How to Produce Heat Sinks With Skiving

Heat sinks are used to maintain the temperature of a component or a system by providing a series of extended surfaces called fins. There are a lot of heat sinks that are produced with skiving available in the market. These types of heat sinks consist of uniformly shaped and closely spaced fins. These narrow and closely spaced fins in heat sink allow larger surface areas for maximizing heat dissipation.

Production of Skived Heat Sinks

For the production of skived heat sinks, a solid block of aluminum or copper, having a certain thickness, is used as a starting material. The block is extruded in a rectangular shape. It is then placed on a worktable. Lubricant is applied to the top of the surface so that excessive heat is not generated during the machining process. The block is then passed through a machine that consists of a sharp blade. The blade slices the top of a block to the desired thickness and bends the slices.

This slicing process is repeated at certain intervals to make a series of fins along the length of the block and to attain the designated spacing between them.

Materials Used for the Production

The preferred material for the manufacturing of heat sink through the skiving process of Aluminum 6063. The reason is that the machinability of this material is better and it has relatively higher strength. Also, the range of fin thickness can lie between 0.25 – 0.8mm. This results in the production of fins which are quite thin, having a lightweight. This manufacturing process can produce fins of height up to 150mm.

Evaluation of This Method

For this kind of manufacturing process for a heat sink, the major advantage is that there are no metal chips or wastage produced and in this process as the block of metal is only sheared into layers. Originally, skiving was used to produce thin natural convection arrays, but recent research has helped to attain a closer spacing between the fins which is necessary for forced convection cooling.

Advantages of Creating Heat Sinks With Skiving

 Fins can offer maximum dissipation of heat in the application where there is a very high flow of air and space is limited. In other heat sinks, fins may be bonded separately to metal sheets with different methods like welding and epoxy resins. However, joining the fins with the base takes time and it costs since more equipment and labor is required. When it comes to skiving, joining pieces of metal is not required since the entire heat sink is made out of a single piece of metal. Another advantage is that there is not any additional thermal resistance that affects the performance of a heat sink. This allows optimal cooling performance in the environment where the skiving heat sink is installed.

Heat sinks produced with skiving have a very high aspect ratio, which reduces the weight of heat sinks. The tooling cost is minimal as only a sharp blade is used. Another advantage is that the lead time of the skiving process is very short as only slicing and bending operation is required to produce a final product. This allows the production of a large number of heat sinks in a relatively shorter time.

Limitation of Skiving

The biggest limitation of a skiving heat sink is that the magnitude of force required to shear the metal block into thin slices and to bend them is very large. This applied force depends upon the flow length of the blade, the thickness of layers and the height of the fins.

Additional Machinery Needed for the Process

The starting metal block used in skiving for creating heat sinks has a very large length to reduce the lead time. To attain the designated length, the block of a skived heat sink is passed through a gear cutting machine which cuts the heat sink into several parts of the desired length. During this process, some burrs and sharp corners are formed at the ends of the fins. In order to remove those burrs and sharp corners, heat sinks are passed through a grinding machine. The tool is a gear generated grinder which removes the burrs and sharp corners. This process also smooths the surface of the heat sink and controls the height of the final product.

Applications of Heat Sinks Produced with Skiving

Skived heat sinks have vast applications. They can allow maximum dissipation of heat in a very limited space as they have a very large surface area to volume ratio due to large packing density. Skived heat sinks are most commonly used in the following applications:

  • Automotive components
  • Industrial components and equipment
  • Electronic equipment like transistors and light-emitting diodes
  • Computer equipment like GPU
  • Household appliances and lighting lamps
  • Satellite and Telecommunication

Design Specifications of Skived Heat sinks:

Aluminum

Many fabricators use Aluminum for creating heat sinks. The following table can give an idea of the specifications of skived heat sinks found in the market. The dimensions are provided in millimeters and inches

Length
(mm/in)
Width
(mm/in)
Height
(mm/in)
Fin
Thickness
(mm/in)
Pitch
(mm/in)
Min025/0.986/0.230.15/0.0060.3/0.01
Max3000/118.11 800/31.49120/4.721.5/0.0610/0.4

Copper

Copper is a great material for creating heat sinks. It is a very good conductor of heat and cooling is much more efficient with copper.

Length
(mm/in)
Width
(mm/in)
Height
(mm/in)
Fin
Thickness
(mm/in)
Pitch
(mm/in)
Min025/0.986/0.230.12/0.0040.2/0.07
Max3000/118.11 800/31.4950/1.960.8/0.0310/0.4

General Design Guidelines for Skiving

  • Aluminum is a better material for high aspect ratios.
  • There has to be some trade-off between different dimensional variables like thickness and height of fin due to the complexity of the manufacturing process.
  • There is a limitation of airflow lengths due to the force required to fold up the fins.

Final Thoughts

This method of creating heat sinks becomes increasingly more popular. I hope that the article is helpful enough to understand the process. It’s an essential part of making the right decisions. You can check my other articles about welding and CNC. I would appreciate it if you could share my article.

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