Microstructure and surface quality of SLM printed miniature helical gear in LSPwC Paper

We are happy to announce that our colleagues from the Industrial Laser Applications (ILA) department Sunil Pathak, Marek Böhm, Jan Kaufman, Sanin Zulić, Ondřej Stránský, Jan Brajer and Tomáš Mocek (Head of the HiLASE Centre) together with Jaromír Kopeček (FZU) and Libor Beránek (CTU) have published a new article in the journal of Surface Engineering. The topic of the article is Microstructure and surface quality of SLM printed miniature helical gear in LSPwC.

The work describes the influence of underwater laser shock peening without coating (LSPwC) on selective laser melting manufactured meso-size (outside diameter ≤ 10 mm) helical gears. Five experiments were conducted using energies in the 200 mJ up to 1 J, while the spot size and overlap were kept constant as 1 mm and 90 %, respectively. Responses were measured and compared in terms of surface residual stresses, surface roughness, and microstructure of LSPwC-treated samples. Results show the development of significant compressive residual stresses in the root of the LSPwC processed helical gear, where it changes the state from tensile +45 MPa to compressive −421 MPa. Surface roughness has shown improvement, while volumetric material peak confirms the reduction by over 50%. Microstructure study was performed at the surface and by cross-section using scanning electron microscopy and electron backscatter diffraction analysis. The grain refinement and change in misorientation were observed, confirming plastic deformation.