Surfaces of polycarbonate Selective Laser Sintering parts are investigated to determine the characteristics aaecting part quality. Surfaces are obtained from experiments by varying four factors, namely, layer thickness, laser power, part orientation, and build angle. First, spatial modes on SLS surfaces are decomposed using a qualitative spectral analysis in an attempt to nd their origins. Ther...

Laser Beam Melting is a promising Additive Manufacturing technology for the production of complex metal components. During batch production of multiple identical parts in a single build job, we observed parts with deviating surface roughness in certain areas, which all faced away from the laser. This suggests a dependency of surface roughness on the part position in the build chamber. In this w...

H. Chmelíčková, H. Šebestová, M. Havelková, H. Hiklová, J. Tomáštík, RCPTM, Joint Lab. of Optics, Faculty of Science, Palacky University, Olomouc, Czech Republic This paper presents a simulation of laser surface remelting with the SYSWELD finite element method software. Micro-structural changes, increase of hardness, and surface profile modification of the remelted samples are evaluated. The mo...

This study demonstrated circular surface nanostructures and femtosecond laser-induced periodic surface structures (FLIPSS) for copper produced by a Ti:Sapphire femtosecond laser beam of wavelength 800 nm and duration 120 fs. The circular textured nanostrucres could be created by a single laser pulse. The nanostructures in the center of the heated spot diminish as laser fluence increases and a c...

Laser polishing is a finishing process based on melting material, with the objective of improving surface topography. Some operating parameters must be taken into consideration, such as laser power, feed rate, offset, and overlapping. Moreover, because of its dependence on the primary process, the initial topography has also an impact on the final result. This study describes a quadratic model,...

The kinetics and microscopic mechanisms of laser melting of a thin metal film are investigated in a computational study that combines molecular dynamics simulations with a continuum description of the laser excitation and subsequent relaxation of the conduction band electrons. Two competing melting mechanisms, homogeneous nucleation of liquid regions inside the crystalline material and propagat...

The kinetics and channels of laser energy redistribution in a target irradiated by a short, 1 ps, laser pulse is investigated in computer simulations performed with a model that combines molecular dynamics (MD) simulations with a continuum description of the laser excitation and relaxation of the conduction band electrons, based on the two-temperature model (TTM). The energy transferred from th...

The vapor-liquid equilibria of three recently proposed water models have been computed using Gibbs-Duhem simulations. These models are TIP4P/Ew, TIP4P/2005, and TIP4P/ice and can be considered as modified versions of the TIP4P model. By design TIP4P reproduces the vaporization enthalpy of water at room temperature, whereas TIP4P/Ew and TIP4P/2005 match the temperature of maximum density and TIP...

An advanced continuum model for nanoscale melting and kinetic superheating of an aluminum nanolayer irradiated by a picosecond laser is formulated. Barrierless nucleation of surface premelting and melting occurs, followed by a propagation of two solid-melt interfaces toward each other and their collision. For a slow heating rate of Q = 0.015 K ps(-1) melting occurs at the equilibrium melting te...

There is a fundamental interest in studying photoinduced dynamics in nanoparticles and nanostructures as it provides insight into their mechanical and thermal properties out of equilibrium and during phase transitions. Nanoparticles can display significantly different properties from the bulk, which is due to the interplay between their size, morphology, crystallinity, defect concentration, and...