The latest material available in additive manufacturing is Copper (C18150), a chromium zirconium copper (CuCr1Zr) alloy defined by its excellent thermal and electrical conductivity. Additive C18150 was developed to fill the void in the AM market and the demand for additive copper.
Stratasys Direct developed the process to produce additive C18150 and implemented controlled heat treat processes to optimize mechanical and material properties. We worked with major aerospace companies to validate results and apply the material to critical thermal transfer applications.
C18150 has stable mechanical and material properties up to 700°F and is age hardenable. Stratasys Direct Manufacturing’s engineers took months validating the copper material, ensuring it would run reliably and produce accurate parts. C18150 is ideal for the production of thermal management applications, and in addition to aerospace, the material is used in the energy and transportation industries.
The design freedom, and the performance increases achieved through design optimization, makes the additive manufacturing process beneficial for many thermal management applications. Design freedom enables the implementation of non-linear and tapered geometries in extended structures like fins, vane blades, capillary wicking structures, heat pipes and conformal internal passages. A byproduct of design freedom is part consolidation, saving time and money on parts production and assembly. Significant weight and space savings can also be realized by designers and engineers utilizing AM.
At Stratasys Direct, we utilize Direct Metal Laser Sintering (DMLS), a type of Direct Metal Laser Melting (DMLM) technology. DMLS produces tough, accurate metal parts and allows for complex geometries including complex internal channels. Utilizing copper material with this technology opens up additional thermal control possibilities for engineers.
We’ve utilized additive copper for integrated regenerative cooling of rocket engines with internal conformal channels within a rocket nozzle. DMLS is also used to print curved and angled heat pipes used in long-range space applications and small satellites, as well as optimized wicking structures.
Additionally, microchannel and jet impingement strategies can be optimized using AM for microelectronic device cooling. Lattice structures have been used for integral thermal shielding within a part and create a passive barrier for heat conduction. DMLS and copper can also be used for conformal induction coils and plastic mold components.
AM with copper provides preferable performance and efficiency gains in many thermal control applications. However, there are key design elements to consider for engineers looking to take advantage of the technology.
There are wall thickness and feature detail considerations for designers utilizing DMLS technology. Conformal cooling, complex internal passages may require designing support structures. Especially with heat exchangers, thinner walls are better, but there are limits on how thin walls can be made, which is roughly 1000 micrometers of 0.040”.
The as-built surface finish of a DMLS part is not ideal for most fluid flow applications, which is why Stratasys Direct offers post-processing operations such as machining to improve the finish of DMLS parts. Other post-processing methods include heat treatments and densification, dependent on geometry and material. The equipment manufacturer (EOS), has a general rule of thumb that is an 8:1 ratio of height to wall thickness. For example if there is a 0.100-in thick wall building unsupported higher than 0.800-in the wall may fail.
These design challenges are mitigated by careful design and attention to the technology’s capabilities. Learn more about DMLS design considerations in our Design Guidelines.
Additively manufacturing parts in copper opens new doors for engineers creating novel geometries for thermal management systems. Improving functionality and heat transfer, AM provides unparalleled geometric freedom with the same thermal conductivity afforded from copper.