Aluminum PCB vs. FR4 PCB: Cost, Materials, and Difference
Aluminum PCB vs. FR4 PCB: Cost, Materials, and Difference
- Nature of Material:
If you are looking for a metal core material, Aluminum can be the best choice. Its main layer consists of an aluminum core infused with fiber glass. The metal clad contains a thermal layer for dissipating the generated heat energy to protect the PCB from heating up. It cools down the electrical components, enhancing their performance.
The FR4 PCBs are composed of woven fiber glass and epoxy resin with copper foil on one side. FR is the short form of Flame Retardant, a halogenated material used as a non-conducive layer with strong adherence to copper. They serve as a self-extinguisher laminating layer.
- Thermal conductivity
If you want PCBs for LED lighting, aluminum is the preferable option, as it serves as a conducive substrate. It enables the current to pass through, unlike FR4, which is non-conducive fiberglass material. PCBs for LED lightning call for electric transfer between components to generate heat, ensuring enhanced performance. FR4 PCBs don’t allow excessive heat generation, so the thermal conductivity of Aluminum PCBs is better than FR4 PCBs.
- CTR values
The CTR value or coefficient of thermal expansion of FR4 PCBs is greater than Aluminum PCBs: 50×106cm/cm-C of Aluminum PCBs and 110*106cm/cm-C of FR4 sheet plus 17*106cm/cm-C of copper. The thermal expansion value of FR4 sheet and copper adds to make the coefficient of thermal expansion for FR4 PCBs greater, and the difference between them shows reliability. It implies that the substrate can easily expand on heat exposure and alter the copper wiring. It can also cause a metal hole rupture on the PCBs, leading to detrimental effects. However, the thermal expansion of Aluminum PCBs provides that there’s less difference between it and the copper’s expansion which signifies that the PCBs are qualitative and reliable. So, Aluminum PCBs are preferable if you want low CTR values for your applications.
- Laminating Layers
In terms of layers, Aluminum PCBs are strict of three layers, unlike FR4 PCBs, which can be of single, double, and multiple layers. The three laminating layers of Aluminum PCBs incorporate an Aluminum substrate, copper conducive layer, and dielectric layer, which make it a suitable option for applications exposed to high thermal temperatures.
- Mechanical Strength and Rigidness
The mechanical strength and rigidness of Aluminum PCBs are greater than FR4 because of the metal core base. Aluminum PCBs are a better alternative for applications requiring large and capacious circuit boards to accommodate several electrical components. The aluminum substrate layer in the PCBs provides excessive strength to the components.
- Manufacturing
The manufacturing process of Aluminum PCBs is different from FR4 PCBs. The manufacturers design FR4 PCB as an electric insulator. The glass fiber material is sandwiched between two layers of copper foil at the top and bottom. The Aluminum PCB material allows two types of drilling PTH in the PCB: with a drilling machine and a gong machine. However, drilling holes with a drill machine provides smooth and accurate results, unlike with gong machines, adding more bucks to the manufacturing cost. Yet, the advantage is Aluminum metal PCBs only require a few mounting holes than proper drilling.
However, FR4 PCBs and single-layer Aluminum PCBs don’t call for electroplating. Aluminum PCBs also require an additional heat sink to let the current pass through the components without shock or inconvenience. Yet, the base of the dielectric layer in the Aluminum PCBs enables the heat to dissipate and prevents the device from heating up. So, when the manufacturers want to incorporate cooling effects in the applications like LED or electrical devices, they use Aluminum alloy material. However, Fiber glass infused with epoxy resin is used in devices requiring a lightweight insulating layer, serving as a self-extinguisher in industrial machinery.
- Thickness
The only aspect where FR4 PCBs surpass Aluminum PCBs is board thickness. FR4 PCBs offer thick printed circuit boards varying due to multiple lamination layers. Yet, Aluminum PCBs have comparatively low thickness ranges generally because of the dielectric or backing metal layer’s thickness. More credit goes to the backup plate, as the thickest element in the Aluminum PCBs is the backing plate for additional heat dissipation.
While comparing the heat dissipation capabilities of PCBs, we can see that this ability is directly related to the dimensions of the insulating layer. If the thickness of the insulating layer is less, it reduces the thermal conductivity and the heat dissipation capability. However, the heat dissipation power and thickness of the PCB are indirectly proportional to the voltage resistance. If the Aluminum PCB is thin, it will have a low resistance to voltage.
