• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.153-158
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• 1999

In the multi-purpose lathe, the design of tilting turret slide system has an important and critical role to enhance the accuracy of the machining process. Tilting turret unit is traveled by 3-axis slide systems. There is a need to design this part very carefully. In this research, the 3-axis slide system with tilting turret unit is modeled and simulated using ADAMS software. The dynamic behavior of this system is visualized by data graphs and dynamic animations. The first step of virtual prototype which makes it possible to design economically and effectively is developed.

• 한국정밀공학회지
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• 제33권1호
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• pp.17-22
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• 2016

In smart factories, the entire manufacturing process from design to the final product is simulated in a virtual manufacturing environment and optimized before starting production. Suppliers and customers make decisions based on the simulation results. Therefore, effective rendering of the information of the virtual products to suppliers and customers is essential for this manufacturing paradigm. In this study, a method of rendering the surface roughness of the virtual products using a tactile display is presented. A tactile display device comprising a $3{\times}3$ array of individually controlled piezoelectric stack actuators is constructed. The surface topology of the virtual products is rendered directly by controlling the piezoelectric stack actuators. A series of experiments is performed to evaluate the performance of the tactile display device. An electrical discharge machined surface is rendered using the proposed method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1008-1013
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• 2003

This paper concerns the structural characteristic analysis and evaluation on the hydrostatic guide way and feeding system of a high precision centerless grinder for machining ferrules. In order to realize the required accuracy of ferrules with sub-micron order, the axial stiffness and motion accuracy of feeding system have to become higher level than those of existing centerless grinders. Under these points of view, the physical prototype of feeding system consisted of steel bed, hydrostatic guide way and ballscrew feeding mechanism is designed and manufactured for trial. Experimental results show that the axial and vertical stiffnesses of the physical prototype are very low as compared with those design values. In this paper, to reveal the cause of these stiffness difference, the structural deformations on the virtual prototype of feeding system are analyzed based on the finite element method under experimental conditions. The simulated results illustrate that the deformation of front ballscrew support-bearing bracket is the main cause of reduction in the axial stiffness of feeding system, and the deflection of bed structure and the bending deformation of hydrostatic guide rails are the main causes of reduction in the vertical stiffness of feeding system.

• 대한기계학회논문집A
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• 제28권7호
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• pp.896-903
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• 2004

This paper proposes the structural characteristic analysis and evaluation on the hydrostatic guide way and feeding system of a high-precision centerless grinder for machining ferrules. In order to realize the required accuracy of ferrules with sub-micron order, the axial stiffness and motion accuracy of feeding system have to become higher level than those of existing centerless grinders. Under these points of view, the physical prototype of feeding system composed of steel bed, hydrostatic guide way and ballscrew feeding mechanism is designed and manufactured for trial. Experimental results show that the axial and vertical stiffnesses of the physical prototype are very low as compared with those design values. In this paper, to reveal the cause of these stiffness difference, the structural deformations on the virtual prototype of feeding system are analyzed based on the finite element method under experimental conditions. The simulated results illustrate that the deformation of front ballscrew support-bearing bracket is the main cause of reduction in the axial stiffness of feeding system, and the deflection of bed structure and the bending deformation of hydrostatic guide rails are the main causes of reduction in the vertical stiffness of feeding system.

• 한국정밀공학회지
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• 제21권1호
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• pp.159-166
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• 2004

Custom-tailored products are meant by the products having various sizes and shapes to meet the customer's different tastes or needs. Thus fabrication of custom-tailored products inherently involves inefficiency. To minimize this inefficiency, a new paradigm is proposed in this work. In this paradigm, different parts are grouped together according to their sizes and shapes. Then, representative shape of each group is derived and it will be used as the work-piece from which the parts in the group are machined. Once a new product is ordered, the optimal work-piece is selected through making similarity comparisons of new product and each representative shape. Then an effective NC tool-path is generated to machine only the different portions between the work-piece and the ordered product. The efficient machining conditions are also derived from this shape difference. By machining only the different portions between the work-piece and the ordered product, it saves time. Similarity comparison starts with the determination of the closest pose between two shapes in consideration. The closest pose is derived by comparing the ray distances while one shape is virtually rotated with respect to the other. Shape similarity value and overall similarity value calculated from ray distances are used for grouping. A prototype system based on the proposed methodology has been implemented and applied to the grouping and machining of the shoe lasts of various shapes and sizes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.70-73
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• 2003

