PCBs are available in most electronic devices. These circuit boards are exposed to different conditions due to the functions they serve. With the rising development in electronics, the demand for high-quality PCBs is increasing.
Thermal dissipation is a problem in high-tech circuits. Hence, metal core PCBs are a solution to thermal problems in advanced circuits. Component thermal dissipation is a major concern during PCB design and component layout. This article seeks to shed more light on Metal core PCB.
Metal Core Printed Circuit Board (MCPCB) – What is it?
A metal core aluminum pcb is a circuit that features high-thermal conductivity. This circuit board features a base made of metal material. The metal material covers one side of the circuit board. The function of the metal material of a metal core board is to redirect heat away. The metal core can be on the back of the circuit board or in the middle.
This type of PCB enhances heat dissipation in electronic devices. It keeps devices at a temperature that is safe. As regards heat dissipation, a metal core PCB performs better than other PCBs. These double side metal core pcb make use of copper, a thermal-conductive metal. The base metal in metal core PCB is an option to CEM3 or FR-4.
MCPCB board can be also referred to as a metal backed PCB or a led metal core pcb. The core of a metal PCB can be copper, aluminum, or a combination of special alloys. Metal core boards feature metal material as their base, unlike the traditional FR4. These boards feature a dielectric layer that provides high thermal conductivity.
Metal core PCBs are ideal in applications that generate high amounts of heat. In this type of application, there is a high need to dissipate heat. Lack of heat dissipation can cause damage to electronic components in the circuit. MCPCBs always have high thickness and are difficult to cut into smaller bits.
The metal core serves as a new replacement for the use of CEM3 and FR4 in circuit boards. metal core pcb dissipate heat faster due to their dielectric material. This material functions as a thermal link from the IC components to the metal plate.
Different Types of MCPCB Board
The MCPCB board is available in three different types.
Single layer MCPCB
The single sided metal core pcb features a layer of dielectric sheet copper. It also features a metallic sheet at its base. The dielectric layer in the board provides heat transfer among various components on the board. Most single sided metal core pcb feature aluminum or copper alloy as their base. However, aluminum is a much cheaper option.
Double sided MCPCB
A 2layer mcpcb features a metal core between the conductor layers of the board. This board uses 2 sheets of copper. The 2layer MCPCB manufacturer places the 2 sheets on a single side of the metallic part. The SMD and vias merge the metal core with the conductors. The metal core aluminum pcb can either be aluminum, copper, or iron alloys.
The structure of the multi-layer MCPCB board is similar to that of FR4. More than 2 sheets of copper material are in this type of MCPCB. There is more complication in the board structure due to the increase in the number of layers. This led metal core pcb utilizes signal layers and many components.
Benefits of Metal Core Printed Circuit Board
Asides from its ability to dissipate heat, an MCPCB board provides other benefits. This board provides enhanced capacitive coupling and high EM shielding. Here are some benefits of metal core printed circuit board;
Enhanced strength and stability
In LED technology, there has been a major concern about heat dissipation. LEDs are usually placed on the circuit boards. These LEDs cause reliability and stability issues for the circuit. Lack of heat dissipation can affect the performance of devices that function at high power. Metal core printed circuit board provides a lasting solution to this problem. Furthermore, aluminum is lightweight and adds strength to the PCB.
This is the greatest advantage of metal core PCBs. In fact, this board was specifically designed to offer higher thermal conductivity. It achieves this by redirecting the heat away from the electronic components on the metal pcb. The best known material used for the substrate of this PCB is aluminum. 2layer alu core pcb dissipate heat much faster than circuits fabricated with FR-4.
This board features a thin dielectric layer. The thickness of metal core PCB is usually between the range of 0.003 and 0.006 inches. For instance, a test carried out on a 1w LED MCPCB showed how the temperature is close to 25°C. The same led metal core pcb placed on an FR-4 circuit board got to 12°C, a temperature greater than the ambient one.
Thermal PCBs feature better dimensional stability than circuits made with FR-4. The size of the MCPCB board doesn’t change in response to environmental conditions. Metal core PCB have undergone small variations in size when exposed to a heating process.
Longer shelf life
An MCPCB provides enhanced durability and strength. Metal core PCBs have longer shelf life than boards made with FR4.
Types of Material Used for the Bases of Metal Core PCBs
There are different types of PCB metals used as the base of a metal clad board. The metal core of this PCB can be copper, aluminum, or a combination of alloys. Some manufacturers use steel or brass. However, this is quite uncommon.
Copper Core PCB
Copper is a type of aluminium metal core pcb that features great properties. Some MCPCB manufacturers use this material for the base of their boards. A copper core PCB is better than aluminum based boards. However, PCB users often prefer aluminum to copper. This is because of the cost of copper. Furthermore, copper core PCB is heavier than aluminum. This type of PCB also involves a complex machining process.
A copper core PCB features copper as its substrate material. This board also includes a prepreg insulation layer. Copper core PCBs can be a chip on board. In this PCB, LED chip put the heat sink to the copper substrate directly
One common material used for aluminium metal core pcb is aluminum. This material features great heat dissipation.led metal core pcb are lightweight and are ideal for use in LED lighting. The thickness of aluminum is between 40 mils and 120 mils. MCPCB boards that feature 2layer aluminum pcb are common in the PCB industry.
