Horizon 5

“Forza Horizon 5” is one of the best racing games you can experience at present. Although it has not changed much compared to the previous game, you can still experience the purest driving pleasure in hundreds of hours of game time.

The Mexico map in the game truly reproduces the beauty of various places, from endless deserts to winding wilderness and other terrains, every link allows you to feel its beauty and diversity. In the game, you will not only feel the excitement of racing, but also the shock from the vehicles and maps.

Why is Black Myth Wukong so popular?

For a long time, the production of 3A games has been basically controlled by game developers in Europe, the United States, Japan and other countries. In the field of domestic games, although many excellent works have been launched, before Black Myth Wukong, no single-player game has reached the international 3A game level, nor has it been so concerned by global media and players before it was launched.

“Chinese people do not have the strength to make 3A game masterpieces” “China does not have the soil for 3A games to grow”… For a long time, these statements are almost a factual description of the domestic game market and a helpless consensus of the majority of game players.

The aura of the Journey to the West theme, the desire for domestic 3A masterpieces, and even the hope for cultural inheritance are all placed on “Black Myth Wukong”. As Black Myth Wukong is about to “break out of the stone”, domestic 3A games will finally be subject to the heavy test of the market and players.

Judging from the current development results, the graphics of Black Myth Wukong have reached a very high level, and the unique classical scenes also make domestic 3A games more Chinese.

Industry insiders said that the reason why 3A games are regarded as the top works in the game industry is that they pursue excellence in content, plot and art, focus on inheritance and promotion of cultural values, and pursue continuous innovation in technology. An excellent 3A masterpiece not only represents the high level of a country in the game industry, but also symbolizes the country’s cultural soft power and technical strength.

The significance behind the explosion of Black Myth Wukong

First of all, the game fully reflects the excellent traditional Chinese culture in character design and scene design. The image of the character Sun Wukong not only retains the basic characteristics of the original work, but also innovates in details. The scene design is deeply drawn from China’s famous mountains, rivers and ancient buildings.

In addition, the game uses the world’s leading “Unreal 5” development engine, which has achieved movie-level picture quality, which is also an important factor in attracting global players. Industry insiders believe that the popularity of Black Myth Wukong is the inevitable result of cultural confidence and a new expression of the vigorous vitality of traditional culture. ‌

The success of Black Myth Wukong has had a profound impact on the Chinese game industry. Within just five minutes of the pre-sale opening, all pre-sale products were sold out, becoming the most watched product in the game industry this year. This game not only meets the expectations of players for domestic masterpieces, but also gives the entire industry great confidence and inspiration. Industry insiders believe that the success of “Black Myth Wukong” will inspire more Chinese game developers to pursue high-quality games and promote the progress of the domestic game industry.

The success of Black Myth Wukong is not only the success of a game product, but also the success of Chinese cultural output. The character design, scene design and props in the game reflect Chinese culture, and these elements have attracted widespread attention worldwide.

The explosion of the game proves that Chinese games have the ability to break the long-term monopoly of European and American companies in the field of high-end games, and open up a new channel for the internationalization of Chinese games. The cultural output of this game is of great significance. It not only shows the charm of Chinese traditional culture, but also provides a new window for the world to understand Chinese culture.

Why were there no 3A games in China before this?

1. One of the reasons why it is difficult to have 3A games in China is that compared with foreign countries, China lacks such a large R&D team and a long R&D cycle.

2. The domestic game market is mainly occupied by mobile games and web games, which have a short development cycle and a fast return on investment, so they are more favored by game companies.

3. Domestic players have a relatively low acceptance of 3A masterpieces, which makes 3A games a relatively niche product in the domestic market.

4. Domestic hardware equipment is relatively insufficient, such as high-end computers are not popular, which also limits the popularity of 3A games in the domestic market.

5. Domestic game companies are technically capable of developing 3A games, but in the current environment, the risks are high and the returns are not stable.

With the improvement of domestic hardware level and the increase in players’ acceptance of 3A games, I believe that more 3A games will appear in the domestic market in the future.

Conclusion:

The response to the launch of Black Myth Wukong has given us a good start. It is undoubtedly very good news for all partners who love games and our Chinese culture. We can believe that this is the beginning of our domestic 3A masterpiece games. Next, better and higher-quality works will emerge like mushrooms after rain. Let us look forward to it together!

