Metal core PCB consists of a layer of thermal insulation, copper foil, and metal plate, and you can also call it MCPCB. The basic benefits of metal core PCB include:
- High magnetic conductivity
- Great heat dissipation
- Excellent mechanical strength
- Easy processing
The base layer of the MCPCB is copper and aluminum, and you can choose to have any of them. Aluminum PCB is cheaper than copper, and you would find them in LED lights, mobile phones, and audio-frequency equipment. However, copper is better than aluminum in terms of performance. MCPCB was developed to overcome the heat dissipation issues occurring in high-power LED lights.
Things To Consider While Designing The Metal Core PCBs
The construction of the MCPCB stack-up depends on certain guidelines that we will discuss here. Such boards consist of a specific base layer, such as aluminum, copper, or even steel. You will have to determine the layer arrangement after selecting your desired metal and dielectric laminates. The type of the layer will determine other aspects, such as components and routing.
MCPCB has different types, depending on the number of layers as single-layer, double-layer, or multiple-layer metal core circuit board.
What Is A Metal-Backed PCB?
This Printed Circuit Board has a metal layer on its back, whereas the opposite layer has electric components. You can’t route traces on the back, however, through-holes are possible for routing between different dielectric layers, bringing ground to the metal substrate.
Metal Core PCB Routing
In the case of a double-side PCB, you can place through holes for routing between the metal core’s sides. You can use the multilayer dielectric stacks on the metal core’s sides to support different layers’ routing.You should ground the metal substrate for shielding, and to prevent it from acting as a monopoly antenna.
Metal core circuit boards are ideal for aerospace and military industries that involve mechanical shocks, as well as high moisture and temperatures. So, MCPCB helps meet such requirements because they have a strong structure and a high thermal conductivity compared to PCB having an FR4. Such highly conductive circuit boards ensure an equal distribution of temperature when there is thermal cycling. So, it does not let the hot spots make closed components.
Metal core PCBs are also suitable for electric products which should work at high temperatures, such as high-current regulators, automotive electronics, and high-power LED lighting. The design of such applications depends on a precise stack up, and the board architecture should perform high at a low temperature.
Metal Core Printed Circuit board Fabrication Process
As there is a metal substrate in the stack up, such PCB involves a specific manufacturing process.You can use the FR4 dielectric in the case of a single-layer board by pressing the layer and bonding it to the metal plate.
If it’s a stack-up with a multilayer dielectric, you should first drill the metal core to have a layer transition independent of a short circuit. In the beginning, large holes are made and plugged with the insulating gels.Then, the gel has to be cured to make copper plating like a standard PCB. After that, you have to press and bond the remaining stack-up with the metal substrate. The stack-up needs through-holes followed by copper plating and residue cleaning.
The single-layer metal core circuit board has a metal base, copper layer, non-conducting or dielectric layer, solder mask, and IC components. Most thermoelectric separation applications consist of a COB or Chip-On-Board metal core circuit board,
It has two layers of copper conductor and both are on the metal core’s same side. Whereas the 2L MCPCB also has the metal core between two conductors, and designers call it a double-sided metal core circuit board.
How to Select the MCPCB Components
It is essential to decide what components to choose when designing printed circuit boards as it can affect the final product. Such electronic components have different shapes and sizes, different power consumption specs, weights, and several other elements.
If you know how to choose PCB components efficiently, it can prevent big mistakes during design. We will help you in selecting the right components for your metal core PCB design.
You have to use certain design software tools to source the MCPCB components. These tools are necessary for all types of circuit boards, including a board with FR4, a rigid-flex circuit board, or a metal core board.
The surface mount technology is suitable for placing the components because it involves a minimum shorting to the metal substrate.You can also use the through-hole components,but you have to be careful to ensure that the solder mask does not get damaged on the back of the metal-backed PCB.
PCB fabrication involves multiple steps and the right design can enhance this process, preventing unnecessary design revisions.The manufacturer should have all documents having the fabrication details of the MCPCB.
Other than using metal cores, some passive techniques also help keep a circuit board cool through thermal management.
Designing MCPCB In A Closed Environment
The design of a multilayer PCB can become complex without compatible design software. You require the layout design tools for precise placement of the components, vias, routetraces, electrical, and thermal load crosscheck, etc.
You must have a good library of materials while designing the MCPCB. Likewise, the PCB layer-stack manager is required to handle your board’s structure. A suitable stack-up manager helps you to design a stack-up with an appropriate placement of the metal core, be it symmetric or asymmetric. Once the dielectric layers are defined, you need some groundwork for route traces and components’ placement.
Choosing The Design Software For PCB Layout
Different software help develop the PC Board layouts but make sure to choose the suitable one such as Altium. It helps you to have very precise CAD features to place the components. It also makes routing simple through special routing tools, whereas the layout engine helps ensure that the MCPCB is according to the design guidelines.
Remember that suitable software includes the 3-D design features to help you to design the complex mechanical parts of the MCPCB. You can also share your design with others through Altium 365, a cloud platform
Parameters of a Multi-Layer MCPCB
The design parameters of aluminum PCB sare described below.
- Desired Aluminum thickness is 0.8-2.0mm
- Solder resistance should be 288℃, >180 sec.
- Breakdown voltage should be >3000v
- The dielectric loss angle should be 0.03
- Flammability should be UL 94V-0
- Thermal conductivity should be 1.5W and 2.0W
- Peeling strength should be >9lb/in
The minimum drilling diameter should be 1 mm in the case of an aluminum core, and the final diameter can be up to 0.3mm. There should be at least 1.2 mm spacing between the drill holes to avoid any damage.
Metal core PCB is also useful in several other areas having high mechanical loads where the dimensional stability should be high. Moreover, you can use it for electric vehicles, backlight units, automotive, audio systems, traffic lights, commercial buildings’ lighting, and solar panels.
The digital devices depend on printed circuit boards for signals transmission to help them operate. These devices need a well-designed structure and manufacturing, but you have to encounter many issues in this case that we will discuss here. Circuit boards have different types and any issue in the design of a PCB would cause delays in its manufacturing, so you must know how to avoid them.
What is A Metal Core Printed Circuit Board?
Metal core PCB has a metal base, such as aluminum, copper, or steel of which aluminum and copper are common.
Which One Is Cheaper, MCPCB with Aluminum or Copper?
MCPCB with aluminum is cheaper than copper. But, copper is better in terms of performance.
How Many Types of Metal Core Circuit Boards are there?
MCPCB has different types, depending on the number of layers, such as a single-layer, double-layer, or multiple-layer metal core circuit board.
Where Can I Use The Metal Core Circuit Board?
Metal core PCB is also useful for electric vehicles, backlight units, automotive, audio systems, traffic lights, commercial buildings’ lighting, and solar panels.
There are several benefits of metal core PCBs, such as high magnetic conductivity great heat dissipation, excellent mechanical strength, and easy processing. The base surface of the MCPCB is copper and aluminum, and you can choose to have any of them. Aluminum PCB is cheaper than copper, and you would find them in LED lights, mobile phones, and audio-frequency equipment. But, copper is better than aluminum in terms of performance. Metal Core PCB was developed to overcome the heat dissipation issues occurring in high-power LED lights.
The design of a multilayer PCB can become complex without compatible design software. You require the layout design tools for precise placement of the components, vias, route traces, electrical, and thermal load crosscheck, etc.
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