Custom-tailored products are meant by the products having various sizes and shapes to meet the customer's different tastes or needs. Thus fabrication of custom-tailored products inherently involves inefficiency. To minimize this inefficiency, a new paradigm is proposed in this work. In this paradigm. different paris are grouped together according to their sizes and shapes. Then, representative shape of each group is derived and it will be used as the work-piece from which the parts in the group are machined. Once a new product is ordered, the optimal work-piece is selected through making similarity comparisons of new product and each representative shape. Then an effective NC tool-path is generated to machine only the different portions between the work-piece and the ordered product. The efficient machining conditions are also derived from this shape difference. By machining only the different portions between the work-piece and the ordered product, it saves time. Similarity comparison starts with the determination of the closest pose between two shapes in consideration. The closest pose is derived by comparing the ray distances while one shape is virtually rotated with respect to the other. Shape similarity value and overall similarity value calculated from ray distances are used for grouping. A prototype system based on the proposed methodology has been implemented and applied to the grouping and machining of the shoe lasts of various shapes and sizes.

• 제어로봇시스템학회논문지
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• 제6권6호
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• pp.514-521
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• 2000

In this study, a surface generating system with a bundle of wires, which can reproduce a certain range of surface roughness of the objects without direct machining process, is implemented. The system consists of a bundle of wires, a PZT actuator, a vertical table system actuated linearly along two perpendicular axes, and an image processing system. Through the development of the operational software for all of those subsystems by a common language(Visual C＋＋) of the implemented system, the complete process except arrangement of a bundle of wires are automated. Lastly, through the experiments of generating the flat surface of some virtual object and then of measuring the reproduced surface roughness, it is confirmed that the implemented system has excellent performance.

• 한국기계가공학회지
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• 제12권6호
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• pp.175-181
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• 2013

The primary element of machining automation is to maximize the utilization of machine tools, which determines the output and lead-time. In particular, 95% of raw materials for wing ribs are cut into chips and 0.6 ton of chips are generated every hour from each machine tool. In order to verify the chip recycling system that controls the chips from the machines in five-axis FMS line, a simulation of the virtual model is constructed using the QUEST simulation program. The optimum speed of the chip conveyor and its operating conditions that directly affect the efficiency of the FMS line are presented including the chip conveyor speed, the maximum capacity of the hopper, and the number of chip compressors.

• 한국생산제조학회지
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• 제23권3호
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• pp.273-278
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• 2014

This study presents a chatter vibration avoidance program for the milling process. Chatter vibration has a negative effect on workpieces and spindle-tools. When chatter vibration occurs, the cutting tool is loaded dynamically, a chatter pattern is generated on the workpiece, and the tool life is reduced. The developed program is composed of various modules such as an FFT analyzer, an impact test analyzer, a chatter vibration indicator, and a spindle speed recommender. The proposed program is verified using an AISI D2 cutting experiment in milling process. The effect of chatter vibration on the machining condition can be simulated by the suggested method, and successfully exploited to avoid chatter vibration.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.456-461
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• 2002

Nowadays, there are required more speed and accurate machining in order to improve the productivity through the reduction of cutting and non-cutting time. In this study, the high-speed HMC is specially designed to do remote control and high-speed mechanism with 30000rpm, 50000rpm, 40m/min, 100m/min and bridge type structure. Every structural deformation and vibration that is generated from all of factor is analyzed being based on the virtual manufacturing technologies: thermal characteristic analysis, machine-ability, tool wear measuring system, driving characteristic of linear motor and so on. As the application of these results had been consisted of three axes to move slight and rigid finally. Therefore, table errors that are resulted in change of work weight can be removed.