Tags: 3A, Black Myth Wukong, Game
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What is a PCB assembly?

August 22nd, 2024

PCB assembly is the process of combining a circuit board with other electronic components (such as connectors, housings, heat sinks, etc.) to embed into a final product. This process is a key step in the production of electronic equipment. Its main function is to provide a platform for electronic components to work together in a coordinated manner so that the equipment can perform its intended tasks.

What is the standard for PCB assembly?

The standards for PCB assembly mainly include PCB panel specifications, ISO standards, IPC standards, JEDEC standards, and ROHS standards. ‌

‌PCB panel specifications‌ involve the width, shape, frame design, center distance between small boards, setting of positioning holes, arrangement of reference symbols, and positioning of large components of the panel. The panel frame should adopt a closed-loop design to ensure that the panel is fixed on the fixture without deformation.

‌ISO standards‌ emphasize key factors such as fit tolerance, surface roughness, contact area, and tightening force in PCB tight-fit installation to ensure the accuracy and stability of installation‌.

‌IPC standards‌ include IPC-7711 and IPC-A-600E, the former provides basic recommendations and guidelines for the design and manufacture of printed boards, and the latter provides acceptable conditions and practice guidelines for printed boards.

‌JEDEC standards‌ provide specifications for circuit board materials, dimensions, interfaces, etc., including material selection, dimension design, interface specifications, test methods and quality assurance.

‌ROHS standard‌ is a directive on the restriction of the use of hazardous substances, aimed at reducing the impact on the environment and human health. It stipulates the use restrictions of hazardous substances such as lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ethers.

Compliance with these standards ensures the quality, safety and environmental friendliness of PCB products, and also provides clear guidance and specifications for the design, manufacture and assembly of PCBs.

Why is PCB assembly so expensive?

The high cost of PCB assembly is mainly due to the combined influence of multiple factors. ‌

First, the production cost of PCB boards is affected by materials, design and manufacturing complexity, precision and quality, and supply chain and regional differences. PCB boards are mainly made of materials such as copper, fiberglass and epoxy resin, and the cost of these materials directly affects the price of PCB boards.

The complexity of the design and manufacturing process, including pre-processing, image transfer, electroplating, etching, inspection and trimming, and post-processing, requires precise tools and professional skills, which will also be reflected in the cost. High-precision PCB boards require higher manufacturing costs because they require more precise tools and more stringent manufacturing processes.

Details in the PCB assembly process, layer selection, and the application of HDI technology will all have an impact on the cost. Every small change may cause the cost to plummet, so if you want to save money without losing performance, you need to consider these factors comprehensively.

In addition, the welding process is also a costly link. Soldering is a key step in fixing electronic components to PCBs. This process requires heating each joint separately for welding, which is a slow and laborious process.

Finally, the price of PCBs is also affected by factors such as materials, surface processing, design standards, copper foil thickness, quality acceptance standards, and mold fees and test frames. For example, different materials, surface processing, and copper foil thickness will lead to price differences.

In summary, the high cost of PCB assembly is mainly due to the combined effect of multiple factors such as material cost, manufacturing complexity, precision and quality requirements, production needs, and specific design and quality requirements.

What does PCB stand for?

PCB stands for Printed Circuit Board. ‌

Printed circuit board (PCB), also known as printed circuit board, is an indispensable component in electronic engineering. It is the support of electronic components and also the carrier of electrical connection of electronic components.

Printed circuit boards are widely used in various electronic devices. Printed circuit boards can be divided into single-sided boards, double-sided boards, multi-layer boards, etc. according to the number of layers of circuit boards. Among them, multi-layer boards refer to printed boards with more than two layers. It consists of connecting wires on several layers of insulating substrates and pads for assembling and welding electronic components. It has the function of conducting each layer of circuits and insulating each other.

The wide application of printed circuit boards makes it possible to miniaturize and visualize the circuits of electronic devices, which plays an important role in the mass production of fixed circuits and optimizing the layout of electrical appliances. This type of circuit board uses polyimide or polyester film as the substrate, and has the characteristics of high wiring density, light weight, thin thickness and good bendability.

What is the difference between PCB and PCBA?

The main difference between PCB and PCBA lies in their definition, function, application and manufacturing process. ‌

Definition:

PCB (printed circuit board) is a basic electronic component made by electronic printing, mainly used as a support for electronic components, and does not contain any active or passive components.

