Printed Circuit Board High Copper Weight

High-power PCB applications need more intensive heat management to cope with high currents and this is possible only through a heavy copper PCB. The copper thickness of traditional PCBs ranges between 1oz. and 3oz. whereas, the thickness of heavy copper goes from 4 oz to 10 oz.

There is also another category of a heavy copper PCB known as a super-copper PCB which is 20oz to 200oz per square foot. Such a PCB is suitable for applications that need a high amount of current and high-power thermal or heat management.

Heat dissipation in a large PCB becomes easier due to thick copper. High temperatures can damage a circuit board, affecting its function but the use of heavy copper can resolve it. Such technology helps manufacturers try different options like the external PCB layers can be combined with heavy copper on the internal surfaces or layers.

The strength of a board is easy to determine through the copper thickness, as well as its width, and purity. A printed circuit board is weak if copper is not pure or it’s too thin. But, you must choose the thickness and width of copper according to the application and board impedance.

Heavy Copper PCB Manufacturing

Heavy copper PCB goes through different levels during construction. It needs electroplating and etching processes just like a traditional PCB, however, the technology is different. The copper foil etching is done to remove extra copper. Then comes pads, planes, traces, as well as electroplating according to the design of the board. You have to make sure the undercuts and the sidewalls of the trace are compatible with the thick copper parameters. Whatever PC Board, you have to laminate the circuit layers through epoxy substrates.

Difficulties That Appear While Making Heavy Copper PCB

• As copper is heavy, etching involves much more copper removal than a traditional PCB. Eventually, the cost of etching also becomes high.
• It is hard to make thin traces in a heavy copper PCB. Whereas the vulnerability of thick traces to unevenness also increases.

Circuit Board Fabrication

Whatever technology or process you choose for PCB construction, you will have to face a common technical issue, such as bumpy copper or the copper thickness is uneven. You also have to adopt certain precautions during the manufacturing of a heavy copper PCB.

• PCB’s inner base material needs traces through etching. However, make sure to open the areas without copper in the same way for all layers of the inner base material. Moreover, the pad should be in an appropriate position. Also, the internal and external layers should be stacked together. Then comes the surface finish, electroplating, and PCB coating or finishing which must be very fine.
• The position of the annular ring should be adjacent to the main material’s open part. The pads should be similar in size, design, or shape. Some shapes in this case include the square, circle, oval, or diamond.
• All pads should be located at an equal distance. Moreover, the position of the lower and top pads should be similar.
• The copper burying technique also varies, and the fabrication should be compatible with a heavy-copper PCB design. Besides, the kind of copper you should buy also varies from a traditional PCB.

Some Common Practices

The Laminate Process: It involves heavy copper as a base, and it remains reliable while etching. This process helps manage a tracing edge, enhancing the trace finish. Moreover, the process also helps have appropriate space between the traces.

The Buried Process: Also known as buried copper where the prepreg already has heavy copper. Moreover, the laser cuttings and thickness of the resin determine the copper thickness.

The Insertion Of A Blue Copper Bar: In this method, the manufacturer puts a heavy copper bar into the PCB. It helps save material, reducing the total weight of the PCB. Moreover, the resin that flows into a copper circuit enhances the evenness of the plane.

Why Use Heavy Copper PCB: Advantages

Heavy copper is used in multiple PCBs, depending on their applications and it has several benefits, such as:

• It enhances the current flow to a high extent.
• It resists high temperatures and heat.
• The wiring arrangement is simple in this case.
• Boards having thick copper can carry large circuits and can send heat to the outer heat sinks.
• The layer of the same circuit can have various copper thicknesses.
• It increases the mechanical strength of different factors, such as PTH holes the connectors on a PCB, and the pads.
• It helps make a PCB compact and allows a circuit board to have different copper thicknesses or weights.
• It helps a single circuit board have a well-managed impedance and high-power current.
• When the copper thickness is high, the heat travels faster from the components to the substrate.
• It helps make the end product compact and more functional.
• When there is a heavy copper plating of holes, it enhances the current.
• The PCB can have cooling when there is heavy copper plating.
• Heavy copper helps have a high-temperature material, reducing the chances of damage.

Difference between a Heavy Copper PCB and A Traditional PCB

Though the above discussion describes the benefits of heavy copper, we would like to discuss the difference between a thick copper circuit board and a traditional board.

Copper Thickness: The copper thickness of traditional PCBs ranges between 1oz. and 3oz. On the other hand, the thickness of heavy copper goes from 4 oz. to 10 oz.

Outer Copper: The external or finished copper surface of a PCB helps assemble different components, like the internal layer, and the outer layer of a traditional PCB requires standard weight. But, in a heavy-copper PCB, copper weight or thickness on the PCB surface can be flexible according to the project requirements.

