< img src="https://mc.yandex.ru/watch/96881261" style="position:absolute; left:-9999px;" alt="" />

Al-Based PCB

  • Al-Based-PCB-1
  • Al-Based-PCB-2
  • Al-Based-PCB-3

Welcome to globalwellpcba

With more than a decade in the field of PCB prototype and fabrication, we are committed to meeting the needs of our customers from different industries in terms of quality, delivery, cost-effectiveness and any other demanding requests. 

As one of the most experienced PCB manufacturers in the world, we pride ourselves to be your best business partners as well as good friends in the every aspect of your PCB needs.
Custom Inquiry

OVERVIEW

Table of Contents
Primary Item (H2)

As we know, PCBs can be manufactured using different metals as substrates. One of the options is aluminum. These aluminum PCBs are used in many industries because they're good at conducting heat and insulating electricity.  These qualities contribute to their superior performance. But what else can they offer? Let’s find out in this comprehensive article.

What is an Al-based PCB?

It's a type of PCB made with an aluminum core along with a standard FR4 material. Instead of fiberglass or plastic, these PCBs use metal substrates. Usually, you'll come across single-sided and double-sided aluminum-based PCBs. However, multilayer PCBs are rare because they're challenging to make. 

This is also why they are mostly utilised in producing LEDs. These light-emitting objects produce heat, which is effectively directed away by the aluminum and increases the lifespan of an LED. Some examples include aluminum substrates in street lights and household lighting. Other industries, too, use aluminum-based PCBs, but are not as common as lighting.

Globalwell Al-Based PCB 1

Types of Al-based PCB?

Multilayer PCB: It has many layers of dielectric material with blind vias and are good at  dissipation of heat. While they are advantageous in heat dissipation in complex devices, however, their cost of production is relatively higher. Therefore, they are mostly used in power supply products. 

Hybrid aluminum PCB: when an aluminum base material is fused with non-thermal material, you get a hybrid aluminum PCB. For instance, 2 or 4-layer FR-4 boards. It can be attached to an aluminum base using a dielectric material. 

Through-hole aluminum PCB: These come with already drilled holes and are filled with dielectric material. After the construction, the thermal material is laminated on both sides with appropriate substances suitable for heat. Finally, holes are drilled. These holes ensure that the electricity does not travel where it shouldn’t. 

High thermal conductivity aluminum PCB: As the name suggests, they are wonderful at thermal conductivity. An epoxy resin material is used to make the insulating layer of these types of aluminum PCB. 

High-frequency aluminum PCB: Contrary to the above, the insulating layer in this comprises polyimide or polyolefin. In some cases, fiberglass may be used in an epoxy resin. But, no matter what material is used in its manufacturing, the aim is to improve the flexibility of the aluminum PCB. 

Universal Aluminum PCB: Epoxy glass fiber prepreg makes the dielectric layer in this.

Flexible PCBs: In this type of PCB, a polyimide layer incorporates ceramic filters. The two materials ensure that the resultant PCBs have sufficient flexibility, thermal efficiency, and electrical insulation.  

In addition, their bending capacity is high. But this doesn’t imply they can be used for applications that demand constant bending. Also, these are cost-efficient and you won’t need cables or connectors in their making. However, there is a downside: you cannot make any changes once it is manufactured. 

Globalwell Al-Based PCB

The Physiology of an Al-based PCB

Copper layer

A 1 to 10 ounces (oz) thick layer of electrolytic copper foil is a distinguishing feature of this layer. Copper material is usually etched during the production. Once set, the back side undergoes oxidation with chemicals, and the surface is treated with zinc and brass to prevent corrosion. 

The main function of this layer is to connect two devices and improve their functionality. 

Dielectric layer

Made up of a thermally conductive dielectric layer, this is somewhere between 50µm and 200µm in thickness. When the current flows through the PCB, it helps in heat dissipation, insulation, and handling mechanical stress. 

Aluminium base layer

This is what gives this PCB its name, Al-based PCB. This is also the layer that makes it different from the other layers. The core of this layer is made up of aluminum substrate and is well-suited for drilling, cutting, and punching.

Remember to look for an aluminum plate that has high thermal conductivity, is firm, and is cost-effective. It would be good if the metal (Al here) fulfill all these pre-requisites. If not, then add iron, copper, or silicon to improve its heat dissipation ability. 

Base membrane

Again, this layer consists of an aluminum alloy substrate. This helps safeguard the substrate layer from unwanted etching and scraping. This layer is 1mm thick and can be divided into an ordinary membrane (less than 120°C) or an anti-high temperature (250°C). The second membrane adheres by the HASL requirements, and can be seen as surface finish. 

The Making of an Al-based PCB

While making an Al-based PCB, a thin dielectric layer is inserted right in between the circuitry and the base. After this, the circuit layer is etched so that you receive the pattern you need. Finally, both the dielectric layer and the circuit board work together to eliminate the heat generated. 

Why use Aluminium in Manufacturing PCB?