PCBA (printed circuit board assembly) is a circuit board assembly with specific functions formed by soldering electronic components to PCB through processes such as SMT (surface mount technology) or THT (through-hole mounting technology). PCBA contains PCB and all necessary electronic components, which work together to realize the preset functions of the circuit board.

‌Function and application‌:

The main function of PCB is to support and connect electronic components, while PCBA integrates electronic components into a complete circuit system, which can be used in the manufacture of various electronic products.

PCBA is the core part of electronic products and directly determines the performance and function of the product.

‌Manufacturing process‌:

The manufacturing process of PCB includes circuit design, PCB board design, PCB template production, copper foil etching, drilling, tin spraying and board making.

The production of PCBA requires component mounting, welding, testing and other processes.

In summary, the main difference between PCB and PCBA lies in their definition, function, application and manufacturing process. PCB is a basic electronic component, mainly used to support and connect electronic components, while PCBA is a finished product formed by welding electronic components to PCB. It has specific circuit functions and is an indispensable part of electronic products.

What is the difference between PCB manufacturing and assembly?

The main difference between PCB manufacturing and assembly is that they involve different processes and focuses. ‌

‌PCB manufacturing‌ mainly involves the process of converting raw materials into printed circuit boards through a series of process flows, including design, layout, etching, lamination, drilling, welding and other steps, and finally forming a complete and usable printed circuit board.

‌PCB assembly‌ is the process of soldering electronic components to the printed circuit board according to the design requirements after the PCB is manufactured. The focus of assembly is to ensure that all components are in the correct position and direction, the pins of each component are fully soldered to the designated pads, and there is no excess solder or other excess materials to ensure the normal operation and reliability of the circuit board.

In short, ‌manufacturing‌ covers the entire production process from raw materials to finished products, including design, production and testing, while ‌assembly‌ is a link in the manufacturing process that focuses on accurately mounting electronic components on printed circuit boards to ensure the final function and performance of the product.

Conclusion:

PCB assembly is an important part of manufacturing and affects the quality of the final product. Therefore, choosing the right manufacturer becomes particularly important. BEST Technology is committed to becoming the world’s most trusted one-stop electronic circuit solution provider, while focusing on PCBA prototyping and small batch production. Choosing us will get the best quality products.

Tags: PCB, PCB Assembly, pcb design, PCBA, SMT
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How to design a PCB board?

August 22nd, 2024

PCB design is an indispensable part of modern electronic product development. An efficient and reliable PCB design can ensure the normal operation of the circuit and meet the performance and manufacturability requirements of the product.

PCB design (Printed Circuit Board Design) refers to the design of circuit boards using electronic design automation software (EDA), designing the layout and circuit connections of printed circuit boards (PCBs). Circuit boards are an important part of electronic products. They can connect electronic components together and transmit signals through wires.

Is PCB design hard to learn?

PCB design is not difficult to learn. The key lies in mastering the relevant basic knowledge and practical experience.

PCB design mainly involves electronic circuit knowledge and software operation skills. For people with electronic circuit foundation, it is relatively easy to learn the use of PCB design software. It is important that learners should use their spare time to learn and practice at the same time. They can assist in learning by watching video tutorials. These resources can help understand the basic concepts and skills of circuit design and software operation.

In addition, the difficulty of PCB design lies mainly in the design of wiring rules, which is the most complex and critical part of PCB design. Beginners should pay attention to the design of conventional constraint rules, such as the size of vias, line width and line spacing, etc., which need to be mastered through practical operation and practice. Just reading materials is not enough. Practical operation and practice are the key to improving PCB design capabilities.

In general, although PCB design involves certain technical difficulties, it can be gradually mastered through systematic learning and practice.

What should I learn before PCB design?

Before PCB design, you need to learn the following key knowledge and skills:

1. Basic knowledge reserve: First of all, you need to understand various electronic components, such as resistors, capacitors, inductors, diodes, triodes, integrated circuits, etc. You also need to be familiar with common circuit topologies, such as amplifier circuits, filter circuits, oscillation circuits, and their functions and representation methods in circuits.

2. PCB design software: Be proficient in at least one PCB design software for schematic design, component layout, wiring, and generation of PCB production files, such as Altium Designer, EAGLE, PADS, OrCAD, etc.

