• Proceedings of the Korean Radioactive Waste Society Conference
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• 2011.05a
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• pp.123-124
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• 2011

• Steel and Composite Structures
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• v.36 no.4
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• pp.417-426
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• 2020

Drilling processes in fiber-reinforced polymer composites are essential for the assembly and fabrication of composite structural parts. The economic impact of rejecting the drilled part is significant considering the associated loss when it reaches the assembly stage. Therefore, this article tends to illustrate the effect of cutting conditions (feed and speed), and laminate thickness on thrust force, torque, and delamination in drilling woven E-glass fiber reinforced epoxy (GFRE) composites. Four feeds (0.025, 0.05, 0.1, and 0.2 mm/r) and three speeds (400, 800, and 1600 RPM) are exploited to drill square specimens of 36.6×36.6 mm, by using CNC machine model "Deckel Maho DMG DMC 1035 V, ecoline". The composite laminates with thicknesses of 2.6 mm, 5.3 mm, and 7.7 mm are constructed respectively from 8, 16, and 24 glass fiber layers with a fiber volume fraction of about 40%. The drilled specimen is scanned using a high-resolution flatbed color scanner, then, the image is analyzed using CorelDraw software to evaluate the delamination factor. Multi-variable regression analysis is performed to present the significant coefficients and contribution of each variable on the thrust force and delamination. Results illustrate that the drilling parameters and laminate thickness have significant effects on thrust force, torque, and delamination factor.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.152-158
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• 2001

In this paper, we have developed an electro discharge machine for micro drilling driven by a voice coil actuator. Because the voltage signal of the electro-discharging circuit shows a lot of peaks and valleys, the active type low-pass filtering technique is adopted to get the average of the signal. Since the motion of the voice coil is precisely controlled by the error value between the object voltage value and the measured one, it is possible to prevent the mechanical contact between the rotating electrode and the workpiece and to maintain the appropriate machining conditions during the process. The electro-chemical machining technology was also adopted to make small diameter electrodes. Pure water is used as a dielectric. The machining procedure is performed to verify the feasibility of the developed system. It takes about 10 seconds to drill the ${\phi}m$100${\mu}m$ hole to the 100${\mu}m$ thickness stainless steel plate. The machining time depends on the values of the resister and the capacitor. There may exist the optimal values of time constant and the tendency is displayed In the appendix.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.4
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• pp.34-47
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• 2000

Since carbon fiber epoxy composite materials have excellent properties for structures due to their high specific strength, high specific modulus, high damping and low thermal expansion, the hollow shafts made of carbon fiber epoxy composites have been widely used for power transmission shafts for motor vehicles , spindles of machine tools, motor base, bearing mount for tool up and manufacturing. The molded composite machine elements are not usually accurate enough for mechanical machine elements, which require turning drilling , cutting and grinding. The experiment are surface grinding wheel GC60 to the carbon fiber epoxy composite specimen with respect to staking angle [0]nT , [45]nT, [90]nT on the CNC grinding machine. In this paper, the surface grinding characteristics of composite plate, which are surveyed experimentally and analytically with respect to the grinding force, surface roughness and wheel loading according to the variable depth of cut, wheel velocity and table feed rate are investigated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.82-89
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• 1996

In this study, to choose the drilling m/c with analysis model for dynamic design of machine tool strctures, are used substucture syntheis method for reduction to degrees of freedom of dynamic model and analysis evaluation of substructures The dynamic factors of substurctures are examined by substructure synthesis method. And that dynamic design of structures for energy balancing are performed. The computer program for calculated of the dynamic and energy distribution analysis was developed. Result of numerical analysis by developed program obtained to conclusion as following. The design of machine tool structures by dynamic avoid the resonances, and are known to considered based on the energy balancing. These methods can be used effectively for the performance evaluation, design modification and improvement of dynamic performance evaluation, design modification and improvement of dynamic performance of machine tools.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.161-170
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• 2001

