Among all Metal core PCBs, Aluminum PCB is the most common type. The base material consists of an aluminum core and Prepreg. It features a thermal clad layer that dissipates heat in a highly efficient manner while cooling components and increasing the overall performance of the products. Currently, Aluminum Backed PCB is regarded as the solution to high power and tight tolerance applications.
Aluminum printed circuit boards (PCBs) are metal-based, copper-clad laminates with a good heat dissipation function. Generally, a single Aluminum PCB is composed of a three-layer structure: a circuit layer (copper foil), an insulating layer, and a metal base layer. Aluminum PCBs are commonly found in light-emitting diode (LED) lighting products. There are two sides—the white side is for soldering the LED pins, and the other side is the natural color of aluminum. Generally, the thermal conductive paste will be applied to come into contact the thermal conductive part. Very few applications are multi-layer aluminum PCB boards, which can mix-press ordinary multi-layer boards like FR-4 (glass-reinforced epoxy) with insulating layers and aluminum core.
LED aluminum substrate is often referred to by the shorthand PCB, but the material is aluminum based. In the past, general circuit board material was glass fiber (FR-4), but because the LED heats up, the circuit board used in LED lamps is generally aluminum substrate, since it has good thermal conductivity and electrical insulation properties compared to fiberglass boards.
Advantages of Aluminum PCB
1. Heat dissipation: High temperatures can cause severe damage to electronics, so it is wise to use a material that can help dissipate heat. Aluminum can actually transfer heat away from vital components, thus minimizing the harmful effect it could have on the circuit board.
2. Higher durability: Aluminum provides strength and durability to a product that ceramic or fiberglass bases cannot. Aluminum is a sturdy base material that can reduce accidental breakage during manufacturing, handling, and everyday use.
3. Lightweight: For its incredible durability, aluminum is a surprisingly lightweight metal. Aluminum adds strength and resilience without adding on any additional weight.
Structure of Aluminum PCB
1. Circuit Copper Layer: The circuit copper layer (usually using electrolytic copper foil) is etched to form a printed circuit, which is used to realize the assembly and connection of the device. Compared with the traditional FR-4, with the same thickness and the same line width, the aluminum substrate PCB can carry a higher current.
2. Insulating Layer: The insulating layer is the core technology of the aluminum substrate, which mainly plays the functions of bonding, insulation and heat conduction. The aluminum substrate insulating layer is the largest thermal barrier in the power module structure. The better the thermal conductivity of the insulating layer, the more favorable it is to spread the heat generated during the operation of the device, and the lower the operating temperature of the device, so as to increase the power load of the module, reduce the volume, extend the life-span, and increase the power output .
3. Metal substrate: What kind of metal is used for the insulating metal substrate depends on the comprehensive consideration of the thermal expansion coefficient, thermal conductivity, strength, hardness, weight, surface state and cost of the metal substrate.
In general, considering the conditions such as cost and technical performance, aluminum plate is an ideal choice. Available aluminum plates are 6061, 5052, 1060 and so on. If there are higher requirements for thermal conductivity, mechanical properties, electrical properties and other special properties, copper plates, stainless steel plates, iron plates and silicon steel plates can also be used.