• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.5
• /
• pp.1071-1082
• /
• 1988

Surface rolling is one of the micro plastic processes which yields local deformation of surface, and improves surface roughness, hardness and fatigue strength. With the use of gray cast iron (GC 30) as material for experiment, the changes in surface roughness were investigated. A number of previous theses were refered to the effects of surface rolling for this study. With the use of steel ball of excellent in surface roughness and hardness, and with the applied force 20Kgf, surface rolling was performed. The summary of the experiment is as follows: (1) With the fixed applied force 20Kgf and the ball of 8.726mm in diameter, surface roughness was found to be the most excellent. (2) Increase in hardness was most prominent in the first rolling, but less effective in the succeeding rolling. (3) Reduction on diameter was affected by the previous process before rolling, and about 70 to 90% of reduction was made in the first rolling.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.05a
• /
• pp.25-33
• /
• 2002

Effect of surface topography on the water wetting nature and micro/nano tribological characteristics of Si-wafer and PTFE was experimentally studied. The ion beam treatment was performed with a hollow cathode ion gun in different argon don dose conditions in a vacuum chamber to change the surface topography, Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribo tester, SPM (scanning prove microscope), contact anglemeter and profilometer, respectively. Results showed that surface roughness increased with the argon ion dose. The water wetting angle of tile ion beam treated samples also increased with the ion dose. Results also showed that micro-adhesion and micro-friction depend on the wetting characteristics of the PTFE samples. However, nano-triboloSical characteristics showed little dependence on the wetting angles. The water wetting characteristics of modified PTFE samples were discussed in terms of the surface topographic characteristics.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.4
• /
• pp.81-86
• /
• 2013

For a 2-dimensional(2D) vibration milling, an excitation work-table was developed using two piezoelectric materials orthogonally arranged, where the trochoidal trajectory of a milling tool is combined with 2 dimensional elliptical vibration of a work-table. Applying 3kHz excitation frequency and 7~8mm amplitude of vibration to micro milling process with brass and nickel materials, the roughness in both bottom and side surface is much more improved compared to the surface by conventional milling process, which is attributed to decreased frictional force, increased cutting speed, and rubbing effect of a 2 dimensional vibration.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.970-976
• /
• 1997

The ultra-precision machining is widely used for final machining process of precision parts, so in this study, mirror surface finishing systems using the micro abrasive film, one of ultra-precision machining method, have to examine mirror surface characteristics of the cylindrical workpiece(SM45) such as surface roughness, workpiece removal and evaluated under the condition varing film feed rate, applied pressure, grinding speed after fixing other condition. It was found that varrious machining condition have significant influences on workpiece removal, surface roughness.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.10a
• /
• pp.273-278
• /
• 1994

The surface finishing systems using the micro abrasive film were designed and manufactured to make the mirror surface of the cylindrical workpiece. An experimental study of surface finishing was carried out to investigate the performance of mirror surface finishing system. The surface roughness of stainless steel was about Rmax 0.2~0.25 .mu.m, Ra 0.02~0.04 .mu.m in abrasive grain size 12, 9 .mu.m. the surface roughness of chrome coated workpiece was about Rmax 0.07~ 0.11 .mu. m, Ra 0.01 in abrasive grain size 3 .mu. m. Also, to measure the mirror finishing time by mirror surface finishing system, the experiment was carried out on the chrome coated and ground roller of diameter 76mm and length 650mm. The finishing time and surface roughness were 40min and Rmax 0.1~0.13 .mu.m, Ra 0.01 .mu.m.

• Laser Solutions
• /
• v.12 no.2
• /
• pp.7-10
• /
• 2009

In this paper, we study experimentally the local polishing of $SiO_2$ surface using the $CO_2$ laser. For laser local polishing, we polished to remove the grooves or to be reformed the surface of grooves after forming the grooves on the material surface. We measured the reflectance, transmittance, and beam profile in order to measure the roughness of polished surface. The Atom Force Microscope (AFM) is used to measure roughness of local polishing surface. We can predict that the laser polishing contribute to the removal of generated debris and surface roughness on the micro processing.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.6
• /
• pp.49-54
• /
• 2007

Electropolishing, the anodic dissolution process without contact with tools, is a surface treatment method to make a surface planarization using an electrochemical reaction with low current density. Nitinol is a metal alloy composed of Ni and Ti around 50% respectively which has shape memory effect. Nitinol can be put various applications which require purity and high pricision surface of products. The aim of this study is to investigate the characteristic of electropolishing effect for nitinol workpieces. In order to analyze the characteristics of electropolishing effect, surface roughness and micro-burr size were measured in terms of machining conditions such as current density, machining time and electrode gap. The tendencies about improvement of surface roughness and deburring effect by electropolishing for nitinol workpieces were determined.

• Advances in materials Research
• /
• v.1 no.2
• /
• pp.129-146
• /
• 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).

• Journal of the Korean Vacuum Society
• /
• v.10 no.3
• /
• pp.361-367
• /
• 2001

Recently, Chemical Mechanical Polishing(CMP) has become a leading planarization technique as a method for silicon wafer planarization that can meet the more stringent lithographic requirement of planarity for the future submicron device manufacturing. The SOI(Silicon On Insulator) wafer has received considerable attention as bulk-alternative wafer to improve the performance of semiconductor devices. In this paper, the objective of study is to investigate Material Removal Rate(MRR) and surface micro-roughness effects of slurry and pad in the CMP process. When particle size of slurry is increased, Material Removal rate increase. Surface micro-roughness is greater influenced by pad than by particle size of slurry. As a result of AM measurement, surface micro-roughness was improved from 27 $\AA$ Rms to 0.64 $\AA$Rms.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2002.02a
• /
• pp.239-244
• /
• 2002

In this study, we developed the manufacturing technology of micro-hole and micro-shaft for micro punching system using micro electrical discharge machining and micro electro chemical machining. Micro punching dies of tungsten carbide with $55\;{\mu}m\;and\;110\;{\mu}m$ diameter and $250\;{\mu}m$ depth were made by micro electrical discharge machining. The form accuracy and surface roughness of die hole were pretty good and it was shown that the punched hole quality was fine. WC micro-shaft with $30\;{\mu}m$ diameter was made by the multistep micro electro chemical machining. The developed technologies can be effectively used in precision manufacturing of micro punching die and mass production of micro-shaft.