Skiving Heat Sink Technology, Advantages and Application

In recent years, with the continuous development of technology and changes in the application market, the machining and forming method of serrations has attracted increasing attention from industry professionals. A large number of manufacturers specializing in the production of CNC serration equipment have emerged, and end customers, especially for products like water-cooled radiators, have also begun to extensively apply serrated products.

 

Why is skiving heat sink? 

1. Skiving heat sinks can achieve high-density teeth and integral material forming with a simple process.
skiving heat sinks use a single block of material (such as copper or aluminum) and cut high-density cooling fins with a dedicated serration machine using a high-precision radiator serration process. The structure includes high-density serrations, high-fin fins, and ultra-long cooling fins. skiving heat sinks overcome the limitations of traditional radiator thickness-to-length ratios and can produce radiators with high-density teeth. The fins and the base are "integral." Because the base and fins of the skiving heat sink are integral, with no other thermal resistance, and due to the high purity of the serration material, the efficiency of serrated cooling fins is much higher than that of welded radiators. The thermal conductivity can also reach a level comparable to that of profiles.

 

2. Small investment, low technical threshold, and rapid realization of mass production.
The serration process mainly depends on equipment, and the equipment is currently very mature. Adding a serration line to a general radiator processing factory is a straightforward task. This has led to a sharp increase in the production capacity of serration processing within the industry, meeting the demand for skiving heat sink products in large quantities and across various fields.

 

 

Skiving heat sink Processing 

Referencing the diagram above, the processing workflow for skiving heat sink manufacturing is as follows:

1. Material Selection:Typically chosen based on the radiator's requirements, utilizing profiles to maximize material efficiency.

 

2. Cutting: Tailored to product dimensions, either creating one product per mold or multiple products per mold. This can involve continuous or individual operations.

 

3. CNC Machining: This step includes milling off unnecessary parts, milling sealing ring grooves, and other relevant processes.

 

 

4. Serration with CNC Serration Machine: Utilizing a numerical control serration machine to create serrations on the material.

 

5. Gear Rolling (or Flattening): Generally carried out on a gear rolling machine.

 

6. Secondary CNC Machining: Following the requirements of product drawings, this step involves milling off teeth from the edges, drilling holes in the middle, creating void spaces, facing surfaces, machining threaded holes, and creating fixture positions.

 

7. Surface Treatment: This step involves applying surface treatments as per the product specifications.

 

Benefits of Producing Heat Sink Fins Using Serration Process

1. Higher Heat Sink Fin Density (Thinner Teeth and Smaller Tooth Spacing):
Serrated heat sink fins exhibit a higher fin density, increasing the heat exchange surface area within a limited volume. Unlike the constraints of profiled mold and extrusion processes, serration allows for significantly smaller tooth thickness and spacing. With precision machinery, tooth thickness and spacing as small as 0.05 can be achieved.

 

2. Taller Heat Sink Fins:
The tooth height of serrated heat sink fins can reach up to 120mm, potentially even higher according to theoretical process capabilities, fully meeting the production requirements for most heat sinks in various applications.

 

3. Thinner and More Precise Serrated Fins:
As mentioned in the first point, thinner and smaller spaced fins contribute to a lighter and more efficient radiator.

 

 

4. Integrated Base and Fins, No Additional Thermal Resistance, and More Reliable Structure:
Serrated heat sink fins are serrated directly on the base material, preserving 100% of the original heat dissipation efficiency without the risk of loosening or detachment, enhancing the reliability of machine operation. In contrast, welding fins may suffer from poor connections, increasing thermal resistance.

 

5. High Compatibility of Serrated Heat Sink Fins:
skiving heat sinks are molded in one piece, offering extensive post-processing possibilities. They can be combined with processes like embedded copper tubing to enhance heat dissipation performance. Whether using soft or hard soldering, it can adapt to the corresponding temperature rise during the manufacturing process.

 

6. Suitable for Mass Production:
With continuous improvements in serration machine performance and material refinement, the process is now suitable for large-scale production.

 

7. Material Compatibility:
Common thermal conductive materials such as copper, aluminum, and various alloys can undergo serration processing. Additionally, there are cases of mass production using copper-aluminum composite materials.

