• Transactions of Materials Processing
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• v.30 no.1
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• pp.27-34
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• 2021

In this study, response surface method (RSM) was used in modeling and multi-objective optimization of the parameters of AA5052-H32 in incremental sheet forming (ISF). The goals of optimization were the maximum forming angle, minimum thickness reduction, and minimum surface roughness, with varying values in response to changes in production process parameters, such as tool diameter, tool spindle speed, step depth, and tool feed rate. A Box-Behnken experimental design (BBD) was used to develop an RSM model for modeling the variations in the forming angle, thickness reduction, and surface roughness in response to variations in process parameters. Subsequently, the RSM model was used as the fitness function for multi-objective optimization of the ISF process based on experimental design. The results showed that RSM can be effectively used to control the forming angle, thickness reduction, and surface roughness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.339-344
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• 1993

A study for a lathe to machine workpieces with noncircular corss-sections is presented. The noncircular cutting is accomplished by controlling the radial tool position synchronized with the revolution angle of spindle. A learning control algorithm is suggested for the toll positioning, of which the control performances are analyzed and simulated on a numerical computer that the effectiveness of the control is convinced. The learning control is tested on a NC-lathe which shows successful results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.352-357
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• 1996

Recently, Permanent Magnet Synchronous Motor(PMSM) drives are widely used for industrial applications due to its high efficiency and high power factor control strategy. PMSM generally have two classifications such as the SPMSM(Surface Permanent Magnet Synchronous Motors) and IPMSM(Inter Permanent Magnet Synchronous Motors). IPMSA has economical merits over SPMSM in higher speed range, mechanical robustness, and higher power rate by the geometric difference. The maximum torque operation in IPMSM is realized by the current angle control which is to utilize additional reluctance torque due to a rotor saliency. In traction, spindle and compressor drives, constant power operation with higher speed range are desirable. This is simply achieved in the DC motor drives by the reduction of the field current as the speed is increased. However, in the PMSM, direct control of the magnet flux is not available. The airgap flux can be weakened by the appropriate current angle control to demagnetize. In this paper, the control method of optimal current vector in IPMSM is described in order to obtain the maximum torque or maximum output with the speed and load variations. The applied algorithm is realized by the proto system with torque and speed control Experimental results show this approach is satisfied for the high performance servo applications. (author). 6 refs., 9 figs., 1 tab.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.144-146
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• 2007

Interior Permanent Magnet Synchronous Motors(IPMSM) are expanding the application extent for industrial applications. Because that High efficiency and wide speed range are required in applications of electric vehicles, spindle drives and compressors and so on. The performance of IPMSM are deeply affected by the current phase control. Therefore, this paper deals with the analysis of the torque performance according to the variation of the current phase angle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.806-809
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• 2000

The factors which can improve tool life in machining are consisted of tool geometries, tool materials, coating methods. cutting environments, cutting conditions and so on. Cutting speed in cutting conditions is one of the important factors which can directly influence on the tool life. This paper deals the machinability which is concerned about the cutting direction and the tilt angle of fret form surface in hot die steel(STD I I). The NC datum were analysrd and the effective tool diameters were calculated according to the change of tilt angle the program which can continue the cutting speed with the change of spindle revolution is developed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.471-478
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• 2000

Endmill is one of the most important cutting tool, not only for machining of mold and die, but also for manufacturing of car industrial. Futhermore with spindle speeds on the increase and machined-surface quality aspiring to higher levels. The purpose of this study is an analysis of endmill's rake angle for appropriate tools design and making for the high speed machining. In this study, Experimental works are also executed to measure shape of endmills, cutting force, on different shape of endmills. Finally, To get concept of endmill design, Tool life was experimented on various design of tool from this study.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.2
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• pp.257-261
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• 2017

Drilling file is medical mini-drill which is made of Ni-Ti material and has tapered shape. It's for removing teeth nervine which helps the endodontic treatment. All files, saled at domestic market, are imported from U.S. and Europe. Also they have low manufacturing efficiency and high price because it is made by universal 5 axis CNC grinding machine. To solve these problem, 3 axis CNC table, controllable tilting angle spindle and helix angle moving table are devised. To confirm divised CNC grinding machine's manufacturing accuracy, conveying amount and finish product size measurement expreiment has been practiced. Also to automate all manufacturing processes, automatic mechanism is designed.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.119-126
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• 2023

Today, in order to improve fuel efficiency and dynamic behavior of automobiles, an era of light weight and simplification of automobile parts is being formed. In order to simplify and design and manufacture the shape of the product, various components are integrated. For example, in order to commercialize three products into one product, product processing is occurring to a very narrow area. In the case of existing parts, precision die casting or casting production is used for processing convenience, and the multi-piece method requires a lot of processes and reduces the precision and strength of the parts. It is very advantageous to manufacture integrally to simplify the processing air and secure the strength of the parts, but if a deep and narrow pocket part needs to be processed, it cannot be processed with the equipment's own spindle. To solve a problem, research on cutting processing is being actively conducted, and multi-axis composite processing technology not only solves this problem. It has many advantages, such as being able to cut into composite shapes that have been difficult to flexibly cut through various processes with one machine tool so far. However, the reality is that expensive equipment increases manufacturing costs and lacks engineers who can operate the machine. In the five-axis cutting processing machine, when producing products with deep and narrow sections, the cycle time increases in product production due to the indirectness of tools, and many problems occur in processing. Therefore, dedicated machine tools and multi-axis composite machines should be used. Alternatively, an angle spindle may be used as a special tool capable of multi-axis composite machining of five or more axes in a three-axis machining center. Various and continuous studies are needed in areas such as processing vibration absorption, low heat generation and operational stability, excellent dimensional stability, and strength securing by using the angle spindle.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.113-118
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• 2007

The flow forming has been used to produce long thin walled tube parts, with the reduced fanning force and the enhanced mechanical and surface quality for a good finished part, compared with the fanned parts using other method. Therefore, flow fanning technique is used widely in industrial production. Spinning and flow fanning techniques are used frequently in automotive, aerial and defense industries. The main factors for the flow fanning machine design are motor power, bed rigidity, mandrel stiffness, spindle power, roller profile, etc. Especially, mandrel, spindle power and roller are important factors for flow fanning machine capacity. In this paper, three dimensional finite element method for analysis of one-roller backward flow fanning of a workpiece has been carried out to study effects of roller profile on fanning force. Applied roller profile have roller lead geometries of angle $20^{\circ},\;30^{\circ},\;40^{\circ}$, concave and convex. Axial and radial fanning forces on various roller profiles are obtained and compared with each analysis cases.

• Journal of Korean Neurosurgical Society
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• v.48 no.2
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• pp.173-176
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• 2010

In this report, we introduce an undetermined fibrous tumor with calcification occurring in the cerebellopontine angle (CPA). A 51-year-old woman was admitted with a short history of dizziness. Computed tomography and magnetic resonance images revealed a $2{\times}2{\times}2\;cm$ sized mass at the left CPA which was round and calcified. There was no dura or internal auditory canal involvement. At surgery, the tumor was located at the exit of 7th and 8th cranial nerve complex. It was very firm, bright yellow and well encapsulated. Histologic findings revealed that the tumor was predominantly composed of fibrous component, scant spindle cells and dystrophic calcification. Immunohistochemical staining demonstrated positive for vimentin and negative for epithelial membrane antigen (EMA), S-100 protein, CD34, factor XIIIa and smooth muscle actin. The diagnosis was not compatible with meningioma, schwannoma, metastatic brain tumors, and other fibrous tumors. Although the tumor was resected in total, long term follow-up monitoring is necessary due to the possibility of recurrence.