WHAT IS AN OPTIMAL SOLUTION FOR MANUFACTURING HEAT SINKS? – THE BENEFITS OF FORGING AND THE KEY POINT

WHAT IS HEAT SINK?

A Heat Sink is a component that absorbs heat and dissipates it into the air. It is also known as “Radiator” and “Radiating Sheet”. Nonferrous metals such as aluminum and copper which have high thermal conductivities, are used for materials for Heat Sinks.

Semi-conductors are used in various fields such as electronic goods, and automotive components. However, many semi-conductors radiate heat when electricity flows and if they remain at high temperatures while radiating, there will be possibilities of errors and failures. Heat Sinks are used to prevent such issues.

STRUCTURE OF HEAT SINK

The efficiency of heat dissipation improves with a larger surface area to touch air, so Heat Sinks have many thin sheets and rods. The performance of a Heat Sink is measured by its “Thermal Conductivity (℃/W or K/W)”. This indicates how difficult it is to conduct heat through the material. When the number is low, it means the Heat Sink is high-spec.

DESIGN OF HEAT SINK

Heat Sinks are manufactured using die-casting, machining, and extrusion methods, yet these methods have issues such as limitations of quality, cost, and geometry.
So, as an alternative method, forging has been in the spotlight lately. Since forging can solve those issues mentioned earlier in a well-balanced way. As a result, demand for Heat Sinks used in automotive inverters has been increasing. It is expected to accelerate further. Reducing materials because society aims to achieve carbon neutrality, and improving material yield rate due to rising raw material costs are also one of the reasons for improving the demand for forging.

FORGING HEAT SINK

Do you know any benefits of manufacturing Heat Sinks using the forging method?

First, forging is similar to extrusion but utilizes back pressure to form fins, making uniform length, which is different from extrusion. So, unlike extrusion, there is no need for cutting the workpiece, and it can be used for the products directly. This results in improved yield and cost reduction. Forging also allows for continuous processing with a press machine, leading to high productivity.

Additionally, by reflecting the fin shapes to the die, you can form not only simple rounds and square shapes but also designs with higher thermal dissipation. This expands the specifications of heat sinks.

Now, we will show you the key point of the Heat Sink design through forging, using our prototype Heat Sink as an example.

PROTOTYPE

We tried forging the Heat Sink with aluminum and copper.
Both materials were between 350 to 400℃, and metal dies were at 200℃ while forming. Forming loads and back pressures were:

Aluminum: Forming Load 430t (Surface Pressure 105kg/mm2), Back Pressure 10t

Copper: Forming Load 540t (Surface Pressure 130kg/mm2), Back Pressure 10t

THE KEY POINT OF HEAT SINK DESIGN

Adding back pressure to the geometry (which means to push the material back giving constant pressure to the die that touches the workpiece) is considered to be one of the key points of Heat Sink design.

By doing so, you can form fins with a small range of variation in heights.

With a CAE simulation, you will learn the suitable geometries and materials, and be able to consider the stress of the dies, underfills, and scratches that occur on the material during forming.

In conclusion, this simulation helped us reduce the number of trials. Also, we could reduce costs and processes of the development, as well as the development period.

CONCLUSION

Thank you for reading! We hope you enjoyed it.

In this article, we explained about Heat Sink, the benefits of forging, and the key points of designing it.

We have a multi-axis servo press, furnace, thermostatic regulating valve, and die-release coating apparatus necessary for trials. We also offer you good use of forming simulations to reduce costs and processes of manufacturing.

If you are considering designing new products, or want to know further information, please contact us.