The dilemma faced by the manufacture of traditional copper heat exchangers
The rapid development of semiconductor technology and communication technology, and the trend of the Internet of Everything have brought about a rapid increase in computing power and high-speed data connection all the time. If the heat cannot be dissipated in time, it will lead to thermal damage to electronic components, bringing serious harm and huge economic losses. Efficient heat dissipation technology is the key to reducing or even avoiding the thermal damage caused by heat accumulation in electronic components. 
Common copper heat exchangers (**network).
Because of its excellent thermal conductivity and easy processing, copper is often made into heat exchangers in consumer electronics, home appliances, automobiles and other industries, and has a wide range of application prospects in thermal management fields such as power generation systems, transportation, oil and gas processing, seawater desalination, etc. Traditionally, heat exchangers have been produced by fabricating individual fins, tubes, or plates and gluing or welding them together. This is a manual technique and if there is a failure between any of these brazed joints, it can lead to a failure of the heat exchanger. And with millions of heat exchangers in use around the world today, the performance and efficiency of heat exchangers are more important than ever in terms of global sustainability and reducing energy consumption. Increasingly complex heat exchange technologies have made traditional processes a bit overwhelming, and it is important to adopt new technologies to achieve a high surface area to promote effective heat flow, while at the same time being small and lightweight. 
Radiators manufactured by traditional processes (** network).
Advantages and limitations of pure copper D-printed heat exchangers
3D printing opens up new avenues for novel heat exchanger designs, which can be optimized for flowability and conductivity, meeting the development trend of products towards compactness, high efficiency, modularity, and multi-material. In particular, 3D printing has the advantages that traditional manufacturing technology does not have, especially for processing special-shaped, structural integration, thin-walled, thin fins, micro-channels, very complex shapes, lattice structures, etc. 
3D printing of copper is particularly suitable for the manufacture of copper heat exchange components. However, due to the very high thermal conductivity and reflectivity of copper, which makes it difficult for copper metal, especially pure copper, to be effectively formed by conventional 3D printing, and the absorption rate of copper to near-infrared light at room temperature is only 5%, which also means that the processing window is very narrow, it is difficult to find perfect parameters, and the processing efficiency is also very slow, and the mechanical properties and electrical conductivity of the workpiece are greatly limited. For example, the most typical metal additive processes, selective laser melting (SLM) and electron beam melting (EBM) can print pure copper materials. However, in the process of laser melting of copper, the absorption rate of SLM process is low, and it is difficult for the laser to continuously melt copper metal powder, resulting in low forming efficiency and difficult control of metallurgical quality. In addition, the high ductility of copper makes post-processing such as removing excess powder more difficult. EBM has a slight advantage because it uses an electron beam as a heat source and is not affected by the high reflection factor of SLM laser, but because copper has a high conductivity, the EBM printing process will be very shortIn addition, due to the high thermal conductivity of copper, the dimensional accuracy and mechanical properties of the printed model will be poor, so the surface quality of the printed copper components is poor. 
Heat sink design resulting from parametric optimization (left) and topology optimization (right) (**Courtesy of Fritz Lange).
PEP provides a better solution for the manufacture of pure copper heat exchangers
The absorption rate of copper for green laser is very high, close to 40%, which is 8 times that of near-infrared laser, which effectively overcomes the problem of laser printing pure copper. In addition, the copper 3D printing process of binder jetting (BJ) process has also been commercialized. However, due to the powder bed method, the cleaning of complex internal flow channels or hollow structures is also a great challenge. byThe powder extrusion printing (PEP) technology launched by Shenghua 3D cleverly avoids the problems of high thermal conductivity and high reflection in the pure copper printing process. The PEP process uses particle melt extrusion to obtain high-performance pure copper components with excellent structure by printing green billets first, and then going through a mature powder metallurgy debinding and sintering process. It is expected to bring better solutions for the next generation of thermal management component manufacturing. 
Pure copper radiator and inductor assembly prepared by Sublimation 3D.
PEP technology is an indirect 3D printing process of metal ceramics combined with "3D printing + powder metallurgy" launched by Shenghua 3D, which has the characteristics of low-temperature molding and high-temperature forming。PEP does not require a high-energy laser beam when printing pure copper. Shenghua 3D has developed pure copper granular UPGM-CU for pure copper 3D printing, which maintains the high purity of raw materials while also having the characteristics of easier densification, which can meet the printing needs of different pure copper parts. Through self-developed 3D printing equipment, pure copper and its alloy materials can be processed to manufacture dense partsPure copper 3D printing fills the domestic gap in one fell swoop。At present, it has been widely used in the product development of heat exchangers, radiators and electric inductors. 
Sublimation 3D pure copper printing product performance data.
3D printing will become a powerful tool to promote the upgrading of thermal management technology
At present, the hottest fields of 3D printing application development in thermal management are mainly related to electric vehicles, high-end computing, aerospace and defense, and the industry's focus is on heat exchangers, aerospace thermal management components, high-end chip heat dissipation components such as micro cold plates, topology optimization channel liquid cooling heat exchangers, etc. 3D printing provides a new and irreplaceable solution for thermal management, and is a powerful tool to solve the problem of high heat flux calculation cooling. However, at present, the mature application market is still mainly based on traditional manufacturing methods, but with the high requirements of manufacturing technology, the application of 3D printing in the field of thermal management will be the future development trend.
At present, Shenghua 3D has built a complete pre- and post-processing process for indirect 3D printing of metal ceramics, covering the whole process chain equipment such as material development, printing materials, internal refining granulators, 3D printers, debinding and sintering furnaces, etc., which can provide high-performance indirect 3D printing solutions. At the same time, we also welcome extensive exchanges between the additive manufacturing industry and friends in the heat dissipation industry, promote technology integration, and provide valuable opinions for the application of additive manufacturing in the field of heat dissipation.