Aluminum PCB

Aluminum PCBs play an integral role in nearly all electronic devices. However, very few people understand what this vital piece of equipment works.

But not to worry.

I have prepared this guide to enable you to understand all the details that you need concerning aluminum PCB.

At the end of this guide, you will be in a position to define what an aluminum PCB is and areas where you can use them.

Without getting into details, let’s begin the guide.

What is an Aluminum Printed Circuit Board?

Before we start, a clear definition of an Aluminum Printed Circuit Board is essential. An Aluminum Printed Circuit Board refers to an electronic circuit that is of everyday use in appliances.

Aluminum PCB

Its function is primarily to offer mechanical support to the electronic components on the circuit. It is composed of an aluminum layer combined with other non-conductive materials and a copper circuitry.

How does an Aluminum Printed Circuit Board Work?

Now that we know what an aluminum printed circuit board is let’s have a look at how it works. Getting to understand how an aluminum PCB works will help you understand how they play an important role in electronics.

This section will take you through step by step through how they work for better understanding.

Have a look.

The parts you mount on the non- conductive board have a pathway that is known as “follows” which are very perceptible to a Gander. The “follows” are very conductive which enables them to interface each segment that is in the circuit.

Aluminum Printed Board Circuit

Within the aluminum PCB board, you will find numerous tiny openings which you can bore them precisely where you want each of your segment to be.

What this means is that for instance if you have a microchip that needs eight association, you will make eight association on the board.

You can mount electronic circuit along these which will serve to flush which recovers important space entirely. Lastly, you have the segments which are mainly tiny electronic gadgets.

You must connect these gadgets to enable the PCB to work. Ideally, these gadgets include microchips, switches, diodes, and resistors.

The gadgets are vital as they make the PCB function while the PCB provides the network needed.

Advantages of Aluminum Printed Board Circuit

There are several advantages that you will experience when using an aluminum PCB. They include the following:

Aluminum PCB

1.Reduces thermal stress for components

Aluminum FCBs have a less thermal expansion when you compare to other FCBs materials.

In applications that don’t need high levels of thermal conductions, you can use an aluminum FCB.

As a component of the PCB, aluminum allows for the spread of heat on the circuit which helps in conducting heat away from crucial elements.

By doing so, it reduces the damage of the heat on the circuit board

2. Durable hence increased service lifespan

During the production of a PCB, accidents and breakages are bound to happen. To prevent this, you can use a material that is durable and won’t break easily.

Generally, aluminum is a material that is highly durable.

Using aluminum in the production of PCB offers strength and durability to the PCB.

3.Mechanically rigid

The mechanical stability aspect of an aluminum PCB allows you to use in applications that can be subject to high mechanical stability levels Aluminum PCB thermal conductivity is superior.

This is because a lot of mechanical stress will be on the board implying a high amount of heat.

4.Better EMI-EMC shielding properties

Aluminum properties allow it to have a better EMI- EMC shielding capacity. Shielding is the process of minimizing electromagnetic field by blocking the field using magnetic materials such as aluminum.

5.Provides better strength during assembly

Aluminum in itself is lightweight and robust which provides durability to the PCB during assembling. When you compare with other PCB materials, aluminum PCB has the best strength ability.

6.Reduces the need for heat sink – efficiently dissipated heat

The ability of the aluminum PCB to dissipate heat from critical elements makes it ideal when you are producing these boards. You won’t have to be concerned with adding a heat sink to your board.

7.Environmentally friendly

You can quickly assemble an aluminum PCB which helps in energy conservation. Also, most of the components of an aluminum PCB are easily recyclable and are non-toxic to the environment.

This ensures that you have minimal waste hence conserving the environment.

8.Lightweight

One of the common advantages you have when using an aluminum PCB is that it is lightweight. Using it, therefore, makes the printed circuit board strong and resilient.

Disadvantages of Aluminum PCB

However, just like any other technology, there are a few limitations that you are likely to experience with the aluminum PCB. They include the following

1.Higher cost than standard FR4 PCB

The initial cost of assembling an aluminum PCB is higher when you compare to that of an FR4. This implies that if you are considering manufacturing these boards, you will have to invest heavily.

FR4 PCB

2.Producing Double Sided Aluminum PCB is more Difficult than Double Side FR4 Board

You may find the process of bonding the layers of a double-sided aluminum PCB more difficult. This means that you will spend a lot of resources producing a double-sided aluminum PCB.

Double sided FR4 PCB

Also, you have to be careful when producing a double-sided aluminum PCB to avoid damaging the components.

