Posts Tagged ‘printed circuit board’

Friday, October 11th, 2024

In the electronic manufacturing process, it is usually necessary to divide a large area of aluminum-based PCB into multiple small pieces so that they can be installed in different electronic devices. Different electronic devices have different requirements for the size of PCBs. Through depaneling, large-area aluminum-based PCBs can be cut into sizes suitable for specific electronic devices.

What is the meaning of depaneling?

Aluminum PCB depaneling refers to cutting multiple circuit boards arranged in a row from a large board into separate small boards. This process is to divide a large aluminum printed circuit board (PCB) into multiple independent and fully functional circuit boards for subsequent assembly and use.

Aluminum PCB depaneling is an important link in the production process of electronic devices, which can improve production efficiency and circuit board flexibility.

What are the methods of PCB depaneling?

There are many ways to depanel aluminum PCBs. Common depaneling methods include:

1. ‌V-cut depaneling‌: Use a V-shaped blade to cut a V-shaped groove on the PCB board, and then separate the aluminum PCB along the groove by external force. This method is suitable for smaller aluminum PCB boards and fine dividing lines.

2. ‌Sawtooth depaneling‌: Cut the aluminum PCB board with a sawtooth cutting tool to form multiple small panels, and then separate the panels by pressure or vibration. This method is suitable for aluminum PCB boards with larger areas.

3. ‌Laser depaneling‌: Use a high-energy-density laser beam to accurately cut the aluminum PCB, which is suitable for production environments with high precision requirements and high efficiency.

4. ‌Chemical corrosion depaneling‌: Corrode the aluminum PCB with a chemical corrosive agent to form a dividing line, and then separate the panels by physical methods.

What is the process of depaneling PCB?

The aluminum PCB depaneling process varies depending on the depaneling method. The common aluminum PCB depaneling methods and processes are as follows:

Manual depaneling

Preparation: Check whether the aluminum PCB board meets the conditions for manual depaneling, such as confirming that there are no stress-sensitive components such as SMD (Surface Mounted Devices) on the board, and prepare suitable fixtures and operating space.

Positioning and fixing: Place the aluminum PCB concatenated or assembled boards that need to be separated on a stable workbench and fix them with fixtures to ensure that the boards do not move during the separation process. For aluminum PCB boards with V-grooves, align the V-grooves with the direction that is convenient for force application, and ensure that the board is placed in the correct direction and position to facilitate the separation operation.

Separation operation: The operator uses both hands or simple tools (such as tweezers, etc., and small cutting tools may be used in some special cases, but they must be operated with caution to avoid damaging the board) along the V-groove to break or separate the aluminum PCB board into individual small boards with appropriate force. During the operation, pay attention to controlling the force and direction to avoid damage to the board due to uneven force or wrong direction.

V-cut board separation machine separation

Equipment debugging: Turn on the power of the V-cut board separation machine, and adjust the upper guide knife position and lower knife height of the board separation machine according to the thickness of the aluminum PCB board, the depth and width of the V-groove and other parameters to ensure that the spacing between the upper and lower knives is appropriate and the aluminum PCB board can be accurately cut.

Upper board positioning: carefully place the aluminum PCB board with V groove on the workbench of the V-cut board splitter, ensure that the V groove of the aluminum PCB board fits tightly with the lower knife of the board splitter, and the position of the board is accurate to avoid deviation during the cutting process.

Board splitting operation: start the V-cut board splitter manually, electrically or pneumatically, so that the blade cuts along the V groove of the aluminum PCB board. During the cutting process, pay attention to the cutting situation to ensure that the cutting depth is moderate and will not cause over-cutting or incomplete cutting of the aluminum PCB board.

What is the manufacturing process of aluminum PCB?

The manufacturing process of aluminum substrate PCB mainly includes the following steps: cutting, drilling, dry and wet film imaging, etching, surface treatment and final inspection. ‌

1. Cutting: Cut the large-sized incoming materials into the size required for production, pay attention to the protection of the aluminum and copper surfaces, and avoid scratches and board edge delamination.

2. Drilling: Position the holes in the board to ensure the correct number and size, and avoid scratches on the board and deviation of the hole position.

3. Wet and dry film imaging: Present the parts required for making the circuit on the board, and pay attention to whether the circuit is open and whether the alignment is deviated after development.

4. Etching: Remove the uncovered parts to form the circuit pattern, and pay attention to the quality and stability of the circuit after etching.

5. Surface treatment: Perform necessary surface treatment on the circuit board, such as tin spraying, to improve the performance and appearance of the circuit board.

6. Final inspection: Perform a final inspection on the completed circuit board to ensure that the quality meets the requirements.

What are the advantages of aluminum PCB?

The main advantages of aluminum substrate PCB include:

Excellent heat dissipation performance: The aluminum substrate uses high thermal conductivity aluminum alloy as the core material, which can quickly conduct and dissipate heat, thereby effectively reducing the operating temperature of components.

‌Lightweight design‌: Compared with traditional FR4 substrates, aluminum substrates have lighter weight, which is particularly important in weight-sensitive fields such as aerospace and automobiles, helping to reduce the weight of the overall equipment and improve energy efficiency and operating performance‌.

‌Good mechanical properties‌: Aluminum substrates have high strength and hardness, providing good support and protection for electronic components. At the same time, its excellent impact resistance and vibration resistance enable it to adapt to various complex working environments and ensure the stable operation of the equipment‌.

‌Excellent electrical performance‌: Aluminum substrates have excellent insulation and voltage resistance, which can meet the electrical requirements of electronic equipment in various working environments and provide stable electrical support for the equipment‌.

