• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.3
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• pp.353-358
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• 2010

This research introduces a new and improved design for a pneumatic cylinder driven roll feeder wherein each of the principal rotating feeder parts is configured so as to have feeding accuracy and to be low manufacturing cost. The feed pitch accuracy of the proposed roll feeder was evaluated by measuring lengths of cut offs of the strip stock with a shear attached to an air press. The air press was designed, manufactured, and mounted on the same table of the proposed roll feeder such that the strip stock maintained horizontal plane until the strip stock entered into the shear. The proposed roll feeder and the air press were designed to be operated automatically by a PLC employed controller. The feed pitch accuracy of the proposed roll feeder was analyzed by setting the pitch as 10, 12.5, and 15mm. At each predetermined feed pitch, the proposed roll feeder was tested 300 times as one test set and replicated three times. The average lengths of the cut offs of the strip stock ranged from 9.98 to 10.13mm, from 12.42 to 12.57mm, and from 14.96 to 15.06mm at the predetermined 10, 12.5, and 15mm feed pitch, respectively, among the total of 900 samples of each feed pitch. Main cause of variation of the length of the cut off of the strip stock fed by the proposed roll feeder was considered to be fluctuation of the air press during recompressing period of the air compressor to pressurize the air in the air tank. The largest difference between the maximum and the minimum length of the cut off was appeared while the air compressor recompressing the air. The air compressor used for this study restricted the air delivered to the proposed roll feeder while it was still running. Thus, this air delivery restriction problem should be improved by stabilizing the air press while the proposed roll feeder is running.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.129-133
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• 2000

Vapor oil fer radiator fm press in heat exchangers of air conditioners is carefully considered as the cooling performance can be affected by the residual vapor oil on the surface of radiator fin after fin press working. In this work, vapor oil for radiator fin press was developed in consideration of several properties such as physical characteristics, the rate of volatility, hazardous properties and material compatibility. In addition, it was confirmed that radiator fin press workability adopting the vapor oil and the cooling performance of air conditioner using the radiator fin were good.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.167-167
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• 1982

Italian poplar (Populus euramericana) rotary veneers were press-dried and air-dried to study drying curves, thickness shrinkage and width shrinkage of them under several drying conditions such as drying temperatures and veneer thicknesses. The results of the study are summarized as follows; 1. In press-drying, drying times from green condition to about final moisture content of 10 percent with veneer thickness of 0.6mm by platen temperatures required about 10 minutes at platen temperature of $100^{\circ}C$, 3 minutes at $110^{\circ}C$, 1 minute at $120^{\circ}C$ and $130^{\circ}C$, respectively. 2. In press, drying, drying times from green condition to about final moisture content of 10 percent by veneer thicknesses required 2 minutes at veneer thickness of 0.6mm, 4 minutes at 1.2mm,6 minutes at 1.8mm and 9 minutes at 3.6mm, respectively. 3. In air-drying, drying times from green condition to air-dried moisture content by veneer thicknesses required 15 hours at veneer thickness of 0.6mm, 18 hours at 1.2mm and 23 hours at 2.4mm, respectively. 4. Thickness shrinkage of press-drying was remarkably greater than that of air-drying, but width shrinkage of press-drying was rather smaller. 5. Difference of thickness shrinkage among platen temperatures was insignificant, and width shrinkage at platen temperature of $130^{\circ}C$ was the least.

• Journal of Biosystems Engineering
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• v.34 no.3
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• pp.155-160
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• 2009

This study was attempted to quality characteristics of ginseng powder using molecular press dehydration(MD) method. Ginseng powder was dried using maltodextrin as dehydrating agents, and the quality of the ginseng powder was compared with that of freeze-drying and hot air-drying samples in terms of colors, moisture contents and grain size. The colors of ginseng powder using MD-drying and freeze-drying was better than hot air-dried ginseng powder. The moisture contents of ginseng powder using MD-drying was 9.49%, while freeze-drying was 4.14% and hot air-drying 11.71% after 72ball mill times. The grain size of ginseng powder using MD-drying and freeze-drying was better than hot air-drying ginseng powder. These results suggest that drying of ginseng powder using molecular press dehydration method is very efficient, because minimal cell destruction may be achieved.