- Dimensional Space:
The Aluminum PCBs incorporate wire bonding for connecting the electrical traces on the boards, substituting heat sinks. It is worth noting because it reduces the space on the printed circuit board, making a place for more components or electrical transistors. Moreover, they contain metal substrates, so there’s no longer a need to use rubber, mica, or other such insulators that are generally mounted on the PCB surface. So, it also frees the space on the circuit board.
While thin FR4 PCBs take less space in the devices and can easily be infused in small-sized applications. So, if you are short on space, you can consider fiberglass material that saves space and is a lighter PCB solution for your electronic equipment.
- Costs
The FR4 PCBs are cheaper than Aluminum PCBs due to several reasons and are more suitable for several applications compared to other PCB materials. The aluminum metal costs more than the woven fiberglass material. The additional chemical milling and resistance layers on Aluminum PCBs make it more expensive. Aluminum PCBs are thicker than FR4 PCBs, implying more material and additional mounting of electrical components. Yet, with the price comes the performance; Aluminum PCBs are expensive but offer high-end performance in industrial applications. If you use FR4 PCBs, you have to add the cost of the external heat sink to reduce thermal hotspots that can damage the device if exposed to high temperatures.
- Usage
The usage of FR4 PCBs is greater than Aluminum PCBs. Yet, Aluminum PCBs are mostly employed in LED industrial applications. The manufacturers prefer Aluminum PCBs in LED lighting applications owing to their higher thermal conductivity and heat dissipation ability. Its dielectric layer also makes this PCB material efficient, ensuring high-glow LED light performance. The manufacturers employ FR4 PCBs in the high-density interconnector or HDI PCBs because of their controlled performance.
| Feature | Aluminum PCB | FR4 PCB |
|---|---|---|
| Substrate Material | Metal core, typically aluminum or copper for enhanced heat dissipation | Woven fiberglass core impregnated with epoxy resin for electrical insulation |
| Thermal Conductivity | High thermal conductivity, enabling rapid heat dissipation | Lower thermal conductivity, may result in localized hotspots |
| Electrical Isolation | Requires dielectric layer or thermal barrier for electrical isolation due to conductive core | Naturally provides excellent electrical insulation |
| Flexibility | Rigid, limited flexibility, not suitable for applications requiring bending or flexible designs | More versatile, can support multilayer configurations and complex circuitry |
| Weight | Lighter, beneficial for applications where weight reduction is crucial | Thicker and heavier, which may be a concern in weight-sensitive applications |
| Cost-effectiveness | Can be cost-effective for high-power applications requiring efficient heat management | Generally cost-effective for a wide range of applications, readily available |
| Applications | Ideal for power electronics, LED lighting, and automotive applications due to efficient heat management | Suitable for a wide range of applications, including low-power consumer electronics and high-frequency communication systems |
| Design Considerations | Less suitable for complex bending or flexible designs due to rigidity | Offers a wide range of design possibilities, including complex circuitries and multilayer configurations |
| Thermal Management | Excellently manages high power dissipation with minimal temperature differentials across the board | May require additional thermal management techniques, like heat sinks or thermal vias, for efficient heat dissipation |
Double-Side LED Aluminum Board
Layers： 4L Thickness： 1.6mm
Out Layer Copper Thickness： 0.5 OZ
Inner Layer Copper Thickness： 0.5 OZ
Min Hole Size: 0.2mm Min Line Width: 3mil
Surface Finish: ENIG
Application: LED Lighting
Single-Side LED Aluminum Board
Layers: 2L Thickness: 1.2mm
Out Layer Copper Thickness: 0.5 OZ
Inner Layer Copper Thickness: 0.5 OZ
Min Hole Size: 0.2mm Min Line Width: 3mil
Surface Finish: OSP
Application: LED Lighting
Double-Side Power Supply Board
Layers:4 L Thickness: 1.6mm
Out Layer Copper Thickness: 0.5 OZ
Inner Layer Copper Thickness: 0.5 OZ
Min hole size: 0.2mm Min Line Width: 3mil
Surface Finish: HASL
Application: Power Supply
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At KKPCB, we specialize in designing and manufacturing metal-core printed circuit boards (PCBs) for various applications. These applications include LEDs (light-emitting diodes), backlit LCD displays for desktops and laptops, street lights, medical and industrial monitoring systems, motor control applications, power converters, audio devices, photovoltaic components, surgical lighting tools, and high-power scanning technology.