‌Environmental protection‌: Aluminum substrates are made of environmentally friendly materials, there is no pollution in the production process, and waste is easy to recycle and dispose, which is fully in line with the current trend of green environmental protection‌.

‌Diverse application forms‌: There are many types of aluminum substrates, including flexible aluminum substrates, hybrid aluminum substrates, multi-layer aluminum substrates, etc., suitable for different application needs.

What are the disadvantages of aluminum PCB?

The main disadvantages of aluminum PCB include high cost, difficult process, electrical strength and withstand voltage problems, mismatched thermal conductivity test, inconsistent material specifications, and more defective products. ‌

First, the price of aluminum PCB is relatively high, usually accounting for more than 30% of the product price. This is because the production of aluminum PCB requires the use of high-purity aluminum materials and special processing technology, all of which push up the cost. ‌

Second, the process of aluminum PCB is difficult, especially when it is made into a double-sided board, the process complexity is higher, and it is easy to have problems in electrical strength and withstand voltage. In addition, the mismatch of thermal conductivity test methods and results of aluminum PCB is also a problem. ‌

In addition, the material specifications of aluminum PCB have not yet been unified, and there are multiple standards such as CPCA industry standards, national standards, and international standards, which brings certain uncertainties to production and application. ‌

Why is aluminum no longer used in integrated circuits?

The main reason why aluminum is no longer used in integrated circuits is that copper has replaced aluminum as an interconnect metal material. Copper has lower resistivity and better anti-electromigration performance than aluminum, which makes copper more reliable and effective in high-speed integrated circuits. ‌

Specifically, aluminum may experience electromigration under long-term current, that is, aluminum atoms migrate inside the wire, causing the wire to break or form voids, which in turn causes the integrated circuit to fail. In addition, as the interconnection spacing decreases, the resistance of the aluminum wire increases and the capacitance between the wires increases, resulting in increased RC delay, which is not conducive to high-speed integrated circuits.

Copper has a lower resistivity than aluminum, can transmit current more efficiently, and can carry more current in thinner metal wires. Copper also has higher electromigration resistance than aluminum, making copper interconnects more reliable under high current conditions. These advantages make copper a preferred material for advanced integrated circuit technology.

Aluminum-based PCB depaneling is an important link in the electronic manufacturing process, which directly affects the quality and performance of electronic equipment. By selecting the appropriate depaneling method, controlling the depaneling accuracy, and avoiding damage to the PCB, the quality and efficiency of aluminum-based PCB depaneling can be effectively improved.

What files do I need to make a PCB?

Making PCBs (printed circuit boards) requires a series of files to ensure the smooth progress of the manufacturing process and the quality of the product.

‌Gerber file‌: This is the most common and crucial file in PCB manufacturing. It contains the geometric information of each layer of the PCB, such as copper lines, pads, solder mask layers and silk screen layers, and also includes separate files for each PCB layer, such as top copper, bottom copper, solder mask, silk screen layer, etc. ‌

What file types are used for PCB design?

‌Drill file‌: Provides drilling coordinates and size information for PCBs, and specifies the aperture size of components, vias and mounting holes. Drill files are usually generated in Excellon format or as separate ASCII files‌.

‌Bill of Materials (BOM): A BOM is a detailed list of all components used in a PCB design, including information such as part number, component value, description, and quantity, which helps ensure that all required components are correctly sourced and placed on the PCB.

‌Center Coordinate File: Also known as a pick and place file, it provides coordinate and orientation information for each component on the PCB and is essential for the automated assembly process. Center coordinate files are usually provided in CSV format.

‌Fabrication Drawing: This is an engineering drawing that includes key information about the PCB, such as board dimensions, drill hole dimensions, layer stackup, tolerances, surface finish, and other manufacturing-related details, which serves as a reference for PCB manufacturers during the production process.

‌Assembly Drawing: Provides additional information for the PCB assembly process, including component placement details, reference numbers, orientation, and any special instructions for assembly technicians.

In addition, depending on the specific design and production needs, other documents may also be required, such as circuit diagrams, special layer files, installation instructions and precautions, etc. ‌ The preparation and provision of these documents is a key step in ensuring a smooth PCB production process.

What are Gerber files? What information do they contain?

Gerber files are a series of ASCII vector format files that define PCB design specifications. They are generated using electronic design automation (EDA) or computer-aided design (CAD) tools and provide information such as board configuration parameters, aperture descriptions, XY coordinate locations, and drawing instructions.

Configuration details include the size and shape of the PCB to be manufactured. Each layer of the board information is recorded in a different file to define components such as copper traces, pads, vias, solder mask, silk screen, and logos. The Gerber file indicates the XY coordinate location of each geometric shape and uses instructions to draw these shapes on the physical board.

The basic components of the Gerber file include: board size, shape, top assembly, top silk screen, top solder mask, top paste, top copper, internal signals, inner layers, bottom copper, bottom paste, bottom solder mask, bottom silk screen, bottom assembly, and manufacturing information (providing stackup, drilling details, cutting, etc.).

Gerber files generated by computer-aided manufacturing (CAM) tools have user-selected extensions, usually using project naming such as “.TOP” for top layer, “.BOT” for bottom layer, and “.drl” for drill data.

How is a PCB designed?

PCB design is a complex process that involves multiple steps and considerations to ensure the functionality and reliability of the final product.

‌Schematic Design‌: First, you need to prepare a schematic and component library. The schematic is the blueprint of the circuit design, while the component library contains information about the various components used in the circuit.

‌Component Symbols and Packages‌: The symbol of the component is used to represent the component in the schematic, while the package defines the physical form of the component on the PCB. The component symbol is used in the schematic design stage, while the package is used in the PCB layout and routing stages.