3. Circuit board manufacturing process: Understand the manufacturing process of PCB circuit boards, including substrate material selection, circuit pattern transfer, etching, drilling, welding, assembly, etc.

4. Component packaging: Familiar with the packaging types and sizes of various components, such as DIP, SOP, QFP, BGA, etc., as well as their characteristics and usage scenarios.

5. Basic terms and concepts: Master some basic PCB terms, such as microstrip, stripline, differential line, via, solder mask, silk screen, structural diagram, etc.

6. Circuit function and signal flow: Understand the function and signal flow of the circuit, and be able to distinguish between digital circuits and analog circuits, as well as places with large and small currents.

By mastering the above knowledge and skills, you can better design and layout circuits, improve the performance and reliability of circuit boards,

Which software is used for PCB design?

1. Altium Designer is a powerful PCB design software that provides a wealth of tools and libraries to quickly create complex circuit board designs. This software has an intuitive interface and powerful simulation functions to help designers quickly verify the correctness of the design. It also supports multiple design file formats, which is convenient for collaboration with other design tools.

2. Cadence Allegro is a comprehensive circuit board design software with powerful layout and routing tools, as well as multiple simulation and verification tools to ensure the correctness of the design. It also supports multiple design file formats for team collaboration.

3. Mentor Graphics DesignX is also a powerful PCB design software that provides a variety of tools and libraries to help designers quickly create complex circuit board designs. It also has an intuitive interface and powerful simulation functions, and supports multiple design file formats.

4. PADS is a professional circuit board design software with powerful layout, routing, simulation and verification functions, which can quickly complete complex PCB design work. It also supports multiple design file formats, which is convenient for collaboration with other design tools.

These software are all commonly used PCB design tools with powerful layout, routing, simulation and verification functions, which can help designers quickly complete complex PCB design work.

What is the basic rule of PCB design?

The basic rules of PCB design involve many aspects, including layout, routing, power and ground design, signal integrity, etc.

1. Layout design:

Follow the design principle of placing in a straight line along the signal flow direction to avoid the signal from circling back and forth to reduce the impact of direct signal coupling.

The filtering, protection and isolation devices of the interface circuit should be placed close to the interface to achieve effective protection, filtering and isolation effects.

For high-speed signals or high-current signals, multi-layer board design should be considered to control the signal loop area.

2. Wiring rules:

Control the length of the trace, especially for important signal lines, such as clock signals, the trace length should be shortened as much as possible to reduce unnecessary interference.

Avoid forming self-loop traces to reduce radiation interference.

Follow the principle of minimum ground loop, design the signal line and its loop to form the smallest possible loop area to reduce external radiation and external interference.

3. Power and ground design:

The power plane should be retracted a certain distance relative to its return ground plane to effectively suppress edge radiation problems.

Avoid overlapping of different power layers in space to reduce interference between different power supplies.

4. Drawing:

When drawing the board frame, a specific line width should be used to ensure that the error between the board frame size and the assembly size is within the allowable range.

Set a reasonable origin to ensure that the coordinates of the SMT original are within the first quadrant.

Set a prohibited area, especially prohibiting routing and placing components within a certain range around the mounting hole.

Following these basic rules can ensure the effectiveness and reliability of PCB design, while improving product performance and user experience.

How long does it take to design a PCB board?

It takes about 1-2 days to design a PCB board, and the specific time depends on multiple factors, including the number of layers of the PCB, design complexity, etc.

‌Number of layers and complexity‌: The more layers the PCB has, the more complicated the design process is, and more time and delicate work are required to ensure the correctness and performance of the circuit.

‌Design stage‌: PCB design includes multiple steps such as design layout, schematic drawing, and PCB design conversion.

The time to design a PCB board is a comprehensive estimate involving multiple stages and factors.

What is the proper PCB layout?

Proper PCB layout involves many aspects, including structural requirements, heat dissipation considerations, component spacing, routing rules, etc. ‌

‌Structural requirements‌: First, the PCB layout must meet the structural requirements, including the location arrangement of structural components such as power sockets and DVI interfaces.

‌Heat dissipation considerations‌: The distribution of heat sinks should be even to ensure good ventilation of the air path. Avoid heat sinks blocking the air path to avoid affecting the heat dissipation effect‌.

