Introduction of Cold Forged Heat Sink

Cold forged heat sink is a good choice for casting complex shapes with excellent thermal conductivity. The cold forging process allows an almost perfect straightness of more fins per square millimeter.

The shapes of cold forged heat sink include plate fin heat sink, round pin heatsink and oval fin heat sinks.The manufacture of forged heat sinks are well suited to the use of copper because the copper heatsink can be shaped without high temperatures and can be formed with minimal damage. Cold forging heatsink manufacturing can often include secondary processing operations such as holes, chamfering and steps to reduce unnecessary waste.

This article will cover cold forged heat sinks in detail, so let’s get started.

What is Cold Forged Heat Sink?

Cold forging material is mostly below room temperature deformation resistance is lesser, plasticity better aluminum and partial alloy, copper and partial alloy, cold forging can make profile produce work hardening in processing process (strain hardening), can make intensity and hardness increase.

• Improved mechanical strength

• Better control of tolerance

• Improved surface finish

• High production rate

• Efficient use of raw materials

• Reduced energy consumption

• Low overall cost

• Combination of copper and aluminum possible

• Standard sizes available

• High-purity aluminum with extremely high thermal

How Does Cold Forged Heat Sink Work?

Cold forging is a manufacturing process in which the aluminum or copper heat sink is formed by using localized compressed forces.  Fin arrays are formed by forcing raw material into a molding die by a punch. The process ensures that no air bubbles, porosity or any other impurities are trapped within the material and thus produces exceptionally high quality products.

Materials for Cold Forged Heat Sink

• Aluminum A1060

• Aluminum AL1100

• Aluminum A6061

• Pure Copper CDA 110

The Pros and Cons of Cold Forged Heat Sink

Compared with other manufacturing methods (machining, die casting, extrusion, hot forging, etc.), cold forging offers the following benefits:

1. Better thermal conductivity:

Made from pure aluminum-AL1070/AL1050 by cold-forging tech. The thermal conductivity of AL1070 is 226W/m.k (In the forging process, the internal structure will be more compact, thermal conductivity of the finished forging parts is even higher than the raw material-AL1070 which is 226W/mk). The thermal conductivity of Aluminum alloy (6063) is 180W/mk, while the thermal conductivity of die-casting aluminum (A380) is only 96W/mk. The better the thermal conductivity is, the faster the heat will be released, the better thermal performance there will be.

2. Better heat dissipation structure:

The base plate of a cold-forged heat sink and its fins are integrally formed, without any gap between. Heat from the base plate can be conducted into the fins without any mediators. The machining and brazing aluminum parts are riveted or brazed together between the base plate and its fins, there must be a gap between which will cause indirect thermal resistance. Meanwhile in the process of expansion and contraction during lamp use would lead to a larger gap, there will be more thermal resistance.

3. Product Specific Structure:

Top and bottom of the base plate can be formed by specific structures by cold forging technology, and the lateral surface as well, in order to have better connection with the heat element.

4. Larger Cooling Area:

Fin thickness can be done with 0.7MM, distance between fins can be done with 1MM.The thin and dense fins greatly increase the contact area with air , more conducive to air convection cooling .

5. Diversified Fins:

Fins of various shapes such as a cylindrical shape, thin sheet shape, square columns, hexagonal columns, etc.

6. Large Size Heat Sinks:

Dimension as large as 200mm * 250mm or even larger is achievable by cold-forging technology.

7. High Aspect Ratio:

High Aspect Ratio as 1:50, while for extrusion is only about 1:25.

8. Multi-direction Air Cooling:

Air flow direction of Cold-Forged heat sinks is three-dimensional, while extruded parts are two-dimensional. In this way, Cold-Forged heat sinks adapt to the environment better, and have better thermal cooling performance.

9. Smaller volume and lighter weight:

Compared to die casting, machining and soldering parts, due to the above-mentioned advantages of cold-forging heat sinks, they can be used for bigger power electronic devices within the same volume and shapes of die casting, machining and soldering parts. Therefore, the use of cold forged heat sinks will reduce the weight and volume of the equipment, and the appearance designing requirements as well, to reduce the overall costs and make products more competitive!

10. Appearance:

The raw-material is aluminum, anodized surface treatment can be done, which makes it clean and beautiful, and different colors such as silver, white and black are also available. While die-cast parts have rough surfaces, they need to be sprayed, which is not ideal for heat dispersion.

11. Technology Characteristics:

High conductivity, high heat dispersion and high-precision CNC machining, all these ensure high dimensional accuracy and stability. According to testing, thermal performance of cold-forged heat sinks is two times greater compared with the same type of die-casting parts, and one time greater compared with extruded parts. Therefore currently, cold-forged heat sinks are the best thermal cooling solution for High-power electronic devices

In making aluminum heat sinks, cold forging can produce pins that are 50 times as tall as their diameters – an aspect ratio that is considered impossible with other methods, such as die-casting or extrusion.

Unlike stamped-fin or bonded-fin heat sinks, the pins on a forged heat sink are an integral part of its base plate – they are simply squeezed out of the base. There is no air gap or thermal interface between the pins and the base. Heat can dissipate easily from the base to the pins without additional resistance.

The Various Applications of Cold Forged Heat Sink

• High performance electronics

• Multi-chip modules

• LED cooling

• Elliptical or round fins

Design Guidelines for Cold-Forged Heat Sinks

To improve manufacturability, please design custom heat sinks based on the following guidelines:

• Maximum Width: 500 mm

• Maximum Length: 500 mm

• Maximum Height: 70 mm

• Minimum Thickness for Base Plate: 2.0 mm

• Minimum Gap Between Fins: 1.5 mm

• Minimum Distance Between Fin and Edge of Base Plate: 0.5 mm

How to Choose an Cold Forged Heat Sink Company

Cold forging technology has been widely used by heat sink manufacturers in the production of light source heat sinks and LED heat sinks. Winshare is one of the few companies who used cold forging to produce heat sinks in the early days and we have accumulated abundant experience of cold forging technology. In addition to the production of cold forged heat sinks for typical light sources, Winshare has gained experience in the manufacturing techniques for high power cold forged heat sinks. We have resolved the problems such as the low thermal conductivity of die-casting micro-channels and higher costs for machining micro-channels. We have already applied cold forging heatsink  to cooling solutions including high-voltage inverters, wind power converters, and electric motor controllers.

Conclusion

Cold forged heat sinks are a good choice for casting complex shapes with excellent thermal conductivity. With the wide application of heat sinks and the increase in demand, all walks of life are increasing their investment in heat sinks to meet market demand.

If you want to pursue reliable quality products, please contact us. Winshare can provide you with better service and high-quality and reliable thermal management solutions and products.