Influence of laser beam size on measurement sensitivity of thermophysical property gradients in layered structures using thermal-wave techniques

2008 ◽  
Vol 103 (4) ◽  
pp. 043510 ◽  
Author(s):  
Chinhua Wang ◽  
Andreas Mandelis ◽  
Hong Qu ◽  
Zhuying Chen
Keyword(s):  
Laser Beam ◽  
Thermophysical Property ◽  
Thermal Wave ◽  
Layered Structures ◽  
Beam Size ◽  
Measurement Sensitivity

Finite laser beam size effects in thermal wave interferometry

1997 ◽  
Vol 82 (11) ◽  
pp. 5305-5311 ◽  
Author(s):  
L. Fabbri ◽  
F. Cernuschi
Keyword(s):  
Laser Beam ◽  
Thermal Wave ◽  
Size Effects ◽  
Beam Size

scholarly journals Uncertainties Induced by Processing Parameter Variation in Selective Laser Melting of Ti6Al4V Revealed by In-Situ X-ray Imaging

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 530
Author(s):  
Zachary A. Young ◽  
Meelap M. Coday ◽  
Qilin Guo ◽  
Minglei Qu ◽  
S. Mohammad H. Hojjatzadeh ◽  
...  
Keyword(s):  
Laser Beam ◽  
Selective Laser Melting ◽  
Small Deviation ◽  
Processing Parameters ◽  
Powder Layer ◽  
Beam Size ◽  
Processing Parameter ◽  
Laser Melting ◽  
Melt Pool

Selective laser melting (SLM) additive manufacturing (AM) exhibits uncertainties, where variations in build quality are present despite utilizing the same optimized processing parameters. In this work, we identify the sources of uncertainty in SLM process by in-situ characterization of SLM dynamics induced by small variations in processing parameters. We show that variations in the laser beam size, laser power, laser scan speed, and powder layer thickness result in significant variations in the depression zone, melt pool, and spatter behavior. On average, a small deviation of only ~5% from the optimized/reference laser processing parameter resulted in a ~10% or greater change in the depression zone and melt pool geometries. For spatter dynamics, small variation (10 μm, 11%) of the laser beam size could lead to over 40% change in the overall volume of the spatter generated. The responses of the SLM dynamics to small variations of processing parameters revealed in this work are useful for understanding the process uncertainties in the SLM process.

Optimum beam size for laser beam propagating through atmospheric turbulence

1999 ◽  
Vol 35 (21) ◽  
pp. 1875 ◽  
Author(s):  
Y.E. Yenice ◽  
B.G. Evans
Keyword(s):  
Laser Beam ◽  
Atmospheric Turbulence ◽  
Beam Size

Simple scanner for measuring laser beam size

1985 ◽  
Vol 56 (11) ◽  
pp. 2176-2177 ◽  
Author(s):  
D. P. Shelton
Keyword(s):  
Laser Beam ◽  
Beam Size

Sub-Beam Size Temperature Measurement of Heavily Doped Silicon Heater Using Two-Wavelength Thermoreflectance Microscopy

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Jinsung Rho ◽  
Bong Jae Lee
Keyword(s):  
Laser Beam ◽  
Fused Silica ◽  
Local Temperature ◽  
Background Information ◽  
Probe Laser ◽  
Beam Size ◽  
Precise Knowledge ◽  
Doped Silicon ◽  
Heavily Doped ◽  
Thermoreflectance Microscopy

This work describes a novel technique for simultaneously determining local temperature and thickness of a heavily doped Si heater having a submicron width by using two-wavelength thermoreflectance microscopy. The doped silicon line heater, whose thickness and width are, respectively, 480 nm and 900 nm, is fabricated by conventional microfabrication techniques on a fused silica wafer. The full width at half maximum (FWHM) of the focused laser beam is measured to be 2.00 μm and 2.28 μm for green (λ = 516 nm) and red (λ = 640 nm) lasers, respectively. Because the heater width is narrower than the focused laser beam size, the reflected beam contains background information (i.e., reflection from the fused silica substrate) in addition to the thermoreflectance signal from the doped silicon heater. With precise knowledge of the laser beam size, heater width, and exact location of the laser beam spot on the heater, one can quantitatively model the reflectance. In reality, however, due to the difficulty of aligning the laser beam with respect to the submicron-wide Si heater, precise determination of local temperature from thermoreflectance signal is not easily attained. In the present study, instead of aligning the laser beam to the center of the submicron silicon heater, the probe laser horizontally scans over a region of the heater. By taking into account the size of the focused laser beam and the width of the doped silicon heater, it is possible to determine the absolute temperature of a local region of the heater from the measured reflectance during the scanning, even though the width of the heater line is only 39% of the size of the laser beam.

scholarly journals Analysis of Infra-Red Laser Power Process Using Response Surface Methodology

2016 ◽  
Vol 3 (2) ◽  
pp. 30-36
Author(s):  
Wahaizad Bin Safiei ◽  
Mohd Rashdan Bin Ab Rashid
Keyword(s):  
Response Surface Methodology ◽  
Laser Beam ◽  
Response Surface ◽  
Water Flow ◽  
Laser Power ◽  
Experimental Studies ◽  
Beam Size ◽  
Laser Marking ◽  
Ir Laser ◽  
Infra Red

High-quality products and shorten manufacturing lead time are very important factors addressed by many companies. Typically, low-quality products are induced by inconsistent of manufacturing process performance. To get a constant laser power in Infrared (IR) Laser Marking process was a common problem facing by many engineers in the manufacturing industry. This consequences might effect on laser marking characteristics such as the possibility of burn marking or blur marking particularly on the products. Therefore, the objective of this paper is to study the interaction between Infrared (IR) Laser Marking input parameters such as current (amp), frequency (Hz), water flow (l/min) and laser beam size (mm) on laser power (watt) as the main response. Furthermore, the response of laser power from Infra-Red laser process can be predicted when all combinations of parameters are tested. The IR marking machine was deployed and experimental studies were conducted in order to meet this objective. The experiments were based on Design of Experiment (DOE) and Response Surface Methodology (RSM) because second order model or polynomial equation was needed to fit for the response. The relationship between input and output parameters can be visualized by 3D graphs which were developed from Mathematical modeling. Based on the experiment results, the parameters that have significant effects on the laser power are current, laser beam size and water flow. However, frequency does not have a significant factor in this study.

Influence of the Laser Beam Size on the Laser-Induced Damage in Thin Films and Substrates

2007 ◽  
Author(s):  
Jérémie Capoulade ◽  
Jean-Yves Natoli ◽  
Anne Hildenbrand ◽  
Laurent Gallais ◽  
Mireille Commandré
Keyword(s):  
Thin Films ◽  
Laser Beam ◽  
Beam Size ◽  
Laser Induced Damage
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