• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1583-1589
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• 2001

Metal matrix composites with whisker reinforcements have significant potentials for demanding mechanical applications including defense, aerospace, and automotive industries. Especially metal matrix composites, which are reinforced with aluminum borate whisker, have been used leer the part of piston head in automobile because of good specific strength and wear resistance. In this study, AC4CH-based metal matrix composites with $Al_{18}$B$_{4}$ $O_{33}$ reinforcement have been produced using squeeze casting method, after T6 heat treatment, we evaluated fatigue life property of matrix and MMC composite and investigated fracture mechanism.m.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.73-78
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• 2012

Recently, the laser processing method has used as micro-machining technologies in industries of aerospace, electronics and automotive. The laser processing newly focused could be alternative to existing machining method. However, there are few practical results of research about the proper setting of the laser machining conditions and the laser machining characteristics for mechanical materials. The purposes of this study was to choose optimum machining conditions and to estimate the laser machining characteristics using taguchi experimental method for various mechanical materials that is S45C, Stainless steel, Aluminum, Copper, Titanium and Tungsten carbide. From obtained results, it was confirmed that optimum machining conditions could be found and laser machinability depends on thermal conductivity and hardness of workpiece.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.20-27
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• 2009

The characteristics of titanium alloy as a relatively advanced material is low density, avirulent and, superior corrosive resistant, therefore the use of titanium alloy is increasing lately in aerospace and mechanical technologies, precision machinery, electronics industry, petro-chemical industries and biomedical areas. In these days, the titanium alloy product is required various surface qualities of not only smooth surface but also rough surface depending on usages. The purpose of this experimental research is to find the optimum surface roughness of titanium alloy of Ti-6Al-4V, by micro abrasive blasting as depending variable conditions of working pressure, nozzle size, working time, stand of distance and power particle size.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.8-13
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• 2020

Carbon fiber-reinforced plastics (CFRPs) are extremely strong and light fiber-reinforced plastics containing carbon fibers. CFRPs can be expensive to produce, but are commonly used wherever high strength-to-weight ratio and rigidity are required, such as in the aerospace, automotive, and ship superstructure industries. In CFRP drilling, the tool performance greatly varies depending on the tool shapes, cutting conditions, and diamond coating. This study developed a new type of tungsten carbide drill with multi-blade edges to evaluate the surface quality of CFRP materials according to the coating thickness of diamond-coated drills. Experiments on tool wear, surface roughness, and burr formation were conducted. The bore exit quality of a 12 mμ -coated drill was better than that of a 6 mμ -coated drill. The superior effects of the 12 mμ -coated drill and the good surface quality of CFRP were also demonstrated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.663-664
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• 2006

In the electronic, medical, aerospace and automobile industries, many products and parts are manufactured by joining. Recently, as these get smaller, micro joining is becoming more and more important. In this study, micro wire-to-micro wire parallel joining was performed using single mode fiber laser. Maximum power of the fiber laser is 100 W. The CCD(Charge- Coupled Device, CCD) camera to observe the specimen was made up. The objective was applied to micro joining system to make a small spot size of laser beam. In order to control the target position, micro-multi-axis-stage was set up. This paper presents results for the single mode fiber laser joining of micro wires.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.65-66
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• 2006

Dancer systems are most widely used mechanism for attenuation of tension disturbances. Lately, demands fur high speed converting machines over 500mpm(m/min) are raising but domestic converting industries can not come up with the machines because capacities for a designing of the converting machine are restricted lower than 300mpm. Moreover roll-to-roll is attracted flexible display manufacturer's attention as a effective method for productivity. A constant tension level in the span before the first printing cylinder is the key of high speed quality printing. This paper presents a modeling and simulations of dancer systems on converting machines.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.22-22
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• 2009

Laser forming is a promising technology in manufacturing, such as in the shipbuilding, automobile, microelectronics, aerospace and other manufacturing industries. This process forms the sheet metal by utilization of laser-induced thermal stresses. Laser forming process has been studied extensively for rectangular shape geometry. This basic study presents the change in deformation behavior of sheet metal during transition from linear to curved geometries and irradiations as well. A series of experiments have been conducted on a wide range of specimen geometries such as quarter-circular and half circular plate. The reasons for this behavior have been analyzed. Results are compared and analyzed by simulations using ABAQUS. Influence of developed stresses on the bending has been investigated. This study provides the more understanding of forming mechanism influenced by geometry effect.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.74-79
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• 2005

Spot welding widely used in automotive and aerospace industries has made it possible to produce more precise and smaller electric part by robotization and systemization of welding process. The quality of welding depends upon the size of nugget between the overlapped steel plates. Recently, the thickness of the steel plates becomes much thinner and hence, it introduces the smaller size of nugget. Therefore, it is necessary to develop the criterion to evaluate the quality of weld in order to obtain the optimal welding conditions for the better performance. In this paper, a thin steel plates, 0.1mm through 0.3mm thickness, have been spot-welded at different welding conditions and the nugget sizes are examined by defocused scanning microscopy. The relationships between nugget sizes and weldability have been investigated experimentally. The result of ultrasonic technique shows the good agreement with that of the tensile test.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.2
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• pp.1-8
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• 2004

Applications of the deep hole drilling process can be found in many industries ranging from large aerospace manufacturer to small tool and die shop. Deep hole drilling process with small diameter generally requires high quality and accuracy. But problems which may arise or result from the deep hole drilling process include drill breakage, the generation of a finished part surface which does not satisfy required quality, and process instability. To guaranty the required machining quality and accuracy, it is important to understand and improve the deep hole drilling process. In this study, deep hole drilling experiments using tingle edge drill with small diameter under 2mm have been carried out for difficult to cut materials such as C42CrMo4 and C45pb and the experimental results were analyzed. Feed force and torque versus feed showed linear relationship in both materials. The feed force and torque are decreased as cutting speed is increased but the trends are not uniform in C42CrMo4.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.982-987
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• 2012

Inconel 718 alloy has been widely used in the aerospace, heavy industry and electronic industry. However, the machinability of this alloy is very poor, which is attributed to their inherent high strength that is maintained at elevated temperatures. The tool life is dominant problem in machining difficult-to-cut materials, so it is necessary to select the efficient cutting conditions for the improvement of tool life. In this study, the cutting force, tool wear and surface roughness are investigated in end milling machining under various cutting conditions. By this experiment, the efficient machining condition of this alloy is suggested to adopt in various industries.