PCB bằng đồng nặng & PCB một mặt: Tìm hiểu mọi thứ về chúng2020-07-27
Introduction to Heavy Copper PCB & Single-Sided PCB
When you use heavy copper PCB & Single-sided PCB in PCB fabrication and design, you are able to achieve maximum reliability. After all, the growing trend of heavy copper Printed Circuit Boards is the new norm for several industries. The reason being, Heavy Copper PCBs offer a number of benefits including reliability, robustness, and efficiency.
Modern electronics can truly benefit from these amazing Printed Circuit Boards. In case, you are unfamiliar with this particular type of Printed Circuit Board, in this blog post, we will talk about them in detail.
Heavy Copper PCB & Single-Sided PCB
Heavy copper PCB is the modern Printed Board offering several benefits. Before, we get down to a detailed introduction of heavy copper PCB, lets us focus on the basics i.e. a Single-Sided PCB.
What is a Single-Sided Printed Circuit Board?
You should use Single layered Printed Circuit Boards for low-density designs. As they lack complexity and efficiency. With their one layer of conductive material, they have been around for a long time. It seems the first Single-sided Printed Circuit board came into existence in the 1950s.
Since then, they have effortlessly dominated the market and have become an integral part of all electronics. The great thing about these boards is that they are not only easy to design, but they are highly cost-effective and simple to the manufacturer.
Since they are cost-efficient, therefore, manufacturers prefer developing them in large numbers.
Manufacturing of Single-Sided Printed Circuit Board
Since it is a single-layer PCB, thus it contains only one layer of thermally conductive material. This material is also an electrically insulating dielectric. It has a lamination of copper, and finally an application of solder mask on top of everything.
Advantages of a Single-Sided PCB
Even though it is effective, it has a low probability in terms of errors when it comes to manufacturing.
They are cost-effective especially when you plan to manufacturer them in large volumes.
They are excellent for equipment that has a low intensity requirement.
Popular, easy to understand, and manufacturer.
Heavy Copper PCB: What You Need to Know
Even now, most commercially available Printed Circuit Boards are developed for low power applications. These Printed Boards have copper traces that are made using a copper that weighs between ½ oz/ft2 to 3 oz/ft2.
On the contrary, in the case of the heavy copper circuit, the copper weight increases drastically. Now, the manufacturer uses copper weighing somewhere between 4 to 20 oz/ft2. It is possible to use copper weight above 20 and up to 200 oz/ft2.
However, you would name them as the Extreme Copper Printed Circuit Boards.
Heavy Copper: Construction
Heavy Copper PCB construction offer the board a number of benefits. Below, we have listed some of those benefits.
- The boards have increase endurance when it comes to thermal strains.
- Enhances the current carrying capacity.
- Increase mechanical strength in the PTH holes as well as at the connector sites.
- The board is able to explore the full potential of the exotic material such as high temperature without causing any circuit failure.
- The Printed boards are small, as it is possible to incorporate the same layer of circuity using multiple copper weights.
- Heavy current is carried out through the board with the help of heavily copper plated vias. Thus, allow better heat dissipation process. The heat is effortlessly carried to the external heatsink.
- The heatsinks are direct plated onto the surface of the board with the help of 120-oz copper planes.
- There are high-power density planar transformers that are present on the Printed Circuit Board.
Construction of Heavy Copper PCB & Single-Sided PCB
Here is the brief construction process of Heavy Copper PCB & single-Sided PCB.
Manufacturers use the combination of copper plating and etching processes, regardless of the PCB type i.e. single-layered, double-layered or multi-layered. The thin sheets of copper foil are the circuit layers. They generally are not thicker than 2 oz/ft2.
It is possible to have a layer as thin as 0.5 oz/ft2. Manufacturers would etch these sheets to get rid of un-wanted copper. Next add copper thickness to the traces, planes, plated through holes and pads the sheets are plated.
They then laminate teh entire circuit so that it comes out as one complete package. For the lamination processes, the manufacturers use a number of different substrates. However, FR4 is the most common epoxy-based substrate. They sometimes even use polyimide as the substrate.
Heavy copper circuit boards have the same production process as other boards. They use specialized plating and etching techniques such as the differential etching, or high-step plating. Previously, for the formation of copper features, manufacturers used to etch thick copper-clad laminated board material.
However, this would cause unacceptable undercutting and uneven trace sidewalls. However, with technological advancement, manufacturers now use a combination of etching and plating for the formation of heavy copper features. Therefore, the boards now have negligible undercut and straight sidewalls.
Heavy Copper Plating
Due to the plating of heavy copper circuit boards, it is possible to increase copper thickness in vias sidewalls and plated holes. You mixing standard features with heavy copper has become a possibility on a single board. This is known as the PowerLink.
Some of the major advantages include smaller footprints, low impedance power distribution, and potential cost savings. Normally, manufacturers use separate boards for the production of the high current circuits along with other control circuits.
