• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.232-236
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• 1987

To improve the surface waviness in the peripheral milling, since the tool deflection is largely affected by cutting force, the feedrate is controlled so that the cutting force measured in the normal direction to the workpiece is constant. A discrete time first order model between the feedrate and the tool deflection is derived for the control. The experimental results show that the surface waviness is greatly improved by the proposed method.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.292-304
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• 2011

The purpose of this study is to draw institutional implications for tree cutting permit system improvement in comparison with Korea and foreign countries (German, Japan). A survey about recognition of cutting system and cutting-invigorating factors for two groups in charge of work for cutting permit (forest-official) and cutting operation (forest owner, tree butcher, forestry association, and forestry corporation) was carried out. The survey provides basic information which is necessary to improve current cutting system. The result of analysis about both German and Japan's cutting system show that clear cutting area to hinder function of forests tends to decrease and flexible final age of maturity considering condition of regional forest not uniform cutting age were applied. As a result of German and Japan's cutting system review flexible cutting system on regional characteristics is used to manage for the purpose of forest regeneration. The survey result about awareness and invigorating factors of cutting system represents that only public official group said final age of pine tree (3.13) and cedar (3.05) was proper and final age of other species of trees should have shortened. In matters of cutover area, current standard is less than 5ha per a felling area and the largest total area limit is 30 ha, only tree butcher, forestry corporation said cutover area must expand. Invigorating factors of current cutting system are reinforcement of cutover area, facility support, enrichment of technical training, increase of equipment support, simplification of administrative procedures, and provision of various benefits. The reinforcement of technical training among them especially represents the statistical significance of the participants' differential recognition.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.107-115
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• 2001

Drilling torque was measured indirectly using the spindle motor current and controlled in real time through feedrate manipulation in a machining center. The PID controller designed in the previous paper was applied to drilling torque control. A series of cutting experiments were performed for various cutting conditions. Experimental results showed that the drilling torque was well regulated at a given reference level by feedrate manipulation in all cutting conditions. The increase in the cutting torque and temperature according to the increase in machining depth was suppressed and the risk of the drill failure and the drill flank wear were reduced remarkably through cutting torque control. Moreover, the suggested cutting torque control system doesn\`t disturb the cutting process and is practical for industrial environment. Therefore, the proposed culling torque control system will contribute to productivity improvement in drilling process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.854-857
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• 2000

This paper presents the experimental results of relationship between the machinability and environmental consciousness due to cutting fluid atomization in machining process. Even though cutting fluid improves the machined part quality through the cooling and lubracating effects, its environmental impact is also increased according to the cutting fluid usage. Cutting tool wear is one of criterion for deciding the machinability. A few turning operations were performed to know the qualitative effectiveness of cutting fluid to tool wear improvement. This research can be used as a basis for environmental impact analysis on the shop floor. It can be also facilitate the optimization of cutting fluid usage in achieving a balanced consideration of productivity and environmental consciousness.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.61-67
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• 2001

The finishing process for die is an important process because it has influence on final quality of products. Recently s study on development of 5-axis die automated finishing machine has been progressed. But die must be moved from the cutting machine to the die automated finishing machine. So manufacturing cost and time increase and machining error occurs by transfer. So, in this study, a 3-axis machining center was applied to die finishing. Because cutting tool can be changed to finishing tool by ATC, both of cutting and finishing process are possible on the machine. However, this application results in the decrease of finishing for the improvement of form accuracy. So this study focused on the generation of finishing tool path suitable to 3-axis die finishing for the improvement of form accuracy. The form accuracy evaluation is performed by the measurement of removal depth using a stylus profilometer. From the result, it is confirmed that form accuracy was improved less than 2$\mu$m of removal depth error.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.206-214
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• 1988

To improve the surface waviness in the peripheral milling, the feedrate is controlled so that the cutting force measured in the normal direction to the workpiece is constant. A discrete time first order model between the feedrate and the tool deflection is derived for the control. It has been shown by the analysis that the tool deflection is directly related to the feedrate and largely affects the surface waviness during cutting. The experimental results shown that the surface waviness is drastically improved by the proposed methods.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.315-319
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• 1999

This paper has been considered on the cutting characteristics such as chip formation and surface roughness for Inconel 690 alloy with difficult-to-cut because of high toughness and strength. We have made efforts solving the problem to difficult-to-cut of Inconel by improvement of tool with TiN coating and the selection of optimum cutting condition. We used the CCD camera and the surface roughness tester to observe the chip formation and the state of machined surface by using the improved tool with diamond coating and various cutting condions. We have found that the chip formation showed the tooth shape of tooth blade and the surface roughness was very poor. but it can be better by selection of optimum cutting condition.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.43-51
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• 2004

A method for form error prediction in side wall machining with a flat end mill is suggested. Form error is predicted directly from the tool deflection without surface generation by cutting edge locus with time simulation. Developed model can predict the surface form error about three hundred times faster than the previous method. Cutting forces and tool deflection are calculated considering tool geometry, tool setting error and machine tool stiffness. The characteristics and the difference of generated surface shape in up milling and down milling are discussed. The usefulness of the presented method is verified from a set of experiments under various cutting conditions generally used in die and mold manufacturing. This study contributes to real time surface shape estimation and cutting process planning for the improvement of form accuracy.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.77-82
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• 2016

When drilling through Inconel 601 nickel-chromium-based alloys, a large amount of cutting oil is required to prevent tools from wear and fracturing due to heat buildup resulting from the high temperature resistance and toughness of this alloy. However, cutting oil supply has become a factor compromising the machining environment, and this has caused attention to shift to a more environmentally friendly cutting fluid supply system called minimum quantity lubrication (MQL). Our aim in this study was to find a more efficient drill processing method using MQL, and to verify its performance. To that end, we proposed a sealed cover, a step feed, and POSS-type cutting oil as measures to increase the effectiveness of MQL in view of the cutting force and tool wear, and established an improvement in efficiency using the proposed measures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.1069-1077
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• 2015

In tunnel excavation using blast, the wire saw rock cutting method generates a discontinuity perimeter around the center cut, and thus prevents blast vibration propagation to reduce vibration and noise. Therefore, the method is expected to be easy to use and economical compared with other methods. In this paper, the cutting mechanism of wire saw in tunnel excavation is investigated. A model describing the changes in cutting depth and wire saw shape inside a rock during cutting is established and validated for this purpose. Through a simulation using the model, the important characteristics of wire saw cut are investigated, and the influences of cutting conditions, such as wire saw tension, wire saw speed, feed speed, depth, and diameter of boring, on cutting performance are also examined. A method to improve the cutting performance is proposed based on the results.