• 한국기계가공학회지
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• 제10권4호
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• pp.121-126
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• 2011

An accumulator placed on the refrigerant cycle pipe lines is a part to relax fluctuations of pressure within the pipe lines and stabilize refrigerants flowed into pipe. The accumulator has been mainly manufactured by the process of tube spinning using CNC(Computer Numerical Control) lathe. However, this process has the defects which are low productivity per hour and high cost. For that reason, tube end-forming using roll die is actively being developed, recently. The purpose of this study is to develope the tube end-forming process using roll die in order to manufacture the accumulator for the refrigeration pipe lines. First, the process design of tube end-forming was performed based on specification of product, and then was verified with FE analysis. Also, the effects of friction coefficient and revolution speed of roll die on forming load were investigated. The analytical results were applied in the final process design of tube end-forming. Finally, tube end-forming test was carried out to verify the validity of the FE analysis and the process design.

• 한국기계가공학회지
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• 제8권4호
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• pp.76-82
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• 2009

A worm screw is widely used in a geared motor unit for motion conversion from rotation to linear motion. For mass production of a high quality worm, the current roll forming process is substituted with the milling cutter process. Since the milling cutter process enables the integration of all machining operations of worm manufacturing on a CNC(Computer Numerical Control) lathe, productivity can be remarkably improved. The tooling system for side milling cutter on the CNC lathe to improve machinability is developed. However, the runout of spindle and cutting tips are important factors to be considered for producing high quality worms because the tooling system has multiple tips. In this study, surface roughness variations accuracy according to runout was investigated in side milling cutter for worm screw. The result shows by simulation and experiment.

• Journal of Advanced Marine Engineering and Technology
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• 제14권2호
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• pp.35-47
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• 1990

The natural frequency of lateral vibration for ship's propulsion shafting tends to become lower as the relative stiffness of supproted system of the propulsion shafting decreases and the weight of shafting increases. Especially, the propulsion shafting of high-power ships such as car ferries, roll-on/roll-off, and container ships are susceptible to lateral vibration for their resonant speeds are happened to be in ordinary operating speed ranges. So far, many papers on the lateral vibration of ship's propulsion shaftings are published but they treated mainly special cases and not explained explicitly the calculation process. In this paper, the calculation processes of undamped and also forced damped lateral vibration by the transfer matrix method are presented and the calculation programs are developed. With the developed computer programs, a ship's propulsion shafting which was introduced on the published paper is analyzed for its lateral vibration and also the lateral vibration of the main drive shaft for a lathe is calculated to show the availiability of developed computer programs.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.1017-1020
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• 2002

The pure Ti is taken annealing process for one hour at 90$0^{\circ}C$. The pure Ti is sufficient for ASTM B348 Grade2. The rolling mill roll the Ti-8Ta-3Nb(wt%) which became vacuum melting in arc furnace until the length is about 45mm and the thickness is about 6.05mm. Then it is made 6mm$\times$6mm$\times$44mm by wire cutting with EDM and it is made ∮ 6mm by rough cutting with the general purpose lathe. The machining accuracy of implant parts in the dental and medical science are decided by dimension, shpe, straightness, surface roughness. It is difficult to cut for the Ti alloy. It is caused problems of straight degree and surface roughness to the Ti alloy have many cases which length is smaller than diameter in cutting. Total 24 specimens different kind of 4 alloies are used in experiment to gain a cutting property. According to the cutting velocity, cutting depth, cutting temperature, feed and clearance angle experiments are performed. Conclusively it is expected that cutting depth of 0.5mm, feed velocity of 0.07mm/rev and cutting velocity of 80m/min could make a suitable result.