• Title/Summary/Keyword: Ultrasonic Machining

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Roundness Improvement and Exit Crack Prevention in Micro-USM of Soda-Lime Glass (유리의 미세 초음파 가공 시 입구 진원도 향상 및 출구 크랙방지)

  • Hong, Ji-Hoon;Kim, Duck-Hwan;Chu, Chong-Nam;Kim, Bo-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.10
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    • pp.1039-1045
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    • 2007
  • Ultrasonic machining (USM) is suitable for machining hard, brittle and non-conductive materials such as silicon, glass and ceramics. Usually, when micro holes are machined on glass by USM, roundness of hole entrance is poor and cracks appear around the hole exit. In this paper the machining characteristics were studied for roundness improvement and exit crack prevention. From experiments, the tool bending and the shape of tool tip affect hole roundness. When the tool tip is hemispherical, good roundness of holes was obtained. The feedrate and the rotational speed of the tool affect the exit crack. With the machining conditions of 150 rpm in spindle speed and $0.5\;{\mu}m/s$ in feedrate, micro holes with less than $100\;{\mu}m$ in diameter were machined without an exit crack.

Study of Optimal Machining Conditions of Ultrasonic Machining By Taguchi's Method (다구찌 방법을 이용한 초음파 가공의 최적가공조건에 관한 연구)

  • Liu, Jun Wei;Jin, Jian;Ko, Tae Jo;Baek, Dae Kyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.2
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    • pp.213-218
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    • 2013
  • Ultrasonic machining (USM) is a new method used in metal cutting. This process does not involve heating or any electrochemical effects, causes low surface damage, has small residual stress, and does not rely on the conductivity of the workpiece. These characteristics are suitable for the machining of brittle materials such as glass or ceramics. However, the use of USM for brittle materials generates cracks on the workpiece. Therefore, in this study, Taguchi's method was used to optimize the processing conditions of micro holes drilled in glass and ceramics. This method was used to successfully reduce the number of cracks at the entrance and the exit of the micro holes.

A Study on the Development of Rotary Ultrasonic Machining Spindle (회전 초음파가공 주축 개발에 관한 연구)

  • Li, Chang-Ping;Kim, Min-Yeop;Park, Jong-Kweon;Ko, Tae-Jo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.4
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    • pp.160-166
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    • 2015
  • Ultrasonic machining (USM) has been considered a new, cutting-edge technology that presents no heating or electrochemical effects, with low surface damage and small residual stresses on brittle workpieces. However, nowadays, many researchers are paying careful attention to the disadvantages of USM, such as low productivity and tool wear. On the other hand, in this study, a high-performance rotary ultrasonic drilling (RUD) spindle is designed and assembled. In this system, the core technology is the design of an ultrasonic vibration horn for the spindle using finite element analysis (FEA). The maximum spindle speed of RUM is 9,600 rpm, and the highest harmonic displacement is $5.4{\mu}m$ noted at the frequency of 40 kHz. Through various drilling experiments on glass workpieces using a CVD diamond-coated drill, the cutting force and cracking of the hole entrance and exit side in the glass have been greatly reduced by this system.

Control of Taper Shape in Micro-Hole Machining by Micro-EDM (방전 가공을 이용한 미세 구멍 가공 시 발생하는 테이퍼 형상의 제어)

  • Kim Dong Jun;Yi Sang Min;Lee Young Soo;Chu Chong Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.4
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    • pp.52-59
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    • 2005
  • When a micro hole is machined by EDM with a cylindrical electrode, the hole diameter is different at the inlet and the outlet of the micro hole. The taper shape of the micro hole is caused by not only wear of the electrode but the eroded particles. The eroded particles cause secondary discharge during machining the micro hole. As a result, the diameter of the inlet becomes larger than that of the outlet. In this paper, a new method is proposed to reduce the difference in diameter between the inlet and the outlet of the hole. Observed was that the feed depth and machining time affect the formation of taper shape On this experimental basis, ultrasonic vibration was applied to reduce machining time, and capacitance was changed during machining to use the difference in discharging energy of different capacitances. Using the proposed method, a straight micro-hole was fabricated.

Glass Drilling using Laser-induced Backside Wet Etching with Ultrasonic Vibration (초음파 진동과 레이저 후면 에칭을 통한 유리 구멍 가공)

  • Kim, Hye Mi;Park, Min Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.1
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    • pp.75-81
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    • 2014
  • Laser beam machining has been known as efficient for glass micromachining. It is usually used the ultra-short pulsed laser which is time-consuming and uneconomic process. In order to use economic and powerful long pulsed laser, indirect processing called laser-induced backside wet etching (LIBWE) is good alternative method. In this paper, micromachining of glass using Nd:YAG laser with nanosecond pulsed beam has been attempted. In order to improve shape accuracy, combined processing with magnetic stirrer has been widely used. Magnetic stirrer acts to circulate the solution and remove the bubble but it is not suitable for deep hole machining. To get better effect, ultrasonic vibration was applied for improving shape accuracy.

