• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.148-152
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• 2000

Detection of tool wear is very important in automated manufacturing. This paper presents tool condition monitoring system based on the wavelet analysis of the AC servo motro current in drilling and milling process. The current measurement system is relatively simple and its mounting will not affect machining operations. The discrete wavelet transform was used to decompose the current signal of a spindle AC servo motor in time - frequency domain. The feature vectors were extracted from the decomposed signals and compared for normal and wear condition. The results show the possibility for the effective application of wavelet analysis to tool condition monitoring.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.338-342
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• 2003

Hybrid machine is based on hardware technologies of machine tool and software technologies of open architecture controller. In machining technology, combination technology of turning, milling, and grinding and in machining energy technology. combination of mechanical, electrical, and chemical technology are developed. This paper describes hybrid machine technology for combination of machining, on-machine measurement, on-machine CAM, and on-machine remote monitoring and control in open architecture controller environment. For on-machine measurement, non-contact measurement technology based on CAD information is developed. For on-machine CAM, interactive CAM program for automatic NC program generation and tool path simulation is developed. For generation on-machine remote monitoring and control, suitable interface method between web program and CNC is proposed. The developed hybrid machine technology is implemented in 3 axes milling machine for evaluation of operablity.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.7
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• pp.800-807
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• 1999

A Periodic disturbance canceller is proposed to compensate for the periodic disturbance due to cutting process in a CNC machining center. The periodic disturbance canceller estimates the Periodic disturbance without phase delay. This is achieved by using linear phase low-pass filter and frequency response reciprocal filter of plant at the frequency of the periodic disturbance. This method is implemented in the position control system of the CNC machining center with general disturbance compensators in order to compensate for both the frictional force and the periodic disturbance. The experimental results are described to show its effectiveness.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.4
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• pp.20-29
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• 2004

A Tool wear monitoring system is indispensable for better machining productivity with guarantee of machining safety by informing the tool changing time in automated and unmanned CNC machining. Different from monitoring using other signals, the monitoring of spindle current has been used without requiring additional sensors on machine tools. For the reliable tool wear monitoring, current signal only of tool wear should be extracted from other parameters to avoid exhaustive analyses on signals in which all parameters are fused. In this paper, influences of force components of parameters on measured spindle current are investigated and a hybrid approach to cutting force regulation is employed for tool wear signal extraction in the spindle current. Finally, wear levels are verified with experimental results by means of real-time feedrate aspects changed to regulate the force component of tool wear.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.554-559
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• 1999

The purpose of this study is the machining of texture shapes by the contour fitting data. The hardware of the system comprises PC and scanning system, CO2 laser machine. There are four steps, (1) text image loading using scanning shapes or 2D image files, (2) generation of contour fitting data by the line and arc, cubic Bezier curve, (3) generation of NC code from the contouring fitting data, (4) machining by the DNC system. It is developed a software package, with which can conduct a micro CAM system of CNC laser machine in the PC without economical burden.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.14-23
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• 1999

This paper proposes a method to generate the velocity trajectory which guarantees user specified contour errors at corners for high speed and high precision motion control of CNC machines. The relation among the desired trajectory, system bandwidth and corner contour error are derived. Experiments show that the corner contour error specified by users can be guaranteed with the proposed velocity trajectory.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.392-397
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• 1993

Generally machine tools can be divided into three components : NC Controller, the electrical drives and the mechanical transmission elements. For high speed, high precision machining, high performance control of servo system must be accommodated and one must carefully define the interface among three components. In this paper, we suggest a way to assist future development of CNC controller by investigating the characteristics resulting from different interface between CNC controller and servo system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.87-93
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• 2011

CNC lathe machining has been widely used for parts machining of vehicles, aircraft, ships, electronics, etc. because cost savings for shortening processing time and increasing productivity are great. In this study, the purpose is to investigate the effect of cooling methods such as oil mist, water-soluble cutting oils on the workpiece surface roughness with the cutting speed, cutting depth, tool nose radius and feed rate of CNC lathe machine as a parameter in the cutting process of the aluminum alloy 2024 which is used a lot recently on aircraft parts. It is found that oil mist is coolant and water-soluble cooled by cutting the experimental conditions, cutting speed and cutting depth without effecting the surface roughness value was constant.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.495-501
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• 2011

The purpose of this study is to improve the roundness of CNC turning so that helps the operator to choose the right turning conditions to produce a product with the given parameters. This paper focuses on determining the optimal levels of machining factors for circular shaft with CNC turning. For this purpose, the optimization of factors is performed based on experimental design method. A design and analysis of experiments are conducted to study the effects of these factors on the roundness by using the SIN ratio, analysis of ANOVA, and F-test. Factors, namely, fixed pressure, wall thickness, depth of cut, and feed rate are optimized with consideration of the roundness. The boring tool used in this study is a tungsten carbide coated. The material of workpiece is Al6061 and the machining method is dry cutting.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.656-659
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• 1996

An universal NURBS interpolation for an open architectured CNC controller is proposed in order to unify internal data structure and algorithm of different interpolations such as linear, circular and spline, and to intelligently interface CAD database of the various workpiece contour. Furthermore, NURBS interpolation may result in better surface roughness and high speed machining due to the continuous generation of cutter movement. The mathematical manipulation of NURBS is presented and the practical implementation on the CNC controller of a lathe is discussed for real machining. The comparison between a computer design and workpieces machined on a lathe shows the feasibility of the NURBS interpolation format as an universal interpolation scheme.