Two weeks ago today, the sixth-annual Laser Additive Manufacturing Workshop opened in Houston with a riveting keynote by GE Aviation’s Todd Rockstroh. Setting an attendance record, LAM 2014 closed the following day with a lively Q&A session on the qualities and varieties of AM alloys for powder-bed and powder-fed applications.
By: Xinwei Wang
Department of Mechanical Engineering, Iowa State University
This work reports on the pioneering molecular dynamics (MD) modeling of shock waves in laser-material processing. For pulsed laser-assisted material processing with an ambient gas, the fast melting, vaporization, and phase explosion of the target is a very complicated process and will form a strong shock wave in the ambient gas. Formation of the shock wave and the interaction between the shock wave and the plume play critical roles in processing control. In this work, the dynamics and internal structure of shock waves in picosecond laser-material interaction are explored at the atomistic level by tracking the movement of individual atoms. The pressure of the shock wave, its propagation, the interaction zone thickness between the plume and ambience, the inside velocity profile at nanoscales are evaluated to study the effect of the laser absorption depth, ambient pressure, and laser fluence. Due to the strong constraint from the compressed ambient gas, the ablated plume could stop moving forward and mix with the ambient gas, or move backward to the target surface, leading to surface redeposition. Under smaller laser absorption depth, lower ambient pressure, or higher laser fluence, the shock wave will propagate faster and have a thicker interaction zone between the target and ambient gas. Plume splitting and secondary shockwave due to strong constraint of the ambient gas are observed and explored to reveal their underlying physics. Continue reading
By: Klaus Loeffler
TRUMPF Laser und Systemtechnik GmbH, Ditzingen, Germany
The automotive industry has been a target market for the laser soon after the invention of the laser in 1960. Mass production and flexibility have been the arguments for the laser. The first installations in 1973 all the way to late 1980 have been successful due to the missing industrial ready laser resonators. But the laser has seen a fast development over the years and with it the use of lasers in the automotive industry.
By: Che Zhi-gang
The technique of laser shock process (LSP) is an advanced surface treatment, which import high pressure shock wave induced by laser beam into target materials to improve their performance. The fatigue life of the materials is prolonged by times through changing the stress distribution. The hardness and strength are increased remarkably and corrosion resistance is improved after LSP. Compared with other treatment techniques, LSP have many advantages, such as high pressure, high energy, high strain rate, noncontact, no heat-affected zone, better controllability and roughness and remarkable processing effect.
By: Alexander Schell and Keming Du
EdgeWave GmbH, Germany
In order to reduce production costs and to increase throughput, great efforts have been put to explore efficient processing in full-automated manufacturing lines. Because of non-contact processing and high flexibility the use of lasers in photovoltaic production has grown in popularity, for example laser fired contact, drilling contact holes, edge isolation, scribing, edge deletion, etc. Different application needs different laser parameters such as wavelength and beam profiles.