How is a PCB designed?

‌PCB Layout‌: The layout stage involves placing electronic components on the PCB, and factors that need to be considered include the orientation, size, and relative position of the components.

‌Routing‌: After the layout is completed, the next step is the routing stage, which is to connect the various components according to the needs of the circuit.

‌DRC Check‌: Design rule checking (DRC) is performed during the design process to ensure that the design complies with predetermined electrical and physical rules. This includes checking for shorts, open circuits, and other possible design errors.

‌Solder mask and solder paste layer‌: The solder mask is used to prevent unnecessary soldering, while the solder paste layer is used to specify solder joints. The correct design of these layers is critical to ensuring the reliability and manufacturability of the circuit board.

‌Network and DRC Check‌: In the final stage of design, network checks are performed to ensure that all components are properly connected, while DRC checks are performed to verify that the design complies with all electrical and physical rules.

‌Through the above steps, designers are able to transform the circuit design in the schematic into an actual, manufacturable PCB. This process requires comprehensive consideration of multiple factors such as the functionality, reliability, and manufacturing cost of the circuit.

‌What is the schematic file for PCB?

‌PCB schematic files are the main files used for circuit design, analysis, and debugging. They mainly show the electrical connection relationship between electronic components, but do not reflect the actual physical location of these components on the PCB board. ‌

Schematic Diagram is the basis of circuit design. It uses symbols and lines to express the connection and working principle of the circuit in a concise and clear manner, and pays more attention to the functional expression of the circuit.

Schematic diagram does not involve the specific layout and wiring of electronic components on the PCB board, so it focuses on the logical representation of the circuit rather than the physical implementation. ‌

In contrast, PCB design files plan the precise location and wiring of electronic components on the PCB board in detail, taking into account the connectivity of the circuit, and also comprehensively considering factors such as signal integrity, power distribution, thermal design, and mechanical strength. ‌

These design files are the main files used to manufacture actual electronic devices, including PCB layout and PCB wiring. The layout determines the location of electronic components on the circuit board, while the wiring involves the electrical connection between components. ‌

In general, schematic files and PCB design files play different roles in the design and manufacturing process of electronic products. The former focuses on the expression of circuit logic and function, while the latter focuses on converting this logic into actual physical implementation, including the specific location and connection method of components. ‌

What is the difference between PCB design and schematic design?

The main difference between PCB design and schematic design lies in their purpose, content and application scenarios. ‌

‌Purpose and content‌:

Schematic design focuses on describing the logical relationship and electrical performance of the circuit, using graphic symbols to display power, components and connections, and can clearly show the logical relationship of the internal circuit of the electronic device. It is mainly used for circuit analysis and design, helping to understand the working principle of the equipment and perform fault diagnosis‌.

PCB design focuses on describing the actual physical size, position and wiring of components, and is the actual circuit board layout and wiring design based on the schematic diagram. It is mainly used to guide the manufacture and assembly of PCBs, reflecting the actual layout and wiring of electronic equipment‌.

‌Application scenarios‌:

Schematic design plays an important role in the process of R&D, debugging and maintenance, and is a key tool for understanding the working principle of the equipment and performing fault diagnosis‌.

PCB design files are an important basis for the actual PCB board manufacturing and subsequent assembly, debugging and other processes‌.

In short, schematic design is the basis of electronic product development. It provides information such as the logical relationship and electrical performance of the circuit, while PCB design is the key link to convert the schematic into an actual circuit board. It is necessary to design components layout and wiring according to the requirements of the schematic.

What is a PCB stencil file?

A PCB stencil file is a pre-designed file template used to quickly generate PCB design files containing specific information.

These template files usually contain basic information such as board size, board layer settings, grid settings, and title bar settings. Users can quickly generate new PCB design files based on these templates, thereby speeding up the design process.

By using these templates, designers can avoid designing these basic settings from scratch, saving time and energy, and focusing on more complex circuit design details.

Conclusion:

There are many types of PCB design files, among which Gerber files are the most important. The information they contain is the most and the most important. The final quality of the PCB circuit board depends on the first step of design. BEST Technology has very professional PCB designers who have many years of industry experience and can meet all your needs.

What is a heavy copper PCB?

Heavy copper PCB is a special printed circuit board (PCB) characterized by a very high concentration of copper, usually up to 200 ounces per square foot, and the copper content of the inner and outer layers of the circuit board is above 3 ounces (oz), which enables heavy copper PCBs to conduct extremely high currents, achieve good heat distribution, and realize complex circuit layouts in a limited space.

In the design and manufacturing process of heavy copper PCBs, thermal stress handling is an important consideration. Engineers need to eliminate thermal stress as much as possible to maintain the circuit while minimizing the power budget, while taking into account environmentally friendly design.

With the development of PCB manufacturing process, modern manufacturing technology such as the use of aluminum PCB can better handle thermal stress problems.

The heat dissipation capacity of Heavy copper PCB is better than the traditional solution of using external heat sink, because it prints the heat sink directly on the circuit board during the manufacturing process, and achieves rapid heat transfer through conductive through-holes, thereby improving heat dissipation performance.

In general, Heavy copper PCB is a high-performance electronic component carrier, which provides an ideal solution for applications requiring high power and high reliability through its high copper content and optimized thermal management characteristics.

What is the difference between PCB and Heavy copper PCB?

Copper board and Heavy copper board look similar in name, and people tend to think that they are the same PCB, but in fact they refer to different things.

1. PCB:

PCB refers to a copper-based PCB. The use of copper as a substrate is to better dissipate heat and extend the life of components on the PCB. The copper substrate is to allow heat to be quickly transferred from the PCB to the outside, such as a heat sink or a metal casing. Because the thermal conductivity of copper is several times that of aluminum or other metals, up to 401W/MK.