Aluminum PCB Structure

If you are to understand an aluminum PCB, you need to understand its structure. A structure involves understanding the composition of the aluminum PCB.

Aluminum PCB Structure

Allow me to take you through the structure of an aluminum PCB in this section.

·Circuit layer

There are two ways that you can have a copper layer on your aluminum board — either a full copper coating or a copper foil.

However, no matter the type you have, the copper layer still serves the same function. That is to transmit electrical signals within the aluminum FCB.

The composition of the circuit layer is the copper foil which varies in weight. They usually range between 1 to 10 ounces.

·Insulation layer/dielectric layer

The composition of this layer includes a layer of conductive dielectric material that has low thermal resistance. The thickness of this layer is between 50μm to 200μm.

This layer is an excellent performance when it comes to anti-thermal aging. Also, it has a perfect character of withstanding thermal and mechanical stress.

·The base metal core layer

The metal core layer primarily consists of two layers of aluminum. That is the aluminum base layer and the aluminum base membrane.

The aluminum base layer is made of an aluminum substrate material and forms the supporting element of the metal core layer.

This part needs to be highly thermal conductive which is favorable for mechanical activities such as drilling cutting and punching.

The aluminum base membrane, on the other hand, helps in shielding the aluminum surface against agent etching and scraping. You can have two classifications of the aluminum base membrane.

That is ordinary and anti-high temperature. You can use the anti-high membrane if you are applying HASL surface finish on your aluminum PCB.

Types of Aluminum PCBs

You will find a wide variety of Aluminum PCBs in the market. Though they function the same, you need to understand them.

Here is a look at these types.

a)Flexible Aluminum PCBs

Flexible aluminum PCBs are the kinds of PCBs that allows you to flex and move them during installation. These PCBs are made up of materials that can flex such as plastics.

You can find these Aluminum PCBs in single, double or even multilayer layout. The flexibility of these PCBs gives you a wide range of applications.

Flexible Aluminum PCB

By using flexible aluminum FCBs, you will experience several advantages including restoring bulky wiring in a superior gear.

b)Hybrid Aluminum PCBs

Perhaps the typical application of this kind of PCBs is in the RF applications. This is because they offer a higher thermal performance especially when you use them in an FR4 standard product.

Hybrid aluminum PCB entails processing a non- thermal material separately and applying it to the thermal material that has an aluminum base.

Hybrid aluminum PCB

Bonding in this manner provides rigidity to the aluminum PCB and also helps in heat dissipation. You have an advantage by bonding a thermal material with a non- thermal material.

This is because it has a great thermal conductance and also cost less regarding production.

You won’t need any heat sink or assembly when producing hybrid aluminum PCB.

c)Multilayer Aluminum PCBs

Common areas where you can find the application of multilayer aluminum PCBs include power supply products.

Just as the name suggests, these types of PCBs consist of numerous layers of dielectrics that are thermally conductive.

Multi layer aluminum PCB – Photo courtesy: JAAPSON

Multilayer aluminum PCBs are essential especially when you link them with more than one layer of circuitry.

You burry these circuitry dielectrics which are thermally conductive between the layers using a blind path. This paths also acts as a thermal or signal path.

Elaborate designs of multilayer aluminum PCBs are essential when you want to offer solutions for applications that have heat dissipation

d)Aluminum Nitride Ceramic PCB Board

The ability of this kind aluminum nitride of having a high thermal conductivity makes it one of the widely used ceramic substrate material.

Aluminum nitride PCB

When you combine that with a high dielectric strength together with a low expansion, you produce a unique PCB.

You can apply this PCB in the production of high-power LEDs, sensor, ICs, and other components. There are many advantages that you have with an aluminum nitride ceramic PCB board including:

Strong dielectric, high operating temperature, low expansion coefficient and a smaller package size due to integration. Depending on the application you are using and the design you want, you can either use copper or silver to print the circuit.

Again, you can have a single- or double-layer aluminum nitride ceramic board.

e)High Conductivity Aluminum PCB

You can use high conductivity aluminum PCB in the manufacture o equipment that requires high power input. The characteristics of the aluminum enable it to fit its usage in these applications perfectly.

High conductivity aluminum PCB

You can either find these kinds of aluminum either in single or double layers depending on the usage.

Aluminum PCB Production Process

Perhaps one of the main areas of concern has to be the production process of the aluminum. Understanding this process can give you the basics of an aluminum PCB.

That’s what I am going to take you through in this section.