The thermal conductivity of aluminium metal core pcb ranges between 5W/m/K and 2.0W/m/K. The dielectric loss angle is also 0.03. 2layer alu core pcb features a breakdown voltage that is more than 3000V.
Iron based PCB
This is another type of metal core PCB. Iron based PCB features materials like steel or silicon steel as the base of its board. Iron is a good conductor of heat. Therefore, it transfers heat away from electronic devices. Also, iron is a cheaper alternative to aluminum and copper core PCB.
MCPCB Manufacturer Considerations
The manufacturing process of MCPCB requires attention. A metal core PCB must follow some processes. This is because they feature a metal layer in their stackup. If a PCB is a single layer without layer transitions, manufacturers can use the standard process for FR4 dielectrics.
Manufacturers can keep their designs to a single layer SMT type. This will make it easy to design your circuit board. You can use other MCPCB configurations if routing your design to a single layer isn’t possible. These configurations include;
- A 2 or more layer circuits designed on standard PCB processes. But a thermal dielectric material is used instead of an FR4.
- A 2 layer board featuring aluminum on the inside. This board needs a pre-drill and also a redrill step to create PTH.
MCPCB is an ideal solution when it is important to cool off multiple LEDs. Metal core boards are gaining popularity in various lighting applications. double side metal core pcb manufacturers follow the same manufacturing process as other 2layer mcpcb.
In metal core boards, there are no PTH holes for single layer boards. All electronic components are SMT. Also, these boards don’t need vias as thermal dissipation, unlike FR-4.
Comparing Metal Core PCB with FR4 PCB
FR4 boards or metal core boards are commonly used in the electronics industry. However, metal core boards dissipate heat faster than FR4 PCB. The decision to use any of these boards depends on the application requirements. Therefore, it is important to know the differences between these two boards.
MCPCB has a higher thermal conductivity. The typical values range between 1 W/m/K to 7 W/m/K. On the other hand, an FR4 board features a low thermal conductivity. The value of its thermal conductivity ranges from 0.3W/m/K to 0.4 W/m/K.
Metal core boards are more ideal in applications where heat dissipation is important. These boards dissipate heat much faster than FR4 boards. They don’t feature vias for the transfer of heat. aluminium metal core pcb can transfer excess heat from areas that can cause damage to the board. In FR4 boards, the rate of heat transfer is very low. These boards use vias to transfer heat.
The thickness variations in a metal printed circuit board are limited. The thicknesses of the backing plate and dielectric sheet determine the board’s thickness. On the other hand, there is a wide range of thicknesses in FR4 boards.
Furthermore, PCB metal can handle vibration and attack. This board is much stiffer than an FR4 board. Metal clad PCB is more expensive than an bare FR4 PCB. Also, an FR4 board uses PTH while MCPCB doesn’t implement PCB in a single layer board.
The manufacturing process of an FR4 board involves v-scoring, drilling, and more. Meanwhile, MCPCB board uses a different v-scoring process. This process involves using diamond-coated saw blades. MCPCB boards use a white color solder mask for the top layer of the board only. Whereas, FR4 boards use dark color solder masks for the top and bottom layers.
Factors to Consider When Designing Metal Core PCBs
Metal core boards vary in their designs. This depends on the type of application they are being used for. Also, MCPCB boards may have different designs based on the customer’s requirements. A metal core PCB design is carried out in a similar way to normal PCBs designs.
However, the only difference in this board is the substrate material used. Rather than using CEM 3 or FR4, PCB metal will serve as the base material. You must consider some factors to achieve a great design.
The thickness of the material used for the base of metal clad PCB matters. The intended application of the board determines the thickness of the PCB. MCPCB manufacturers would most time work with the thickness provided by their customers. The material thickness will impact factors like heat resistivity and conductivity.
The Type of Material
Different materials are used in metal core PCBs. MCPCB manufacturers can use copper, iron, or aluminum for metal core PCBs. The type of material will help you determine the number of components in your design. This factor will also influence the size of the design.
Size of the Metal Core Circuit Board
This is another factor you should take into consideration. The size of the MCPCB varies based on the components of the circuit board. Different applications require various sizes of PCBs. The intended application of your metal core PCB will determine the size of the board.
The weight of the device will depend on the size of the MCPCB board. Bigger MCPCBs will result in heavier devices. Also, these MCPCBs provide wider surface areas that allow faster heat dissipation.
Applications of Metal Core PCB
MCPCBs are crucial in certain applications. Metal core boards feature faster heat dissipation than other PCBs. Hence, these boards are ideal for use in high-frequency applications. The metal core helps to transfer heat away from components. This further helps to maintain a great performance of the electronic device. Metal clad PCBs are available in applications such as;
- Audio equipment like audio amplifiers, preamplifiers, and more
- Automation equipment
- Power modules
- Equipment for electronic communication
- Computers and computing devices like the CPU motherboards
- Light emitting diodes
- Power converters
- Hybrid or electric motor control
- Photovoltaic cells
- Solar panels
PCB metal plays a significant role in PCB manufacturing since it is a good conductor of heat. Electronic devices have the tendency to generate heat when in use. Hence, heat dissipation is a serious concern for PCB manufacturers. The use of metal clad PCBs in electronic devices provides a solution to heat dissipation. Metal core printed circuit boards help to improve the functionality of a circuit.