JLA Vol:15 Iss:4 (Induction heat treatment of laser welds)

Authors:
Claus Bagger
Joakim Ilsing Sørensen
Flemming O. Olsen
Manufacturing Engineering and Management, Materials and Process Technology, Technical University of Denmark, Building 425, DK-2800 Lyngby, Denmark

In this article, a new approach based on induction heat treatment of flat laser welded sheets is presented. With this new concept, the ductility of high strength steels GA260 with a thickness of 1.8 mm and CMn with a thickness of 2.13 mm is believed to be improved by prolonging the cooling time from 750 to 450 °C. Initially, a simple analytical model was used to calculate the ideal energy contributions from a CO₂ high power laser s...

JLA Vol:19 Iss:4 (Ablation and cutting of silicon wafer and micro-mold fabrication using femtosecond laser pulses)

Authors:
Ying Wang
Nengli Dai
Yuhua Li
Xinlin Wang
Peixiang Lu
Wuhan National Laboratory for Optoelectronics and School of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China

Femtosecond laser micromachining of silicon wafer at a relatively higher energy fluence level (>50 J/cm²) is investigated. Laser ablating spots and cutting kerfs are examined by means of charge coupled device camera and scanning electron microscopy. The area of ablated spots increases linearly with increasing the shot number from 1 to 16 and shows saturation with t...

JLA Vol:9 Iss:4 (Dual wavelength laser beam alloying of aluminum alloy for enhanced corrosion resistance)

Authors:
Z. Liu
K. G. Watkins
W. M. Steen
R. Vilar
M. G. Ferreira

Aluminum alloys are known for their poor resistance to localized attack and, in particular, for pitting in chloride‐containing electrolytes. In this paper, improvement of the pitting corrosion resistance of 2014‐T6 aluminum alloy has been investigated by means of laser surface alloying of Cr into the substrate. Since aluminum is a highly reflective and thermally conductive material, it is often difficult to process with laser beams. Oxide films on the surface can prevent surface alloying as with the case of Cr alloying into aluminum by in‐situ...

JLA Vol:4 Iss:1 (The Impact of European Standards, Directives and the CE Mark)

Authors:
A. Roy Henderson
Bioptica, St. John's Innovation Park, Cambridge U.K.

JLA Vol:14 Iss:1 (Multiple reflection and its influence on keyhole evolution)

Authors:
Hyungson Ki
Pravansu S. Mohanty
Jyotirmoy Mazumder
Center for Laser Aided Intelligent Manufacturing, Department of Mechanical Engineering and Applied Mechanics, The University of Michigan, Ann Arbor, Michigan 48109-2125

In laser drilling and keyhole welding, multiple reflection phenomena determine how the energy is transferred from the laser beam to the workpiece, and, most importantly, all other physics such as fluid flow, heat transfer, and the cavity shape itself depend on these phenomena. In this study, a multiple reflection model inside a self-consistent (or self-evolving) cavity has been developed based on the level set method and ray tracing t...

JLA Vol:18 Iss:2 (Laser ablation of silicon wafer with a water microdrop)

Authors:
Kouki Shimizu
Kunimitsu Takahashi
Photonics and Materials Research Department, Institute of Research and Innovation, 1201 Takada, Kashiwa, Chiba 277-0861, Japan

Hiroshi Morikazu
Nobumori Ogoshi
Koichi Takeyama
DISCO Corporation, 13-11 Omori-Kita 2-chome, Ota-ku, Tokyo 143-8580, Japan

Yoji Wakayama
LINTEC Corporation, 5-14-42 Nishiki-cho, Warabi-shi, Saitama 335-0005, Japan

Tetsuro Obara
Saitama University, 255-Shimo-okubo, Sakura-ku, Saitama-shi, Saitama 338-8570, Japan

We have developed a new laser ablation process using a water-microdrop with a diameter of 70 μm....

JLA Vol:23 Iss:4 (Investigation of the effect of irradiance and pulse duration in industrial percussion laser-drilling of Waspaloy)

Authors:
Robin Bright
Harris L. Marcus
Institute of Materials Science and the Department of Chemical, Materials, and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut 06269-3136

As the use of pulsed lasers in the manufacture of cooling holes in high-temperature gas-turbine engine components continues to increase, understanding the material behavior during laser-material interaction and the subsequent effects on hole quality becomes critical. In this study, atomic emission spectroscopy is used to monitor the optical characteristics of ejected material during percussion laser-drilling of Waspaloy over irradiance and pulse duration values in the ranges...

JLA Vol:6 Iss:2 (National Science Foundation undergraduate faculty enhancement workshop on advanced laboratory experiments using lasers)

Authors:
James E. Parks
Charles S. Feigerle
Robert Deserio
Joseph Wiest

A National Science Foundation undergraduate faculty enhancement workshop on advanced laboratory experiments using lasers was developed at the University of Tennessee, Knoxville, with the authors as the instructors. The workshop emphasized the development and implementation of laser‐based experiments primarily suitable for advanced undergraduate physics and chemistry laboratories. Participants gained practical, hands‐on experience in approximately 16 unique laser‐based experiments in atomic and molecular physics, physical chemistry, and biophysics. The wo...

JLA Vol:25 Iss:5 (Numerical and experimental study of the effect of groove on plasma plume during high power laser welding)

Authors:
Cai Yan
Xie Wen-Jing
Wu Yue
Sun Da-Wei
Wu Yixiong
Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240, China and Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai 200240, China

The influence of groove on the static feature and dynamic behavior of plasma plume during high power CO₂ laser welding process was studied using a hydrodynamic three-dimensional model and corresponding experiments. The temperature, composition, and velocity of plasma plume along the incident path of laser beam were computed. The static morphology of plasma plume was analyzed through both models ...

JLA Vol:3 Iss:1 (Nursing Perspective: Clinical Laser Safety Issues Survey)

Authors:
Penny J. Smalley
Laser Resources & Consulting Services, Chicago, Illinois