Flexible Aluminum PCB: All You Need To Know

//

Oakley Mae

Home » Blog » Flexible PCB » Flexible Aluminum PCB: All You Need To Know

If you have been keen enough, you have noted how PCB manufacturers are designing new products daily, with the latest product being flexible aluminum PCB.

Generally, an aluminum circuit board uses an aluminum core as the base material and an FR-4 as the insulating component.

Moreover, the PCB has a thermal-clad layer responsible for heat dissipation. 

And when compared to flexible copper PCBs, aluminum options are more cost-effective.

According to experts, aluminum experiences limited corrosion, thus high durability.

But do you understand flexible aluminum PCB layout, manufacturing process, or pricelist? 

Today’s article shed more light on the flexible aluminum PCB to help you make informed electronic-related decisions.

Let’s get rolling.

Table of Contents

Understanding Flexible Aluminum PCBs

With constant research, manufacturers and designers realized that flexible aluminum circuit boards offer efficient performance cost-effectively.

Generally, the boards have single or multiple layers of silkscreen, copper coat, and solder mask. 

Moreover, it has a base material consisting of an aluminum core and regular FR-4 materials.

And what many don’t realize is that instead of fiberglass and plastic substrates, aluminum PCBs use purely metallic substrates.

And the materials can bend to acquire different shapes, thus fitting into the tightest areas. 

PCBs Manufacturers prefer using flexible aluminum circuit boards in high-power and tight-tolerant electronics.

Furthermore, there is a clad thermal layer that dissipates heat with efficiency. 

Flexible Aluminum PCB Benefits

Why would you discard other circuit boards and rely on the flexible aluminum PCB functionality?

This section focuses on the benefits that flexible aluminum PCBs offer: 

Heat Transferring: All electronic components converts some of their energy into heat.

And when the electronics fail to dissipate the heat energy, the device’s performance reduces drastically.

Fortunately, flexible aluminum PCBs are designed with aluminum and dielectric layers, improving the board’s heat dissipation characteristics. 

These layers boast up to 10 times better dissipation than fiberglass materials.

As a result, you won’t experience any cases of damage to the circuit, and the board will have higher performance. 

Lightweight: Aluminum can’t be left out when discussing lightweight metals.

And this feature enables them to offer high performance in smaller, compact electronics. 

Durable: The circuit boards are designed with flexible aluminum alloy that can stay for years without damage.

And no matter how much you bend, it’ll remain intact. 

Cost-effectiveness: Finally, the cost is why manufacturers and designers are shunning copper for aluminum in circuit boards.

Generally, aluminum is easier to mine and refine.

Therefore, they’re cheaper to manufacture, thus providing the best approach for managing heat in high-power circuits. 

Types of Aluminum PCBs

The common thing about aluminum PCBs is that they have an aluminum core as the base material and an FR-4 insulating material.

Additionally, they have thermal clad responsible for thermal dissipation.

A circuit board with through holes

(A circuit board with through holes)

However, the configurations of these circuit boards vary widely, giving rise to the following different types:

Through-hole PCBs: These are aluminum circuit boards with drilled holes having dielectric materials.

Also, the aluminum undergoes a thorough lamination process which involves adding a laminate to the aluminum sides.

And the plated through-holes finally pass through the metal clearances to offer electrical insulation. 

Flexible aluminum PCB: We consider flexible circuit boards the latest Insulated Metal Substrates (IMS) materials developments.

They offer excellent flexibility, good conductivity, and proper insulation.

Therefore, flexible aluminum circuits can bend while maintaining their stability.

As a result, they find usage in wearables and other compact electronics. 

Multilayer circuit boards: When you look at a flexible circuit board, you might be tempted to think it has only a single layer.

However, some aluminum circuit boards have more than one layer.

We call these boards multilayer PCBs and are designed with several dielectric layers.

Therefore, the PCB acquires complex designs with high heat dissipation properties. 

Hybrid aluminum PCBs: This category involves blending processed non-thermal material with the aluminum base material.

This results in a two or four-FR4 layer circuit board with high rigidity and better heat dissipation.

