• 한국정밀공학회지
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• 제5권3호
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• pp.31-42
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• 1988

This paper describes a computer aided process planning system called "Deep-Drawing", "Deep-Drawing" is designed for the drawing sequence of cylindrical and rectangular cups with or without taper and flange. The computer program has written in BASIC language with personal computer. Design Rules for process planning are formulated from process limitation, plasticity theory and experimental results including the know-how of many manufacturing factories. "Deep-Drawing" Capabilities include the analysis of drawing sequence by the determination of optimal drawing ratio, the determination of intermediate shape, dimensions, punch and die radius etc., the calculation of drawing loads and blank holder force to perform each drawing step, and the graphic outputs for the operation sheet.tputs for the operation sheet.

• 한국기계가공학회지
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• 제20권10호
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• pp.50-55
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• 2021

In this study, to create circular holes on an inclined conic face, we developed a novel process of vertical piercing on the plane before drawing, instead of applying an expensive cam-piercing method. The pierced holes are deformed during the drawing, and their shapes are affected by the size of the center hole. Using the Abaqus CAE program, the deformation tendency of the holes, according to the diameter of the center hole, was identified, and the diameter for securing the roundness of the side holes were determined through actual experiments. The developed process was successfully applied to mass production of the part, and a cost reduction is expected.

• 한국전산유체공학회지
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• 제16권1호
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• pp.22-29
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• 2011

In this study, the glass fiber drawing from a silica preform in the furnace for the optical fiber manufacturing process is numerically simulated by considering the radiative heating of cylindrically shaped preform. The one-dimensional governing equations of the mass, momentum, and energy conservation for the heated and softened preform are solved as a set of the boundary value problems along with the radiative transfer approximation between the muffle tube and the deformed preform shape, while the furnace heating is modeled by prescribing the temperature distribution of muffle tube. The temperature-dependent viscosity of silica plays an important role in formation of preform neck-down profile when the glass fiber is drawn at high speed. The calculated neck-down profile of preform and the draw tension are found to be reasonable and comparable to the actual results observed in the optical fiber industry. This paper also presents the effects of key operating parameters such as the muffle tube temperature distribution and the fiber drawing speed on the preform neck-down profile and the draw tension. Draw tension varies drastically even with the small change of furnace heating conditions such as maximum heating temperature and heating width, and the fine adjustment of furnace heating is required in order to maintain the appropriate draw tension of 100~200 g.

• 열처리공학회지
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• 제18권2호
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• pp.105-111
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• 2005

In sheet metal forming, drawbeads are often used to control uneven material flow, which may cause defects such as wrinkles, fractures, surface distortion and springback. Appropriate setting and adjusting of the drawbead force is one of the most important parameters in sheet forming process control. Therefore in this study, drawbead test was performed at various bead surface treatment conditions to clarify the frictional characteristics between sheet and drawbead. Furthermore, the differences in drawing force between circular and rectangular shape beads have also been measured to estimate the effectiveness of bead shape on the material flow control. The results show that drawing and friction characteristic were strongly influenced by surface treatments of bead and bead shapes.

• 한국전산유체공학회지
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• 제18권4호
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• pp.69-73
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• 2013

Mass manufacturing of optical fiber includes the process of very thin glass fiber drawing by heating and softening the high purity silica preform and applying the draw tension on the softened tip of preform neck-down profile in a draw furnace. In this computational study, this process is numerically modeled with simplified geometry of the draw furnace which is comprised of essential parts such as concentric graphite heater, muffle tube, and insulation surrounding the heater. The iterative computational scheme is employed between one-dimensional model of neck-down profile prediction and two-dimensional axisymmetric thermo-fluid CFD computation of radiative heating and working gas convection. The computational results show the experimentally observed neck-down profile in heated section of preform, while yielding the reasonable values of draw tension and heater wattage. Also, this study analyzes and discusses the effects of heating conditions such as heater length and temperature on several important aspects of glass fiber drawing process.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.508-513
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• 2006

In construction of RC buildings, the quality of shop and detail drawings is very essential for the quality and safety of buildings. Nevertheless, most of thess works are left to site workers and the requirements about bar detailing such as anchorage and splice have been done without rational design and engineering. The purpose of this research is to develop a computer-aided drawing system of rebars for RC buildings. The system is based on an integrated structural design system, that is SDP. SDP manages an engineering database for structural design information. It provides all the information needed to draw rebar drawings. The drawing system consists of three modules, 1) Structual Plan Drawing System, 2) Shop Drawing System, and 3) Detail Drawing System. It is expected that not only the productivity of detail drawing works but also the quality and safety of buildings will be improved using the rebar drawing system developed in this research.

• 한국생산제조학회지
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• 제24권4호
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• pp.374-385
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• 2015

In this paper, effective and user friendly CAM software is presented that automatically generates any three dimensional complex toolpaths according to a CAD drawing. In advanced manufacturing, often it is essential to scan the sample following a complex trajectory which consists of short (few microns) and multidirectional moves. The reported CAM software offers constant velocity for all short trajectory elements and provides an efficient shift of tool path direction in sharp corners of a tool trajectory, which is vital for any laser, based precision machining. The software also provides fast modification of tool path, automatic and efficient sequencing of path elements in a complicated tool trajectory, location of reference point and automatic fixing of geometrical errors in imported drawing exchange files (DXF) or DWG format files.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.92-95
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• 2011

In manufacturing optical fibers, the process starts with the glass fiber drawing from the heated and softened silica preform in the furnace, and the freshly drawn glass fiber is still at high temperature when it leaves the glass fiber drawing furnace. It is necessary to cool down the glass fiber to the ambient temperature before it then enters the fiber coating applicator, since the hot glass fiber is known to cause several technical difficulties in achieving high quality fiber coating. As the fiber drawing speed keeps increasing, a current manufacturing of optical fibers requires a dedicated cooling unit with helium gas injection. A series of three-dimensional flow and heat transfer computations are carried out to investigate the effectiveness of fiber cooling in the fiber cooling unit. The glass fiber cooling unit is simplified into the long cylindrical enclosure at which the hot glass fiber passes through at high speed, and the helium is being supplied through several injection slots of rectangular shape along the cooling unit. This study presents and discusses the effects of helium injection rates on the glass fiber cooling rates.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1410-1413
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• 2003

Drawing is a basic plastic deformation method and productive manufacturing process make wire. rod and variety section geometry bar. Study for the rod drawing process of rod was researched long littles. but non-axisymmetric drawing process is weak. So metal flow is very irregular in non-axisymmetric drawing process and difficult to define about material deformation generally. In this paper, to solve material deformation, use finite element method and then define suitable shape for rod to hexagonal drawing dies. And research corner filling rate and surface roughness for the high strength steel hexagonal bar produced defined dies.

• 소성∙가공
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• 제24권4호
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• pp.234-240
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• 2015

Multi-pass shape drawing is very important to produce steel profiles in round samples. In the current study, a process design system is developed for a multi-pass shape drawing. In general, the number of passes for a multi-pass shape drawing is 2 to 3 when the reduction ratio, drawing stress, and productivity are considered. Therefore, calculating the drawing stress and designing the intermediated die shapes are very important. In order to calculate the drawing stress, a shape drawing load prediction method is proposed using a general axisymmetric drawing load prediction model. An intermediate die shape design method is proposed using the initial and the final product shapes. Based on this analysis, a process design system is developed for multi-pass shape drawing for steel profiles. The system works with AutoCAD. The system was applied to design a shape drawing of a spline.