What is a Heat Sink?
A heat sink is a thermally conductive component engineered to increase the surface area available for heat dissipation from a hot surface; typically a semi-conductor device, power module, or LED array. By enhancing thermal convection (natural or forced), a heat sink transfers heat away from the component and into the surrounding environment, maintaining safe operational temperatures and extending component lifespan.
Heat sinks can be passive (relying on natural airflow) or active (assisted by fans or blowers), and their effectiveness depends on material selection, geometry and surface finish. Among available materials, aluminium remains the most widely adopted in high volume applications due to its superior balance of thermal performance, manufacturability, and cost-efficiency.
Why Aluminium? Engineering Advantages
Aluminium’s suitability for thermal management applications stems from a combination of material properties and manufacturing advantages:
- High Thermal Conductivity: With a thermal conductivity of approximately 205 W/m·K (for 6063-T5 alloy), aluminium provides efficient heat dissipation across a broad temperature range
- Lightweight: Aluminium is about 60% less dense than copper (2.7 g/cm³ vs. 8.9 g/cm³), making it ideal for weight-sensitive applications such as aerospace and automotive electronics
- Extrudability: Aluminium’s excellent extrudability allows for the design of complex fin geometries, optimising surface area and airflow. Multi-void, high aspect-ratio, and integrally mounted profiles can be extruded to tight tolerances with minimal post-processing
- Corrosion Resistance: Naturally forming a protective oxide layer, aluminium is inherently resistant to corrosion, especially when anodised; a feature critical for heat sinks exposed to moisture or harsh environments
- Cost-Effective / Recyclable: Aluminium is significantly more economical than copper, both in raw material cost and in fabrication, especially at scale
Key Industries and Applications
Aluminium heat sinks are indispensable in industries where thermal regulation is mission-critical. Common sectors include:
- Consumer Electronics: Smartphones, tablets, and laptops rely on compact heat sinks to cool processors, GPUs, and power management units
- Automotive and EVs: In electric vehicles, heat sinks are integrated into battery packs, power electronics, and LED lighting systems to ensure reliable operation under dynamic conditions
- Telecommunications: Data centres and 5G infrastructure deploy high-performance aluminium heat sinks in routers, servers, and base stations to manage thermal loads from continuous data transmission
- Industrial Automation: Motor drives, inverters, and PLCs use extruded aluminium heat sinks for robust thermal performance in high-duty cycles and elevated ambient temperatures
- LED Lighting: Aluminium is the material of choice for LED housings, providing both structural support and efficient heat dissipation to preserve luminous efficacy and lifespan
- Renewable Energy: In photovoltaic inverters and wind turbine controllers, aluminium heat sinks protect electronic assemblies from thermal overload in variable environments
Aluminium vs. Copper: A Practical Comparison
Thermal conductivity is typically measured in watts per metre-kelvin (W/m·K). While copper boasts higher thermal conductivity (~385 W/m·K), it comes with trade-offs that make aluminium the superior choice in real-world applications:
|
Property |
Aluminium (6063-T5) |
Copper (C11000) |
|
Thermal Conductivity |
-205 w/m·K |
-385 W/m·K |
|
Density |
2.7g/cm³ |
8.9 g/cm³ |
|
Cost |
Low |
High |
|
Manufacturability |
Easy to extrude and machine |
Difficult to extrude |
|
Corrosion Resistance |
Excellent (with finishing such as powder coating / anodising) |
Moderate (requires plating) |
|
Weight |
Lightweight |
Heavy |
The reason aluminium (and other metals) conduct heat so well comes down to free electrons. These electrons carry thermal energy through the material rapidly, which is why good electrical conductors tend to be good heat conductors as well.
In applications where weight, cost, and manufacturing flexibility are critical - such as automotive, aerospace, and portable electronics - aluminium outperforms copper in system-level efficiency. Aluminium's compatibility with surface treatments (such as powder coating) also enhances both its thermal emissivity and corrosion resistance, making it a versatile thermal solution.
Aluminium Extrusion: Precision & Performance
Through the aluminium extrusion process, heat sinks can be produced in virtually any shape to maximise airflow and thermal efficiency. Custom extrusions allows engineers to design heat sinks with:
- Optimised fin spacing and thickness for forced or natural convection
- Integrated mounting features and channels for simplified assembly
- Tailored profiles for specific enclosures or component footprints
By leveraging tight-tolerance extrusion dies, we can deliver consistent, scalable, and application-specific solutions for demanding environments.
Choosing the Right Aluminium Alloy
Pure aluminium has excellent thermal conductivity but is typically too soft for most structural uses. That’s where alloys come in — offering improved strength with only a slight reduction in conductivity.
Common aluminium alloys used for heat sinks in the UK include:
- 1050 – Offers very high thermal conductivity (up to 229 W/m·K) but is relatively soft and limited in strength
- 6060, 6061, and 6063 – Provide a balance of conductivity (166–201 W/m·K) and mechanical performance, making them well-suited for most heat sink designs
The exact thermal performance also depends on the temper of the alloy, so it's essential to match the alloy specification with your application’s precise needs.
Conclusion
Aluminium heat sinks represent a cornerstone of modern thermal engineering. With a powerful combination of thermal conductivity, lightweight properties, corrosion resistance and design flexibility, they provide a cost-effective alternative to copper without compromising performance. Whether in electronics, automotive, telecommunications, or industrial applications, extruded aluminium heat sinks continue to shape the future of reliable thermal management.
Looking to optimise your thermal design with bespoke aluminium heat sinks?
As a trusted UK aluminium extrusion provider, we understand the importance of reliable thermal management in high-performance systems. From concept to final profile, our team offers expert support in alloy selection, design optimisation, and extrusion production — helping ensure your heat sink delivers on both function and form.
Contact us today to discuss custom aluminium extrusion solutions tailored to your industry specific needs.