What is Heavy Copper PCB?
Heavy copper PCBs are boards that use up to 20 ounces of thick, heavy-duty copper. Manufacturers of heavy copper boards undertake special etching and plating techniques for fabricating these boards. This includes techniques like differential etching and step plating. In the industry, such boards are also known as thick or heavy copper PCBs, and their copper weights are typically in the range of 4 oz/ft2 to 20 oz/ft2.
Copper, being a good conductor of electricity, can handle high currents and high power circuits along with control circuits on the same board. Integrating control circuits and high-power circuits on the same board results in long-term cost-effectiveness and effective power distribution with low impedance.
Advantages of Heavy Copper PCBs
Heavy copper PCBs are beneficial for applications that must handle high currents and high power. The use of heavy copper in PCBs offers advantages like:
- Low resistance to high current flow
- Low voltage drop across traces
- Low power dissipation when high currents are flowing
- PCB temperature rise remains within limits
- Copper tracks act as a heat sinks for high-power components
- High current handling capability
- High temperature withstanding capability
- Higher mechanical strength
- Longer lifespan
- Better capability to withstand thermal strains
Rush PCB UK offers heavy copper PCBs with exotic materials also. The use of such materials not only enhances the mechanical characteristics of the board, but also improves its electrical efficiency, power delivery, and heat dissipation capabilities.
Heavy Copper PCB Manufacturing Considerations
Manufacturing standard PCBs, whether double or multi-layered, requires a combination of copper etching and plating process. Manufacturers start with a thin copper layer, etching them to remove unnecessary copper. Then they plate the remaining copper to add thickness to the pads, traces, planes, and plated-through holes. They laminate the circuit layers into a complete package. This requires an epoxy-based substrate, such as polyimide or FR4.
Manufacturing heavy copper PCBs require the same process, but with special techniques for etching and plating, such as differential etching and high-speed/step plating. Earlier, manufacturers used etching of thick copper clad laminate material. However, this caused trace sidewalls to be uneven and undercut, which led to unacceptable results. With advances in plating technology, manufacturers are able to form straight sidewalls with negligible undercuts using an advanced combination of etching and plating.
With plating techniques, manufacturers of heavy copper circuits can effectively increase the amount of copper thickness in the sidewalls of plated through holes. They can also mix heavy copper with standard features on a single board. This results in advantages like reduced layer count, smaller footprints, low impedance power distribution, and potential cost savings. Earlier manufacturers produced separate boards for control circuits and high-power circuits. With heavy copper plating, it is now possible to integrate low-power control circuits and high-power, high-current circuits on the same board. This results in a highly dense, but simple board structure.
Rush PCB UK manufactures heavy copper boards where heavy copper features connect seamlessly to standard circuits. We can place standard features along with heavy copper with minimal restriction. However, this requires a clear communication between the designer and fabricator for deciding on manufacturing tolerances and abilities prior to finalizing the design.