In the current electronic world, PCB manufacturing is undergoing a great evolution. Therefore, designers need to consider more durable and highly reliable materials for manufacturing PCBs. Additionally, the world is working towards achieving a more mobile, automatic electronic environment. However, achieving such an environment may be difficult due to extreme conditions. To solve this, we must incorporate the best printed circuit boards in our electronic setups. Aluminum printed circuits are the most efficient among all metal-based printed circuit boards. The following information will take us through Aluminum base PCB.
Aluminum Base PCB
Aluminum base printed circuit boards comprises a metallic dielectric base with a circuit layer of bonded copper. In addition, the bonded copper provides excellent heat conduction, hence cooling the circuit components.
Layers Of Aluminum Printed Circuit Boards
The following are the Aluminum PCB layers:
Dielectric Layer
The dielectric layer has a dielectric thermal conductor with a thickness of between 50µm and 200 µm. Furthermore, this layer withstands thermal and mechanical stress.
Copper Foil Layer
The Aluminum copper-clad laminate (CCL) consists of a copper foil layer and a relatively huge current carrying capability to facilitate the circuit layer. Consequently, the copper circuit must be thick enough to support the large currents. Usually, the copper circuit has a thickness of between 1oz and 10oz. Moreover, the copper foil‘s back side must undergo chemical oxidation treatment, while its side surface undergoes brass plating and zincing to boost peeling strength.
Aluminum Base Layer
The Aluminum base layer contains an Aluminum substrate that supports the base layer components. In addition, the substrate must have a high thermal conductivity. Moreover, it must be suitable for standard mechanical manufacturing processes like punching, cutting, and drilling.
Aluminum Base Membrane
The base membrane protects the Aluminum surface against agent etching and scraping. We can classify the membrane into anti-high temperature (set at 250°C) and common type (120°C). The anti-high type satisfies the hot air solder leveling (HASL) requirements and is, therefore, a suitable surface finish.
Classification Of Aluminum base PCBs
Factors like dielectric material and application field can help us classify Aluminum PCBs into the following three categories:
- High thermal-conductive Aluminum – In this case, the dielectric layer mostly has epoxy resin or any other resin type of high thermal conductivity.
- Universal Aluminum PCB- The dielectric layer has epoxy glass fiber prepreg.
- High-frequency and Microwave Aluminum – The dielectric layer of such a PCB has a glass fiber prepreg made of polyimide resin or polyolefin resin.
Aluminum base PCB types
We can classify Aluminum PCBs as either flexible, mixed, or through-hole.
Flexible Aluminum Printed Circuit Board
The most recent advancement in materials for insulating metal substrates is the flexible aluminum PCB dielectric. The adjustable aluminum PCB material offers improved electrical insulation, thermal conductivity, and flexibility with a ceramic filler and polyimide resin. We can tilt and mold the PCB when using it with flexible aluminum materials (like 5754), which allows us to do away with pricey components like wires, fittings, and connectors. Even though these flexible aluminum PCB materials are flexible, we can bend them and keep them firmly in place. Therefore, they are inappropriate for applications where the material must undergo repeated bending.
Through-Hole Aluminum PCB
In more intricate systems, a single layer of Aluminum can serve as the center core of a complicated thermal structure. Before the lamination procedure, drill the Aluminum in a through-hole aluminum PCB and backfill the hole with a dielectric. The next step is to apply thermal glue on both sides of the PCB and laminate the thermally conductive material (or sub-assembly). Additionally, the components do drill like a PCB after lamination. As a result, we can provide electric insulation by drilling plated holes that can pass through the gaps in the aluminum PCB.
Mixed Aluminum PCB
Using hybrid aluminum PCBs, we can control non-thermal materials and thermally fuse them to aluminum substrates. Typically, we can utilize an aluminum PCB with two or four layers of FR-4. Moreover, we can combine the aluminum-clad PCB substrate with this layer and thermoelectric medium to increase flexibility, dissipate heat, and serve as a heat shield. In addition, the mixed aluminum PCB has the following benefits:
- Mixed aluminum PCBs do away with associated assembly procedures, and pricey heat sinks.
- Compared to PCBs composed entirely of thermally conductive materials, the hybrid aluminum PCB structure is less expensive.
- The thermal performance of mixed aluminum PCB is superior to that of FR-4 devices in general.
- For RF applications, we can use mixed aluminum PCB. Furthermore, we can improve the lost function in these applications by PTFE surface lavers.
Advantages of Aluminum Base PCBs
Aluminum base PCB boards can reduce thermal resistance in comparison to conventional FR-4. It has excellent thermal conductivity as a result. Moreover, its mechanical characteristics are better when compared to thick-film ceramic circuits. Additionally, aluminum base PCB board has the following exceptional benefits:
- Environment friendly- Aluminum base PCB materials are recyclable and non-toxic. Therefore, they have no adverse effect on the environment.
- Durability- Compared to glass fibers and ceramic-based PCBS, Aluminum base PCBs are more robust and durable.
- Excellent quality- Applying Aluminum base PCBs reduces PCB components’ shrinkage and thermal expansion. Moreover, Aluminum PCBs meet RoHS specifications and are therefore suitable for surface mount technology (SMT).
- Heat dissipation- Aluminum base PCBs have a better heat loss capability than other PCB types.
- Fabrication Cost- Since Aluminum PCBs do not require heat sinks and thermal interface materials, the cost of assembling them is lower compared to other PCBs.
- Convenience- Aluminum PCBs are lighter than typical PCBs and are, therefore, more mobile.
Applications of Aluminum Base PCBs
The PCBs apply to the following fields:
- Automotive electronics- Automotives require highly reliable PCBs that withstand relatively high temperatures. Consequently, due to Aluminum’s high efficiency and dependability, it is the most suitable in such automotive parts as lighting systems.
- Power Conversion- Aluminum is compatible with inductive circuits and mechanical fasteners due to its excellent thermal performance.
- Consumer electronics- Aluminum base PCBs are applicable in such consumer products as:
- Street lights
- Interior building lights
- Camping gear
- Traffic lights etc.
- Solid State Relays- Owing to their high thermal efficiency and lightweight, Aluminum boards are mainly applicable in thermal protective systems. Moreover, it conducts heat away from sensitive circuit components like floppy disk drives, CD ROMs, flash drives, etc.
- Communication- Aluminum PCBs work excellently in such communication products as OP amplifiers, high-frequency amplifiers, wireless transmitters, etc.
- Building automation- Interfacing Aluminum PCBs with programmable Arduino boards creates an excellent controller circuit for application in automation.
Conclusion
From the above information, Aluminum base printed circuit boards are lighter and more suited for high-temperature applications. However, Aluminum base flex PCBs may not work well in dynamic setups requiring repeated and intense bending. Therefore, employ Aluminum PCBs for static electronic applications for excellent results.