Heavy copper PCB

Heavy copper PCB

Nowadays, PCBs are becoming an essential part of almost every electrical product, equipment, or appliance. They are necessary because they create a perfect and reliable path for the flow of current. There are many different types of PCBs available in the market, and all of them are used for multiple purposes. It is impossible for one type of PCB cannot fulfill all requirements. Some products require a heavy current flow in the circuit for their working. This is a specific case in which a standard PCB cannot be used. To pass-heavy current from the circuit, it is a necessary condition that the copper/conduction layer must have a thicker copper layer, so that’s why here the heavy copper plating makes PCB plays its role.

What is a Heavy Copper PCB Board?

A heavy copper PCB is named because it contains a heavy amount of copper in its inner and outer layers. The heavy copper circuit layer on a heavy copper PCB is capable of conducting a high amount of current through it. In our industry, any PCB with a copper thickness from 4oz/ft2 to 20oz/ft2 is called Heavy Copper PCB. Due to the high thickness of copper, the conducting capability of the traces increase, which is why heavy copper PCBs are used for applications where excessive current flows from the circuit.

Why choose Heavy copper PCBs?

In simple words, we can say that heavy copper PCBs are essential for applications where a high current flow is required in the circuit. Without heavy copper traces or lamination, a standard PCB cannot bear the flow of heavy current. Whenever current flows through a circuit, the electronic components use electrical energy. There are a large number of heat losses that are commonly known as I2R losses. Common PCBs cannot take away the heat from the board as heavy copper PCBs do, so the components and the board will become overheated, and due to the failure of components, they stop working on the board.

Thus, a standard PCB cannot deal with the flow of heavy current. The Power Dissipated can be given as I2R. According to the relation, the magnitude of current highly affects the generated heat. Heat increases drastically, and it is visible from the square foot power of the current. We cannot reduce current because of the load, but we still have another factor, which is resistance. Heavy copper thicknesses traces have a low value of resistance compared to thin traces. The most important feature of heavy copper PCBs is that they can easily flow heavy currents through them and help in taking the heat away from the board. There can be heat sinks, and the traces transfer heat to them.

How is Heavy Copper PCB Fabricated?

In the fabrication of heavy copper PCB, plating or etching are the common methods that are used. The main aim is to add copper thickness to sidewalls and plated holes. The methods used in fabricating heavy copper PCB are not easy. Heavy copper PCB board needs special etching and plating methods for the extra thickness of copper. Using the normal etching techniques for the fabrication of heavy copper PCBs is not ideal at all. Normal etching methods produce over-etched margins and edge lines that are drastically uneven.

Heavy copper PCB producers now use advanced etching and plating methods to achieve straight edges. During the copper PCB manufacturing process, heavy copper PCBs are electroplated. This will help in making thicker walls of PTH on PCB. With this technique, the layer count shrinks and the impedance distribution reduces. When PCBs are exposed to several cycles during the manufacturing process, the plated holes can become weak. The fabrication of heavy copper PCBs has many limitations which include;

  • The etching process increases the cost of the heavy copper PCB.
  • Heavy copper traces make the surface drastically uneven.
  • The etching process requires a huge amount of heavy copper to be removed from the surface.
  • It is hard to fabricate completely fine lines and copper thickness on the circuit board.

Methods for Fabricating Heavy PCBs:

Many manufacturers use different techniques for fabricating heavy copper PCBs. Let us explain to them as follows:

Embedded heavy copper method:

In this method of fabrication heavy copper PCB by using a flat surface. Here the heavy copper is added to the prepreg resins. The thickness of the resin determines the thickness of the copper. The fabricator positions the laminate into a plating tank for electroplating.

Blue bar method:

The blue bar method is done by adding thick copper bars into circuit boards. This method saves a large amount of material and reduces the weight of the PCB. During the process of fabrication, the resin flows into space within the copper traces, this helps to achieve an even top surface. Generally, all the fabricators pay attention to the level of copper fill between inner layers when it comes to multilayer boards with heavy copper layers. Low levels of fill and low levels of resin can lead to resin hunger.

Difference between a Standard PCB and Thick Copper PCB:

Standard PCBs can also be produced with copper etching and plating processes. These PCBs are plated to add copper thickness to planes, traces, PTHs, and pads. The amount of copper used in the production of standard PCBs is generally 1oz. For the production of heavy copper PCB, the amount of copper used is greater than 3oz. For standard circuit boards, copper etching and plating techniques are usually used.

However, heavy copper PCBs are produced by differential etching and step platting. Standard PCBs perform lighter activities while heavy copper boards perform multiple and heavy duties. Standard PCBs conduct a low amount of current while heavy copper PCBs conduct a higher current. Thick copper PCBs are considered ideal for high-end applications due to their efficient thermal distribution over the board. Heavy copper PCBs have better mechanical strength than standard PCBs. Heavy copper circuit boards enhance the capability of the board in which they are used.

Some other features that make thick copper PCBs different from all other PCBs:

Copper weights:

This is the main distinguishing feature of heavy copper printed circuit boards. Copper weights are generally a concern to the weight of the copper used in a square foot area. This weight is measured in ounces. It shows the actual thickness of the copper layer.

Outer layers:

These are referred to as the finished copper layers of the board. Electronic components are placed to the external layers. The external layers begin with copper foil which is also coated with copper plating. This helps to increase the thickness of the board. The copper weight of the external layers is selected in the initial stages for standard designs. Heavy copper PCB manufacturers can easily change the weight and thickness of the copper that suits customers' requirements.

Inner layers:

For any standard project or product, the thickness of dielectric and mass of the copper is defined at the initial stages of designing. While the copper weight and thickness in these layers can be adjusted based on customers' needs and requirements.

Performance of Thick Copper PCB:

Thick copper PCB has the best elongation performance and is not limited by the processing temperature. It can be used in hot melt welding methods such as oxygen blowing at a high melting point and not brittle at low temperatures. Even in extremely corrosive atmospheric environments, heavy copper PCB forms a strong, non-toxic passivation protective layer.

Applications of Heavy Copper PCB:

Thick copper PCBs are used for multiple purposes, for example, in planar transformers, thermal propagation, high power dispersion, control converters, and so on. In PC, automotive, military, and mechanical control, interest in the overwhelming copper-plated sheets is growing rapidly.

A large number of copper printed circuit boards are also used:

1. Power supply, control converter

2. Appropriation of authority

3. Welding tools

4. Automobile industry

5. Solar board producers and much more.

Copper PCBs are more costly to deliver than standard PCBs. Hence, the more confused the structure, the more it will cost to deliver an overwhelming copper PCB. In simple words, the cost of the thick copper PCB for your project will increase if the project is complex. Moreover, there are several other applications of thick copper PCB for both industrial and domestic usage.

Why choose LT PCBA for Heavy Copper PCB?

AtLT PCBA you can get an instant quotation for heavy copper PCB service for your home or office. So, you don’t have to waste your time looking for services providers because you can easily reach us for any kind of estimation. LT PCBA has specialist people that deliver the best services for the best prices. Moreover, our team will also provide you with the estimated costs of your project and board surface. These estimations are based on several factors and you can compare our prices with other providers to see the difference PCB thermal management experts. We can help you create heavy copper PCBs according to your needs. We can deal with extreme copper PCB and handle small to medium volume orders. You can even order only one PCB of your choice. We also offer PCB prototype and turnkey assembly services with thicker plating. Your PCBs will be delivered to your doorstep without any delay. Get in touch with us for further details.


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