scholarly journals Influence of the laser cutting front geometry on the striation formation analysed with high-speed synchrotron X-ray imaging

2021 ◽  
Vol 1135 (1) ◽  
pp. 012009
Author(s):  
Jannik Lind ◽  
Christian Hagenlocher ◽  
David Blazquez-Sanchez ◽  
Marc Hummel ◽  
A. Olowinsky ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Laser Beam ◽  
Film Thickness ◽  
High Speed ◽  
Angle Of Incidence ◽  
Time Resolved ◽  
X Ray ◽  
Cut Edge ◽  
Local Increase ◽  
X Ray Imaging

Abstract The generation of low surface roughness of the cut edge during laser beam cutting is a challenge. The striation pattern, which determines the surface roughness, can be distinguished into regular and interrupted striations, the latter resulting in an increased surface roughness. In order to analyse their formation, the space- and time-resolved cutting front geometry and melt film thickness were captured during laser beam fusion cutting of aluminium sheets with a framerate of 1000 Hz by means of high-speed synchrotron X-ray imaging. The comparison of the contours of the cutting fronts for a cut result with regular und interrupted striations shows that the contour fluctuates significantly more in case of interrupted striations. This leads to a strong fluctuation of the local angle of incidence. In addition, the average angle of incidence decreases, which results in an increase of the average absorbed irradiance. Both phenomena, local increase of absorbed irradiance and its dynamic fluctuation, result in a local increase of the melt film thickness at the cutting front which is responsible for the formation of the interrupted striations.

scholarly journals Thermal behavior of single-crystal scintillators for high-speed X-ray imaging

2019 ◽  
Vol 26 (1) ◽  
pp. 205-214 ◽  
Author(s):  
Alan Kastengren
Keyword(s):  
Single Crystal ◽  
High Speed ◽  
Thermal Loading ◽  
Indirect Detection ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Damage And Failure ◽  
Light Levels ◽  
X Ray Imaging

Indirect detection of X-rays using single-crystal scintillators is a common approach for high-resolution X-ray imaging. With the high X-ray flux available from synchrotron sources and recent advances in high-speed visible-light cameras, these measurements are increasingly used to obtain time-resolved images of dynamic phenomena. The X-ray flux on the scintillator must, in many cases, be limited to avoid thermal damage and failure of the scintillator, which in turn limits the obtainable light levels from the scintillator. In this study, a transient one-dimensional numerical simulation of the temperature and stresses within three common scintillator crystals (YAG, LuAG and LSO) used for high-speed X-ray imaging is presented. Various conditions of thermal loading and convective cooling are also presented.

scholarly journals Analysis and optimization of the piercing process in laser beam cutting by means of high-speed X-ray imaging

2021 ◽  
Vol 69 ◽  
pp. 303-310
Author(s):  
Jannik Lind ◽  
Niklas Weckenmann ◽  
Christian Hagenlocher ◽  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Laser Beam ◽  
High Speed ◽  
X Ray ◽  
X Ray Imaging

Time-resolved X-ray PIV technique for diagnosing opaque biofluid flow with insufficient X-ray fluxes

2013 ◽  
Vol 20 (3) ◽  
pp. 498-503 ◽  
Author(s):  
Sung Yong Jung ◽  
Han Wook Park ◽  
Bo Heum Kim ◽  
Sang Joon Lee
Keyword(s):  
Temporal Resolution ◽  
Exposure Time ◽  
High Speed ◽  
Light Flux ◽  
Image Intensifier ◽  
Time Resolved ◽  
X Ray ◽  
Physiological Conditions ◽  
Blood Flows ◽  
X Ray Imaging

X-ray imaging is used to visualize the biofluid flow phenomena in a nondestructive manner. A technique currently used for quantitative visualization is X-ray particle image velocimetry (PIV). Although this technique provides a high spatial resolution (less than 10 µm), significant hemodynamic parameters are difficult to obtain under actual physiological conditions because of the limited temporal resolution of the technique, which in turn is due to the relatively long exposure time (∼10 ms) involved in X-ray imaging. This study combines an image intensifier with a high-speed camera to reduce exposure time, thereby improving temporal resolution. The image intensifier amplifies light flux by emitting secondary electrons in the micro-channel plate. The increased incident light flux greatly reduces the exposure time (below 200 µs). The proposed X-ray PIV system was applied to high-speed blood flows in a tube, and the velocity field information was successfully obtained. The time-resolved X-ray PIV system can be employed to investigate blood flows at beamlines with insufficient X-ray fluxes under specific physiological conditions. This method facilitates understanding of the basic hemodynamic characteristics and pathological mechanism of cardiovascular diseases.

scholarly journals High-Speed X-Ray Investigation of Pore Formation during Full Penetration Laser Beam Welding of AA6016 Aluminum Sheets Contaminated with Lubricants

2020 ◽  
Vol 10 (6) ◽  
pp. 2077 ◽  
Author(s):  
Christian Hagenlocher ◽  
Jannik Lind ◽  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Laser Beam ◽  
Pore Formation ◽  
High Speed ◽  
Laser Beam Welding ◽  
Welding Process ◽  
X Ray ◽  
Aluminum Sheets ◽  
Full Penetration ◽  
X Ray Imaging ◽  
The Stability

The presence of lubricants on the surface of sheets favors the formation of pores in laser welded seams. This formation process was investigated by means of high-speed X-ray imaging of the full penetration laser beam welding process of two AA6016 aluminum sheets in overlap configuration. The measurement of the growth velocity of the bubbles indicated their sudden growth once they started to form. Further analysis of the X-ray images identified the point of origin of the pores: a few millimeters behind the capillary between the two aluminum sheets. The study shows that the lubricant does not affect the stability of the capillary, which evidences that the formation of these pores is not caused by the fluctuations of the capillary. These results explain for the first time why pore formation cannot be avoided by process strategies, which stabilize the capillary, when welding uncleaned sheets.

High-speed X-ray imaging camera for time-resolved diffraction studies

2002 ◽  
Vol 49 (5) ◽  
pp. 2415-2419 ◽  
Author(s):  
S.V. Tipnis ◽  
V.V. Nagarkar ◽  
V. Gaysinskiy ◽  
S.R. Muller ◽  
I. Shestakova
Keyword(s):  
High Speed ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Camera

scholarly journals High-speed x-ray imaging with the Keck pixel array detector (Keck PAD) for time-resolved experiments at synchrotron sources

2016 ◽  
Author(s):  
Hugh T. Philipp ◽  
Mark W. Tate ◽  
Prafull Purohit ◽  
Darol Chamberlain ◽  
Katherine S. Shanks ◽  
...  
Keyword(s):  
High Speed ◽  
Array Detector ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Imaging ◽  
Pixel Array ◽  
Pixel Array Detector

Characteristic properties of AlTiN and TiN coated HSS materials

2015 ◽  
Vol 67 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Mumin Sahin ◽  
Cenk Misirli ◽  
Dervis Özkan
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Wear Properties ◽  
Content Type ◽  
X Ray ◽  
Number Of Cycles ◽  
Future Work

Purpose – The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail. Design/methodology/approach – In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components. Findings – It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively. Research limitations/implications – It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials. Practical implications – The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials. Originality/value – This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

UFO — a scalable platform for high-speed synchrotron X-ray imaging

2016 ◽  
Author(s):  
Andreas Kopmann ◽  
Suren Chilingaryan ◽  
Matthias Vogelgesang ◽  
Timo Dritschler ◽  
Andrey Shkarin ◽  
...  
Keyword(s):  
High Speed ◽  
X Ray ◽  
X Ray Imaging
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