Aluminum PCB Board Manufacturing Service
MCPCB | Single-sided Aluminum PCB | Double-sided Aluminum PCB | Multilayer Aluminum PCB | LED Aluminum Base PCB | COB Aluminum PCB | High Thermal Conductivity Aluminum PCB | Ultra-long Aluminum Substrate PCB
Metal core PCBs have gotten massive attention due to their heat dissipation features and durability. Aluminum PCB is the most prevalent metal core PCB nowadays. It is used for many applications, but the most common form is in the LED circuit and other high-power circuits. Today, we are going to discuss Aluminum PCBs in detail.
What is Aluminum PCB Circuit Board ?
Aluminum Printed Circuit Board, Recognized Best Solutions for High Power and High Thermal Conductivity
Aluminum PCB is just like a common PCB; the only difference is in the base material. The base material in the aluminum PCBs is aluminum, which has more excellent heat dissipation capability, durability, and dimension stability.
Normal PCBs cannot handle high temperatures, and due to high heat-dissipating components, they bend quickly. Therefore, it’s necessary to use aluminum PCB where high temperature or heat dissipation is expected.
Aluminum Based PCBs are a unique metal-based copper clad laminate. These types of Printed Circuit Boards have good thermal conductivity, electrical insulation, and excellent machining performance.
According to the different design structures and application scenarios of aluminum PCB, there are mainly single-sided aluminum PCB, double-sided aluminm PCB, Flexible aluminum PCB, mixed aluminum PCB, multi-layer aluminum PCB, through-hole aluminum PCB, and so on.
As a printed circuit board Manufacturer in China, JingHongYi PCB has rich experience in manufacturing aluminum PCB boards. It provides customers with high-quality aluminum substrate Manufacturing and one-stop aluminum PCB turnkey assembly services, prompt delivery on time, and competitive prices.
Layers of Aluminum PCB
Aluminum PCB consists of three layers, which are the copper layer, dielectric layer, and aluminum base layer. There can be a fourth layer, which is known as the aluminum base membrane layer. The membrane layer protects the aluminum from scraping, scratches, and unwanted etching.
- Copper Layer: At the top of the aluminum PCB, there is a copper layer, which creates the circuit. The layer is common in all types of PCBs, including FR-4. It offers the electrical connection and conductivity of current among the components.
- Dielectric Layer: Aluminum can also conduct electricity; therefore, a dielectric material is used between the copper layer and the aluminum layer. This layer can be of different materials depending on the temperature range. Although this layer is electrically insulated, it can conduct heat efficiently. It has excellent thermal conductivity to hold the heat from the components to the aluminum layer.
- Aluminum Base Layer: This is the most crucial layer of the PCB. It provides thermal conductivity, durability, and strength to the PCB. The layer is made of aluminum substrate. The substrate can be of different types, such as Aluminum 505, Aluminum 6061, etc. You can choose the perfect aluminum substrate according to your requirements.
- Aluminum Base Membrane Layer: The aluminum base film is selective. It has a protective effect by protecting the aluminum surface from scratches and unnecessary corrosion. It has two types, namely less than 120 degrees or about 250 degrees (high-temperature resistance)
Advantages of Aluminium PCB
There are various advantages of aluminum PCBs, some of them are,
Aluminum PCBs are much cheaper than other metal core PCBs. They have higher thermal conductivity as compared to commonly used FR-4 PCBs. In contrast, if you use copper or stainless-steel PCBs, then it will be higher in cost. Thus, you can save money by getting the cheapest type of metal core PCBs. The reason behind the low cost is that aluminum is easily available and has a low cost as compared to other metals used for MCPCBs.
Aluminum is used because of its high thermal conductivity. It can easily dissipate the heat generated by the components on board. It can withstand high temperatures. The dielectric conducts the heat from the components and helps in dissipating the heat. Thus, it protects the components working on the board and can increase life. Moreover, there is no need to use heat sinks. If your PCB needs many heat sinks, then a better option could be aluminum PCB. It could save you money.
The problem with the FR-4 board is that they cannot retain their shape at high temperatures. The board starts to bend, and it cannot retain its dimensions. On the other hand, the aluminum board can retain the shape under temperature and pressure stress.
Aluminum is environmentally friendly, and there is no harm in using it. It’s according to international standards. It’s 100% non-toxic. It can also be recycled.
