• Explosives and Blasting
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• v.24 no.1
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• pp.57-62
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• 2006

The typical blasting method adopted in Pasir Coal Mine is a surface blasting technique with a single free face. It means that there is only one free face, which is usually the ground surface. This kind of blasting method is easy to use but inevitably causes enormous ground vibrations, which, in turn, can affect the stability of the slopes comprising the various boundaries of the open pit mine. In addition, the method also has the problem of lowering the blast efficiency compared to other methods such as bench blasting methods or ones with more than two free faces. In this respect, a project was launched to develop a new blasting method that is suitable for controling the ground vibration and enhancing the blast efficiency. As a part of the project, authors investigated the current blasting method as well as the overall pit developing process in the mine, and established some important guidelines that should be observed during the whole development process. This paper presents the details of the typical blasting pattern and the pit developing method in the mine, and suggests the guidelines determined from the results of the observations.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.1
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• pp.34-42
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• 2007

Powder blasting technique has been considered one of the most appropriate micro machining methods for hard and brittle materials, since the productivity is high and the heat layers caused by material removal are very thin. Recent development of special purposed parts, such as the parts for semiconductor processing, the parts for LCD, sensors for micro machine fabrication and so on, has been expanded. Thus, it is essential to develop powder blasting technologies for micromachining of hard and brittle materials such as glass, ceramics and so on. In this paper, the characteristics of powder blasted glass surface were tested under various blasting parameters. Finally, we proposed a predictive model for powder blasting process using the neural network and the response surface method. Detail analysis of the simulation results is carried out and the performance of two predictive models is compared.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1280-1287
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• 2002

The old technique of sandblasting which has been used for decoration of glass surface has recently been developed into a powder blasting technique for brittle materials such as glass, silicon and ceramics, capable of producing micro structures larger than $100{\mu}$ m. This paper describes the performance of powder blasting technique in micro-line grooving of glass and the effect of the number of nozzle scanning on the depth and width of line groove. Experimental results showed that increasing the no. of nozzle scanning resulted in the increase of depth and width in grooves. Increase of width which may cause several problems in the precision machining results from wear of mask film. Therefore, well-controlled masking process is the most important factor for micro machining of glass with accuracy.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.120-125
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• 2003

This research analyzes blasting accident cause that is happening construction and engineering works spot taking advantage of AHP (Analytic Hierarchy Process) techniques as metrical. Result that apply AHP with blasting accident that is happened the South Korea and Japan, appeared by thing which relative importance by human cause is highest. Specially, it is observance of safety rule that dominate the highest ratio among of human cause, and if observe a little, causes that prevention is possible are much. By result of this research, necessity of safety education is important first of all for prevention of blasting accident. Also, thorough safety control plan of during work and enough on-the-slut probe before work should be established. Because explosives uses gunpowder and explosive high energy, work by qualified person is essential. Ant it may become help to minimize dissipation of important life and property preventing beforehand explosion accident of gunpowder.

• Explosives and Blasting
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• v.34 no.1
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• pp.11-18
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• 2016

It is necessary to minimize ground vibration and noise due to blasting work in urban environment. The blast induced ground vibration and noise are generally generated by a portion of detonation energy, where most of the energy is utilized for rock breakage and movement of rock mass. Recently a blast method utilizing U-shaped steel charge holder was suggested to reduce the ground vibration without decreasing destructive power toward the free surface. In this study, single hole blasting utilizing U-shaped steel charge holder were simulated and the stress waves caused by the detonation of explosives were monitored using AUTODYN software. In order to examine the fragmentation efficiency of the U-shaped steel charge holder, one free face blasting models which adapt the blast induced stress waves were simulated by dynamic fracture process analysis (DFPA) code. In addition, the general blasting models were also simulated to investigate the fragmentation effectiveness of the U-shaped steel charge holder in rock blasting.

• Explosives and Blasting
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• v.17 no.3
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• pp.60-71
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• 1999

• Explosives and Blasting
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• v.13 no.2
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• pp.20-34
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• 1995

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.2
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• pp.33-39
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• 2004

Sandblasting has recently been developed into a powder blasting technique for brittle materials. In this study, the machinability of $Si_3N_4$-hBN based machinable ceramics are evaluated for micro - pattern making processes using powder blasting. Material properties of the developed machinable ceramics according to the variation of h-BN contents give a good machinability to the ceramics. The effect of scanning times, the size of patterns and variation of BN contents on the erosion depth of samples without mask and samples with different mask patterns in powder blasting of $Si_3N_4$-hBN ceramics are investigated. The Parameters are the impact angle of $90^{\circ}$, the scanning times of nozzle up to 40, and the stand-off distances of 100mm The widths of masked pattern are 0.1mm 0.5mm and 1mm. The powder used is Alumina particles, WA#600. and the blasting pressure of powder is 0.2MPa. Through required experiments, the results are investigated and analyzed. As the results, the machinability of the developed ceramics increases as the BN contents in the ceramics.

• Journal of the Korean institute of surface engineering
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• v.51 no.5
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• pp.303-308
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• 2018

Currently hydrofluoric acid (HF) based glass etch method is widely used for anti-glare (AG) surface treatment since it can effectively alleviate the specular reflection problem with relatively low processing cost. However, due to the environmental regulation and safety problem, it is essential to develop alternative technology to replace this method. For this, in this paper, we propose sand blasting based AG surface treatment method for display glass. To characterize the sand blasting process, surface roughness, haze, surface durability, and flatness are considered as process outputs and central composite design (CCD) method and response surface model (RSM) method are applied to model each process output. Models for surface roughness and haze showed 96.44% and 97.24% of R-squared values, respectively and they can be applied to optimize AG surface treatment process for various haze level requirements of display industries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.310-315
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• 2017

Although studies evaluating the effects of the blasting vibration on the adjacent structures from various angles have continued, cases of securing the safety of the adjacent buildings and researching the proper blasting method for the field condition by analyzing the vibration waveform of the measuring field while performing the open pit blasting are poor. Therefore, it is necessary to present a remedy for blasting pattern selection through test blasting that is appropriate for field conditions, and is economical and efficient. In this study, open pit blasting work was conducted based on the separation distance applied according to the standard blasting method by test blasting and the vibration regulation standard in the road expansion construction site to measure the blasting vibration value, and the vibration prediction equation by blasting methods was examined using a regression analysis computer program to calculate K, N, and R of the confidence level 95%. By setting the blasting allowed vibration standard of the test blasting target area to 0.3cm/sec, and the charring weight and blasting method by the separation distances according to the blasting vibration estimation equation of the open pit blasting guideline and the blasting vibration estimation equation of the test blasting were compared/analyzed, it was possible to identify the factors that increased the working expenses. In addition, the measurement and analysis of the adjacent structures during open pit blasting and the blasting vibration were performed after selecting the most adjacent structure to the open pit blasting spot to analyze the problems on the test blasting procedure and analysis method in the open pit blasting design/construction guidelines, which appeared in the process of completing open pit blasting construction, and a remedy is presented.