2. Heavy copper PCB:

Heavy copper PCB refers to PCB with copper thickness exceeding 3OZ. The substrate can be aluminum or FR4. Heavy copper is to enable PCB to carry large current. Please note that Heavy copper here does not refer to the thickness of PCB, but the thickness of copper foil on PCB. Both aluminum PCB and FR4 PCB can thicken the copper foil.

What is the maximum copper thickness on Heavy copper PCB?

‌The maximum thickness of copper on Heavy copper PCB can reach 20oz. ‌

In circuit board design and manufacturing, copper thickness is an important parameter, which directly affects the electrical performance, heat dissipation capacity and mechanical strength of the circuit board. For applications that need to carry large currents, it is necessary to choose a thicker copper layer.

The copper layer thickness of Heavy copper ultra-thick PCB is generally between 2oz and 20oz. This range of copper layer thickness can ensure the stability and reliability of the circuit board while providing good heat dissipation performance.

In practical applications, according to international standards, the copper thickness of PCB boards can be divided into standard copper thickness and non-standard copper thickness. Standard copper thickness includes 1oz (35um) and 2oz (70um), while non-standard copper thickness covers 0.5oz (17um), 3oz (105um) and 4oz (140um). For some special applications, such as high-power LED lights, electronic high-frequency circuits, etc., a higher copper thickness may be required. At this time, non-standard copper thickness will be selected, up to 20oz.

During the manufacturing process, a Heavy copper foil is first adhered to the substrate, and then the circuit pattern is transferred to the copper foil through a photolithography process. Then chemical etching is performed to remove excess copper, and finally the thickness of the copper layer is further increased through an electroplating process to ensure that the Heavy copper PCB can meet the requirements of high current and high power applications.

Finally, surface treatment is performed to protect the copper circuit from oxidation and corrosion. Common surface treatment methods include hot air leveling (HASL), lead-free tin spraying, nickel gold (ENIG), etc. During the entire manufacturing process, process parameters must also be strictly monitored to ensure the uniformity and thickness consistency of the copper layer.

What are the advantages of Heavy copper PCBs?

1. Heavy copper PCBs have better current conductivity and can withstand excessive current loads. Because thicker copper wires have higher current carrying capacity, their current carrying capacity can be increased by increasing the copper wire width.

2. Heavy copper inner layers are ideal power distribution layers in multi-layer PCBs, which minimize ground bounce and power supply noise

3. Improve thermal performance and increase heat dissipation. Can withstand repeated thermal cycles during manufacturing and assembly.

4. Provide high mechanical strength in connector locations and plated through holes.

5. Due to the presence of copper layers, the size of the circuit board is reduced.

What are the disadvantages of Heavy copper PCBs?

1. Heavy copper PCBs are more expensive to manufacture than standard PCBs because more specialized equipment and richer expertise are required.

2. Heavy copper PCBs are more difficult to process because the PCBs may be heavier and bulkier than other PCBs.

What are the properties of Heavy copper PCBs?

High mechanical strength: After Heavy copper is applied to the circuits and vias of the board, the printed circuit board has super high mechanical strength, and the weather resistance of the circuit board and electrical system is more stable and has a high melting point. Hot melt welding methods such as oxygen blowing can be used, and it is not easy to become brittle at low temperatures. Even in an extremely corrosive atmospheric environment, Heavy copper PCBs can form a strong, non-toxic passivation protective layer.

Excellent weather resistance: Because Heavy copper PCB boards support the selection of a variety of dielectric materials. It improves the overall weather resistance of the board and can ensure the stability of circuit transmission signals under certain high temperature or extreme special environments.

Thermal management: With the advancement of modern technology, PCBs are becoming more and more complex, and high-density currents increase the difficulty of thermal management. Excessive temperature will affect the normal operation of electronic equipment and even cause damage. Heavy copper PCB boards can provide stronger heat dissipation capabilities. With heat sinks and copper plating on through holes, the heat generation of the board can be greatly reduced.

Excellent current conductivity: In the operation of electronic equipment, Heavy copper printed circuit boards are excellent current conductors that can connect and transmit power between various boards.

Diversity: Plating of Heavy copper circuits allows Heavy copper PCB manufacturers to increase the copper weight of via sidewalls and plated holes, thereby reducing the number of layers and occupied space.

Ductility: Heavy copper PCBs have the best ductility and are not limited by processing temperature.

High performance: Heavy copper plating integrates high current and control circuits, allowing high density with a simple board structure.

Where are Heavy copper PCBs used?

1. Automotive electronics

2. Grid switching systems

3. Power line monitors

4. Security and signal systems

5. Radar monitoring systems

6. Industrial control

7. Aerospace

8. Telecommunications

9. Medical devices

Conclusion:

In PCB production, Heavy copper PCBs require special processes, are difficult to operate, and have certain technical barriers, so the production cost of Heavy copper PCBs is higher than other ordinary circuit boards. Although the price is not cheap, the quality and service are the best.

BEST Technology has more than 18 years of PCB manufacturing experience. Focusing not only on fast PCB prototyping and PCB assembly, but also on small and medium batch PCB manufacturing, customer satisfaction is our goal, we will do our best to manufacture your circuit boards in the highest quality to meet your needs, and are committed to complying with the most stringent standards in PCB manufacturing and assembly. ‌

What is the standard thickness of a copper layer on a PCB?

