3D printing of intricate sand cores for complex copper castings

Copper cast machine components are largely used in high temperature applications. Provision of internal water cooling channels in the cast, coupled with the high thermal conductivity of copper, enables cast components to perform reliably in extreme temperature ambient. However, creation of geometrically intricate internal structures in the cast is critical to improving component’s cooling efficiency and service life. Unfortunately, many of the ideal complex internal structures (cores) either cannot be manufactured using traditional methods or are not cost competitive.

This research focuses on the proof of concept. It demonstrates printing sand cores for employment in the manufacture of copper castings with complex inner cooling channels. The technique of binder jetting is used. A binder is selectively deposited onto a sand bed at room temperature to reduce dimensional distortions. The binder jetted sand is printed into cores. The cores are placed into a sand mould and filled with molten copper.

Simulation method is employed to determine the properties of the printed cores. The results are compared with that of traditional cast samples. It is found that the printed cores have consistent properties compared with the handmade cores. The surface roughness of the internal core faces is 2.03 Ra (μm). Finning is not present due to the absence of split lines found in most traditional sand cores.

The use of binder jetting technique increases manufacturability of intricate geometric cores for copper sand casting.