Aluminum PCBs are durable. They can withstand wear and tear and extreme temperatures. Aluminum is much stronger than a common FR-4 substrate, and it has a high capability of preventing accidental damages. It can handle more pressure and stress. There is a very low probability of the breakage of the board.
Aluminum has a very lightweight as compared to copper and stainless steel. So, the final product can have less weight.
Disadvantages of Aluminum PCBs
- Indeed, there are many benefits of Aluminum PCBs, but there are some disadvantages. The disadvantages cannot beat the advantages, but it’s important to discuss them.
- The first disadvantage of the PCB is that its cost is more than FR-4 PCBs. The reason is simple, which is the use of aluminum. If your project can work with normal PCBs, then you should not invest money on aluminum PCBs. It will save you money. But if the project needs a high thermal conductivity, then there is no choice, and aluminum is the next feasible option. The other reason for the high cost is the manufacturing process. The process is a bit more complicated than manufacturing normal PCBs.
- The next disadvantage is the limitation of the layers. You cannot have as many layers as you want for an aluminum PCB. Usually, there is only one layer. But there can be two layers as well. You cannot expect more than two layers in aluminum PCBs.
Aluminum Base PCB Performance
- Better heat dissipation and conductivity: Compared with ordinary FR4 PCB, aluminum PCB has excellent heat dissipation performance. For example, Fr4 PCB with a thickness of 1.5mm will have a thermal resistance of 20-22 degrees per watt, while aluminum PCB with a depth of 1.5mm will have a thermal resistance of 1-2 degrees per watt.
- There is no serious problem of thermal expansion or contraction: each substance has its coefficient of thermal expansion. The CTE of aluminum (22ppm/C) and copper(18ppm/C)is quite close. Since aluminum PCBs work well in terms of Thermal dissipation, they do not have the severe expansion or contraction issues. They work excellently and are durable and reliable.
- Dimensional Stability: aluminum PCBs show dimensional stability and stable size. For example, when they are heated from 30-140 degrees, their size only had a change by 2.5%-3.0%.
- Others: Aluminum PCBs can be used in power device surface mount technology. They are valid for use in circuit design because of their performance in terms of thermal expansion of circuit design. They help to prolong product shelf life and product power density. They are also extremely reliable. They can help to shrink the overall volume of the product and is also a cheaper option. They show electromagnetic shielding and high dielectric strength.
Aluminum PCB Circuit Board Applications
- The most common use of aluminum PCBs is where high heat dissipation is required. Aluminum can dissipate the heat and omit the need for heat sinks. It can be cost-effective and a reliable option to manage the heat of the board. The heat generated by different components can be quickly dissipated with the help of the dielectric material. Thus, the parts never experience high thermal stress; it increases the life of the elements.
- Nowadays, aluminum PCBs are mostly used for LEDs(LED PCB). It’s primarily used in LED lights, lamps, tube lights, car lights, etc. LEDs dissipate a lot of heat, and they cannot work on common PCBs; thus, they need a metal core PCB.
- Other than LEDs, aluminum PCBs are used in the power supply. They are used to make DC/DC and DC/AC converters. The other applications are in automotive, telecommunications, computers, power modules, and many other sectors.
Electronic regulator, ignition, power supply controller, etc.
Switching regulator, DC / AC converter, SW regulator, etc.
Inverter, solid-state relays, rectifier bridges.
CPU board, floppy disk drive, power supply devices, etc.
Motor drive, etc.
Input, output amplifier, balanced amplifier, audio amplifier, pre-amplifier, power amplifier.
High-frequency amplifier, filtering appliances, the transmitter circuit
As the advocated promotion of energy-saving lamps, aluminum PCB used in LED lights also begin large-scale applications.
Types of PCB Aluminum Board
There are several types of aluminum PCBs which are used in many applications based on their construction and design. However, the primary purpose of all the aluminum PCBs is almost the same; providing heat dissipation solutions for the applications involving high temperatures.
The following are the main types of aluminum PCB.
Flexible Aluminum PCB Board
Firstly, Flexible aluminum PCB is a new flexible dielectric developed in the development of aluminum products. It is also a kind of flexible circuit board. Because of the combination of polyimide resin and ceramic filter, it has high flexibility, thermal efficiency, and excellent electrical insulation. When used in aluminum PCB products, the expensive cables and connectors no longer need to be used.
Flexible circuit boards have unparalleled flexibility, so flexible aluminum PCB can be arbitrarily folded, twisted, or formed in any other desired form.