Internal Copper: Traditional circuit boards need standard parameters in terms of copper thickness and dielectric constant. However, you can change these factors in heavy copper according to the PCB design or customers’ requirements.

The Technique: Heavy copper involves a refined process of pair etching, whereas step plating is essential to have fine traces. On the other hand, the construction of a traditional PCB involves hole drilling, etching, and electroplating.

Note: While designing the heavy copper circuit board, you should select the right thickness of copper compatible with the carrying current.

Heavy-Copper PCB Applications

As technology and science are advancing faster, it has made electronics smarter than before. Heavy-copper circuit boards can carry high currents and provide excellent heat dissipation. Heavy-copper plates are more in demand than the past years because they help develop smart products having different functions.

You will find the application of heavy-copper PCBs in several industries, such as:

• Military and defense military, including radar detection and weapon handling, monitoring and security systems, and switchboards and signaling systems.
• Industrial applications, such as HVAC and UPS systems hydropower, welding equipment, and energy storage systems.
• Commercial and electrical applications, such as high-power LEDs and transformers, grid operating systems, power converters, power equipment conditioners, and suppliers, overload and protection relays, charging equipment for vehicles, and surge protectors a d fuses.
• Computer industry
• Automobiles
• Solar panel engineering
• Aerospace and nuclear power industry
• Medical equipment
• Railway industry

Frequently Asked Questions

What Is A Copper PCB?

A copper-based printed circuit board is known as copper PCB. Copper is used as a substrate to dissipate heat better than other materials.  Moreover, it enhances the PCB components’ life. A copper base transfers the heat faster from the board to the heat sink or an outer surface or casing. Copper has around 401 W/M.K thermal conductivity which is much higher than other metals like aluminum.

What Is The Heavy Copper PCB?

When copper thickness in a PCB goes beyond 3oz, we call it a heavy-copper PCB. The substrate or base can also be FR4 or aluminum. When copper is thick in a PCB, it can carry or transfer more current than a thin-copper PCB.

Are Copper Thickness And PCB Thickness The Same?

No, copper thickness means it’s the thickness of copper foil used in the PCB for plating or as a base material. Even aluminum or FR4 PCB can have heavy copper foil.

What Characteristics Describe A Heavy-Copper PCB?

Heavy-copper PCB has high mechanical power, high weather resistance, high-end heat management, excellent current conductivity, great performance, longer lifespan, diversity, and reduced layer count and footprints.

Is Manufacturing Of A Heavy Copper PCB Similar To A Traditional PCB?

The manufacturing of a thick-copper PCB has the same basic steps and processes as a traditional PCB, but the techniques are different. But, you can change the design parameters according to a project, unlike a traditional PCB where you have to strictly follow the standards.

Final Thoughts

Though a heavy-copper PCB is costly, it is much more powerful than a traditional PCB. You can use it in high-power and high-temperature devices without damaging the board during assembly. Multiple industries use heavy copper PCBs in their equipment, such as military, aerospace, nuclear, solar systems, transformers, computers, automobiles, etc. You have to buy copper carefully for constructing a heavy copper PCB.

Would like to know more about Heavy Copper PCBs or PC Board assembly? Just Email us at sales@pnconline.com

Written by Sam Sangani

Sam Sangani is the President & CEO of PNC Inc., a Nutley, NJ based Printed Circuit Board manufacturer. Sam graduated from L. D. Engineering College with a BS Degree in Mechanical Engineering. He also continued his education and graduated from Steven’s Institute of Technology where he acquired a Master’s degree in Computer Science.

After completion of his BS, Sam worked as a QC Manager, for Xerox, Romania and London. He was responsible for the Quality Control of Cable and Wire Harness imports from Romania. After completing his Master’s Degree, he worked as a Senior Programmer with IBM, Tucson, Arizona. Sam was responsible for leading the Mainframe System Programming Team.

In 1997, Sam acquired PNC INC., a Nutley, NJ based PC Board fabrication Shop. From 1997-2013, Sam has made tremendous improvements and changes within PNC INC., as he added many new Products and Technologies in PNC’s portfolio. With his proven track record and leadership, PNC has never had an unprofitable year and has continued its growth yearly since 1997.

His current responsibilities are Strategic Planning, Corporate Management, New Business Ventures, Sales & Marketing, Trade Shows, Professional Services and leading productive teams to achieve peak potential. He has also utilized Lean Management techniques which have built a foundation for PNC’s high-paced growth. Sam also enjoys real-estate investing, web design & SEO, trading stocks, options, futures and Forex markets.