Dr Robert Groarke
Postdoctoral Researcher

Dr Groarke completed his undergraduate degree in Chemical and Pharmaceutical Sciences in 2004 and his PhD in 2009, both at Dublin City University. His doctoral thesis was focused on the understanding of excited state photophysical processes in transition metal complexes, both in solution and on substrates. These complexes were investigated as potential solar cell sensitizers.

In 2015, he joined the Prof Brabazon’s group in DCU working on using additive manufacturing for chromatography and sensor applications. His current research interests are in metal powder characterisation and additive manufacturing using metals, shape memory alloys and polymeric materials, with potential applications in heat exchangers and heat engines.

Research Interests (Lay Summary)

Dr Groarke is interested in the characterisation and application of metal powders in additive manufacturing. Understanding how powder size, shape, surface chemistry and porosity affect final part properties is of critical importance to additive manufacturing, from the first use of the powder through to understanding how reusing powder affects subsequent part properties. This is an important step towards making metal additive manufacturing a sustainable manufacturing route.

His current project will investigate a nickel-titanium alloy (Nitinol) which has very interesting shape memory properties. Such shape memory properties lend themselves to a heat exchanger application where hot and cold water are used to expand and contract the rods in the device. The project will aim to demonstrate that it is possible to manufacture heat exchanger components via additive manufacturing that possess similar mechanical and shape memory properties to parts fabricated using conventional manufacturing methods. It will also produce heat exchanger parts with complex shapes that would be impossible to fabricate using conventional means.

 

Technical Summary

The scope of this project is focused on determining if the introduction of an additively manufactured (AM) Nitinol heat exchange component can lead to a more efficient and/or robust heat engine design.

A key component of this research is the use of the Aconity MINI metal Selective Laser Melting (SLM) machine. This has novel capabilities such as pyrometric based process monitoring and high temperature powder heating (up to 800 °C). The latter will allow for fine control of the cooling rate of the part layer, which will allow for a desired microstructure to be formed. This is crucial in obtaining the shape memory properties of Nitinol. It will also mean that the thermal cycle is less extreme, therefore reducing the thermal stresses in the final part.

Expertise

Additive Manufacturing (3D Printing), Multi-material Jetting, Materials Processing, Design for Manufacture (DfM), Materials Characterisation, Metrology, Additive Manufacturing Post Processing, Powder Bed Fusion, Powder Characterisation, Selective Laser Melting (SLM)

Publications