• Journal of the Korean Society for Precision Engineering
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• v.26 no.4
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• pp.107-113
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• 2009

In this paper, we studied of measurement the vibration of natural frequency using optical fiber sensor. The boring bar for measurement of vibration in use optical fiber sensor has the advantage of direct measure for the frequency than accelerometer. Because it deal with output value on electrical signal of optical fiber in physical disturbance when it measures the frequency of vibration. The optical fiber sensor measured the vibration of boring bar by the gap in sensing jig while optical fiber just kept contact with boring bar. A prototype system was composed of jig part with gap and optical system part. In this paper, we found out the possibility to measurement of vibration by the gap in use optical fiber.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.24-30
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• 1998

Strength and displacement of jig body in index machine utilized for multiprocess machining such as drilling, boring and tapping, etc, at the same time were analyzed by the use of finite element analysis soft ware ANSYS 5.2A. The whole geometry was constructed by 4048 elements and 7016 nodes employing 8 node brick element. The analyses were carried out on five loading cases combining vertical and horizontal machining to simulate the case occurring large displacement and the one occurring small displacement one and provided following conclusions. (1) Jig body had sufficient strength because its safety factor was 6.95 even in the most severe loading case. (2) The largest displacement in Z direction was 549 m and that in radial direction was 43.7 m. (3) In order to reduce the displacement, vertical machining rather than horizontal or two or three processes should be adopted in the same station. (4) Alternate change of horizontal machining direction at consecutive stations can reduce the displace ment. (5) The dimension of the slider should be increased to reduce the displacement by the tolerance in the sliding part. (6) A bypass idle piston head needs to be installed to give a counterpart supporting load from opposite direction for a single horizontal machining case.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.5-19
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• 1995

항공기 기술의 발전은 다양한 과학기술 분야의 발달에 끊임없이 큰 영향을 주어왔고, 또 기기서 파생된 신 기술도 수없이 발생하였다. NC 공작기계도 그 하나이다. 제 2차 세계대전 후 미공군은 복잡한 형상의 항공기 부품가공과 고정밀도의 검사용 Gauge를 제작할 필요성을 얻게 되었다. Helicopter의 Rotor blade의 Prifile 검사용 Plate gauge를 가공할 수 있는 기계를 개발 중에 있었던 J.T.Person이 Jig boring machine을 저자적으로 제어하면서 Gauge를 가공하는 방법을 1947년 미공군에 제안하게 되었다. 이것이 NC 발달사에 기록된 역사적인 사실이며 이 Project는 후에 MIT로 넘아가고 1952년에 NC milling machine을 완성시켰다. 그 후, 1955년 Gidding & Lewis사가 최초로 NC 공작기계를 공업화한 제1호기 Numericord를 시장에 내 놓게 되었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.249-254
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• 1992

Hydrostatic Bearings have been applied to ultra high precision machine tools and precision instruments, because of their low friction characteristic, high load carrying capacity and high moving accuracy at all range of speed. In regard to realizing the Hydrostatic Bearing, various restrictors such as capillary, orifice, diaphram valve, spool valve, and etc can be used. However, their stiffness and flexibility are not sufficient in practical use for ultra precision machine tool elements. In this study dynamic equations were derived and the dynamic characteristics were simulated for both orifice and flow control servo valve. Simulation was carried out on the condition that static and sinusoidal dynamic loads were applied to the table of CNC jig Boring machine. The simulation results indicate the improvement of the performance of the Bearing system when flow control servo valve has been used as restrictor of Hydrostatic Bearing.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.98-104
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• 2012

In this paper, precision processing is carried out for the pre hardened steel(HRC 54), which is one of injection mould materials. Processing characteristics are estimated according to the number of tool cutting blade and roundness is observed by the 3-Dimensional measuring machine. The surface roughness affected by the wire electric discharge machining are measured. Cutting component force of STAVOX is the highest in condition of 2F processing because load per a blade of cutting tool is high. Especially, the difference in Fz is over 20N by cutting load. The slower spindle rotation speed and tool feed rate are, the better cutting component force is. The roundness of hole processed in condition of 4F is good because feed rate is able to be fast. When rotation speed is increased, the surface roughness is decreased. The surface roughness acquired in condition of 2F processing is higher about 50% than 4F processing.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.114-125
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• 1993

In the present study the newly developed CAD/CAM system is applied to the process of the molding design, machining for mini-sized and precise processive die, and the production of press-stamped parts. When the design of a die was completed by means of CAD, wire cut NC data were generated with the aid of a design drawing in the CAD system and then inputed into the wire cut machine, and with the aid of a hole chart which had been made for this purpose, all the data were classified into the categories of CNC milling, jig boring, jig grinding, and machine center, and then developing a program of generating NC data, errors in process were reduced and programming time was shortened. The program was developed by using Autolisp language which was built-in the CAD, and realizing the intergation of designing a die, generating and processing NC data directly by a designer, designing time and machinery processing time were shorted. And the traditionally required working time for design. NC program required 6 days of work becomes 4 days of work by using the developed CAD/CAM system so that the efficiency shows 150% of the reduction working time. The prpgram of the design of the automation a progressive die mold was developed in the PC-Class Autocad system, therefore development expense could be reduced, and the integration of the CAD/CAM of the progressive die mold with the standard DB being built could be realized.