Pin Fin Array Heat Sinks by Cold Spray Additive Manufacturing: Economics of Powder Recycling

As a result of the rise in processing power demands of today's personal computers, water-cooled pin fin heat sinks are increasingly being employed for the cooling of graphical processing units. Currently, these high-performance devices are manufactured through high-cost, high-waste processes. In recent years, a new solution has emerged using the cold gas dynamic spray process, in which pin fins are manufactured onto a base plate by spraying metallic powder particles through a mask allowing for a high degree of adaptability to different graphics processing unit shapes and sizes. One drawback of this process is reduced deposition efficiency, resulting in a fair portion of the feedstock powder being wasted as substrate sensitivity to heat and mechanical residual stresses requires the use of reduced spray parameters. This work aims to demonstrate the feasibility of using powder recycling to mitigate this issue and compares coatings sprayed with reclaimed powder to their counterparts sprayed with as-received powder. The work demonstrates that cold gas dynamic spray is a highly flexible and economically competitive process for the production of pin fin heat sinks when using powder recycling. The heat transfer properties of the resulting fins are briefly addressed and demonstrated.