With heavy copper plating, it is now possible to integrate control circuits along with the high-current circuits to enjoy a simple, yet highly dense board structure. It is also possible to connect the heavy copper features to standard circuits.
Standard features and heavy copper are easily placeable on the board with minimal restriction, thus allowing the fabricator and designer to discuss manufacturing abilities along with tolerance before the final design.
Temperature Rise and Current Carrying Capacity
Copper circuit’s current-carrying ability greatly depends upon the amount of heat a project can withstand. After all, there is a connection between the current flow and the increase in the heat level. When the current flows in along trace, there is a power loss, this then leads to the localized heating.
For cooling, the traces use the conduction process along with the convection. The conduction is with the neighboring components and convection is into the environment. So, to calculate the right trace distance, you should estimate the heat that would rise due to applied current.
For a perfect situation, you need to reach an ideal situation. It means that the cooling rate should be equal to the heating rate. There is a formula that you can use in this instance.
IPC-2221A, External Track’s Current Capacity: I = .048* DT(.44) * (W * Th)(.725).
DT: Temperature Rise
W: Width of Trace mil
Th: Thickness of Trace mil
NOTE: Derate the internal traces by 50% for heating’s same degree.
Use the above IPC formula and you will be able to generate the current carrying capacity of number traces that have different cross-sectional areas, however, there is an increase of temperature by 20 degrees.
Circuit Board Survivability and Strength
Since engineers and developers are working hard to obtain maximum performance and value from their equipment, thus they are putting more and more pressure onto the circuits. Printed Circuit Boards are becoming highly complex and dense.
The need for using power efficiently, miniaturizing components, and meeting the high-current demands make thermal management imperative. Manufacturers need to control the losses in the form of heath. They need to generate electronics’ operations that would be able to dissipate heat in an effective manner.
The great thing about heavy copper circuit boards is that they are extremely good heat dissipators. They can reduce I2R losses significantly. The board is effective for carrying away the heat from important components, thus significantly reducing the failure rates.
Heat sinks are a great way to achieve heat dissipation. Therefore, the heavy copper Printed Circuit Boards have them employed onto the boards. The objective of these heatsinks is to dissipate the heat away from its source. To emit the heat, they would be using environment convection.
In general, the manufacturers use a thermally conductive adhesive in order to bind the heat sinks to the bare copper surface. Nonetheless, there is also a possibility of bolting or riveting. To create the heat sinks, you can use either aluminum or copper.
Heat Sinks Assembly Process
The assembly process of heat sinks is highly extensive and complicated. It consists of majorly 3 main steps, each step is not only costly but also extremely labor extensive. Manufacturers would have to put in a lot of effort, time, and energy to complete the process.
On the other hand, choosing the built-in sinks would yield better results in terms of price and time. After all, manufacturers create these sinks during the PCB manufacturing Process. There is no need for an extra assembly process.
Thanks to heavy copper circuit technology, you can have access to in-built heat sinks. You can have the thick copper heat sinks on the outer surface of the board. To connect the heat sinks to the head conducting vias, they need to be electroplated. Make sure that there is no interference that would obstruct the thermal conductivity process.
Additional Copper Plating
The additional copper plating in the heat vias, result in better, and enhance thermal conductivity. The reason being, it helps in reducing the board’s thermal resistance. Allowing the manufacturers to aim for the same degree of repeatability and accuracy innate in Printed Circuit Board Manufacturing.
In comparison to cylindrical wire conductors, the planar windings improve the current density. The reason being, they are basically fat traces that are conductively created onto the copper-clad laminate. Therefore, the PCB ensures a higher and efficient current carrying ability while reducing the impact of the skin.
With Planars, it is possible to achieve secondary-secondary and primary-secondary dielectric isolation onboard. This happens due because there is the same dielectric material that the manufacturer uses between Printed Circuit Board layers. Thus, guaranteeing complete sealing of all windings.
Moreover, it is possible to split the primary windings, thus allowing the second windings to stay in the middle of primaries. This would help achieve extremely low leakage inductance. With basic Printed Circuit Boards, it is possible to sandwich around fifty layers of windings – copper- while using a number of epoxy material. Every winding can have a thickness of 10 oz/ft2.
Importance of Using Heavy Copper in PCB Design
You might think that a heavy copper PCB & single-sided PCB can manage the same result, but you cannot be more wrong. Yes, single-sided PCBs are cost-efficient, easy to manufacture, and extremely simple. However, they do not have the power that a heavy copper PCB has.
It lacks in terms of functionality, density, and performance. Since modern electronics require more than just regular PCBs, therefore, manufacturers are turning towards heavy copper PCBs. Below, we have listed the reason why it is important to use heavy copper in PCBs design.
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Lượng đồng nhỏ
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Khả năng chịu nhiệt vượt trội
Copper being the top material when it comes to offering thermal resistance has become important for modern Printed Circuit Boards. Heavy copper PCB & Single-sided PCB both use copper to yield effective results. A high amount of copper would allow the product to withstand extreme conditions. Copper, no doubt, increase the plated through holes mechanical resistance.