In the manufacture of printed circuit boards (PCBs), the thickness of the copper layer is an important parameter that directly affects the electrical performance and reliability of the circuit board. Depending on the application requirements, the thickness of the copper layer can vary within a certain range. Generally speaking, the conventional copper layer thickness is between 1-35μm, with 35μm being the most commonly used thickness. For some applications with high reliability requirements, the copper layer thickness may reach more than 50μm.

The selection of the thickness of the copper layer is a decision-making process that takes into account a variety of factors, including the conductivity, heat dissipation, mechanical strength, cost and manufacturing difficulty of the circuit board. A larger copper thickness can reduce resistance and improve the conductivity and heat dissipation of the circuit board, but it will also increase material costs and production difficulties. Therefore, when designing PCB boards, engineers need to select a suitable copper thickness standard range based on specific application scenarios and design requirements to ensure the performance and reliability of the circuit board.

1oz copper thickness in mm = 0.035mm

0.5 oz copper thickness in mm = 0.0175mm

1.5 oz copper thickness in mils = 0.0525mm

2 oz copper thickness in mils = 0.07mm‌

How thick is PCB copper after plating?

PCB printed circuit boards are usually bonded to glass epoxy substrates with a layer of copper foil, usually 18, 35, 55 and 70 microns thick. The most commonly used copper foil is 35 microns thick.

The copper foil used by PCB manufacturers is generally 35~50 microns thick, and some are thinner than this, such as 10 microns, 18 microns, and thicker such as 70 microns. The thickness of the composite copper foil on a 1~3 mm thick substrate is about 35 microns. The thickness of the composite copper foil on a substrate with a thickness of less than 1MM is about 18 microns, and the thickness of the composite copper foil on a substrate with a thickness of more than 5 mm is about 55 microns.

The copper layer thickness of PCB (printed circuit board) can be adjusted according to different needs and designs. Common copper layer thicknesses include 1oz (35μm), 2oz (70μm), 3oz (105μm), and other thicker options. For most applications, a copper layer thickness of 1oz is sufficient and suitable for general signal transmission. ‌For circuit boards that need to carry large currents, such as switching power supplies, a copper layer thickness of 2oz or higher is usually used. ‌In addition, there are some special cases where manufacturers provide extremely heavy copper up to 20 oz/ft2 (26.8 mils or 0.34 mm) to meet special needs. ‌

When choosing the thickness of the copper layer, factors such as the purpose of the circuit board and the magnitude of the signal voltage and current need to be considered. ‌For example, for circuit boards that require excessive current, a copper thickness of 70μm or 105μm may be used. ‌For thin laminates that require ultra-high density patterns, a copper thickness of 12μm may be used. ‌Therefore, the specific thickness of the PCB after copper plating is determined according to design requirements and specific applications.‌

How thick is 2 oz copper for PCB?

If 1 ounce (28.35 grams) of copper were flattened to evenly cover a surface area of 1 square foot (0.093 square meters), the resulting thickness would be 1.37mils (0.0348mm). A conversion chart for different units of measurement can be found below.

What is the difference between different copper thicknesses in PCB?

‌Copper is an excellent conductive material, and the thickness of the copper layer directly affects the conductive effect of the circuit board. ‌Thicker copper layers can provide lower resistance, reduce signal transmission losses, and are particularly suitable for high-frequency and high-speed digital circuits. ‌

During the operation of electronic equipment, good heat dissipation is a key factor in ensuring the performance and life of components. ‌Thicker copper layers can conduct and dissipate heat more effectively, preventing components from overheating. ‌

In high-power electronic devices, thicker copper layers can carry larger currents, avoiding burnout or performance degradation caused by excessive current.

Below is the conductivity corresponding to different copper thicknesses.

How thick is high current PCB copper?

In PCB design, copper thickness (also called copper thickness) is an important parameter, which directly affects the performance indicators of the circuit board such as current carrying capacity, heat dissipation and reliability. For PCBs that need to withstand high currents, such as high-power LED light strips, power circuit boards, high-power motor control boards or high-power inverter control boards, thicker copper layers are usually used to increase current carrying capacity.

Different uses have different copper foil thicknesses. Common 0.5oz, 1oz, and 2oz are mostly used in consumer and communication products. Thick copper products above 3oz are mostly used for high currents, such as high-voltage products and power boards.

The thickness of copper foil (track width) will affect the current size. Although there is a formula that can directly calculate the maximum current carrying capacity of copper foil, it is not so simple when actually designing the circuit. Therefore, the safety factor should be fully considered during the design.

How thick is the copper in a flex PCB?

The thickness of copper foil in flexible PCB is generally 18μm, 35μm, 55μm and 70μm. These thickness specifications are suitable for different types of circuit board requirements, among which 35μm is the most commonly used copper foil thickness.

For flexible PCB, the choice of copper foil thickness depends on the specific purpose of the circuit board and the size of the signal voltage and current. For example, for PCBs that require excessive current, some parts will use 70μm copper thickness, while for signal transmission, 1oz (35μm) thickness is usually sufficient. In addition, for substrates of different thicknesses, the thickness of copper foil is also different. For example, the thickness of the composite copper foil on a 1mm thick substrate is about 18μm, and on a substrate thicker than 5mm, the thickness of the composite copper foil is about 55μm.

Conclusion:

PCBs for different usage scenarios correspond to different thicknesses of copper, and its thickness directly affects the conductive effect of the circuit board. If the copper layer is too thin, the conductivity may decrease, resulting in signal transmission attenuation or current instability. If the copper layer is too thick, although the conductivity will be very good, it will increase the cost and weight of the circuit board and easily lead to serious glue flow. In PCB manufacturing, it is necessary to select the appropriate copper thickness according to the design requirements and actual applications of the circuit board to achieve the best conductive effect.

