• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.10a
• /
• pp.251-256
• /
• 1999

"Ploughing" on the flank face of the tool in the metal cutting process is due to the tool in the metal cutting process is due to the finite edge radius of the tool and due to the development of flank wear. Because of the high stresses near the cutting edge, elastic-plastic deformation would be caused between the tool and the machined surface over a small area of the tool flank. The deformation would affect the roughness of the machined surface. Recently, some attempts have been made to predict the surface roughness, but elastic-plastic effect due to ploughing in the cutting process has not been considered. The research has analyzed mechanism of the ploughing of the cutting process using contact mechanics. Tool and workpiece material properties have been taken into account in the prediction of the surface roughness. The surface roughness has been simulated by the surface-shaping system. The results between experiment and simulation have been compared and analyzed. analyzed.

• Journal of the Korean Society of Safety
• /
• v.18 no.3
• /
• pp.29-33
• /
• 2003

The objective of the present work is to examine evaporation cooling of droplet due to surface roughness on a heated surface. The surface temperatures varied from 80-$160^{\circ}C$ on aluminum alloy (AL 2024) md surface roughness was 0.l8$\mu\textrm{m}$ 1.36$\mu\textrm{m}$. The results are as follows; Regardless of surface roughness, as droplet diameter is bigger, the in-depth temperature of solid decreases and evaporation time increases. In the case of same initial temperature on the heated surface, as droplet diameter is smaller and small surface roughness is bigger, evaporation time decreases and time averaged heat flux increases.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.283-286
• /
• 2002

In fiber optic sensor, the error of the measurement is influenced by the surface roughness of the target and surroundings, especially the outside light. To reduce or modify this error, the sensitivity of the fiber optic sensor and the noise change by the surface roughness of the target should be known. The purpose of this paper is to observe the sensitivity of the fiber optic sensor and the noise according to the surface roughness of the target.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1998.03a
• /
• pp.184-189
• /
• 1998

In the CNC lathe working, the study of the effects of various cutting conditions on cut surface roughness is less active than that of the ordinary latee. After lathe working of SM45C, a carbon steel material for machine structure, its surface roughness was measured using a stylus surface roughness tester. In most cases, good surface roughness was obtained over 160m/min cutting speed and then the proper cutting depth was found as 1.0~1.5mm.

• The Journal of Engineering Geology
• /
• v.25 no.2
• /
• pp.165-178
• /
• 2015

Physical and chemical weathering degrades rock, affecting its structural properties and thus the stability of stone buildings or other structures. Confocal laser scan microscopy (CLSM) is used here to observe temporal changes in the surface roughness of rock samples under simulated accelerated weathering. Samples were pressurized to 50, 55, or 70 MPa using a pressure frame, and subjected to freeze/thaw cycling controlled by a thermostat. The temperature was cycled from -20℃ to 40℃ and back. After each 20 cycles, CLSM was used to assess the change in surface roughness, and roughness factors were calculated to quantify the progression of the surface condition over time. Variations in cross-section line-roughness parameters and surface-roughness parameters were analyzed for specific parts of the sample surfaces at 5× and 50× magnification. The result reveals that the highest and lowest values of the roughness factors are changed according to elapsed time. Freezing/thawing at high pressure caused larger changes in the roughness factor than at low pressure.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.2
• /
• pp.408-417
• /
• 1995

A study on the surface roughness variation of work roll and strip at the temper rolling was performed. The results were obtained with changes according to the surface roughness of work roll and method to make the peak count on the roll in the temper rolling, and factors to affect to the work roll surface in actual rolling machine (ie. Temper mill). The results suggests that the electro-discharge textured roll has mere uniform roughness distribution than shot blasted roll and its life time is two times longer than shot blasted because it has more sine wave roughness, and it is possible to control the Rmax. In shot blasting method, Surface roughness is related to the impeller speed, But it can't control the peak count.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.10 no.2
• /
• pp.89-94
• /
• 2001

This paper presents a study of surface roughness prediction model by orthogonal design in turning operation. Regression analysis technique has been used to study the effects of the cutting parameters such as cutting speed, feed depth of cut, and nose radius on surface roughness. An effect of interaction between two parameters on surface roughness has also been investigated. The experiment has been conducted using coated tungsten carbide inserts without cutting fluid. The reliability of the surface roughness model as a function of the cutting parameters has been estimated. The results show that the experimental design used in turning process is a method to estimate the effects of cutting parameters on sur-face roughness.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.15-16
• /
• 2006

In-process surface roughness prediction is studied in this research. To implement in-process prediction, spindle displacement is introduced. Machined surface's roughness is assumed to be expressed in terms of spindle displacement. In-process measurement of spindle displacement is conducted using CCDS (cylindrical capacitive displacement sensor). Two prediction models are developed. One is simple linear model between measured surface roughness and values by spindle displacement. The other is multiple regression model including machining parameters like spindle speed, fee rate and radial depth of cut. Relation between machined surface roughness and roughness by spindle displacement are verified.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.11a
• /
• pp.267-272
• /
• 2001

The effect of characteristic of surface roughness and roughness patterns on frictioin was studied experimentally in boundary lubrication with reciprocating tribometer. Roughness was changed from Ra=0.2 $\mu\textrm{m}$ to Ra=1.2 $\mu\textrm{m}$. Three roughness patterns-transverse, oblique, longitudinal- were tested for various load. Ra=1.0 $\mu\textrm{m}$ roughness showed lower friction coefficient and transversal pattern showed lower friction and high scuffing load in the test conditions.

• Restorative Dentistry and Endodontics
• /
• v.5 no.1
• /
• pp.13-18
• /
• 1979

The purpose of this study was to measure the roughness on the acid -etching surface. The etching agents of three-kinds composite resins were used to etch the tooth surface. Newly extracted I5-anterior teeth were invested with self-curing acrylic resin, and the labial surface was exposed. The exposed labial side was polished with abrasive papers and finally polished on polishing machine with zinc oxide powder. After the teeth were polished, the specimens were washed by water and dried by air. Surface roughness tester, Taylor-Habson's Taly Surf-10, (Fig-1) was used to measure roughness of this unetched tooth surface. And that, the specimens were divided into three groups. The first group was etched with Restodent etchant, the second group was etched with Nuva-system etchant, and Hi-pol etching agent was used in the third group. And the surface roughness tester was used to measure roughness of the etching teeth surface. The results obtained were as follows. 1. The roughness of acid-etched enamel were increased $2{\mu}m$ to $6{\mu}m$. 2. Hi-pol etchant produced the smoothest surface($2.3{\mu}m$). 3. Restodent etchant($3.8{\mu}m$) and Nuva-system etchant($3.7{\mu}m$) produced rougher surface than Hi-pol.