A Study on the Fabrication of Prototype Ultrasonic Machine Tool and It's Experimental Machining (실험용 초음파 가공기의 제작 및 가공실험에 관한 연구)

  • 김종광;서용위
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.930-933
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    • 2000
  • In this report experimental ultrasonic machine system has been fabricated and experimental machining has been performed using glass as a workpiece material. As grit size increases, material removal rate(MRR) was observed to be increased at decreased applied tool pressure on the workpiece, however at the higher applied pressure above $2-4\;kg/cm^2$ for smaller grit size, the MRR was not increased. Also better surface roughness was obtained for smaller grit size. Microchipping was observed from the microscopic examination and the pattern is similar to the iso-stress field where cracking is considered to be initiated near the surface.

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초음파 진동절삭에 의한 광학 플라스틱의 미소표면성상 분석

  • 최인휴;김정두
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1992.10a
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    • pp.115-120
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    • 1992
  • Mirror-surface machining is very important machining technology to manufacture optical parts. especially brittle materials. In case of optical plastics, it is produced through both grinding and polishing till now. New machining method which is more efficient and contributed to the protection of the environmental pollution is, therefore, studied. In this , experimental results and an analysis of surface roughness in ultrasonic vibration cutting of optical plastic (CR-39) which is used for optical lens is presented. In results, a comparison of the micro-structure of machined surfaces produced by cutting with ultrasonic vibration and conventional turning is presented by analyzing S.E.M. photograph. Also, wavelength spectrum analysis is performed to investigate the surface-characteristics machined by ultrasonic vibration cutting.

A study on micro grooving characteristics of planar lightwave circuit and glass using ultrasonic vibration cutting (초음파 진동절삭을 이용한 평면 광도파로와 유리의 미세 홈 가공특성에 관한 연구)

  • 이준석;김병국;정융호;이득우
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.167-172
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    • 2002
  • Recent years, optical components'are widely used in optical communication industry for high speed and mass storage data processing. Micro grooving of planar lightwave circuit and glass, those are widely used in optical component, are realized by polycrystalline diamond tool with ultrasonic vibration. To know the characteristics of brittle materials cutting, ultrasonic vibration cutting tool and machining system are built for the experiment. Grooving on planar lightwave circuit and glass experiments are performed and their shape are measured by photograph with microscope. It reveals that better groove shape with low chipping of planar lightwave circuit and glass are obtained by micro grooving machining with ultrasonic vibration. These experiments are considered as a possibility to the micro grooving of optical communication components.

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Study on the Effect of Thermal Property of Metals in Ultrasonic-Assisted Laser Machining (초음파 원용 레이저 가공에서 재료의 열적 물성이 표면상태에 미치는 영향에 관한 연구)

  • Lee, Hu Seung;Kim, Gun Woo;Park, Jong Eun;Yang, Min Yang;Cho, Sung Hak;Park, Jong Kweon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.8
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    • pp.759-763
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    • 2015
  • The laser machining process has been proposed as an advanced process for the selective fabrication of electrodes without a mask. In this study, we adapt laser machining to metals that have different thermal properties. Based on the results, the metals exhibit a different surface morphology, heat-affected zone (HAZ), and a recast layer around the machined surface according to their thermal conductivity, boiling point, and thermal diffusivity. Then, we apply ultrasonic-assisted laser machining to remove the recast layer. The ultrasonic-assisted laser machining exhibits a better surface quality in metals with higher diffusivity than those having lower diffusivity.

Modeling and multiple performance optimization of ultrasonic micro-hole machining of PCD using fuzzy logic and taguchi quality loss function

  • Kumar, Vinod;kumari, Neelam
    • Advances in materials Research
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    • v.1 no.2
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    • pp.129-146
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    • 2012
  • Polycrystalline diamond is an ideal material for parts with micro-holes and has been widely used as dies and cutting tools in automotive, aerospace and woodworking industries due to its superior wear and corrosion resistance. In this research paper, the modeling and simultaneous optimization of multiple performance characteristics such as material removal rate and surface roughness of polycrystalline diamond (PCD) with ultrasonic machining process has been presented. The fuzzy logic and taguchi's quality loss function has been used. In recent years, fuzzy logic has been used in manufacturing engineering for modeling and monitoring. Also the effect of controllable machining parameters like type of abrasive slurry, their size and concentration, nature of tool material and the power rating of the machine has been determined by applying the single objective and multi-objective optimization techniques. The analysis of results has been done using the MATLAB 7.5 software and results obtained are validated by conducting the confirmation experiments. The results show the considerable improvement in S/N ratio as compared to initial cutting conditions. The surface roughness of machined surface has been measured by using the Perthometer (M4Pi, Mahr Germany).