Keep reading:

The first step will involve you preparing cavities in a sheet where you will place the components of the circuit. You can coat the aluminum using an insulating material to make it nonconductive.

There are different ways you can prepare cavities in the sheet. Some of these methods include chemical machining, laser cutting, punching, and mechanical machining.

You can also emboss or cast the sheet with cavities if you want. While forming the holes, remember they need to be the same depth as the height of the component that you will place into them.

These ensure that when you place the component into the cavity, the lead’s termination will always flush along the surface while the edge faces up. Another way is by using a bare die.

In this method, you need to ensure that the IC component that you will be using are adequately packed. The advantage of using packed IC components is because you can quickly test them.

Also, their lead pattern and physical outlines are standardized. This simplifies the design process more comfortable, especially when using a single lead pitch for all components.

Lastly, the base metal for all packed component is usually copper.  Place and fix all the elements on the aluminum carrier place.

You can do this on either one or both sides of the plate. Once you complete, apply layers of insulation on either one or both sides of the metal sheet that covers the components.

Here, you can process the board as a standard rigid printed circuit that has a high-density layer that built on either one or both sides. You can drill holes to access the termination of components using a laser to form the circuits.

However, you may have to fill the holes if they expose the metals.  In cases where you are using untreated aluminum, you can seal the edges.

Fabricated Aluminum PCB

Sealing the edges minimizes the risk of contaminating the aluminum during the processing chemistries you will follow during manufacturing.

Overall, there are fewer steps that you will use in the manufacture of aluminum PCBs as compared to traditionally printed circuits.

Aluminum PCBs Storage

If there is one area that you need to take care of when it comes to an aluminum PCB is the storage aspect.

Poor storage may lead to distortion or making the aluminum PCB to become faulty.

To minimize that, here is a look at the environment that you need to avoid when storing your aluminum PCB.

Aluminum PCB

To start with, in areas where there is moisture, you can prevent your aluminum from getting moisturized by using dehumidifiers. Moisture is terrible when it comes into contact with your aluminum PCB.

You can also use a moisture barrier bag which prevents moisture from reaching the PCB.

In as much as you would want to avoid moisture on your PCB, you also need to avoid the heat. If you have a warehouse for the storage of your PCB, it should be well ventilated.

You can also have a functioning air conditioner which will help in maintaining the temperature of your PCB. The effect of too much heat can cause warping on your PCB materials

Cold is another environment that is not conducive to your PCB. When the internal elements get too cold, there is a risk of having briefs.

Troubleshooting such issues can be impossible when they occur impossible. So, the natural way of preventing the occurrence of such problems is to avoid cold environment.

Humidity exposes your aluminum PCB to mildew and mound which causes damage to the PCB. You can avoid this by sealing your PCB correctly with an airtight material.

You also need to keep your aluminum PCB away from animals and insects. You see, animals such as rodents can do a lot of harm to your PCB such as urinating.

Urine, in particular, contains ammonia which can cause the elements of your PCB to soften leading to malfunction.

You can also store your aluminum PCB properly by preventing dust from getting in contact with it. Accumulation of dust by your aluminum PCB leads to temperature reduction potency leading to slow performance.

Lastly, you need to avoid static electricity on your aluminum PCB. Electrically charged particles have a potential of slowing down the performance of your PCB.

Aluminum PCB Assembly Process

There are several processes of assembling an aluminum PCB that you need to identify yourself with if you are considering joining one.

For you to understand these processes, I have broken down into simple steps that you can easily follow.

PCB Assembly

I.Choose an Aluminum PCB Design

The first step in the assembling process is to choose which design you want four your aluminum PCB. There are different types of designs that you can choose depending on the purpose and your preference.

They include the following:

· Single Side Aluminum PCB

A single side aluminum PCB refers to a PCB that has a copper coated film that you can only access from one side.

You can bond the conductive layer between insulating covers or leave them exposed on one side.

· Double Side Aluminum PCB

A double-sided aluminum PCB consists of a dual layer conductor that is made using a layer of preservative on both sides.

You can fix the copper board on both sides to give you access from either side. This, may include having plated through paths or holes.

· Multiple Layer Aluminum PCB

As the name suggests, this type of an aluminum PCB has several one sides coated copper boards which you press together using pressure sensitive adhesive. By doing so, you form a multi-layer structure that is highly pliable.

II.Make Aluminum PCB Garber File

Once you have chosen an aluminum PCB design, the next step will include you making an aluminum PCB Garber file.

A Gerber file is what will describe the image on your PCB including the copper layers and the solder masks.