However, it should be noted that once a specific shape is created, it can no longer be changed like other conventional flexible circuit boards or deform.
Classification of Aluminum PCB
Aluminum PCBs are mainly divided into three categories.
- Universal Aluminum PCB: the dielectric layer used here is made up of epoxy glass fiber pre-preg.
- High Thermal-Conductive Aluminum PCB: the dielectric layer is made up of epoxy resin. The resin used must have high thermal conductivity.
- High-frequency Aluminum PCB: the dielectric layer is composed of polyolefin or polyimide resin glass fiber pre-preg.
Hybrid Aluminum PCB Board
In hybrid aluminum construction, nonthermal material is processed and refined separately before it is applied to the thermal materials with aluminum base.
The most common practice is developing a two-layer or four-layer structure which comprises of FR4 material.
A nonthermal material that is bonded with thermal material and the aluminum base provides rigidity and helps in the dissipation of heat.
This nonthermal bonding is preferred over using all thermal materials because it features less cost and encompasses efficient thermal conductance over regular FR4 products.
No heat sinks or assembly steps are required for the development of this product.
Through-hole components can be easily adjusted using component windows on the aluminum base.
This helps in passing the cables and connectors through the substrate. Also, the seal created by solder fillet eliminates the need for costly adapters
Multilayer Aluminum PCB Board
Multilayer Aluminum PCBs are ubiquitous in power supply products and come with multiple layers of thermally conductive dielectrics.
These materials are beneficial when they are combined with one or more layers of circuitry in which thermally conductive dielectric is buried between the sheets with the help of blind vias, which also act as a signal or thermal vias.
Single-layer construction of these designs is not very active; however, when they come with more elaborate designs, they provide an ideal solution for many applications involving heat dissipation.
Through-Hole Aluminum PCB
When it comes to most complex constructions, a single layer of aluminum is back-filled and pre-drilled with before applying lamination, forming a Core of a multilayer construction.
Thermal bonding materials are then used for laminating the thermal materials on both sides of the aluminum.
Once lamination is done, drilling is applied to the assembly.
To maintain proper electrical insulation, the plated through holes created as the result of drilling must pass through aluminum clearances.
Manufacturing Difficulties of Aluminum PCB Board
The manufacturing process for nearly all aluminum PCBs is essentially the same. Here we will discuss the major manufacturing processes, the difficulties and their solutions.
- Copper Etching: the copper foil used in Aluminum PCBs is comparatively thicker. If the copper foil is over 3oz, however, the etching requires width compensation. If it is not according to the demand of the design, the trace width will be out of tolerance after print. Therefore the trace width compensation should be designed accurately. The etching factors need to be controlled during the manufacturing process.
- Solder Mask Printing: due to the thick copper foil, there is a difficulty in solder mask printing of aluminum PCB. This is because if the trace copper is too thick, then the image etched will have a massive difference between trace surface and baseboard, and solder mask printing will be difficult. Therefore, the two-time solder mask printing is used. The solder mask oil used should be of good quality, and in some cases, the resin filling is done first and then solder mask.
- Mechanical Manufacturing: the mechanical manufacturing process involves mechanical drilling, molding, and v-scoring, etc. which Is left on internal via. This tends to reduce electrical strength. Therefore, the electric milling and professional milling cutter should be utilized for low-volume Manufacturing of products. The drilling parameters should be adjusted to prevent burr from generating. This will help your mechanical production.
Learn more about PCB Fabrication Process
Essential Requirements When Selecting an Aluminum PCB Manufacturer
For the most part, all PCB manufacturing follows the same production process regardless of where they are made. The only actual differences in suppliers are the level of automation in their process, the newest technology and equipment, and having specific equipment designed to focus on certain types of end products.
For aluminum PCBs, there are several vital items that a PCB manufacturer needs to consider if they are going to be able to produce aluminum PCBs in any quantity, including effectively.
- Dedicated Imaging Equipment
Many of our aluminum backed PCBs go into LED applications that are much longer than the standard 18″ x 24″ or 20″ x 24″ production panels used in traditional PCB manufacturing. To be able to register and economically produce these parts accurately, a manufacturer must have either a custom piece of 60″ full UV light imaging equipment or a setup capable of screen printing (at one time) an image and then UV curing through an oven.
The old manufacturing process of screen printing half the image and then trying to hand register the first image while screen print the second half is much less effective.
