• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.5 no.1
• /
• pp.43-50
• /
• 1996

From a manufacturing standpoint it would be desirable to monitor the degradation of drawing die, that is essential for the maintenance of die quality, the evaluation of product integrity and the reducing scrap. Acoustic emission is powerful method in monitoring fine wire drawing process, especially in detecting the die fracture at early stage. Experiments also suggested that acoustic emission sigals contained valuable information regarding the stage of a drawing process such as the surface appearance of products and the condition of lubrication. These informations are AE monitoring techniques a possible tool in monitoring the drawing process operation. In order to approach this, this paper discusses the nature of acoustic emission signal presented which illustrate the effects of wire and die material, lubricants, and drawing speed on the generation and the mean voltage level of acoustic emission signal. From these experimental, results, we understanded controlling factors of acoustic emission generation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.593-597
• /
• 1996

This paper describes a method for drawing check of dimension errors, such as deficiency and redundancy of dimensions, input-errors in dimension figures and symbols, etc. The logic for finding dimensional errors is written by using the Turbo C language. Checking for deficiency and redundancy of global dimensions has been performed applying Graph Theory. Especialy, this paper gives an account of checking method for annular parts.

• Journal of the korean Society of Automotive Engineers
• /
• v.13 no.6
• /
• pp.90-100
• /
• 1991

This paper represents the analysis of the sheet drawing by applying the Matrix method to Hill's slip-line field for small reduction and indirect type slip-line field in case of large reduction. Results of the analysis represent the relation between the reduction ratio and the die wall pressure, mean drawing stress through rough die. The limitation on the use of this slip-line field is described. When the reduction ratio is given, the optimum die angle is analyzed in this paper.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1998.06a
• /
• pp.65-73
• /
• 1998

The design analysis of axisymmetric, multi-stage deep drawing dies was performed using the rigid-viscoplastic finite element formulation. In the formulation, the axisymmetric CFS algorithm was employed. Hill's non-quadratic normal anisotropic yield criterion and isotropic hardening rule were considered. For trial initial displacements and tool contact points, the geometric force equilibrium method was adopted. In order to see the validity of the formulation, the multi-stage deep drawing processes of shell-cylinder front part of hydraulic booster were simulated. The simulation showed good agreements with measurements and PAM-STAMP.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.1333-1334
• /
• 2011

• Cartoon and Animation Studies
• /
• s.38
• /
• pp.71-91
• /
• 2015

This study is a process to study the life drawing teaching method considering professional characteristics in animation and has a study objective to design the model and teaching method which applies the strategies considering the creative mechanism of the brain. Recently, study results about integrated teaching method are being announced which apply brain based learning principles as the alternative arguments about teaching methods in each area based on creativeness. In other words, integrated education based on creative mechanism in the brain is applied not only to fine arts and drawing education, but also to the entire areas of the arts. Life drawing is an area which demands comprehensive teaching method that vivid expressions could be skillfully obtained by understanding the communication methods with the objects through cognitive senses, creativeness and movements beyond the structural knowledge about human body. Therefore in this study, the strategies and methods for the skillfulness of life drawing and consequently arranged education model structure drawing are to be designed based on the creativeness, study materials and content factors which were analyzed in previous stages of this study. In order to combine the content factors based on creativeness and study materials of the brain which are the results of previous studies, the conclusion has been reached that 5 step cognitive strategy stages to wake brain senses, flexibilize the brain, purify the brain, integrate the brain and become the master of the brain. Strategic methods to execute this were designed with brain gym, right brain energization drawing and HSP(high-level cognizance) training. Teaching and learning model structure diagram which is designed based on this is to be continued to teaching and learning guidelines during the relevant semesters after the research.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.6
• /
• pp.101-108
• /
• 2010

The drum clutch investigated in this study is formed in 5 forming steps, which are 1st deep drawing, 2nd deep drawing, restriking, embossing, and $Grob^{TM}$ processes. Dimensional accuracy of the final products greatly depends upon how much more accurate pre-form is manufactured in the previous forming processes before the $Grob^{TM}$ process. The deep drawing, restriking and embossing processes in which the pre-form is formed are very important and decisive steps. Thus in some cases, excessive strain by these operations causes dimensional inaccuracy and cracks initiated from the base and wall of the product. Process variables such as the punch shapes both of 1st and 2nd deep drawing, and punch angle were selected to evaluate the deformation characteristics. The optimum parameters were determined from forming simulations using commercial FEM codes, DEFORM and Tauchi method, specifically developed for metal forming simulation. Finally, experiments for the whole drum clutch forming processes were carried out to verify the optimized forming parameters and the analytical results.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.3
• /
• pp.276-282
• /
• 2009

Wrinkling in the flange and wall of a deep-drawn part is one of the major defects in sheet metal processes. Wrinkling is influenced by many factors, such as material properties, shape of the body, forming conditions, stress state and thickness, etc. It is difficult to analyze the wrinkling initiation and growth according to the factors because the effects of the factors are very complex and the wrinkling behavior may show wide variation even though small deviation of factors. In this study, the influence of wrinkling parameters, such as material properties (Al1050, Al5052), the blank holding force and the drawing depth on the wrinkling initiation and growth is investigated by using the experimental method and the dynamic explicit finite element analysis. From the results, it is shown that the dynamic explicit finite element method can be used effectively to prevent the wrinkling problems advancely in the deep drawing process. Also, there is a good agreement between the experimental result and the dynamic explicit finite element analysis.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.13 no.1
• /
• pp.41-53
• /
• 1988

Line drawing images are the most proper information to represent the characteristics and shapes of digital images and used for recognition and communication. For the coding of line drawing images, common eight-direction chain code is used mostly. In the paper, the new mode selection chain code method is proposed which can compress the eight-direction chain code about twenty percents and be used for the reversible coding method of line drawing images. In this coding techniques, we set a reference mode for each quadrant around an abject pixel, and assign 3-directional code for these reference modes. Therefore a line pixel is coded with 3 bits. Also, a new corner finding method of line drawing images using this mode selection chain code is proposed in this paper.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.11 s.188
• /
• pp.78-84
• /
• 2006

The objective of this study is to design the optimal die profile that can prevent material fracture in the tube drawing process for automobile steering input shaft. First, the CDV(Critical Damage Value) of material is obtained by the compression test and FE-analysis. The occurrence of fracture is estimated by the FE-analysis considering the CDV. In order to achieve the objective of this study, optimization technique and FE-analysis are applied. FPS(Flexible Polyhedron Search) method, which is one of the non-gradient optimization techniques often used in engineering, is used to search optimal die profile. The drawing die profile is represented by Bezier-curve to generate all the possible die profile. Using FPS method and FE-analysis the optimal drawing die profile is determined. To verify tile effectiveness of the redesigned optimal die, the tube drawing experiment is performed. In the experimental result, it is possible to produce sound product without material fracture using the redesigned optimal die.