You can choose from one of the two main formats for your aluminum FCB. That is, the extended Gerber which allows you to add meta information to the FCB.

You can also choose the standard Gerber.

III.Be clear on Aluminum PCB Specifications

Once you have your aluminum PCB Garber file, you will have to go through the specification that you want for your FCB. Some of the spec you can go through include the following:

IV.PCB Board Thickness

You are free to pick any thickness that you may want depending on your purpose. However, the common thickness is between 30 millimeters to 125 millimeters.

· Minimum spacing/track

When we talk about the minimum spacing, we primarily refer to the minimum distance between lines, paths or layers on the PCB board. The choice of this will depend on the size of the copper you are using to design your PCB.

The spacing can range between 2 millimeters for lighter copper to 3 millimeters for heavy copper.

· The minimum size of holes

The size of the holes that you will drill on the PCB will depend on several factors. These include the purpose of the PCB and the kind of surface finishing you will apply.

·Surface finish

Surface finishing refers the coat that you apply between the components and the aluminum board. The reason as to why you apply surface finishing is to protect the exposed copper circuitry and also to ensure solderability.

There are factors you need to consider before selecting a surface finish for your aluminum PCB board. Some of them include Lead vs. Lead-free, component Type, cost, reworkability, productivity, and environment.

You can choose of the following surface finish for your aluminum PCB. That is, Hot Air Surface Levelling (HASL), Organic Protective Film (OSP), Immersion Silver, Immersion Gold and Immersion Tin.

· Aluminum PCB material

Aluminum is the best material that you can use for your PCB. The reason for this is because of the strength and ability to withstand high temperature.

 V.Aluminum PCB Production

Once you have all the components and specifications that you need to produce an aluminum PCB board, you now go ahead and produce.

As we have discussed above, you need to adhere to the guidelines while producing an aluminum PCB that meets your standards.

VI.Parts Sourcing (for Parts not in Stock)

When it comes to sourcing for parts and components of an aluminum PCB, always ensure that you source them from the original manufacturer.

By doing this, you can minimize the chances of your elements not fitting or getting substandard components.

VII.Aluminum PCB Quality Control Process

You need to ensure that the aluminum PCB that you produce meets the standards set for quality assurance.

A quick way of doing this is by ensuring you follow all the laid down procedures when assembling and producing them.

Standard Aluminum PCB Metal Base Material Types

Getting the right aluminum PCB metal base material for your PCB can save you in ensuring you comply with the regulations in place.

Let’s go through the standard aluminum PCB metal base material types that are available.

Different layers of Aluminum PCB – Source: LT CIRCIUT

The first kind is having an aluminum base for your PCB. This type of metal base consists of three part that is the insulating layer, copper layer, and the metal layer.

You can check the description of these parts in this guide.

The other kind of material is the copper core. You can have different types of the copper core that you can for your PCB.

The last material you can have for your PCB is iron which comes on various forms depending on the purpose of your PCB.

Aluminum PCB vs. FR4

One of the common questions I get is comparing an aluminum PCB and an FR4. Though they both serve the same purpose, they are different.

In this section, I compare an aluminum PCB and an FR4 taking into consideration the differences and similarities that they have.

6 Layer FR4 PCB – Source: Twisted Traces

But before we start, we need to define what FR4 is now that we know what an aluminum PCB is.

FR4 stands for Flame Retardant. The application of this term is mostly in sheets that have reinforced Fiberglass which you can use in the printed circuit board.

When you compare regarding price, the aluminum PCB is a bit expensive than the FR4. Also, regarding performance, aluminum PCB has a higher performance than an FR4.

On the thermal conductivity, the thermal conductivity of an aluminum PCB is higher than FR4. As such, they have a standard application in the LED lighting industry.

The thermal conductivity dielectric element of an aluminum PCB is the thermal bridge which joins the metal plate and the components. This bridge automatically transfers heat through the core to the heat sink.

You can assemble aluminum PCB using an aluminum backing, a standard circuit layer, and a high thermally conductive dielectric layer.

The composition of the circulation layer consists of a thin PCB bonding on the aluminum backing.

On the other hand, FR4 uses mechanical practices including drilling, routing, v-scoring, countersink counterbore. This means that you will have to source for another heat sink which will conduct heat from the circuit layer.

Typically, the substrate of an aluminum PCB is one-sided which is in contrast with an FR4 that can either be double or single sided.

Even though the FR4 has a broader application than the aluminum PCB, most engineers use aluminum PCB in the LED industry.