- Specialized Scoring Equipment
The more common equipment that can V score through traditional FR-4 materials is not suited to manage aluminum PCBs. To get the lowest cost possible, we need to get the best yield potential, which means we need to be able to place these parts as close as possible to each other on the production panel. Without V scoring, you must mechanically rout the elements out, which could result in up to 20% loss of your yield, subsequently increasing cost.
Our engineering team has many years of experience helping our customers’ design arrays that are the most cost-effective for them to depanelize.
- Higher Than 40-ton Punch Presses
For aluminum PCBs that are round or have unique features – (slots, large holes, cutouts, etc.) – you will want a manufacturer that can punch out these features. Trying to rout aluminum PCBs mechanically is a very costly way to get these features done in a production environment.
- In-Line Hi-Pot Test
A unique requirement of aluminum PCB is that customers want to know that the product they are getting has passed a hi-pot test. While most PCB manufacturers can do this, it is usually a separate process in a lab that is not located in electrical testing. JHYPCB‘s electrical test set up includes a hi-pot analysis, which dramatically reduces cost for the customer.
The following table presents some of our Aluminum Core materials:
|Items||Performance Index (Measured value)|
|Peeling strength (n/mm)||1.8|
|Insulation resistance (ω)||>1*10 g|
|Breakdown voltage (VDC)||>2 k|
|Soakable soldering (°C/m)||280°C / 260°C, 1 min, no bubble & delamination|
|Thermal conductivity (ω/m-k)||>0.8|
|Thermal resistance (°C/ω)||< 1.2|
|Dielectric constant (1mhz)||4|
|Dielectric loss angle (tangent)||0.03|
Check our Aluminum core PCB manufacturing capabilities:
|Quality Grade||Standard IPC 2|
|Number of Layers||1- 24 layers|
|Order Quantity||1pc – 10000+pcs|
|Build Time||2days – 5weeks|
|Material||Aluminum core (Domestic 1060), Copper core, FR4 covering|
|Board Size||Min 6*6mm | Max 610*610mm|
|Board Thickness||0.8mm – 5.0mm|
|Copper Weight (Finished)||0.5oz – 10.0oz|
|Solder Mask Sides||As per the file|
|Solder Mask Color||Green, White, Blue, Black, Red, Yellow|
|Silkscreen Sides||As per the file|
|Silkscreen Color||White, Black, Yellow|
|Surface Finish||HASL – Hot Air Solder Leveling|
|Lead Free HASL – RoHS|
|ENIG – Electroless Nickle/Immersion Gold – RoHS|
|Min Annular Ring||4mil|
|Min Drilling Hole Diameter||6mil|
|Other Techniques||Countersink holes|
Design Guidelines for Aluminum Core PCB Circuit Board (include MCPCB)
The task of the aluminum core circuit board is to dissipate the heat generated by power components. Therefore, we recommend installing pure power components in this part of the circuit. The control unit shall be installed on a separate standard PCB.
The most important criterion for this is the minimum drilling distance required for such PCBs.
Drilling distances and diameters
In the case of double-sided aluminum-core circuits, the aluminum core must be insulated against through plating. This is done using an excess of resin when press-molding the aluminum core with prepregs and copper or by plugging. To this end, the aluminum core must be pre-drilled.
The smallest drilling diameter in the aluminum core is 1,0 mm, the lowest final diameter in the PCB is 0,3 mm. So that the drills are not damaged in these close-set drill holes, a minimum spacing of 1,2 mm is required. This is generally the knock-out criteria for a densely-packed control unit.
Variants of aluminum core circuits
- Single-sided PCBs on aluminum carriers
A copper foil is laminated onto an aluminum carrier using a prepreg.
Usually, this variant only has drill holes for fastenings.
- Multilayer PCBs with aluminum core
Copper foils are laminated onto both sides of an aluminum core using prepreg. The PCB can be through-plated. This means that it is also possible to produce multilayers with a 0,5 mm aluminum core.
- PCBs on metal heat-conducting sheets
Completed PCBs are press-molded to an aluminum carrier using a prepreg. Benefit: Multilayers can also be used (only single-sided SMD). Partial aluminum carriers are possible—disadvantage: Poor heat dissipation, as the heat has to be dissipated through the entire PCB.
One further possibility is a Rigid- Flex PCB structure, where the aluminum carrier works as the rigid area of the PCB. This means that it is also possible, for example, to connect a control unit as a plug connector over the exposed flex area.