Flexible Aluminum PCB Applications

An aluminum PCB with LEDs

(An aluminum PCB with LEDs)

Due to aluminum’s excellent thermal dispersion and conductivity, we use it mainly in high-power applications.

Below are some applications and areas you’ll find flexible aluminum PCBs:

Power: It’s common knowledge that most high-electronics emit much heat energy.

Therefore, we use flexible aluminum PCBs to emit heat faster and more efficiently.

Some electronics under this category include DC/AC converters, power supplies, and power switch regulators. 

Lighting: Another major application of flex aluminum PCBs is non-consumer and consumer lighting applications.

Here, we fix light-emitting diodes on the circuit boards to create products like traffic control, landscape, interior, and street lighting. 

Automotive: When you check your vehicle, you’ll find flexible aluminum PCBs in power regulators, controllers, and lights. 

Medical: Nowadays, high-power scanning applications and surgical lighting use flexible aluminum PCBs. 

Flexible Aluminum PCB Layout

SMD LED on an aluminum circuit board

(SMD LED on an aluminum circuit board)

A flex aluminum PCB layout contains four layers. 

Copper Foil Layer: This layer is thicker than the copper-clad laminate layer and is about 1 to 10 oz.

Generally, a thicker copper layer translates into a higher current-carrying capacity. 

Dielectric layer: This layer contains a section that supports thermal conductivity.

The layer is about 50μm to 200μm and has a low thermal resistance. 

Aluminum base: This layer is designed from an aluminum substrate and has a high thermal conductivity.

Also, the layer is flexible and can bend to various shapes without damage. 

Aluminum base membrane layer: This layer helps with protecting the aluminum layer against etching and scratching.

Moreover, this layer is available in two types:

  • An anti-high temperature layer of about 250 degrees Celsius
  • Lower temperature layer of less than 120 degrees Celsius

Flexible Aluminum PCB Production Challenges and Solutions

Workers assembling a circuit board in a factory

(Workers assembling a circuit board in a factory)

The aluminum circuit board production process is not all that smooth.

And although there are several challenges present, we have reliable solutions to them.

This section highlights these challenges and their relevant solutions: 

Copper Etching

Aluminum PCBs have thicker copper foils.

And if the copper thickness exceeds 3 oz, a width compensation for the etching is always critical. If, for some reason, the circuit board fails to meet design demand post etching, the trace width goes out of tolerance.

Therefore, you must always design the trace width with precision and accuracy.

Moreover, focus on controlling etching during manufacturing. 

Solder Mask Printing

Flexible aluminum PCBs are designed with thicker copper foils that make solder mask printing challenging.

Generally, thicker copper traces causes image etching which is responsible for the difference between the trace surface and the baseboard.

Therefore, the solution is to use two-time solder mask printing.

Moreover, we recommend applying quality solder mask oil or employing resin filling before solder mask printing. 

Mechanical Manufacturing

PCB manufacturing involves critical processes like mechanical drilling, v-scoring, and molding that cause electrical strength reduction.

Therefore, we recommend using electric milling and a professional milling cutter when producing PCBs in low volumes.

FAQs

Why is aluminum perfect for use in circuit boards?

Regarding circuit board development, we recommend aluminum for the following reasons: 

  • High electrical conductivity
  • It has an excellent thermal conductivity
  • Aluminum presents a cost-effective option
  • It’s highly durable
  • Aluminum is lightweight

How long does flexible aluminum PCB last?

We understand that you don’t want to invest in a product that gets damaged after a few months or years of use.

And we can assure you this is one area in which aluminum PCBs won’t disappoint you.

These boards are among the most durable and might last you for more than ten years.

However, the lifespan depends on multiple factors, including the solder type and soldering method. 

Final Remarks

Most of the electronics you’re using are likely benefiting from the quality features of flexible aluminum PCBs.

These include DC/AC converters, interior lighting, power regulators, and high-power medical scanners.

Moreover, flex aluminum PCBs are highly durable, have high conductivity, and support lightweight applications. 

If you want to understand flex aluminum PCB, you have everything in this piece.

And if you feel something is missing that you’d like addressed, contact us anytime.