Common Applications of Aluminum PCB

At this stage you might be asking which applications can you use aluminum PCB. Well, let me break down the common applications o aluminum PCB in this section for you.

Take a look.

 Aluminum PCB for high power LED

1.Mounting high power LED

Aluminum PCB has a standard application in mounting high power LED due to their ability to quickly dissipate heat that is generated by 1W and 3W power devices.

The reason for this is due to the aluminum which when bonded acts like a heat sink which dissipates heat efficiently from FR4 component of the PCB.

2.High-temperature circuits

The advantage of an aluminum PCB is that it can withstand high temperature and it conducts heat away from the components. This character makes it ideal if you want to make a high-temperature circuit.

3.Power equipment – power modules

One of the typical applications of aluminum PCB is in the production of power equipment especially power nodules. The fact that it can withstand high temperature and transfers heat faster makes it an ideal component in power modules.

4.Automotive systems

You can find the applications of aluminum PCB in a variety of automobile systems. For instance, you can use aluminum PCB together with high-frequency signals such as millimeter- wave in sensor applications.

Some of the areas you can find the use of aluminum PCB in the automotive systems include Navigation systems, control systems, audio, and video systems.

The application of this aluminum PCB needs to adhere to a particular design as per the working environment they are.

5.RF Industries

In RF industries, aluminum PCBs have wide usage. You can use them in making circuits for radio signals.

They are ideal due to the high amount of energy needed to transmit the radio frequency. Some of the products that make use of an aluminum PCB include amplifiers, digital radio, transmission lines, and antennas.

6.Computer industry

Nowadays, you will find the application of aluminum PCBs on various aspects of the computer industry. You are likely to see these PCBs on computer and laptop displays and indicators.

Since computer technology is mostly heat sensitive, these PCBs are ideal for use because they can tolerate high temperature.

FAQs on Aluminum PCBs

FAQs are common when giving important information like this. I know you too have questions that you need clarification.

But before we get to your questions, have a look at these questions asked by our clients and the responses we have given.

1.Is it possible for me to solder aluminum trace PCBs?

Yes, you can solder aluminum trace PCBs either for application of the standard or fine pitch aluminum trace PCB.

2. Do Aluminum PCB board and aluminum trace circuit board mean the same thing?

1. Aluminum trace circuit board electrically connects components using a fine aluminum circuitry line. On the other hand, the aluminum PCB board consists of an aluminum plate which helps in transferring heat away from critical elements.

3. What is the number of PCB that I can nest on a standard panel?

Given that the outside dimensions of a standard panel averagely are 12.4’× 16.5”, you can nest as many PCBs as you want. If you have a rectangular PCB which is greater than 1.0” lengthwise, you can give a gap of 100millimeters between the boards.

For other types, you can allow a 300-millimeter gap.

4.What does aspect ratio mean?

Aspect ratio refers to the between the length of a hole and its diameter. If for instance, you find your manufacturer has stated aspect ratio as 8:1, it implies that the diameter of the hole is 0.20mm in a PCB that is 1.60mm thick.

5.How can I define copper wrap?

Copper warping refers to the continuous depositing of plated copper inside the barrel of the hole reaching up to the PCB’s surface.

6.Explain to me what is a buried via hole.

A buried via hole refers to a hole that between inner layers of a PC. You can mechanically drill these holes.

7.What is a blind via hole?

A blind via hole refers to the hole that cuts across the outer layer to the inner layer excluding the entire PCB. There are two ways you can drill these holes on the PCB board. That is either mechanically or using laser technology.

8.What is the definition of CAF?

CAF is an abbreviation for Conductive Anodic Filament. This implies that there is a reaction between the copper cathode and anode which is electrochemical resulting in an internal material short circuit.

In case you didn’t get a clarification to your question based on the above feedback, feel free t get in touch with us. We will be glad to answer any question that you have on aluminum PCB.

9.How thick is the dielectric supposed to be in aluminum PCBs?

The ideal thickness for a single layer aluminum PCB needs to be 0.0003”. However, it can be as thin or thick as you want.

10.Is it possible to have score lines and break- away on my aluminum base PCBs?

Yes, it is possible to have them just like any FR4 product. However, unlike FR4, the holes of the aluminum PCB will be large to allow for drilling.

Conclusion

By now you should be in a position to understand every detail that involves an aluminum PCB including the production process. As you can see, aluminum PCB plays a major role in many electronics.

As such, if you are in the production industry or you want to manufacture your PCB, then you will need quality products and components.

Lastly, understanding these basics can help you when it comes to troubleshooting your device.