• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.1-7
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• 2008

This paper research the trend of technology of the high efficient and reliability machining center and high flexibility parallel manipulator machining center including linear motor machining center, submicron machining center and direct drive 5 axis machining center using patent information of Korea, U.S.A, Japan and Europe. By using this, the technique level of Korea, the International trend of technology and condition of cooperation research was estimated and the necessity of research and development performance about the machining center for the IT part processing were inquired.

• Journal of Mechanical Science and Technology
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• v.17 no.3
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• pp.336-342
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• 2003

Increasing demand on precision machining using computerized numerical control (CNC) machines have necessitated that the tool move not only with the smallest possible position error but also with smoothly varying feedrates in 3-dimensional (3D) space. This paper presents the simultaneous 3D machining process investigated using a retrofitted PC-NC milling machine. To achieve the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non Uniform Rational B-Spline (NURBS) curve is proposed. With this accurate and efficient algorithm for the generation of complex 3D shapes, a real-time NURBS interpolator was developed using a PC and the simultaneous 3D machining was accomplished satisfactorily.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.3
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• pp.13-19
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• 2003

The high speed machining technology has been improved remarkably in die/mold industry with the growth of parts and materials industries. Though the spindle speed of machine tool increases, the condition monitoring techniques of the machine tool, tool and workpiece in high speed machining ate incomplete. In tins study, efficient sensing technology in high speed machining is suggested by observing the characteristics of cutting force, gap sensor and accelerometer signal also, machinability of high-speed machining is experimentally evaluated sensing technique to monitor the machine tool and machining conditions was performed.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1349-1354
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• 2003

Ultrasonic Machining process is an efficient and economical means of precision machining on glass and ceramic materials. However, the mechanics of the process with respect to crack initiation and propagation, and stress development in the ceramic workpiece subsurface are still not well understood. In this research, we investigate the basic mechanism of chemical assisted ultrasonic machining(CUSM) of glass through the experimental approach. For the purpose of this study, we designed and fabricated the desktop micro ultrasonic machine. The feed is controlled precisely by using the constant load control system. During the machining experiment, the effects of HF(hydrofluoric acid) characteristics and machining condition on the surface roughness and the material removal rate are measured and compared.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.878-881
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• 2000

Recently high speed machining is being studied actively to reduce machining time and to improve machining precision. To perform efficient high speed machining, evaluation of high speed machinability must be studied preferentially and it can be identified by investigation of cutting force, tool wear and surface roughness. In this study. the cutting force and tool wear and surface roughness are investigated in case of various cutting conditions for hardened die steel.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.439-444
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• 2004

A new efficient intelligent machining strategy named the Steepest Directed Tree method is presented in this study, which makes surface model discrete with triangulation meshes and the cutter paths track along the tree directions. In order to formulate these algorithms practically, it is deduced the multi-stage machining approach of uncut volume caused by cutter gouging in the course of milling using flat end mill. It is systematized the checking process the cutter interference by grouping the 6 kinds of gouging types, which yields the environment of connectivity data lists including CL-data, and then the multi-stage machining strategy, that minimizes uncut area by continuously sequencing the generative subsequent CL-paths, is shamed to determine the second tool path for the next uncut area and to compose the operating multi-stage cutting processes. The completed machining system of curved surfaces is evaluated by testing the practical machining experiments which have various kinds of shape conditions.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.83-90
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• 2004

This paper proposes a tool path generation method for machining impellers with 5-axis machining center. The shape of impeller is complex, being composed of pressure surface, suction surface and leading edge, and so on. The compound surface which is made of ruled surface such as pressure surface and suction surface and leading edge such as fillet surface, makes the tool path generation much complicated. To achieve efficient roughing, cutting area is divided into two region and then tool radius of maximum size that do not cause tool intereference is selected for shortening machining time. In finishing, accuracy is improved using side cutting for blade surface and point milling for leading edge.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.10
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• pp.42-47
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• 2019

Helical machining is an efficient method for machining holes using an endmill. In this study, a surface roughness prediction model was constructed for improving the productivity of hole machining. Experiments were conducted to form holes by the helical machining of AL6061-T4 aluminum sheets and correlation analysis was performed to examine the relationships between the variables based on the measured results. Meanwhile, a regression analysis technique was used to construct and evaluate the prediction model. Through these analyses, the parameter which has the greatest influence on the surface roughness when the hole is formed by the helical machining is the feed, followed by the number of revolutions of the endmill. Moreover, for the axial feed of the endmill, it was concluded that the influence of the surface roughness is small compared to the other two parameters but it is a factor worth considering to improve the accuracy when constructing the predictive model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1285-1288
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• 2005

Screw rotors, the key parts of screw compressors, are used in compressing air and refrigerant due to their high productivity, compact size, low noise and maintenance. In general, a screw compressor is composed of a pair of rotors of complex geometric shape. The manufacturing cost of the screw rotors is high because the complicated helical shapes of the screw rotors are manufactured usually by the dedicated machine tools. In this study, rotor profile is divided into three parts for the efficient machining. The formed tools are designed and shared for the respective split region. By cutting the screw rotor using the formed tools, this method is more efficient than the end mill in machining rotor. Experimental results show that 4-axis machining using formed tools needs less time and has the accuracy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.761-769
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• 2008

The majority of mechanical parts are manufactured by milling machines. Hence, geometrically efficient algorithms for tool path generation and physical considerations for better machining productivity with guarantee of machining safety are the most important issues in milling tasks. In this paper, an optimized path generation algorithm for direction parallel milling which is commonly used in the roughing stage is presented. First of all, a geometrically efficient tool path generation algorithm using an intersection points-graph is introduced. Although the direction parallel tool path obtained from geometric information have been successful to make desirable shape, it seldom consider physical process concerns like cutting forces and chatters. In order to cope with these problems, an optimized tool path, which maintains constant MRR in order to achieve constant cutting forces and to avoid chatter vibrations at all time, is introduced and the result is verified. Additional tool path segments are appended to the basic tool path by using a pixel based simulation technique. The algorithm has been implemented for two dimensional contiguous end milling operations, and cutting tests are conducted by measuring spindle current, which reflects machining situations, to verify the significance of the proposed method.