1. Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore e-mail:
2. Assistant Professor Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore e-mail:
3. Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075, Singapore e-mail: