• International Journal of Precision Engineering and Manufacturing
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• v.1 no.2
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• pp.67-75
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• 2000

virtual computer numerical control(VCNC) arises from the concept that one can experience pseudo-real machining with a computer-numerically-controlled(CNC) machine before actually cutting an object. To achieve accurate VCNC, it is important to determine abnormal behavior, such as chatter, before cutting. Detecting chatter requires an understanding of the dynamic cutting force model. In general, the cutting process is a closed loop system the consists of structural and cutting dynamic. Machining instability, namely chatter, results from the interaction between these two dynamics. Several previous reports have predicted stability for a single path, using a simple cutting force model without run out and penetration effects. This study considers both tool run out and penetration effects, using experimental modal analysis, to obtain predictions that are more accurate. The machining stability during a corner cut, which is a typical transient cut, was assessed from an evaluation of the cutting configurations at the corner.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.85-94
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• 1994

The cutting mechanism of ultrasonic vibration machining is characterized as two phases, that is, an impact at the cutting edge and a reduction of cutting force due to non-contact interval between tool and workpiece. In this paper, in order to identify cutting dynamics of a system with ultrasonically vibrated cutting tool, an ARMA modeling is performed on experimental cutting force signals which have a dominant effect on cutting dynamics. The aim of this study is, through Dynamic Date System methodology, to find the inherent characteristics of an ultrasonic vibration cutting process by considering natural frequency and damping coefficient. Surface roughness and stability of cutting process under ultrasonic vibration are also considered

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.437-446
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• 2013

There have been numerous studies on end milling processes. However, these have been restricted to the application of tools for special cutting purposes. A side milling cutter can handle long, deep, and open slots in a more efficient manner, and it provides the best stability and productivity for this type of milling. In this paper, a method to predict the cutting forces in side milling is described, and simulated cutting forces are compared with those obtained by cutting experiments. In particular, the side milling process easily generates relative motion between the tools and the workpiece because it produces intermittent cutting forces that cause vibrations over a wide frequency range. Therefore, the application of a dynamic cutting model instead of a static cutting model is appropriate to forecast the cutting forces more accurately.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.80-85
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• 2001

In Part 2, dynamic cutting force model, thermal behavior model, and feed drive model are presented for development of a virtual machine tool. Some relevant results with brief descriptions for each model are presented to verify the proposed models. Experimental results for each model agreed well with the estimated ones. The developed models in this two-part paper are partially integrated as a comprehensive software environment.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.3
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• pp.42-47
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• 2003

In Part 2 of this paper, the dynamic cutting force model, thermal behavior model, and feed drive model used in the development of a virtual machine tool (VMT) are briefly described. Some results are presented to verify the proposed models. Experimental data agreed well with the predicted results fer each model. A comprehensive software environment to integrate the models into a VMT is also proposed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1768-1771
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• 2003

Hard turning replaces grinding for finishing process with expectations of higher productivity and demanded surface quality. Especially for the surface roughness as surface quality demanded in finishing process of hard turning, know-how of machining characteristics of hardened materials by cutting force analysis should be accumulated in company with achievement of precision of elements and high stiffness design technology in hard turning. Considering chip formation mechanism of hardened materials, adequate cutting conditions are selected for machining experiments and cutting forces are measured according to cutting conditions. Increase of cutting forces especially thrust force and increase of dynamic instability could occur in hard turning. Analysis of dynamic characteristics of the cutting forces is executed to investigate relation between dynamic instability and surface roughness in hard turning. Investigation on effects of relative motion of machining system generated by vibration due to dynamic instability shows that ultimate surface roughness could be predicted considering relative motion of machining system with geometrical surface roughness.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.38-46
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• 1994

The vibration amplitude of boring bar is generally large at the tool tip, because it has the high length-diameter(L/D) ratio. A new dynamic cutting force model is presented by considering the change of shear angle under dynamic cutting. The boring bar is modelled as a cantilever with dynamic force acting at the tool end point. Based on this realistic continuous system model, the equation of motion of borring bar is solved by numerical computations. A good agreement is found between the proposed model and the experimental results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.2
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• pp.91-99
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• 1998

This paper presents a methodology for identifying the cutter runout geometry in end milling process. Cutter runout is common but undesirable phenomenon in multi-tooth machining because it introduces variable chip loading to insert which results in a accelerated tool wear. amplification of force variation and hence enlargement vibration amplitude From understanding of chip load change kinematics, the analytical cutting force convolution model was formulated as the angular domain convolution model was formulated as the angular domain convolution of three dynamic cutting force component functions. By virtue of the convolution integration property, the frequency domain expression of the local cutting forces and the chip width density of the cutter. Experimental study is presented to validate the analytical model. This study provides the in-process monitoring and compensation of dynamic cutter runout to improve machining tolerance and surface quality for industrial application.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.46-54
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• 2004

A cutting force model predicting the dynamic force induced by the axial vibration of it plate in face milling is introduced. When a plate face is milled, deformation in tool axial direction is considerable. Therefore, cutting forces are affected by not only inner-outer modulation in feed direction but also by axial deformation. A PTP (peak-to-peak) diagram made by the simulated dynamic force model is evaluated. The stability of the face milling process such as the chatter outset, and the stable cutting region can be simply estimated. Simulation results are compared with that of experiment.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.104-115
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• 1999

Cutting process, in general, is a closed-loop system consisting of structural dynamics and cutting dynamics, with the cutting forces and the relative displacements between tool and workpiece being the associated variables. There have been a number of works on modeling the cutting process of endmilling, most of which assumed that either one of the tool or workpiece be negligible in tis displacement. In this paper, the relative displacement between tool and workpiece was considered. The proposed model used experimental modal analysis for structural dynamics and an instantaneous uncut chip thickness model for cutting dynamics. Simulation of the model, a time varying cutting system, was performed using 4th order Runge-Kutta method. Subsequent simulation results were utilized to predict chatter over a variety of experiments in slotting operation, showing good agreement.