How Are Insert Fin Heat Sinks Manufactured?

In modern electronic devices, a small heat sink is often critical to the performance and service life of the entire system. Among various heat dissipation components, insert fin heat sinks have emerged as a key technology for addressing high heat density challenges, thanks to their excellent heat dissipation efficiency and high design flexibility.

Different from common extruded or stamped heat sinks, the core of the insert fin process lies in bonding a large number of independent metal fins to the base plate through precision methods. This approach not only enables the easy realization of copper-aluminum hybrid use (e.g., aluminum base plates with copper insert fins) but also allows for the fabrication of fin structures with extreme height, density and thinness—features that are difficult to achieve with traditional processes.

So, how is such a precision heat dissipation component produced step by step? Its core production process can be condensed into the following four key steps:

Step 1: Grooving

Production begins with precise preparation work. First, base plates and individual heat dissipation fins (made of aluminum or copper) are machined separately in accordance with design drawings.

Subsequently, the most critical pre-treatment is carried out on the base plate: precision grooves are milled with uniform spacing. The width, depth and shape of these grooves are crucial and must perfectly match the fin thickness and the subsequent connection process (e.g., welding, riveting or gluing), as this directly determines the bonding strength and thermal conductivity of the final product.

Step 2: Fin Insertion and Assembly

The machined fins are precisely inserted one by one into the grooves of the base plate—similar to inserting a card—forming the basic framework of a complete heat sink initially.

Immediately after, the fins are permanently fixed to the base plate using a specific connection process based on design requirements:

• Welding: Metal fusion is achieved through high-temperature brazing or low-temperature solder paste, delivering the optimal thermal conductivity for the connection.
• Riveting: The base plate grooves are extruded and deformed with a mold to physically lock the fins in place, ensuring a firm connection.
• Gluing: Bonding is performed with high thermal conductivity epoxy resin, offering process flexibility and being particularly suitable for special-shaped or ultra-thin fins.

Step 3: Precision Machining

After the main structure is formed, the heat sink enters the precision machining stage. Based on the installation and application requirements of the final product, the following operations are performed at this stage:

• Drilling and tapping the base plate to create standard mounting holes.
• Milling and cutting the entire or partial heat sink to finish the shape forming or create special relief structures.
• Conducting necessary deburring and cleaning to ensure the product is neat and smooth.

Step 4: Surface Treatment

Finally, corresponding surface treatment is applied to the heat sink to improve its durability, aesthetics or electrical performance. Common processes include:

• Anodizing (mostly for aluminum): Increases surface hardness and corrosion resistance, and can be applied in a variety of colors.
• Sandblasting or brushing: Creates a uniform, aesthetic matte finish.
• Nickel plating or passivation (mostly for copper): Prevents oxidation and rusting of copper materials.

• Written by

  CoolingThermal Engineering Team

  CoolingThermal is an automation equipment manufacturer based in Kunshan, China, specializing in heat pipe and vapor chamber production equipment since 2017. Our engineering team designs, builds, and commissions complete production lines covering forming, degassing, welding, testing, and assembly processes. The technical content on this blog is written by the same team that develops the equipment — based on real production experience, not secondary research.