‌Component spacing‌: Capacitors, ICs, etc. should be kept away from thermal components to avoid being affected by heat.

‌Routing rules‌: The design of the current loop should consider the convenience of threading, and the lead hole spacing should not be too far or too close. The layout of input/output and AC/socket should meet the consistency of the length of the two lines, leaving a certain space margin, and pay attention to the position of the plug wire buckle and the convenience of plugging and unplugging‌.

‌Special component layout‌: For high-frequency components and components with high potential difference, the distance between them should be increased to avoid electrical interference and damage.

Wiring design parameters‌: including the line width of the copper trace, the minimum gap between the copper foil traces, the minimum distance between the copper foil traces and the edge of the PCB board, etc. ‌ .

In summary, the correct PCB layout is a process that comprehensively considers the structure, heat dissipation, component spacing, routing rules and wiring design parameters, aiming to optimize the performance and reliability of the circuit board.

Conclusion:

Designing a PCB board is a complex and meticulous process involving multiple steps and considerations. Systematically complete the design process of a PCB board. Each step requires careful operation and multiple checks to ensure the quality and reliability of the final product. ‌ BEST Technology’s PCB designers have many years of design experience and are far ahead in the industry design. We can meet any PCB design you need.

Tags: PCB, pcb board design, pcb design
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How do you identify a diode symbol?

August 21st, 2024

‌A diode is an electronic component with unidirectional conductivity. Its circuit symbol usually includes an arrow pointing to a vertical line, which represents the positive pole, while the vertical line represents the negative pole. This representation method is suitable for most types of diodes. If the diode symbol is bidirectional, it means that it has no polarity.

What is the symbol of diode LED?

The symbol of a diode in a circuit diagram usually consists of an arrow pointing to a vertical line, with a line extending from the arrow, where the arrow represents the positive pole of the diode and the vertical line represents the negative pole. If it is bidirectional, there is no polarity. In addition, there will be obvious markings on the appearance of the diode to distinguish its polarity.

Do LED diodes have a positive and negative?

LED diodes have a positive and negative pole. ‌

LED diodes are electronic devices with two electrodes: positive (anode) and negative (cathode). These two electrodes play different roles in the circuit. The positive pole is the end point where the current enters, and the negative pole is the end point where the current flows out. The unidirectional conductivity of the LED diode means that it will only conduct when a forward voltage is applied to its two ends, that is, it allows current to pass; when a reverse voltage is applied, it is cut off, preventing current from passing. This characteristic allows the LED diode to be used as a switch in the circuit to control the direction of current flow.

In practical applications, it is very important to determine the positive and negative poles of the LED diode, because incorrect connection may cause damage to the device or malfunction.

How to identify LED positive and negative?

There are many ways to determine the positive and negative poles of the LED diode, including observing the pin length, the position of the missing corner, the shape and size of the pin, the direction of the surface marking, etc. Some LEDs will have a “T” or inverted triangle symbol at the bottom, where the horizontal side of the “T” is the positive pole and the other side is the negative pole.

1. Observe the pin length: For direct-plug LED lamp beads, the longer end of the pin is usually the positive pole, and the shorter end is the negative pole. This is because the positive electrode is usually designed to be longer than the negative electrode during the manufacturing process.

2. Observe the size of the internal electrode: Inside the LED lamp bead, the smaller end is usually the positive pole, and the larger end is the negative pole.

3. Check the printed mark on the back of the board: On the back of the board of the SMD LED lamp bead, there is usually a “T”-shaped or inverted triangle symbol, where one end close to the horizontal side or the triangle side is the positive pole, and the other end is the negative pole.

4. Observe the printed lines on the board: One side of the colored line is usually the negative pole, and the other side is the positive pole.

5. Determine the size of the pad: The larger pad is the negative pole, and the smaller pad is the positive pole.

6. Check the missing corner of the front panel: One end of the missing corner is often the positive pole, and the other end is the negative pole.

7. Use a multimeter to test: Set the multimeter to the resistance or diode range. If the lamp bead lights up, the red test pen is in contact with the positive pole. When the light is on, the red test lead is connected to the positive pole and the black test lead is connected to the negative pole.

8. Use battery test: Use a 1.5V battery to connect the LED lamp bead. If the lamp bead lights up, the positive pole of the battery is connected to the positive pole of the LED lamp bead.