BEST Technology is a professional PCB circuit board manufacturer with a large area of site and equipped with useful and experienced production personnel. Corresponding to different thicknesses of copper, we have rich production and processing experience. We can meet the requirements of any circuit board copper layer thickness.‌

What is A Printed Circuit Board (PCB)?

A Printed Circuit Board is a fundamental component in modern electronics, providing the physical and electrical connections for various electronic components. It consists of multiple compositions, including a non-conductive substrate, conductive pathways, and insulating layers, which facilitate the complex circuitry required in contemporary devices. A PCB can be made into single sided PCB, double sided PCB and multilayer PCB.

PCBs are integral to the functionality of a wide range of electronic products, from consumer gadgets like smartphones and computers to industrial machinery, medical devices, and aerospace systems. The advanced design and manufacturing processes involved in PCB production ensure high reliability and performance, making them essential in virtually all electronic applications.

PWB Vs. PCB: What Are the Manufacturing Process Differences?

Basic manufacturing process of PCB

Design and Layout

PCBs are designed using sophisticated computer-aided design (CAD) software. Designers create detailed layouts, specifying the placement of components, conductive pathways, and vias (interlayer connections). The design is converted into Gerber files, a standard format for PCB fabrication that contains all the necessary information for manufacturing. These files are essential for ensuring precision and accuracy during the manufacturing process.

Material Preparation

The substrate, typically FR4 (fiberglass epoxy laminate), is prepared. FR4 is known for its excellent mechanical strength and thermal stability, making it an ideal base material for PCBs. Copper sheets are laminated onto the substrate, which will form the conductive pathways after the etching process. This preparation stage is crucial for creating a reliable foundation for the PCB.

Printing the Circuit Pattern

A photoresist, a light-sensitive material, is applied to the copper-clad substrate. The board is exposed to ultraviolet (UV) light through a mask that defines the circuit pattern. The UV light hardens the photoresist in the exposed areas. The board is then developed in a chemical solution that removes the unexposed photoresist, revealing the copper to be etched away. This step accurately transfers the circuit design onto the board.

Etching

The board is immersed in an etching solution, commonly ferric chloride or ammonium persulfate, which removes the unprotected copper, leaving only the desired circuit pattern. This etching process is crucial for defining the conductive pathways on the PCB, ensuring that the correct connections are made according to the design specifications.

Drilling

Precision drilling machines are used to create holes for through-hole components and vias. These holes are then cleaned to remove any debris that could affect electrical connectivity. Drilling is a critical step in the PCB manufacturing process as it ensures proper placement and connection of components across different layers of the board.

Plating

The drilled holes are plated with copper to create electrical connections between the layers, which is especially important for multilayer PCBs. Additional layers of plating, such as nickel or gold, may be applied to improve conductivity and protect against oxidation. This plating process enhances the durability and performance of the PCB.

Solder Mask Applying

A solder mask is applied to protect the copper traces from oxidation and prevent solder bridges between closely spaced solder pads. The solder mask is exposed to UV light and then developed to reveal the solder pads. This layer not only protects the PCB but also improves its appearance and reliability.

Silkscreen Printing

A silkscreen layer is printed on the board to add text, component labels, and other identifiers. This layer helps in the identification and assembly of components, making it easier for technicians to work with the PCB during the manufacturing and repair processes.

Surface Finishing

Generally, a layer of surface finishing is coated on the PCB to protect its surface, it also called surface treatment. The common surface treatments are HASL-LF, ENIG, ENEPIG, OSP, Immersion Silver/Tin. Of course, different treatment offers different function, like OSP is to protect surface from oxidation, HASL-LF provides a good solderability, ENEPIG make sure the chemistry corrosion. Choose a suitable one according to your specific demands.

Assembly and Testing

Components are placed on the board using automated pick-and-place machines, and soldered using techniques like reflow soldering for surface-mount devices (SMD) and wave soldering for through-hole components. The finished PCB undergoes various tests, such as automated optical inspection (AOI), electrical testing, and functional testing, to ensure quality and performance. Want see the whole manufacturing process of a multilayer PCB, click here: Manufacturing Process of Multi-layer PCB.

What is the definition of Printed Wiring Board (PWB)?

A Printed Wiring Board is a term historically used to describe a type of circuit board that focuses primarily on the layout and wiring of electronic connections rather than the overall circuit functionality. PWBs emphasize the physical arrangement of conductive paths to connect various components but do not necessarily include all the integrated features found in modern PCBs.

This term was more prevalent during the earlier stages of electronic development, where the primary concern was establishing reliable electrical connections. As technology advanced, the term PCB became more common, reflecting the expanded capabilities and comprehensive role of these boards in forming complete electronic circuits. Despite being less common today, understanding the term PWB is crucial for historical context and certain niche applications.

How to Manufacture A Printed Wiring Board (PWB)?

Design and Layout

PWBs typically have simpler designs focused on wiring patterns rather than complex circuitry. In some cases, the layout may be done manually or using basic design software.

Material Preparation

Simpler substrates such as phenolic or epoxy resins may be used for PWBs. Copper sheets are laminated onto the substrate to form the conductive pathways. These materials are cost-effective and suitable for applications where advanced performance characteristics are not required.

Printing the Wiring Pattern

Similar to PCBs, a photoresist is applied to the copper-clad substrate. The board is then exposed to UV light through a mask and developed to reveal the copper to be etched away. This process creates the wiring pattern necessary for connecting electronic components.

Etching

The board is immersed in an etching solution to create the wiring pattern. This step is straightforward compared to the more intricate etching processes used in PCB manufacturing, reflecting the simpler requirements of PWBs.

