Material selection, technical challenges and industry cases of 3D-printed heat exchangers

The heat exchangers produced by 3D printing have a larger heat exchange area, superior thermal performance and lighter weight, completely changing the production method of radiators.

However, it should be noted that for 3D printing to achieve these advantages, a series of technical challenges need to be overcome, such as controlling thermal stress and deformation to maintain structural integrity; optimizing surface roughness to enhance heat transfer and durability, etc.

In this article's case, the 3D printing technology reference will list application cases covering various materials and industries.

The surface quality directly affects the performance, safety and lifespan of metal 3D-printed heat exchangers.

A smooth and uniform surface can minimize stress concentration and crack propagation, thereby reducing the risk of fatigue failure, reducing flow resistance, improving heat efficiency and heat dissipation capacity. Moreover, a smoother surface can also reduce the accumulation of dirt and contaminants, not only prolonging the lifespan of the heat exchanger but also making the later maintenance simpler.

The manufacturing precision of 3D printing is extremely high, enabling the production of high-performance heat exchangers. These heat exchangers can maintain high efficiency over a long period and have already played an important role in aerospace, automotive, shipping, nuclear energy, AI computing power, and other industrial fields.

Heat exchangers usually use metals with good thermal conductivity, high mechanical strength and corrosion resistance. However, apart from the heat exchange performance, the mechanical properties of the materials also vary. Here are some commonly used materials for heat exchangers:

1.316L stainless steel

It is inexpensive and corrosion-resistant, but has limited strength and is not suitable for high-pressure or high-temperature environments.

2.In718

The mechanical properties at high temperatures and corrosion resistance are good, but the cost is high and the thermal conductivity is low.

3.AlSi7Mg and AlSi10Mg

Light in weight, good thermal conductivity, but low in strength and fatigue resistance.

4.Ti-6Al-4V

The strength-to-weight ratio is high, the corrosion resistance is good, but the price is relatively higher. The thermal conductivity is poor.

5.Copper-Chromium-Zirconium (Cu-Cr-Zr)

It has excellent thermal conductivity and excellent high-temperature performance, but its corrosion resistance is weaker than 316L stainless steel and titanium alloys, and the cost is higher than aluminum alloys.

6.Pure Copper

It has the best thermal conductivity among metal 3D printing heat exchange materials, but the mechanical strength is very low.

At present, almost all metal 3D printing enterprises are developing applications for 3D printing in the field of heat dissipation. The following are several cases disclosed by the French well-known enterprise AddUp.

1.Heat exchanger in the aerospace industry

This project originated from the European Space Agency. The application scenario is for heat exchangers in thermal components in the aerospace industry.

The goal is to use the LPBF process to manufacture complex geometric shape components with thin walls and efficient internal structures, requiring compact design and improved heat exchange efficiency.

The challenges to be overcome are to achieve higher heat dissipation performance within a smaller volume, create precise and sealed geometric structures, and achieve high-performance heat dissipation.

The final part was printed in one go using AlSi7Mg, with a product size of 116x116x60mm and a weight of 244g. The volume is smaller, but the thermal performance is excellent. It has passed the thermal performance and sealingity tests.

2.Optimized Heat Exchanger for 3D Printers

This project is to develop a compact, more efficient cooling heat exchanger for AddUp's FormUp 350 metal printer.

The main challenge is the same as its requirements - high heat exchange efficiency, small size, and low cost!

The internal channels, fins, and interfaces were all customized and printed with aluminum alloy. The final size was reduced by 64%, the weight was reduced by 6 times, the heat dissipation efficiency was improved, and the cost was comparable to that of the traditional design.

3.Aviation Double-Surfaced Heat Exchanger

This case involves the development of a heat exchanger that is compatible with aerospace systems. It requires the use of In718 for manufacturing and optimization of thermal performance and compactness through 3D printing.

The challenges to be overcome include the need to ensure adequate airflow through the heat exchanger while maintaining high heat transfer efficiency; In718 is heavier and has poorer conductivity than aluminum; and it must meet the required aerospace surface and volume requirements.

The density of In718 is more than three times that of aluminum. However, for additive manufacturing, it exhibits superior characteristics. Using this material, fins with a wall thickness of only 0.15 millimeters can be printed, and the entire device has no leakage. With this ultra-thin design, the heat exchanger achieves performance and weight characteristics similar to those of aluminum.

4.Green Laser 3D Printed Electronic Device Small Pure Copper Heat Sink

This case showcases a pure copper heat sink jointly designed and manufactured by domestic Mangge Technology and Yanyun Magnetic Additive. It is specifically designed to address the heat dissipation bottleneck of electronic devices in miniaturized and high-power scenarios.

The material used is pure copper, with a lattice wall thickness of 0.5mm, and the density reaches over 99.8%. Moreover, this heat sink has passed an 8MPa water pressure test and can maintain no leakage for 5 minutes.

Mangge Technology used its independently developed VoxelDance Additive (VDA) software to design this heat sink. By relying on implicit modeling technology, it can quickly achieve parametric filling of the TPMS structure, significantly shortening the design time.

Yanyun Magnetic Additive developed the green laser 3D printer, which creates conditions for high-quality 3D printing of pure copper and also provides the possibility to break through the deadlock in pure copper applications. Compared to traditional infrared lasers, pure copper has a higher absorption rate for green lasers. Now, Yanyun Magnetic Additive has started batch manufacturing of pure copper 3D printing.

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