Through the above method, the positive and negative poles of the LED lamp bead can be effectively determined to ensure the correct connection of the circuit and avoid damage to the LED lamp bead.

What color is LED diode?

The color of the LED diode can be red, green, blue, yellow, white, etc. ‌

The color of the LED diode mainly depends on the semiconductor material used. According to different application requirements, LED diodes can emit different colors of light, including but not limited to red, green, blue, yellow and white. In addition, white LEDs can be further subdivided into warm white, neutral white, pure white and cold white. The differences in these colors are mainly reflected in color temperature and hue, so as to meet different lighting and display needs.

1. Red LED: Mainly used in occasions such as indicator lights to provide eye-catching visual signals.

2. Green LED: Commonly used for digital display in display devices, such as calculators and electronic displays.

3. Blue LED: Combined with red and green LEDs, it can produce white light and is an important component in modern lighting technology.

4. Yellow LED: Used in various indicator lights and display devices to provide eye-catching visual prompts.

5. White LED: By combining red, green and blue primary color LEDs, it can produce rich colors and high-quality white light, which is widely used in lighting and display technology.

The packaging method of LED diodes also affects their appearance and application areas. For example, surface mount LEDs (SMD) are widely used in various electronic products due to their small and light characteristics. In addition, LED diodes can also be classified according to current levels to meet the needs of different circuits. These characteristics make LED diodes an indispensable component in modern electronic technology and lighting.

What happens if LED polarity is reversed?

LED polarity reversal may cause the LED light to not light up or be damaged. ‌

When the positive and negative poles of an LED lamp are connected in reverse, the following situations may occur:

1. No light: This is the most common situation because the current flows through the LED in the opposite direction to the normal situation, causing the LED to not light up normally.

2. Unstable light: In some cases, certain types of LEDs may cause unstable light, such as flickering or frequent dimming, due to reverse polarity connection.

3. Damaged LED: Although some new LEDs may be able to withstand incorrect connections with reverse polarity, most common LEDs may burn out when the polarity is reversed, causing them to not work properly.

4. Lamp does not light up: If the positive and negative poles of an LED lamp are connected in reverse, it will generally not burn out, but it may cause the lamp to not light up. This may be because the current cannot pass through the LED normally, or because the circuit protection mechanism is activated due to reverse polarity, thereby preventing the current from passing.

Why do LED diodes fail?

The main reasons for the failure of LED diodes include overheating, overvoltage breakdown, current overload, and aging effects. ‌

‌Overheating‌: When the heat generated by the LED during operation cannot be effectively dissipated, the temperature is too high, which may damage the internal structure of the LED and affect its performance.

‌Overvoltage breakdown‌: When the voltage across the LED exceeds its rated value, it may cause damage to its internal structure and fail.

‌Current overload‌: If the current flowing through the LED exceeds its rated value, it may cause the LED to burn out. Current overload is usually caused by improper circuit design or external factors.

‌Aging effect‌: Over time, LEDs may fail due to material aging. Aging effects are usually manifested as performance degradation, increased leakage current, etc.

‌Electrostatic discharge (ESD) damage‌: When the LED is subjected to electrostatic discharge shock, its internal structure may be damaged. To prevent electrostatic discharge damage, appropriate anti-static measures should be taken‌.

How do I know if my LED diode is bad?

If the LED diode can emit light normally under the appropriate operating voltage, it means that it is fine‌.

Make sure that the positive and negative poles of the LED diode are correctly connected to the circuit. Use the voltage measurement function of the multimeter to test the open circuit voltage of the circuit. If the test voltage is different from the expected value, there may be a problem with the circuit connection or the LED light-emitting diode.

Use the “diode test” position of the multimeter to test the diode. Insert the diode into the test hatch, connect the anode and cathode of the diode with the clamp, and connect the cathode to the test port. Observe the reading of the multimeter. If the reading is positive, it means that the diode is normal and can be turned on; if the reading is negative, it means that the diode is not good and cannot be turned on or reverse conduction.

Conclusion:

The application of diodes in daily electronics is very extensive. It can be used in almost all electronic circuits. The key to identifying diode symbols is to understand their basic shape and signs. It is necessary to correctly understand the symbol of the diode so that it can be safer and more efficient during use. ‌

Tags: diode, diode symbol, LED
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