When to choose aluminum heat dissipation materials
Conventional heat sinks for street lights/flood lights, profile fins for garden lights, back panel heat dissipation for panel lights, and low/medium high power lamps that require large area heat sinks
1. Why is aluminum used in the heat dissipation structure of the lamp?
The thermal conductivity of pure aluminum at room temperature is about ≈ 205 W·m⁻¹· K⁻¹, which is lower than copper but still conducts heat effectively; The key advantages are light weight (approx. 2.7 g/cm³) and low cost, making it easier to mold into thin/fin structures, thereby increasing the surface area for better heat dissipation. It can be extruded and profiled, and is suitable for mass production of long/regular fins (low unit price). It also has a good surface oxide layer (anodization) and post-coating process, which is suitable for outdoor lighting with anti-corrosion treatment and is easy to make decorative forms.
2. Different aluminum processing processes are suitable for lamp types
Different aluminum materials and processing methods directly affect thermal properties and costs. Extruded profiles (commonly used 6063 and other extruded alloys) are suitable for the production of regular fins and profiles, with low cost per piece and stable shape after mold input, and are suitable for large-scale street lamps and strip heat sinks. Die casting is suitable for shells with complex appearances and integrated mounting positions (common die-casting alloys such as ADC12 and A356), which are simple to mold and assemble at one time, but the thermal conductivity of die-casting alloys is usually not as good as pure aluminum or extrusion materials when the silicon content is high, and the mold cost is high, making it suitable for medium and large volumes. CNC machining and CNC milling are suitable for prototypes and small batches of high-precision parts, which can do fine grinding and polishing for hot contact surfaces, but the single processing cost is high and the material utilization rate is low; Fast stamping and bending speed and low cost, suitable for thin light discs or decorative parts, but limited heat dissipation in high power density scenarios. A common compromise solution in engineering is to use aluminum as the main heat dissipation structure and use copper as a thermal bridge at hot spots, which not only retains local high thermal conductivity, but also controls the overall weight and cost.
3. Specifications of common materials
Pure aluminum/high-purity aluminum: 1050 / 1060 / 1100, use: prototype, small batch of high thermal conductivity requirements. It has good thermal conductivity but low mechanical strength, making it suitable for scenarios that require higher thermal conductivity and uncomplicated post-processing. Extruded alloy: 6063 (commonly used for profiles) Usage: Most extruded profile radiators have good appearance and anti-corrosion performance after anodizing. Structural alloy: 6061 (machined parts) Usage: structural parts or machined heat sinks that require good mechanical strength and processability. Die-casting alloys: ADC12 / A356, etc. (regional names vary greatly) Use: Die-casting parts with complex shapes, suitable for heat dissipation enclosures with strong decorative or integrated mounting positions. Thermal conductivity is generally lower than pure aluminum/extrusion (silicon content affects thermal conductivity).
FAQ
Q1: Does aluminum “rust”?
A: Aluminum will not rust like iron, but it will form a film of alumina (patina corresponds not to aluminum). Anodizing/coating can further improve corrosion resistance, and anodizing or protective coating is recommended outdoors and passing the salt spray test.
Q2: How much does aluminum heat dissipation drop compared to copper?
A: Depends on the design and power density. At the same volume, copper monomers conduct heat better, but aluminum can compensate for with thinner and more fins, optimized structure, and larger surface area. The final result is based on thermal simulation and prototype testing.
Q3: Can I use bare aluminum directly in an outdoor salt spray environment?
A: It is not recommended to expose it to strong corrosive environments for a long time. Anodizing, powder spraying, or electrophoresis protective layers are recommended and salt spray testing.
Q4: Does aluminum significantly increase weight and cost?
A: The density of aluminum is much smaller than that of copper (about 1/3 of copper), so the weight is usually lighter; The cost is usually lower than copper. If a hybrid scheme of copper thermal bridge + aluminum heat sink is considered, it can not only take into account thermal conductivity but also control the total weight and cost.