Lighter in weight

One of the perks of using PCBs is the weight of the metal. Aluminum weighs 169lb/cubic foot, which is significantly light, making it easy for the manufacturer to add more power and resilience to the Printed Circuit Board.

Durable

As a metal, aluminum is considered highly durable. Even if there is a slight risk of it tearing during the production or shipping, you should rest easy. The inclusion of an aluminum circuit board ensures it doesn’t. Not only this, aluminum is believed to have better strength than a ceramic base or fiberglass. 

Good for the environment. 

The metallic substance is 100 percent recyclable, which means it is good for the environment. What makes Al-PCB even better is that they are easy to assemble and are non-toxic. 

Cost efficiency 

This metal is a great investment as it is all-weather friendly. They are easier to mine as well as refine, making it easy to procure the raw materials. This, in turn, makes the production process much cheaper. 

Excellent heat dissipation

PCB components are prone to damage due to high thermal temperatures. But not with aluminum. This is one of the only substances that can dissipate heat really well. It takes away the heat produced by the components, eliminating any risk to the essential elements.

Disadvantages of Al-based PCB

  • These are single-sided. Installing components on both sides of an aluminum PCB is tough. Therefore, you will have Al-based PCBs as single-sided boards only. 
  • Expensive. These cost the manufacturers much more than the standard PCBs
  • Works for specific applications only: As these circuits are mainly applied where heat generation is so high, therefore they can be used in some specific electronic components only. An example of this is LED. 

Performance of Al-based PCB

Dimensional stability

As compared to the traditional PCB, the dimensional stability of aluminum PCB is much higher. For example, the dimensions will change only 2.5 ~ 3.0% till 150 °C. However, the story may change at higher temperatures. 

Heat dissipation

You might be aware that several substrates that are used to make PCBs, including FR4, are bad conductors of heat. The situation turns worse when the heat produced by the electronic devices that contain a specific PCB-design produces heat that moves rapidly. The two combined can play havoc, sometimes leading to the failure of the electronic component. An aluminum substrate handles this really well. 

Thermal Expansion

Aluminum, as we have discussed already, is great at spreading out the heat evenly so that no damage occurs to the components. This essentially controls the expansion and contraction of the material. Thus, it makes the PCB more durable and reliable. 

Other performance indicators

Apart from the above three, there is yet another material, which is ceramic substrate. This substance provides enhanced protection from heat and, thus, reduces the cost of production in the end. 

Globalwell Al-Based PCB 2

Troubleshooting Difficulties in Manufacturing Aluminium PCB and Solutions

Issue no. 1: Thick Copper Foil Etching

These aluminum circuit boards are generally used in high-power density appliances, and therefore, they require thick copper foil. However, when the copper foil is thicker than 3oz, it is important to change the width of the lines. Or else the trace width will be either too wide or too narrow after etching. Therefore, to ensure all goes well, adjust the trace width to match the design.

Solutions:

  • Design the etch compensation for trace width correctly
  • Control the elements involved in etching strictly
  • Remove any effects that the making of traces may have on how wide or how far apart they are

Issue no. 2: Mechanical Manufacturing

The mechanical processes included in the making of Al-based PCBs include milling, drilling, and molding. While these processes are carried out, v-scoring and burr may remain behind inside the holes. This can make the electrical connections weak. 

Solutions: Here is how this can be overcome. 

  • Use professional milling cutters and electric milling for small-scale manufacturing.
  • Adjust drilling parameters on thick copper aluminum PCBs. 
  • Keep an eye on the technique and pattern during die molding.

Issue no.3: Solder Mask Printing

Applying a solder mask on a thick copper foil of aluminum PCB is difficult. So, if the copper is thicker than usual, even after etching, then it will be a visible between the surface of the trace and the remaining board. This makes the solder application difficult. 

Solutions: 

  • Consider two-time solder mask printing.
  • Use high-quality solder mask oil.
  • A method that uses resin filling followed by a solder mask can also be used. 

Applications of Al-based PCB

  • Audio equipment: audio amplifiers, power amplifiers, preamplifiers, input and output amplifiers, balanced amplifiers, etc.
  • Communication electronic equipment: high-frequency amplifiers, filter electric circuits, 
  • Computers: power supply device, motherboard, and floppy disk drive.
  • Electronic control: the several components in the circuit, transistor base, relays
  • Lighting: LED lights
  • Power modules: inverters, rectifier bridges, solid relays
  • Power supply: conditioner, DC-AC adapter, stabilizer
  • Automatic office: motor driver
  • Industrial vehicles: ignition, automatic safety control system, lighting conversion system, and voltage regulator
  • Switches: semiconductor devices, semiconductor devices, motor controllers, 
  • Office: motor driver

Parting Thoughts

So, by now, you know that aluminum PCBs offer high thermal conductivity and heat dissipation and are a good replacement for the ceramic substrates. These make them perfect for use in different sectors. However, you must ensure that these boards are from a reliable manufacturer. So, check the experience and their ability to match your specific requirements.

Need PCB/PCBA/OEM? Get a Free Quote Now!

en_USEnglish