• Transactions of the KSME C: Technology and Education
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• v.3 no.4
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• pp.265-271
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• 2015

The bonding process should be achieved in vacuum environment to avoid air bubble. In this study, we studied about pressure uniformity that became an issue in thermo compression bonding usually. Uniform press is realized by the method that use air spring and metal form spring. The concept of uniform press using air spring is removed except pressing direction in the press processing so angle between the vector of pressure surface and the pressure axis is parallel automatically. Air spring compensate the errors of machining and assembly. Metal form compensate the thermal deformation and flatness error.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.107-112
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• 1997

In this study of made Autmation system is moving linear transfer system for mainly forming of small electronic unit and other at press line. This system for loading and unloading a workpiece has been installed in a press in order to load and unload a workpiece from a press die. Main Control method be used PLC. It took data of input from each sensor and send signal of output to actuator by sequence program also, we try to Characteristics test of this system has good condition when operating with raser measurmant.

• Journal of the Korean Society of Safety
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• v.11 no.4
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• pp.34-41
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• 1996

The purpose of this study is to obtain an effective enclosing method for noise reduction of press machine operating in a manufacturing company located in Taegu region. Noise level of the machine is about 95～120 ㏈ which is higher than legal standards by industrial safety and health law. In this study, two experiments were conducted to achieve the above purpose. In the first experiment in which the effects of three independent variables-type and depth of sound-absorbing materials, and depth of air space-on noise level was investigated, it was found that depth of sound-absorbing materials and air space was significant at $\alpha$ = -0.01. In the second experiment studying relationship between depth of sound-absorbing materials and air space and noise level, it was shown that noise level lowered as depth of sound-absorbing materials and air space became thick. Based on these results, two alternatives of enclosing method adequate for the selected company's noise characteristics were suggested.

• Journal of Drive and Control
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• v.19 no.4
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• pp.10-18
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• 2022

Air-drop hammer press and counterblow hammer press are widely used power-drop forging hammersemploying different forging blow mechanisms. It is important and necessary to analyze mechanical vibrations of these two different hammers in their forging processes in order to develop high performance forging hammers. In this study, these two forging hammers were mathematically modelled as mass-spring-damper systems. For these two different types of forging hammers, the forging efficiency and mechanical vibrations due to hammer forging blow were theoretically analyzed and compared. The force transmitted to the ground was also determined and compared. Especially, effects of mass ratio and restitution coefficient on forging efficiency were investigated.

• Advances in Energy Research
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• v.4 no.3
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• pp.239-253
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• 2016

Air quality in hospitals has always concerned hospitals' health officials due to its dangerous particles and gases. Because of the importance of air conditioning in the operating room, a system must be embedded in operating rooms to direct the contaminated air outside, and inject fresh filtered air from outside back into the room. In this study, laminar flow air conditioning system is implemented in the operating room by slot linear diffusers and with the help of air curtain. For this, stimulation Computational Fluid Dynamic (CFD) was used due to its efficiency. The aim of the present study was to find a proper solution to overcome the unfavorable factors, namely, contamination, humidity, and also temperature, velocity and pressure inside the room. These factors were implemented with different values and then stimulated through FLUENT software program. Results showed that the aforementioned factors can be overcome using air curtain and slot linear diffusers.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.345-348
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• 2006

In sheet metal forming process using press and draw die some defect can be made because of the high pressure of air pocket between draw die and the product. The purpose of this study is to develop a program to decide an optimal combination of air vent hole size and number to prevent those defect on product. The air inside air pocket is considered as ideal gas and the compression and expansion is assumed as isentropic process. The mass flow is computed in two flow condition: unchocked and chocked condition. The present computation obtains required cross-sectional area of air vent hole for not exceeding the user specified pressure such as the pressure for yielding strength of the product or the pressure for unchocked flow. To validate the program the present results are compared with the results of other researchers and commercial CFD code.