• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.223-238
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• 2002

This paper presented on an environment estimation of cutting fluid which is a mouse model of acute bacterial rhinosinusitis using cutting fluid in grinding and cutting. Above results will be remarked the necessity of friendly environmental cutting skill when it had used in workshop. The results of a mouse experimental using cutting fluid showed that it are occurred to the respiratory organs sickness. Also cutting fluid are occurred to hurtfulness a person when it used to grinding and cutting in workshop. Also, the results of grinding experiments in avitation materials showed that surface roughness are superior to more emulsion type oil than vegetable type oil according to increase of the depth of cut. Grinding force are similar to both emulsion type oil and vegetable type oil.

• 한국정밀공학회지
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• 제26권1호
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• pp.138-145
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• 2009

High-efficiency and high-quality machining has become a fact of life for numerous machine shops in recent years. And high-efficiency machining is the most significant tool to enhance productivity. In this study, to achieve high-efficiency machining in turning process, a spindle speed optimization method was proposed based on a cutting power model. The cutting force and power were estimated from the cutting parameters such as specific cutting force, feed, depth of cut, and spindle speed. The time delay due to the acceleration or deceleration of spindle was considered to predict a more accurate machining time. Especially, the good agreement between the predicted and measured cutting forces showed the reliability of the proposed optimization method, and the effectiveness of the proposed optimization method was demonstrated through the simulation results associated with the productivity enhancement in turning process

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.69-73
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• 1996

Tool wear monitoring is very important aspect in metal cutting because tool wear effects quarity and precision of workpiece, tool life etc. In this study we detected force signal through tool dynamometer in turning and using it we conducted 6th AR modeling and fractal analysis. Finally the back-propagation model of the neural network is utilized to monitor tool wear and features are extracted through AR model and fractal analysis.

• Coupled systems mechanics
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• 제2권1호
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• pp.23-51
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• 2013

An analytical algorithm for the estimation of the resistance forces exerted on the dipper of a cable shovel and the specific energy consumed in the cutting-loading process is presented. Forces due to payload and to cutting of geomaterials under given initial conditions, cutting trajectory of the bucket, bucket's design, and geomaterial properties are analytically computed. The excavation process has been modeled by means of a kinematical shovel model, as well as of dynamic payload and cutting resistance models. For the calculation of the cutting forces, a logsandwich passive failure mechanism of the geomaterial is considered, as has been found by considering that a slip surface propagates like a mixed mode crack. Subsequently, the Upper-Bound theorem of Limit Analysis Theory is applied for the approximate calculation of the maximum reacting forces exerted on the dipper of the cable shovel. This algorithm has been implemented into an Excel$^{TM}$ spreadsheet to facilitate user-friendly, "transparent" calculations and built-in data analysis techniques. Its use is demonstrated with a realistic application of a medium-sized shovel. It was found, among others, that the specific energy of cutting exhibits a size effect, such that it decreases as the (-1)-power of the cutting depth for the considered example application.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.27-33
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• 1999

In order to regulate cutting force at a desired level during NC lathe process, a feedrate override Adaptive Control Constraint system was developed. Nonlinear model of the cutting process was linearized as an adaptive model with a time varing process parameter. Performance of the ACC system was confirmed on the NC lathe equipped with the developed NC system through a large amount of experiment.

• 한국기계가공학회지
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• 제13권5호
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• pp.50-56
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• 2014

A technique based on the finite element method (FEM) is used in the simulation of metal cutting process. This offers the advantages of the prediction of the cutting force, the stresses, the temperature, the tool wear, and optimization of the cutting condition, the tool shape and the residual stress of the surface. However, the accuracy and reliability of prediction depend on the flow stress of the workpiece. There are various models which describe the relationship between the flow stress and the strain. The Johnson-Cook model is a well-known material model capable of doing this. Low-alloy steel is developed for a dry storage container for used nuclear fuel. Related to this, a process analysis of the plastic machining capability is necessary. For a plastic processing analysis of machining or forging, there are five parameters that must be input into the Johnson-Cook model in this paper. These are (1) the determination of the strain-hardening modulus and the strain hardening exponent through a room-temperature tensile test, (2) the determination of the thermal softening exponent through a high-temperature tensile test, (3) the determination of the cutting forces through an orthogonal cutting test at various cutting speeds, (4) the determination of the strain-rate hardening modulus comparing the orthogonal cutting test results with FEM results. (5) Finally, to validate the Johnson-Cook material parameters, a comparison of the room-temperature tensile test result with a quasi-static simulation using LS-Dyna is necessary.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 2000년도 추계 학술논문발표회 논문집
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• pp.39-45
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• 2000

In recent years, composite materials such as fiber reinforced plastics (FRP) have gained considerable attention in the aircraft and automobile industries due to their light weight, high modulus and specific strength. In practice, control of chip formation appears to be the most serious problem since chip formation mechanism in composite machining has significant effects on the finished surface ［1,2,3,4,5］. Current study will discuss frequency analysis based on autoregressive (AR) time series model and process characterization in orthogonal cutting of a fiber-matrix composite materials. A sparsely distributed idealized model composite material, namely a glass reinforced polyester (GFRP) was used as workpiece. Analysis method employs a force sensor and the signals from the sensor are processed using AR time series model. The experimental correlation between the different chip formation mechanisms and model coefficients are established.(omitted)

• 한국생산제조학회지
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• 제9권2호
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• pp.72-79
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• 2000

A new optimal tool design model which can be minimized the resultant cutting forces under the constrains of variables was developed. The resultant cutting forces are used as the objective function and tool angles are used as the variables. Cutting experiments of tool wear and chip length using the new and conventional tools wee carried out. Tool life of optimized cutter are more increased than those of conventional cutter by 2.29 times and 2.52 times at light and at heavy cutting conditions respectively. Chip length of optimized cutter are more increased than those of conventional cutter It is considered that the decrease of the resultant cutting forces is the cause that an effective rake and shear angles by the shape of optimal cutter.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.77-82
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• 2003

In end milling process, undeformed chip thickness and cutting force vary periodically with phase change of the tool. Recently, a model has been proposed to simulate the shear and friction characteristics of an up-end milling process in terms of the equivalent oblique cutting to this. In the current study, the varying undeformed chip thickness and the cutting forces in a down-end milling process have been replaced with the equivalent ones of oblique cutting. And, the down-end milling characteristics of SM45C has been compared with that of the up-end milling previously presented with different helix angles.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1480-1486
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• 2002

In this study, the cross-coupling control (CCC) with three new features is proposed to maintain contour precision in high-speed nonlinear contour machining. One is an improved contour error model that provides almost exact calculation of the errors. Another is the utilization of variable controller gains based on the instantaneous curvature of the contour and the variable command. For this scheme, a stability is analyzed. As a result, the stability region is obtained, and the variable gains are decided within that region. The other scheme in the proposed CCC is a real-time feedrate adaptation module to regulate cutting force fur better surface finish through regulation of material removal rate (MRR). The simulation results show that the proposed CCC system can provide better precision than the existing method particularly in high-speed machining of nonlinear contours.