Drilling

Holes for through-hole components are drilled, but the process may not require the precision needed for complex PCBs. This basic drilling process is adequate for the less demanding applications of PWBs.

Plating (if necessary)

Plating is done to ensure electrical connectivity but may not involve advanced techniques like those used for multilayer PCBs. It suffices for the simpler construction of PWBs.

Solder Mask Application

A basic solder mask may be applied to protect the wiring pattern. This layer provides sufficient protection for the relatively simple designs of PWBs, preventing short circuits and oxidation.

Silkscreen Printing

A simple silkscreen layer may be added for component identification. This helps in the assembly process but does not require the detailed labeling often necessary for PCBs.

Assembly and Testing

Components are manually or semi-automatically placed on PWBs and soldered using standard techniques. Basic electrical testing is conducted to ensure functionality. This simpler assembly and testing process aligns with the less complex nature of PWBs.

Which Kind of Materials used in PCB and PWB?

Substrate Materials

FR4 (fiberglass epoxy laminate) is the most common substrate material for PCBs due to its excellent mechanical strength and thermal stability. Phenolic resin, used in PWBs for simpler applications, is less durable and has lower thermal stability compared to FR4, but it is cost-effective and suitable for basic electronic devices. Polyimide is used for flexible PCBs due to its high flexibility and thermal resistance, making it ideal for applications requiring bending and flexing, such as wearable electronics and flexible displays.

Conductive Materials

Copper is the primary conductive material for both PCBs and PWBs. It is used to create the conductive pathways and pads, providing excellent electrical conductivity and reliability. Gold, nickel, and silver are used for plating to enhance conductivity and protect against oxidation, primarily in PCBs. These materials improve the durability and performance of the PCB by providing a reliable contact surface for soldering and component connections.

Insulating Materials

Prepreg, a fiberglass cloth impregnated with resin, is used in multilayer PCBs to bond the layers together. Prepreg provides mechanical strength and electrical insulation between the layers. Dielectric materials are used between layers in multilayer PCBs to provide electrical insulation, maintaining signal integrity and preventing short circuits.

Solder Mask Materials

Liquid Photo Imageable (LPI) solder mask is the most common type used in PCBs, providing excellent protection and durability. LPI solder masks are applied using a photolithographic process, ensuring precise coverage and protection. Dry film solder mask is used for simpler applications and PWBs. This type of solder mask is less expensive and easier to apply but may not offer the same level of protection as LPI solder masks.

Key differences between PCB and PWB

Feature	PCB (Printed Circuit Board)	PWB (Printed Wiring Board)
Design and Layout	Designed using sophisticated CAD tools for complex circuitry, including detailed simulation and optimization.	Simpler designs focused on wiring patterns, often done manually or with basic software.
Layer Count	Can have multiple layers (e.g., double-sided, multilayer) to support intricate circuit designs.	Generally single or double-sided, less commonly multilayer.
Component Types	Supports surface-mount technology (SMT) and through-hole technology (THT) components.	Primarily supports through-hole technology (THT) components.
Signal Integrity	Designed to maintain high signal integrity, minimizing electrical noise and interference.	Basic signal integrity management, sufficient for simple applications.
Flexibility and Rigidity	Includes both rigid and flexible PCBs, allowing for a wide range of applications.	Typically rigid, not commonly used in flexible applications.
Terminology and Usage	Universally used in the industry to refer to boards that integrate all necessary components to form complete circuits. Also called “bare board”.	Universally used in the industry to refer to boards that integrate all necessary components to form complete circuits.
Industry Standards	Recognized by standards organizations like IPC, IEC, and ANSI with specific performance and quality criteria.	Covered under broader standards but with fewer specific guidelines due to limited modern use.
Cost and Efficiency	Higher cost due to advanced materials and processes, offering superior performance and reliability.	More cost-effective for simple applications, but with limited performance and reliability.
Applications	Used in consumer electronics, industrial equipment, medical devices, aerospace, and defense.	Historically used in simpler electronic devices and early computers, still relevant in niche applications.

(Summary Differences: PCB VS PWB)

Other Terms Related to PWB and PCB

Based on the PCB and PWB, you may still hear about CCA, PCA, PWA during the PCB working. These terms are also related to printed circuit board. Here is a detailed explanation of each:

Printed Wiring Assembly (PWA)

PWA is the abbreviation for printed wiring assembly. This is an archaic term that was once used to describe what we now refer to as PCB assembly or PCBA. Although it is less common today, understanding this term is useful for historical context and when dealing with older documentation.

Circuit Card Assembly (CCA)

CCA stands for circuit card assembly. It is essentially the same thing as PCBA, where the PCB is assembled with all necessary components to create a functional unit. CCA is a less frequently used term compared to PCBA but is still recognized in certain industries and contexts.

Printed Circuit Board Assembly (PCBA)

PCBA is the abbreviation for printed circuit board assembly. When the PCB is assembled with all its electronic components by SMT technology, it is called PCBA or PCB assembly. Since a change in terminology in 1999, PCBA has become the standard term used for all assembled circuit boards. From users to technical committees, PCBA is the preferred term for referring to assembled boards. The assembly process involves placing and soldering components onto the PCB, making it a functional electronic circuit.

Printed Circuit Assembly (PCA)

PCA stands for printed circuit assembly, which is another term for PCBA. Like CCA, PCA is not commonly used in modern terminology but refers to the same concept of an assembled printed circuit board.

In a word, whatever for PWB, PCB, or circuit cards, they are refer to bare printed circuit boards (bare boards). While PCA, CCA, PWA, and PCBA refer to assembled circuit boards. Among these terms, PCB and PCBA are the most widely used in both industry and technical documentation.

