• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.225-229
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• 2003

When hot strip is trimmed in the side trimming process at the entry side of tandem cold rolling mill, due to bad quality of trimming face and burr, product quality(saw ear)becomes so bad that it causes drop of yield and claim from customers. Therefore, it was examined that applying ultrasonic vibration is an effective method to improve quality of strip trimming face and decrease burr magnitude by decreasing shear force acting between strip trimming face and knife in side trimming process of cold rolling.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.101-108
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• 2004

It is very important to diagnose state of knife and strip cutting face in real time in the side trimming process due to improvement of quality of trimming face. In this study, diagnosis system for knife and strip cutting face was developed. CCD camera was installed at the both side of strip in the entry of burr masher roll. This system offer to operator the diagnosis result that was analyzed image obtained from CCD camera. As a result, bad quality of trimming face is decreased below 1/10 and knife breakage is detected $100\%$.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.29-34
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• 2006

In this paper, the mechanical characteristics of ultrasonic cold forged technology (UCFT) used for the trimming knife and the effects of ultrasonic vibration energy (UVE) into the trimming process on the state of the strip cutting face were studied. And a diagnosis system to quality control for trimming knife and strip cutting face was developed and installed in plant. By the plant application of UCFT, service life of knife was more increased over 100% than that of conventional knife. And using the developed diagnosis system, the knife breakage and saw ear have been perfectly detected and quality control of trimming face is obtained effectively.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.144-147
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• 2002

In this study, springback analysis of side rear member is carried out. Side rear member is one of the parts which shows severe springback problems. Forming, trimming, flanging and springback stages can be analyzed successively. From forming analysis, we identified the possible spots in which tearing may occur and can prevent failure. In springback analysis we used the boundary conditions same as applied to the blank on the checker so that the computational result can be compared with experimental one. Form .the comparison, springback analysis can yield relatively good results in a qualitative sense. However, in order to get good deformation result quantitatively, there still remains unsettled tasks in the forming analysis with very small die radius. It is found that we have to develop the element with better bending characteristics and precise contact treatment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.93-99
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• 2016

The trimming process is required for satisfying the dimensions of a final product in the hot stamping process. In general, the mechanical trimming or laser trimming process is applied after hot stamping. However, these processes have several disadvantages such as short tool life and low productivity. Therefore, in this study, the optimal trimless blank shape for the hot stamping process of a sill side was designed to remove the trimming process after hot stamping. In order to design the trimless blank, numerical analysis was performed. Firstly, CFD analysis was carried out to predict the cooling temperature and holding time of the hot stamping process. Then, the optimal trimless blank shape was determined through FE analysis. The effectiveness of the designed trimless blank shape was verified through a hot stamping experiment at an actual industrial site.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.146-150
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• 2015

Steel is produced through the steel-making process with a desired shape by a rolling press. Scrap is removed according to the sheet edge to improve the quality of the product. This machine is called a side trimmer. This study aimed to develop a side trimmer for automatically changing the width of the trimming knife without line stopping. This machine consists of a housing opening device and a turning device. The measuring technologies of sheet width, trimming knife rotation angle, and knife gap for increasing the control accuracy. This experiment was conducted to evaluate the performance of the developed technologies. It was reduced by 10% compared with the operation time of the conventional method.

• Archives of Plastic Surgery
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• v.32 no.6
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• pp.710-716
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• 2005

A total of 21 patients were operated. Via a columellar labial incision, the upper lateral cartilages were separated from the septum. A submucous resection of the septal cartilage was carried out. After rasping the convex lateral nasal wall of the unaffected side, a low-to-low lateral nasal osteotomy was conducted. Along the deviated dorsal line at the bony vault passing the submucous tunnel, a paramedian nasal osteotomy was performed. The convex side of the nasal bone flap was contoured by rasping. The convex side of the "T"-shaped dorsal septum was trimmed. A total direct septal extension graft of the septal cartilage was done and the alar cartilages were suspended to it. The postoperative results were evaluated by photogrammetric analysis processed by a "neon glow" filter in Adobe Photoshop. The distance from the nasal midline to the most deflective point at 5 levels was measured, and the proportion indices were obtained in regard to intercanthal distance. The results revealed improvement in all levels (p < 0.05), although not perfect. In summary, this technique can result in a clinically good-looking in spite of a slight deflection that still exists

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.376-385
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• 1991

For manufacturing trimming-free plates which have rectangular shaped edges and straight edges in as-rolled state, it is necessary to investigate rolling characteristics of overlap, bulge and width deviation etc. in a standardized plate rolling process. The present wok is for preventing edge overlap as the first approach to develop trimming-free plate rolling technique. An experimental study on overlap control was done with plasticine material in order to examine influence factors and find a control method by use of a laboratory mill scaled down to one tenth of actual production mill. It was found that edge overlapping was increased with the increase of slab thickness and of broadside rolling ratio, but decreased with the increase of chamfered amount on slab edges. In the simulated rolling experiment with edge chamfered slabs of various chamfered angles, the chamfered angle of 60.deg. was the most effective one for reducing overlapping irrespective of slab thickness and of broadside rolling ratio.

• Transactions of Materials Processing
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• v.15 no.4 s.85
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• pp.281-288
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• 2006

Most of automobile member parts experience severe springback problems because of their complicated shape and high yielding strength. Now it becomes imperative to develop an effective method to resolve these problems. However, there remain several obstacles to get accurate estimation of dimensional shape. Especially the effective algorithms to simulate sheet metal forming processes including drawing, trimming, flanging and springback is demanded for the multi stage simulation of automobile member parts. In this study, for the purpose of accurate springback calculation, a simulation program which is robust in springback analysis is developed. Favorable enhancement in computation time for springback analysis by using latest equation solving technique and robust solution convergence by continuation method are achieved with the program. In analysis, the multi processes of rear side member are simulated to verify the system. For the evaluation of springback accuracy practically, all conditions including boundary conditions for springback analysis and inspection conditions for dimensional accuracy are applied. The springback results of simulations show good agreement with the experiments.

• The Korean Journal of Food And Nutrition
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• v.19 no.3
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• pp.332-341
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• 2006

The goal of this study was to determine a method of reducing food wastes in the dietary home lifestyle. Statistical analyses were conducted of 491 questionnaires answered by housekeepers living in Daejeon city. The data were analyzed by SAS program and the results are summarized as follows. Among the respondents, 51.53% answered that they purchased the foods in consideration of the family number, 60.45% that they occasionally throw away foods because the date of expiry had passed, i.e., the foods threw away by mistake of storage, 68.23% that they make side dishes at a time for three meals in a day, 52.95% that they make three or four kinds of side dishes, 82.28% that they prepared meals according to the favorite foods of the family, 48.04% that they left food at home, and 47.32% that they threw away foods because too many foods had been prepared. The major reasons for food wastes at home were listed as meal leftovers (32.72%), vegetable trimming (31.29%), and non-planned purchase (25.77 %). The perception of housekeepers on the reduction of food waste were listed as the preparation of accurate meal quantity (50.92%), planned purchase (28.31%), development of recycling foods (14.05%), and reduction of side dishes (6.72%). Further reduction of food wastes of dietary home lifestyle can be summarized to emphasize the preparation of accurate meal quantity, planned purchase, development of recycling foods, and reduction of side dishes. In addition, studies should be conducted to examine the systematic administration method and standard education for the reduction of food wastes.