 

8. Diverse Structural Types:
In addition to standard single-sided serration, serration processes can create double-sided serration, four-sided serration on tubular structures, circular serration, and irregular serration. Current technology can meet the structural design requirements of the majority of heat sink fins.

 

9. Reduced Mold Investment, Saving Development and Production Costs:
The serration process eliminates the need for additional molding tools. For different-sized and structured product demands, only material and serration tool changes, along with the setup of a new serration program, are required, significantly reducing prototyping time and costs. This, in turn, lowers production costs.

 

Skiving Process and Common Applications of Skiving Heat Sinks

1. Various Types of Serrated Heat Sink Fins:
Serrated heat sink fins can replace profiled radiators, pinned radiators, folded fin radiators, die-cast radiators, and forged radiators in many applications.

 

2. Precision Heat Dissipation Applications: Water-Cooled Heads and Micro-Channel Heat Exchangers:
In the current landscape, water-cooled radiators are widely used in products such as computer CPUs, servers, and graphics cards. The design of water channels in water-cooled heads is crucial for the heat absorption efficiency during system operation. Previously, complex mechanical processing or processes like diffusion welding and brazing were needed to create water channels, increasing the heat absorption area and improving efficiency.

However, the application of serration processing can produce ultra-thin tooth thickness, extremely small tooth spacing, and various heights of water-cooling channels, meeting the heat exchange requirements.

 

3. Large-Sized Heat Dissipation Applications:
The current challenges in heat management for data centers and thermal management in energy storage systems mostly involve the demand for large-sized radiators. The introduction of the serration process perfectly addresses the processing requirements for these large-sized radiators.

 

Common Types of Materials for Serrated Heat Sink Fins

1. Copper Skiving Heat Sink Fins:
Copper serrated fins exhibit excellent thermal conductivity, and when combined with serration technology, they achieve the maximum heat dissipation surface area per unit volume. This significantly enhances overall heat dissipation performance. Therefore, copper serrated heat sink fins are used in high-end applications such as advanced chips, CPU cooling, and servers.

 

 

2. Aluminum Skiving Heat Sink Fins:
Typically made from pure aluminum, these fins have a higher thermal conductivity than aluminum alloys. Using the aluminum radiator serration process ensures that the heat dissipation performance is more stable compared to extruded aluminum heat sink fins. Aluminum serrated heat sink fins are widely applied in the photovoltaic industry, electric vehicles, inverters, LED lights, communication products, and more.

 

 

3. Copper-Aluminum Composite Material Skiving Heat Sink Fins:
Integrating the advantages of copper and aluminum serrated heat sink fins, this material typically uses copper as the thermal conductivity base, with serrations applied to the aluminum substrate. The manufacturing process for this material involves continuous casting and semi-molten state pressing technology.

 

 

4. Customizable Serration Types:
Depending on requirements, serrated heat sink fins can be single-sided, double-sided, or partially serrated to meet various heat dissipation needs.

 

Considerations in Designing and Implementing Skiving Heat Sink

1. Designing Tooth Thickness and Spacing
When designing tooth thickness and spacing, it's essential to consider overall factors such as heat exchange area, airflow speed, and heat exchange efficiency, rather than solely pursuing density and tooth height. I have encountered cases where a client's product had not only a small tooth spacing but also very high teeth. Even with a powerful fan, the internal airflow was significantly hindered. This not only fails to improve heat dissipation efficiency but also leads to heat accumulation, making it challenging to dissipate. Additionally, thin teeth may reduce the cross-sectional area of the fins, affecting heat transfer efficiency.

 

2. Avoid Mythologizing Skiving Heat Sink
It's crucial not to mythologize serrated heat sink designs. Consider the application scenarios and explore the combined use of various cooling methods. When devising cooling solutions, it's essential to have an open-minded approach and adopt simple, cost-effective, and reliable cooling methods. Cooling methods should not be restricted to a single type; instead, a combination of methods can be employed to ensure effective heat dissipation while reducing the difficulty in manufacturing and the overall cost of the final product. Examples include the use of heat pipes and heat spreaders, Thermoelectric Coolers (TECs), and the combination of liquid cooling and air cooling.