Photoacoustic detection of microcracks induced in BK7 glass by focused laser pulses

Aspherical lenses are produced using glass molding technology in a temperature close to its glass transition temperature. Friction and wear between the moving mold surface and the heated glass is one of the important aspects of the optical lenses production. This paper presents an experimental study on the tribological behavior of BK7 optical glass at elevated temperatures using pin-on-disk test rig. Thirty experiments have been conducted to study the effect of operating temperature, applied load, and sliding speed on the friction coefficient and wear rate of BK7 optical glass disks in contact with alumina pin. Also, the relation between the generated entropy and the weight loss under different operating conditions has been studied. The experimental results show that with increasing the temperature up to the glass transition temperature, the wear volume and friction coefficient increase. Further increase in the temperature results in a decrease in the wear volume and friction coefficient. Increasing the applied load results in an increase in the wear rate. An investigation on the correlation of wear rate and the dissipated power shows a linear relation between these two parameters.

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“…Navarette et al. 1 experimentally investigated the damage induced in BK7 optical glass using Nd:YAG laser. Sun et al.…”

Section: Introductionmentioning

confidence: 99%

“…The BK7 optical glass has received literature attention during recent years. Navarette et al 1 experimentally investigated the damage induced in BK7 optical glass using Nd:YAG laser. Sun et al 2 investigated the parallel and cross grinding of BK7 optical glass.…”

Section: Introductionmentioning

confidence: 99%

Tribological behavior of BK7 optical glass at elevated temperatures

Mosaddegh

Akbarzadeh

Mostafa

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…Microcracks tend to expand and merge, forming a macroscopic crack, may eventually lead to the fracture of metal parts. Therefore, in order to ensure the safety and reliability of metal components, whether in the manufacturing or service period, it is necessary to monitor the metal status [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Computer Simulation of Metal Surface Micro-Crack Inspection Using Pulsed Laser Thermography

Tang

Liu

et al. 2016

IJMUE

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“…Optical engraving of three dimensional figures is one of the typical applications [1]. In this technique, laser power density is controlled to be greater than the material damage threshold to induce microcracks [2], which results in an opaque portion and forms desired marks inside the transparent material. It has been found that focusing femtosecond (fs) laser into glass at power density above the refractive index change threshold of the glass results in an increase of refractive index about 0.04 at the focal point inside the glass [3].…”

Section: Introductionsmentioning

confidence: 99%

Direct patterning in sub-surface of stainless steel using laser pulses

Li¹,

Liu²,

Khin³

et al. 2010

Opt. Express

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This paper reports for the first time on the direct creating microcavities in sub-surface of stainless steel using a single Nd:YAG laser pulse. The low peak power density is used in the process, which is in the order of 1 MW/cm(2). The formation of the microcavities in the sub-surface of stainless steel is an evidence of volume expulsion during laser-metal interaction. Direct patterning in the sub-surface of stainless steel is demonstrated by realizing a series of microcavities to form a pre-designed pattern. Potential applications of sub-surface patterning in metal, such as security marking, micro-heater, micro-insulator and micro-sensor, are discussed.

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Photoacoustic detection of microcracks induced in BK7 glass by focused laser pulses

Cited by 15 publications

References 10 publications

Tribological behavior of BK7 optical glass at elevated temperatures

Tribological behavior of BK7 optical glass at elevated temperatures

Computer Simulation of Metal Surface Micro-Crack Inspection Using Pulsed Laser Thermography

Direct patterning in sub-surface of stainless steel using laser pulses

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