• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.406-411
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• 2003

It is clearly demonstrated that deeper cups could be formed by single and double stretch-drawings from smaller circular blanks due to such wall-thinning action than in the usual deep-drawing of larger blanks. From this fact, it is emphasized that the deep-drawability of a sheet metal Is not evaluated simply by the conventional L.D.R (limiting drawing ratio), but the depth of the drawn cup should also be taken into account. Many experimental data about various metals and thicknesses given in this paper offer a valuable information in this process for more general use which recommends to replace the conventional deep-drawing process by the stretch-drawing process both for single and double operations. In the single stretch-drawing, it is also confirmed that a deeper cup can be produced by raising the blank-holding force at later stage of operation.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 춘계학술대회 논문집
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• pp.42-47
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• 1997

In this study, the drawing characteristics of circular drawbead are examined with the plane strain elastic-plastic FE Method by varying the process variables such as friction coefficient, drawbead radius, and closing depth. Numerical analysis are carried out by 2-D elastic-plastic F.E.M. The results are compared with the existing experimental results about the drawing force, the die clamping force, and the strain distribution of upper and lower sheet faces

• 한국염색가공학회지
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• 제22권3호
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• pp.272-281
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• 2010

This paper surveys the effects of drawing conditions of the worsted staple yarns on the mechanical properties of the knitted fabrics for highly aesthetical fabrics. The drawn worsted yarns were made on the yarn drawing system with various draw ratios under the fixed conditions of setting time, reduction and oxidation. The knitted fabric specimens were prepared on the 16 gauge circular knitting machine using these drawn worsted staple yarns. The tensile, shear, bending, compression and surface properties of these knitted fabrics were measured by KES-FB-AUTO-A system and also discussed with the drawing conditions. The tensile linearity, shear stiffness and bending rigidity decreased with increasing draw ratio. Any changes were not shown on the compressional properties with drawing conditions. But the friction coefficient of the knitted fabric on the course direction increased with increasing draw ratio, while there was no change according to the draw ratio on the wale direction.

• 한국정밀공학회지
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• 제20권9호
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• pp.126-134
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• 2003

This paper investigates the multi-pass wet wire drawing process considering the slip between the wire and the capstan. The production of fine wire through multi-pass wet wire drawing process would be impossible without backtension. The backtension is affected by many process parameters, such as slip, dies reduction, coiling number of wire at the capstan, machine reduction, characteristic of lubricant etc. Up to date, die design and dies pass schedule of multi-pass wet wire drawing process have been performed by trial and error of expert in the industrial field. In this study, an analysis program which can perform the analysis and considering the effect of slip at each capstan was developed. The effects of many important parameters (drawing force, backtension force, needed power, slip rate, slip velocity rate etc.) on multi-pass wet wire drawing process can be predicted by this developed program. It is possible to obtain the important basic data which can be used in the pass schedule of multi-pass wet wire drawing process by using this developed program.

• 한국정밀공학회지
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• 제29권10호
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• pp.1043-1049
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• 2012

The FEM analysis of machine tools is the general analysis process to evaluate machine performance in the industry for a long time. Despite advances in FEM software, because of difficult simplicity of CAD drawing, little experience of joints stiffness modeling and troublesome manual contact area divide for bindings, the industry designers think the FEM analysis is still an area of FEM analysis expert. In this paper, the automation of modeling process with simplicity of drawing, modeling of joints and contact area divide is aimed at easy FEM analysis to enlarge utilization of a virtual machine tools. In order to verify the effects of modeling automation, a slant bed type model with tilting table is analyzed. The results show FEM modeling automation method only needed 45 minutes to complete the whole modeling process, while manual modeling method requires almost one month with 8200 calculations for coordinate transformations and stiffness data input.

• 소성∙가공
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• 제24권3호
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• pp.187-193
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• 2015

The objective of the current study is to determine cross-sectional profile of intermediate dies in order to improve the plastic strain homogeneity which directly affects not only the dimensional accuracy but also the mechanical properties of final product by redesigning the intermediate dies using the conventional electric field analysis (EFA) method. Initially, the multi-pass shape wire drawing was designed by using the equivalent potential lines from EFA. The area reduction ratio was calculated from the number of passes in multi-pass shape wire drawing but constrained by the capacity of the drawing machine and the drawing force. In order to compensate for a concentration of strain in a region of the cross section of the wire, the process for multi pass wire drawing from initial round material to an intermediate die was redesigned again using the electric field analysis. Both drawing process designs were simulated by the finite element method in which the strain distribution and standard deviation plastic strain of the cross section of drawn wires were examined.

• 한국공작기계학회논문집
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• 제11권4호
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• pp.6-11
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• 2002

Formability in deep drawing process depends not only on a drawability of workpiece material but also on process conditions such as die punch comer radius, lubricant conditions, punch-die clearance etc. For instance, bending resistance should be reduced by increasing die round appropriately, drawing load should be minimized by improving the lubricant condition between die and material, and blanking load should be increased by selecting a pertinent punch round and by augmenting the friction resistance in punch. In this study, a multi-stage deep drawing process is analyzed using ABAQUS. The effects of formability factors, such as die shoulder radius, punch-die clearance and friction coefficient are investigated, and the results are also discussed in detail.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.280-285
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• 2001

A good drawability of material itself is required. To improve the formability in deep drawing process. Besides that bending resistance should be reduced by increasing die round appropriately, drawing load should be minimized by improving the lubricant condition between die and material, and breaking load should be increased by selecting a pertinent punch round and by augmenting the friction resistance in Punch. In this study, a multi-stage deep drawing process is analyzed using ABAQUS, the effects of formability factors. Such as die shoulder radius, punch-die clearance and friction coefficient are investigated.

• 한국공작기계학회논문집
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• 제14권3호
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• pp.60-66
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• 2005

Design of drawing dies was used In real industrial environments. It was designed by CAD software in many small & medium companies, but many products require various types, and sizes. There(ore many companies are required to reduce process time and design mistakes. In this paper, it was developed the automatic program in order to learn and use easily for design of the drawing dies. It was composed with Visual LISP/DCL language in a commercial CAD package, AutoCAD, and CUI in design system. The system is based in the knowledge base system which is involved a lot of expert's know-how. We have built database of design type and detail sizes. The automatic design system requires basic product type and sizes, and then the system accesses to the database and finds out sizes by comparing with input parameters, after then finally generates drawing dies file.

• 한국산업융합학회 논문집
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• 제23권2_2호
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• pp.225-232
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• 2020

In this paper, we introduce the results of investigating and overhauling bearing drawings in the defense field, and propose an effective bearing drawing management system. We identify the features and performance items that must be regulated in the bearing drawing. After reviewing the validity of the bearing drawings, we classify the incorrect drawings by factor. To achieve greater effect, standardized formats are needed to incorporate into the drawing in the early stage. We propose the introduction of a bearing drawing management system so that the developing bearing technology can be applied quickly to the defense sector. As other elementary parts of the machine have similar problems, we think this study will help develop improvement plans.