• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.463-464
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• 2009

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.195-199
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• 2001

The flow turning process, an incremental forming process, is a cost-effective forming method for axi-symmetric intricate parts to net shape. However, the flow turning process shows a fairly complicated deformation, it is very difficult to obtain satisfactory results. Therefore extensive experimental and analytical research has not been carried out. In this study, an fundamental experiment was conducted to improve productivity with process parameters such as tool path, angle of roller holder($\alpha$), feed rate(v ) and comer radius of forming roller(Rr). These factors were selected as variables in the experiment because they were most likely expected to have an effect on spring back. The clearance was controlled in order to achieve the precision product which is comparable to deep drawing one. And also thickness and diameter distributions of a multistage cup obtained by flow turning process were observed and compared with those of a commercial product produced by conventional deep drawing.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 추계학술대회 논문집
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• pp.101-104
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• 2000

Milli-structure components are classified as component group whose size is between macro and micro scale. that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In order to conventional metal forming, where numerical process simulation is already idly applied, the micro-forming process is characterized by some scale effects which have to be considered in an advanced process simulation. milli-structure rectangular cup drawing is analyzed and designed using the finite element method and experiment. The result of the finite element analysis is confirmed by a series of experiment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1016-1020
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• 2001

The spinning is a very effective manufacturing technology for short production runs in a variety of sizes and shapes, because it can form the cross-section or tubular parts various shapes. However extensive experimental and analytical research has not been carried out. In this study, and fundamental experiment was conducted to improve productivity with process parameter such as tool path, angle of roller holder(a), feed rate(v) and corner radius of forming roller(Rr). These factors were selected as variables in the experiment because they were most likely expected to have and effect on spring back. The clearance was controlled in order to achieve the precision product which is comparable to deep drawing one. And also thickness and diameter distribution of a multistage cup obtained by shear spinning process were observed and compared with those of a commercial product produced by conventional deep drawing.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1000-1009
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• 2008

Hydro-mechanical forming process has numerous advantages compared to those of a conventional deep drawing process such as an excellent surface quality and low costs of dies. In fact, Hydro-mechanical forming is a desirable forming process for producing complex parts in automotive body components, and it is an excellent candidate for the forming process of aluminum panels. In this research, Hydro-mechanical forming process with a cross shape punch has been studied for Al-Si-Mg alloy sheets. Finite element analysis by LS-Dyna has predicted the deep drawing depth of the aluminum sheets, and the experiment has confirmed that result. Put Abstract text here.

• 소성∙가공
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• 제7권5호
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• pp.445-449
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• 1998

In order to obtain optimum process variables during the drawing of stainless steel sheets rectangular cup drawing tests were carried out with several technically available stainless steel sheets. As parameters on testing materials for die and punches lubrication and blank holding forces were selected. Testing parameters played an important role if the deformed material was thin. Effect of material properties on the deformation behaviors was also discussed by using testing parameters selected in this experiment. From the test results we suggest the appropriate conditions to be applicable to the actual manufacturing processes

• 소성∙가공
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• 제10권2호
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• pp.115-122
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• 2001

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup drawing, we set up cushion pressure control system on the hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system. A cushion pressure control experiment was carried out using the NC cushion and it was shown that the proposed system produced good performance. The comparison of drawability of square cups with and without NC cushion showed that the drawability could be greatly improved when S-shaped pressure curve was applied. This paper includes design details of the NC cushion system and experimental analysis of drawability with NC cushion system.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.175-179
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• 2004

Since the formability of AZ31 magnesium alloy is not good in room temperature, it is known that high temperature forming is advantageous. However, many studies are necessary to find the proper forming temperature for Mg alloy. In this study, experimental and FEM analysis are performed to investigate the forming temperature for AZ31 sheet. The deep drawing process of square cup is used in forming experiment and FEA. The investigations are performed in three forming temperature, room temperature, $250^{\circ}C\;and\;400^{\circ}C$. The square cup is well formed in $250^{\circ}C$ forming temperature, on the other hand, the crack and failure is presented in corner section in room and $250^{\circ}C$ forming temperature. The main cause is investigated as the effect of hardening range by the experimental and FEM results.

• 한국해양공학회지
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• 제14권4호
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• pp.86-91
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• 2000

Numerical simulation of sheet metal forming for panels as other components has wide acceptance in the automotive industry. Therefore this paper was focused in the drawability factors (which are friction coefficient , radius of die and punch ) on the square cup deep drawing by the explicit finite elements code $PAM-STAMP^{TM}$. The computed results are compared with the experimental results to show the validity of the analysis. In order to compare the simulation results with the experiment results and predict the effect of drawability factors, the relationships between punch load punch stroke, and the relationships between thickness strain and distance are used. According to this study, the results of simulation by using $PAM-STAMP^{TM}$ will give engineers good information to access the drawability of square drawing.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.385-388
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• 2005

The use of magnesium alloys meets the need of reducing weight of componests(especially in automotive and aerospace industry) keeping unmodified their mechanical properties. The adoption of magnesium alloys in sheet forming processes is still limited, due to their low formability at room temperature caused by the hexagonal crystal structure. In this study, the authors aim to understand the process condition which can lead to a successful improvement in the formability of a magnesium alloy(AZ31). Experiment and simulations of deep drawing were doned at various warm temperature for the blank and tool(holde and die)while the punch was kept at room temperature by cooling wale. in order to confirm that the deep drawing performance of magnesium alloy can be considerably enhanced with using the local heating and cooling technique.