• Design & Manufacturing
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• 제17권4호
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• pp.14-23
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• 2023

The electric vehicle market is developing rapidly around the world. Also, parts of electric vehicles require precision.In order to produce high-precision motor cores,Press equipment must also have good precision. Drive motor cores are an important technology for electric vehicles. It uses a large high-speed press to mass-produce drive motor cores. Because it's a large high-speed press, there are many reasons why the precision is not good. One of the causes is vibration and noise. Recently, as environmental demands have become stricter, regulations on noise and vibration have been strengthened. It is important for press machines to reduce vibration first for sound insulation and dust proofing. This is because the "breakthrough" phenomenon occurs in the press. Dynamic precision is the precision under the load of the press, Design considering strain and stiffness shall be made. Vibration and noise may occur due to SPM of high-speed press,And vibration and noise can cause structural deformation of the press. Structural deformation of the press can affect the precision of the product.Noise and vibration also cause problems for workers and work environments. Problems with vibration and noise occur during press processing, and vibration and noise lead to damage to the mold or defects in the product. Reliability in high-quality technology must be secured with low noise and low vibration during press processing. Modular shape and deformation energy effects were analyzed through finite element analysis. In this study, a study on vibration and noise countermeasures was conducted through finite element analysis of a large high-speed press.

• 한국기계가공학회지
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• 제9권4호
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• pp.14-25
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• 2010

Small cracks or chips of a product appear very frequently in the course of continuous production of an automatic press process system. These phenomena became the cause of not only defective product but also damage of a press mold. In order to solve this problem AE(Acoustic emission) system was introduced. AE system was expected to be very effective to real time detection of the defective product and for the prevention of the damage in the press molds In this study, for the pick and analysis of AE signals generated from the press process, AE sensors/pre-amplifier/analysis and processing board were used as frequently found in the other similar cases. For the analysis and processing the AE signals picked in real time from the normal or the detective products, specialized software called AE-win(software for processing AE signal from Physical Acoustics Corporation) was used. As a result of this work it was conformed that intensity and shape of the various AE signals differ depending on the weight of the press and thickness of sheet and process type.

• 대한기계학회논문집A
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• 제32권1호
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• pp.54-62
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• 2008

In this paper the fretting wear of press-fitted specimens subjected to a cyclic bending load was simulated using finite element analysis and numerical method. The amount of microslip and contact variable at press-fitted and bending load condition in a press-fitted shaft was analysed by applying finite element method. With the finite element analysis result, a numerical approach was applied to predict fretting wear based on modified Archard's equation and updating the change of contact pressure caused by local wear with influence function method. The predicted wear profiles of press-fitted specimens at the contact edge were compared with the experimental results obtained by rotating bending fatigue tests. It is shown that the depth of fretting wear by repeated slip between shaft and boss reaches the maximum value at the contact edge. The initial surface profile is continuously changed by the wear at the contact edge, and then the corresponding contact variables are redistributed. The work establishes a basis for numerical simulation of fretting wear on press fits.

• 한국기계가공학회지
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• 제12권6호
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• pp.69-76
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• 2013

This paper presents the development of the FCF method for the manufacturing of final products using numbers related to the minimum amount of work. The utilized product is a drum clutch, which is part of the transmission of an automobile. A double acting press is secured first and a prediction of the forming load on the practical material is made through an experiment with a plasticine model. Also, a finite element simulation using product shape and properties is performed, as well as a press experiment. A double acting press is manufactured that is suitable for a double acting experiment with a conventional hydraulic press(200 tons). A peripheral device for the press is additionally designed for experimental purposes. And, the press has as its essential points the drive speed, stroke control, etc., all of which influence the forming and is modified. Especially, a laser system is used for velocity measurement of two punches. The forming load of a practical material is predicted in order to derive a forming load formula for cold conditions on the basis of approximate similarity theory. Finite element analysis of the relative velocity ratio(RVR), etc., for most suitable flow defect(unfilling, etc.) prevention is achieved as well. The results are verified through a press experiment.

• Earthquakes and Structures
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• 제10권4호
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• pp.829-847
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• 2016

Generally seismic isolation is achieved by supporting the structure on laminated rubber bearings, friction pendulum bearings, roller bearings etc. Very little work has been performed using soil as a base isolation media. Experiments and analytical work has been performed on a structural model with isolated footing and found encouraging results. Details of this work are presented in this paper.

• Advances in concrete construction
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• 제15권5호
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• pp.349-358
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• 2023

Aim of this work is investigating effect of thickness-stretching formulation on the quasi three-dimensional analysis of micro plate based on a thickness-stretched and shear deformable model through principle of virtual work and micro-scale dependent constitutive relations. Governing differential equations are derived in terms of five unknown functions and the analytical solution is derived using Navier's technique. To explore effect of thickness stretching model on the static results, a comparison between the results with and without thickness stretching effect is presented.

• 대한기계학회논문집A
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• 제21권7호
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• pp.1141-1148
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• 1997

In the stamping industry the blank shape to be stamped into a designed shape has been conventionally determined from the try out process by the press engineers. The work needs a lot of time and thus leads a loss of productivity. In this study boundary element method for 2-dimensional potential problem was used to design optimum blank shapes for irregular press forming. Here we assumed that the blank is controlled by blank holder only and material flow at blank holder was under potential flow. The developed PC code for designing the optimum blank shape shows that the blank shapes for optimal drawing can be calculated within a few minute in pentium PC and the calculated shapes agree well with the experiments. However the application of this method is constrained only to the pressed product with flat bottom.

• 소성∙가공
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• 제8권1호
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• pp.57-64
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• 1999

The press formability analysis of welding parts was studied in the current work by the tailor welded blank. As the body panel is used in the press forming of welding parts by a weld method of the tailor welded blank, the following conditions are demanded: 1) The strength of welding parts must be the higher than base metals. 2) After the welding, severe welding deformatins must be avoided. 3) The press formability of welding parts is similar to that of many base metals. 4) The productibility of a welding has to be higher. There are many welding methods satisfying these conditions, but the purpose of this study is to inbestigate the upset weldability and formability of the material (SPCC). SPCC steel sheet showed good weldability and formability under some welding conditions. The experimental results were discussed by the evaluation of the results obtained from tensile tests, hardness tests, micro-structures and Erichsen cup test was a little lower than that of parent material.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1997년도 International Conference MULTIMEDIA DATABASES on INTERNET
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• pp.129-136
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• 1997

The Multimedia Press System is an integrated tool for electronic archiving and evaluating articles and documents from all types of media. It may be used by the following departments of a company, a government agency or other organisations in their work with the media and publications: 1. press and/or public relations 2. information and/or documentation 3. internal relations 4. investor relations 5. marketing and advertising 6. economics. It may also be used in 7. independent agencies for public relations and advertising and in 8. media-archives of publishing houses and broadcasting stations.(omitted)

• 대한기계학회논문집A
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• 제28권9호
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• pp.1276-1283
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• 2004

This study is an inspection of press forming product and mould using reverse engineering system. The inspection process on production field involves a lot of errors because of the hand-work so we focussed on improving the measured precision through performing the effective inspection using 3D non-contact scanner. By so doing that, we improved the precision of press forming product by analyzing the cause following the inspection result. Through the inspection, we applied it to the reverse engineering and we could improve the inspection process.