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Heavy Copper PCBs Fabrication and Manufacturing

2022-09-10

What are Heavy Copper PCBs (Printed Circuit Boards)?

Heavy copper PCbs or printed circuit boards consist of outer layers and inner layers that each contain 4 ounces of copper. Therefore, each layer requires at least 4 ounces of copper. Due to their superior heat management capabilities, these printed circuit boards command a very high price.

The high extreme copper content helps in maintaining a cool interior temperature, which improves the performance of the internal components. These printed circuit boards facilitate temperature control and power distribution.

In addition to this, Heavy Copper PCBs are significantly better at dissipating heat than other forms of PCBs, such as ordinary PCBs. A heat sink must be incorporated into the design of a durable and long-lasting circuit. Not only may incorrect handling of heat signals affect the operation of electrical devices, but it can also shorten the lifespan of circuitry.

Heavy Copper PCBs & Single-Sided PCB in china

The Benefits Of A Printed Circuit Board With Thick Copper

The fundamental advantage of heavy copper material is its resistance to excessive current, high temperatures, and repeated thermal cycling. In a couple of seconds, these elements can cause damage to a conventional circuit board. Moreover, heavy copper printed circuit boards are in high demand in the computer, vehicle, military, and industrial controls industries.

 In addition, the demand for heavy copper PCB board is used for a variety of other purposes, including the following:

The heavy copper PCBs provide their consumers the following extra benefits:

  1. Reduced overall product size due to the presence of many copper weights on the same layer of circuitry. 
  2. Heavy copper-plated vias are excellent for transporting heat from the PCB to an outside heat sink. 
  3. Onboard planar high-power-density transformers. Heavy copper plating on the vias.

Technical Advantages Of Using Thick Copper PCBs

PCBs composed of thick base copper offer a number of advantages, including the ones listed below:

  1. Fewer wired bus configurations produce a smaller printed circuit board.
  2. Integration with high-power circuits and control circuits is rather straightforward.
  3. Copper plating added to the heat vias leads to a decrease in thermal resistance.
  4. Enhanced current carrying capacity as well as resilience to the effects of high thermal stress
  5. Reduced layer count due to the simplicity of incorporating many copper weights onto a single layer. 
  6. Strengthened mechanical integrity of PTH holes and connecting points
  7. Make it possible to use uncommon materials to their full potential without risking circuit failure.
  8. Heavy copper-plated vias not only aid in heat transfer to the device’s outside heatsink, but also carry high currents through the circuit board.
  9. PCBs that use heavy copper are able to tolerate high levels of heat cycling.
  10. Best for Industries that use Heavy Copper Printed Circuit Boards

Industrial Applications Using Heavy Copper PCBs

Here are some examples of where heavy copper PCBs are used in industry:

  • Power supplies, power converters
  • Overload Relays
  • Torque Controls
  • Automotive industry
  • Welding equipment
  • Power distribution
  • Power Line Monitors
  • Solar panel manufacturers and so on.
  • Protection Relays

Heavy copper PCB manufacturing Tips

How is Heavy Copper PCB Fabricated?

Heavy copper PCBs are often made by plating or etching. The primary objective is to thicken the copper on the walls and in the plated holes. Heavy copper PCB fabrication isn’t impossible to imagine. However, special etching and plating processes are required to maintain the additional copper thickness on heavy copper PCBs.

For the manufacture of large copper PCBs, standard etching methods are suboptimal. Over-etched edges and ragged corners are typical results of conventional etching techniques. Manufacturers of printed circuit boards (PCBs) today use cutting-edge etching and plating techniques to ensure perfectly straight edges.

PCBs made from heavy copper are electroplated during manufacture. As a result, the PTH walls on the PCB will be strengthened. The layer count is reduced and the impedance distribution is simplified using this method. So the strength of the plated holes in printed circuit boards (PCBs) can degrade after being subjected to multiple cycles in the manufacturing process.

Important Precautions

There are several restrictions on what may be done while making thick copper PCBs.

  • The etching procedure adds to the total price.
  • Etching removes a lot of copper, making it difficult to make thin lines and dense traces.
  • Unevenness in the surface is caused by heavy copper traces.
  • Making Sturdy Printed Circuit Boards
  • Copper-heavy printed circuit boards (PCBs) are made using a variety of methods, depending on the manufacturer.

The Copper Embedding Process: This process utilizes a flat surface in the fabrication of heavy copper PCB. In this step, the prepreg resin is injected with the heavy copper. The copper’s thickness is equivalent to the resin’s thickness.

To give just one example, the fabricator may start with a 6-mil laminate and a 1-oz copper clad. After that, on copper clad a photoresist is applied nicely. The laminate’s circuit layout is then sliced from one side using a 5-mil laser beam.

For the laser to reach the copper foil, it must first cut through the lamination. Fabricators can protect copper foil from laser burns by keeping the beam under tight control.

Fabricator electroplates the laminate by positioning it in a plating tank. After filling the laser cut groove on the laminate, the copper plating creates around 6 mil of plating thickness.

Modernized Blue Bar Method

Blue bar technology includes the installation of heavy copper bars onto motherboards. The PCB can be made smaller and lighter because of this method’s material savings. Resin seeps into the empty spaces between the copper traces during production, leveling off the final product.

When fabricating multilayer Printed Circuit Boards, especially ones with thick copper layers, fabricators need to pay close attention to the amount of copper fill between inner layers. Moreover, resin deficiency occurs when there is not enough filler to hold the resin.

What Is The Difference Between A Standard PCBs and Heavy Copper PCBs

 

Thin/Standard PCBs Thick/Heavy Copper PCBs  
Copper etching and plating is utilized in the production of standard PCBs. Utilizing step plating and differential etching, thick copper PCBs are produced.
The unit of measurement for standard PCBs is the ounce (oz). The amount of copper utilized in these PCBs is 1oz, hence their thickness is minimal. The Thick copper PCBs have a larger diameter than the Standard size because they include a greater quantity of copper. The unit of weight for thick copper PCBs is the ounce (oz). 2 to 4 ounces of copper are used in their construction.
Standard PCBs are designed for less demanding tasks. Thick copper PCBs are intended for heavy-duty applications.
They Conduct lesser amount of current Can conduct higher values of current
Standard PCBs has low thermal distribution as compare to the  thick or heavy copper PCBs Thermal distribution is efficient in Thick copper PCBs therefore they are efficient in performance
Standard PCBs have lesser mechanical strength As a result of their increased copper content, they have greater mechanical strength.
Standard PCBs are most commonly used Heavy copper PCBs are used for specialized purposes. 
Standard PCBs have a lower tensile strength PCBs with a higher copper content are more durable
Standard PCBs do not improve the performance of boards that use them. Using thick copper PCBs can boost the anti-stress performance of the Board.
1oz of copper is used in the manufacturing of typical PCBs. The amount of copper utilized in the fabrication of heavy copper PCBs exceeds 3oz.
They are cheaper in price They cost more than Standard PCBs

 

Heavy Copper PCBs In a Nutshell

In most cases, commercial items will require a heavy Copper PCB design, which is why 4 oz Copper PCBs are used in their fabrication. Up to 200 ounces of copper can be found per square foot.

When it comes to electronics and electrical circuitry, heavy Copper PCB are commonly utilized because of their ability to transmit large amounts of power. In addition, these PCBs provide unrivaled thermal strength. So the high temperatures are very bad for electronic parts and make circuits work much worse. This makes the temperature range a very important factor in many applications, especially electronics.

Interested to learn about solder masking for PCB? check our blogs.

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