Synthetic water-based metal-cutting fluids are increasingly popular in the metal-working industry because of its environmental friendliness. The propose of this study is to investigate the synergistic effect of combining polyethylene glycol and common fatty acid in formulating a metal-cutting fluid. The tested metals were aluminum, copper and steel, and the test was performed with a modified drilling machine. From the study, it was found that there existed some synergistic effects on the drilling efficiency of the metals to decrease of cutting time, cutting energy, torque as well as the smoothness of surface depended on the formulation ratio of the two fluids.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.10-16
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• 2021

Drilling is a crucial process that takes up a significant amount of weight during machining operations. In addition, drill tip-type tools and related operations have been developed for manufacturing industries to achieve economic efficiency. In this study, SM45C carbon steel, widely used for machine structures, was utilized as the working material after quenching and tempering. Insert-tip types of carbide tools, such as TiN and TiAlN, were used as tool materials. Drilling conditions such as the spindle revolution, feed rate, step of cut, and tool diameter were used to measure roughness, roundness, and straightness using the orthogonal array table statistical method. The surface roughness, roundness, and straightness characteristics based on the conditions were analyzed using ANOVA. The results showed that the spindle speed and feed rate were the main factors influencing carbide insert-tip drilling under the same conditions as the experimental conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.493-499
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• 2023

Recently, with the development of construction machinery, low-vibration construction machine such as Tricone-Bits, which can drill both soil and rock layers and minimize vibration, is being used frequently. However, although many studies have been conducted on the prediction of vibration values for earth augers and pile drivers, the reality is that studies on the effects of vibration on low-vibration drilling equipment are lacking. In this paper, ground vibration values for Tricone-Bits were measured, and a vibration distance damping formula was proposed using this. In addition, after predicting the vibration of the earth auger and pile driver using the previously proposed vibration distance damping formula, the degree of vibration damping for the Tricone-Bits was evaluated by comparing and analyzing it. As a result, the Tricone-Bits showed a vibration reduction effect of 97% and 93% compared to these machine and It will help with management and prediction of the ground vibration effects evaluation on the low-vibration equipment such as Tricone-Bits.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.478-480
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• 2004

다이아몬드 톱날을 이용한 얇은 Si 웨이퍼의 기계적인 다이싱은 chipping, crack 등의 문제점을 발생시킨다. 또한 stacked die 나 multi-chip등과 같은 3D-WLP(wafer level package)에서 via를 생성하기 위해 현재 사용되는 화학적 etching은 공정속도가 느리고 제어가 힘들며, 공정이 복잡하다는 문제점을 가지고 있다. 이러한 문제점을 해결하기 위해 현재 연구되고 있는 분야가 레이저를 이용한 웨이퍼 다이싱 및 드릴링이다. 본 논문에서는 UV 레이저를 이용한 얇은 Si 웨이퍼 다이싱 및 드릴링 시스템에 대해 소개하고, 웨이퍼 다이싱 및 드릴링 실험결과를 바탕으로 적절한 레이저 및 공정 매개변수에 대해 설명한다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.37-42
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• 1997

This paper describes result of experiment of parameters affecting the micro hole drilling time, kind of assisting gas and it's pressure. The result reveals that parameter value of 0.08J, 20Hz, dwell time of 300 microseconds can be a good machining condition to make micro hole diameter range of 50-70${\mu}{\textrm}{m}$, Assistant gas such air, O2, Ar, N2 was adapted. Assistant gas of air makes heat affected zone enlarge due to burning of material, also it makes hole irregular and damage because of refusion stick to caused by chemical reaction with Al2O3 ceramic material. O2(99.9%) has good characteristic to get good drilling and smooth surface on pressure of 0.2kgf/$\textrm{cm}^2$, but it is expensive. Ar, N2 makes material burn and crack severely and proved to be an appropriate but, Ar was better than N2.