This is the end of this introduction of PWB and PCB, welcome to contact us if you want more about PCB knowledge.

Stack up of 2L MCPCB and Double Sided MCPCB

For a 2L MCPCB, the metal core is positioning on the bottom side of the MCPCB as a cooling carrier to the whole MCPCB, while the metal base of double sided MCPCB is located in the middle of two copper trace. In generally, some PTH (plated-through-hole) vias are needed to designed to connect the bottom and top traces.

Below are the stack ups of these two kinds of products, from the structure, we can easily distinguish which one is 2L MCPCB and which one is double sided MCPCB.

Heat dissipation of 2L MCPCB and Double Sided MCPCB

Due to the different structure of the two products, their heat dissipation performance is also different. The main reason is the heating of double-sided metal core circuits can be spread out through both top and bottom side, while the heating generate by SMD components of 2 layers circuit only can be dissipated through bottom (metal) side and the heat need to go down layer by layer. In addition to this, the dissipation of FR4 is not good than metal materials, so double-sided metal core printed circuits perform better heat dissipation performance than 2 layers MCPCB.

Surface mounted locations (SMD populate)

Nowadays, surface mounted technology (SMT) is widely used in printed circuit board industry, more and more designers prefer to populate electronic components of the circuit surface to achieve high density, stable electrical performance and high reliability. 2L metal core circuit boards and double-sided metal core circuits also show their different mounted locations in this aspect.

The populate location of a 2L MCPCB only available on copper trace side, that is top side. And a double-sided metal core PCB can mount components on both top and bottom side, because both of them exist copper trace on it.

Manufacturing technology

May somebody will curious about “Are these two products produced in the same process/technology?”

The answer is obvious “NO, they have a different laminate process when fabricating.”

Different with single layer MCPCB, double sided MCPCB requires an additional pressing step to laminate the thermal conductive layer and metal core together. But sometimes, some raw Metal Clad material vendor will supply board material which already laminated.

For 2 layers metal core PCB, due to it is made of a single MCPCB and a double-sided FR4 PCB, the first thing we should make a double sided FR4 PCB, then laminate the PCB together with the single MCPCB. But due to the thermal conductive layer (pure adhesive) is easy to overflow during laminating process, which will cause the poor adhesion and crack between metal core and FR4 PCB. In the meantime, to avoid such problem, an experienced operator is needed to proceed the laminated process. That is why the lead time and cost of a 2 layers metal core circuit is much longer and expensive.

This is the end of this post, if you still have some questions or difficulties about the metal core PCB, welcome to contact us at sales@bestpcbs.com, our professional sales team and engineering team will give you a best solution for free.

Part 1: What is Solder Mask?

If you had ever seen a printed circuit board, you may see there is a layer of green ink cover on the PCB surface while some orange-yellow areas didn’t cover by ink. In PCB industry, the green ink we called Solder Mask, or abbreviated as S/M, and exposed area is copper, they were leave as GND plane or soldering pads to mount electronic components.

Solder mask is a liquid acrylic oligomer, which has variety of colors such as red, blue, green, white, black. Green is commonly used in the process of PCB manufacturing, so some professional engineers call it as green oil.

Solder mask applied on the PCB designed as a protection layer to avoid oxidation, corrosion and other environmental impacts when they leave production line. In addition, solder mask between solder pads also can help to prevent forming to solder bridge when assembly.

Below are some other functions of coating a layer solder mask:

Prevent physical line breaking of copper trace
Only weld in the area that must be soldered to avoid waste of soldering
Reduce copper pollution to soldering groove
Prevent insulation deterioration and corrosion caused by dust, moisture and other external environmental factors
With high insulation, so that the high-density circuit is possible

Part 2: What is Solder Paste?

Solder Paste also known as “Solder cream”, is a most important soldering material used in surface mount technology (SMT) process. Mainly function for soldering resistors, capacitors, ICs and other electronic components onto the PCB surface to form a permanent connection.

The solder particles are a mixture of solder formed by mixing solder powder, flux and other surfactants and thixotropic. Traditionally this used to be tin and lead, but with the legislation has been introduced around the world, to only use lead free solders. These may be made from a variety of mixtures, Best Technology commonly used is SAC305 which includes 96.5% tin, 0.5% copper and 3.0% silver, some manufacturers also use 99.7% tin and 0.3% copper, whereas there are other mixtures that include other metals including tin.

Due to the role of solder paste in assembly, solder paste storage is extremely important. However, solder paste got into drying during storing became a common problem faced by most PCBA manufacturers, so How to solve solder paste dry problem is premier.

Part 3: The Difference Between Solder Mask and Solder Paste

Solder mask is a formal part of PCB, but solder paste ONLY for PCB assembly.
Solder mask is not allowed on the solder pads while solder paste can be printed on the solder pads openings.
Solder mask is used for applying solder mask ink, but solder paste is used for applying paste.
Solder mask has many available colors, but paste mask visually gray.
Solder mask is coating during PCB fabrication, but solder paste is printing when PCB assembly.

With over 16 years in PCB industry, Best Technology is one of the most reliable PCB and PCBA supplier in Asia, we commit to provide high quality products with excellent service before and after sales, to take care our customers wholeheartedly, and to treat customers’ business as ours. At the same time, we keep learning and continually to improve ourselves so that we can catch up the latest technology trend and provide better and better service for our customers.

Copper thickness	Minimum circuit width	Minimum circuit spacing
0.5-2oz	0.25mm	0.23mm
3oz	0.35mm	0.3mm
4oz	0.4mm	0.38mm

Posts Tagged ‘printed circuit board’

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Part 2: What is Solder Paste?

Part 3: The Difference Between Solder Mask and Solder Paste

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