When should I choose a composite heat dissipation material?
COB high-power floodlights, stage lights (high heat flux density), automotive headlamp modules (space-constrained and fast temperature equalization), ultra-thin panel lights (thin but uniform temperature), and laser lighting/industrial light sources (very high point heat density).
1. Why are composite materials used in the heat dissipation structure of lamps?
When a small area of a luminaire dissipates heat too quickly (heat concentration), a single material often overheats in a small area before it can be removed, resulting in shorter LED life and reduced brightness. The idea of composite heat sinks is simple: put a fast, heavy, and expensive material (such as copper, heat pipes, or graphite) in the “hottest” place, and take cheap, light, and easy-to-make finned aluminum to dissipate the heat – it can quickly cool down the hot spot without making the whole lamp heavy and expensive.
2. Different composite material processing processes are suitable for lamp types
Cold pressing embedding / punching riveting and cold riveting: This process mechanically presses copper columns, copper blocks or metal inserts into the aluminum matrix and is the most common mass production compounding method. The advantages are simple process, high production capacity, and low cost per piece, and are often used for local thermal bridge treatment of floodlights, street lights, and high-power COB modules. Friction stir welding / explosion welding (high-strength metal bonding): Used for copper-aluminum interfaces with high reliability and heat transfer requirements, metal-to-metal bonding through local plastic flow or impact. Adaptation scenarios are key parts that require long-term heat resistance cycles and cannot be peeled off, such as high-end stage lights or automotive-grade electronic cavities. Welding (soldering/silver soldering) and bonding (thermal adhesive): This practice is mostly used for combining small area copper patches, graphite sheets or heat pipes with aluminum parts, and is typically used for light plates, backplates or prototype prototypes. Heat pipe and vapor chamber assembly (pressure groove + fixation): The heat pipe/vapor chamber is typically embedded in a reserved groove in the aluminum heat sink and is secured by mechanical pressing, fixture fixing, or thermal adhesive curing. They excel at quickly transferring hot heat to the remote heat dissipation area and are commonly used in car lights, ultra-thin panel lights, and high-power floodlights. Graphite thermal conductive sheet lamination (thermal conductive adhesive/mechanical pressing): The graphite has extremely high thermal conductivity and extremely thin thickness, which is suitable for ultra-thin structures and backlight uniform temperature (ultra-thin panel lights, line lights). And do repeatable verification.
3. Commonly used material specifications
The “composite” of composite heat sinks refers to the combination of different materials at the structural or component level (e.g., local copper blocks embedded in the aluminum body, heat pipes embedded in aluminum grooves, or graphite sheets between the aluminum backplate and the chip), rather than mixing copper and aluminum into a new alloy. The following is a summary of common materials according to their use, which is convenient for engineering selection and inquiry: Aluminum and common aluminum alloys (1060/1100/6063/6061): Volumetric heat dissipation and extrusion profiles are preferred, with a typical thermal conductivity of 120–205 W/m·K and a density of ~2.7 g/cm³. Low cost and easy to form. Copper-aluminum composite (explosive welding/FSW/cold pressing, etc.): through the process of combining copper and aluminum into one, it is used to localize the high thermal conductivity of copper to hot spots, aluminum to dissipate heat in a large area, and need to deal with electrochemical corrosion problems. Graphite thermal conductive sheet (high thermal conductivity in the plane): suitable for ultra-thin temperature chamber, the thermal conductivity in the plane can be very high (hundreds to thousands of W/m·K), the thickness is extremely thin, and the assembly process requirements are high. Heat pipes / vapor chambers (components): used for rapid heat transfer over long distances or in planes, often used in combination with aluminum heat sinks. Ceramics (e.g., AlN) and TIMs: for electrical insulation + thermal conductivity scenarios, as well as filler materials to reduce thermal resistance at the interface.
FAQ
Q1: Will copper-aluminum composites cause electrochemical corrosion?
A: Yes. It can occur in a humid/salt spray environment and must be plated on the contact surface or insulated with insulation.
Q2: Can the heat pipe be bent?
A: The diameter is small and the short distance is easy to bend, but the bending will affect the internal capillary structure and performance, so it is recommended to use prefabricated bending pipes or vapor chamber solutions.
Q3: Will the graphite sheet warp or break?
A: Thin graphite is fragile, so it is recommended to use uniform pressing or protective film to avoid local concentrated pressure points during assembly.
Q4: Is the composite solution easy to maintain?
A: It depends on the design. The modular design (removable heat exchanger, replaceable copper block) is more conducive to maintenance.