Heat sinks made of aluminum alloy still dominate line in China

Mainstream heat sinks use Al 6061, Al 6063 and Al 1050. There are also hybrid types with a copper base and those based on other kinds of metal.

Aluminum alloy remains the material of choice among China manufacturers of heat sinks, although they keep a range of metal types to suit different applications. The commonly used types are Al 6061, Al 6063 and Al 1050.

Compared with copper, which has the advantages of high thermal conductivity and corrosion resistance, aluminum alloy is less expensive, easier to process and meets most requirements. To increase the latter’s thermal conductivity, companies continue to use the option of adding a copper plate to the base without significant impact on the cost.

Besides aluminum alloy, the choices are stainless steel, iron, carbon steel, zinc alloy, brass and pure copper, all of which are usually sourced from local providers. The processes employed are extrusion, skiving, CNC turning and milling, die-casting, friction stir welding, TIG welding and stamping. The surface treatments and methods include anodizing, powder coating, passivation, sandblasting, painting, hot-dip galvanization, and electroless nickel, zinc and chrome plating.

To ensure consistent output quality, facilities are typically equipped with heat resistance, electric resistance, strength, salt-spray, oxidation film and hardness testers.

Despite the local industry’s OEM emphasis, makers invest in R&D. In 2017, about 11,000 patented sinks were released.

The line’s main applications are computers, consumer and automotive electronics, communications products, lighting, and those in the medical, high-speed rail, and solar and wind power industries. This year, the automotive, new energy and communications fields are expected to lead demand. In China, heat sink sales are projected to increase by 7 to 10 percent YoY in the near term.

From exports, Shenzhen Kohong Precision Metal Co. Ltd and Shenzhen Xiangfu Precision Industry Co. Ltd are anticipating a 20 percent increase in revenue by end-2018. The former plans to purchase 10 automatic punching machines, which can process 10,000 pieces daily, to boost production efficiency.

Shanghai Esme Corp. Ltd expects greater demand from the aviation and automotive sectors, and is prepared to enlarge its workshop when overseas orders rise. Heat sinks currently account for 45 percent of total exports.

Kingka Tech Industrial Ltd will consider facility expansion and machinery acquisition if more orders pour in from abroad, but at present believes shipments will not change much. It exports 30 percent of heat sinks.

China accounts for more than 60 percent of global shipments in the line. The main overseas destinations are North America and Europe. Products are also sent to South America and Southeast Asia.

Active heat sinks represent 60 percent of outbound production and passive types the rest. All are RoHS-compliant, with those for automotive applications having an additional certification from IATF.

There are more than 1,500 heat sink makers in China and 90 percent are local businesses. Most are in the Pearl River and the Yangtze River Delta regions, where the electronics industries they are servicing are based. The key city locations are Shenzhen and Dongguan in Guangdong province and Ningbo in Zhejiang.

Besides heat sinks, these manufacturers turn out stamped, CNC-machined and die-cast metal parts.

Industry challenges

As with other manufacturers in China, companies in the heat sink sector face higher labor and material expenditure. The cost of aluminum alloy rose by 7 percent YoY. The current quote is $2,338 to $2,397 per ton, according to the China aluminum website.

In addition, makers may find difficulty in finding factories that provide surface treatment services. The number of companies in this support industry is decreasing because of the national government’s environmental protection campaign. This can affect overall cost and lead time.

To cope, many suppliers are pushing for automation to achieve greater efficiency and lower production costs, while some are considering handling all processes in-house. Shenzhen Kohong, which has automated its riveting process, is looking to implement a 5 percent quote reduction.

The products in this gallery have been handpicked by our China-based market analyst for representing current trends in heat sinks from China makers.

Aluminum heat sink

The HLC-Heat Sink-07 model from HLC Metal Parts Ltd is made entirely of aluminum and can be customized. It complies with RoHS guidelines. The product is priced between $2 and $5.

The minimum order is 2,000 pieces. Delivery is in 20 to 25 days.

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Al 6063-T5 heat sink

Kingka Tech Industrial Ltd’s Kingka LED Heat Sink KF188 model uses Al 6063-T5 and comes in black. It is quoted at $5.30.

The supplier requires an order of at least 1,000 pieces for delivery within 20 days.

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Liquid-cooling heat sink

This heat sink from Shanghai Esme Corp. Ltd, HKSGS-0.69-4244DK.09.1080.1 model, is a liquid-cooling heat sink. It is made of Al 6061-T6. Dimensions are 700x120x20mm and weight is 3.5kg. Price is $135.

The minimum order is 200 pieces and delivery takes 4 weeks.

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Anodized Al 1050 heat sink

Shenzhen Kohong Precision Metal Co. Ltd can turn out model KH-888 heat sink in a maximum size of 500x500mm. The product is made of Al 1050 and can be anodized in any color. It is priced at $2.30.

The minimum order of 10,000 pieces is for delivery within 30 days.

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