• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.31-37
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• 2011

Recently, the technology of surface treatment is being more important which affects the material cost reduction and substitution to the expensive material. The material used for the mechanical processing should have not only high intensity, but also strength toughness, wear resistance and corrosion resistance. In order to increase the durability and have better quality of the parts using such kind of tooling material, various kinds of research of the surface hardening through many kinds of heat resources is being done and practically applied. In this study, the characteristics of hardening surface zone for high strength of the press die material through laser beam irradiation are researched. In this study, it is experimentally observed by the status of the surface morphology, tensile strength, the hardness distribution of the base metal and wear condition by the surface hardness pattern by the laser beam based on the process parameters of $CO_2$ laser by using SM45C and STD11 used for press tool. Through this research, the characteristics of surface hardened zone for high strength of the thin metal by laser beam irradiation is done.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.4
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• pp.353-358
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• 2015

Energy consumption reduction has become an important key word in manufacturing that can be achieved through the efficient and optimal use of raw materials and natural resources, and minimization of the harmful effects on nature or human society. The successful implementation of this concept can only be possible by considering a product's entire life cycle and even its disposal from the early design stage. To accomplish this idea with milling, minimum quantity lubrication (MQL) strategies and cutting conditions are analyzed through process modeling and experiments. In this study, a model to predict the cutting energy in the milling process is used to find the cutting conditions, which minimize the cutting energy through a Kriging meta-modeling process. The MQL scheme is developed first to reduce the amount of cutting oil and costs used in the cutting process, which is then employed for the entire modeling and experiments.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.32-39
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• 1996

The overall purpose of this study was to investigate the dimensional changes of melamine sheet laminated medium density fiberboard(MDF) floorings by sub-heating system(Ondol). This study was also conducted to improve the properties of melamine sheet laminated MDF floorings. The effects of density, resin content, manufacturing speed of MDF and types of melamine sheet on dimensional and weight changes of floorings were investigated. The results were as followings. 1. Dimensional and weight change of melamine sheet laminated MDF flooring by heating decreased with decreasing the density of MDF. 2. Dimensional and weight change of melamine sheet laminated MDF flooring by heating decreased with increasing the resin content of MDF. 3. Dimensional and weight change of melamine sheet laminated MDF flooring by heating decreased with decreasing the manufacturing speed of MDF. 4. Dimensional change of melamine sheet laminated MDF flooring in width direction by heating was doubled than that in machine direction. 5. Dimensional change and curling of high pressure melamine laminate(HPM) laminated MDF flooring by heating was less than those of low pressure melamine laminate(LPL) flooring. 6. Weight loss of melamine sheet laminated MDF flooring by heating has linear relationship with shrinkage.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.66-72
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• 2016

The applicability of rice husk fiber as a raw material for eco-friendly pulp mold was evaluated in this study. The higher demand of environmental friendly packaging material resulted in the more interest for the natural fiber based pulp mold. The rice husk which is an abundant agricultural byproduct in Asia could be defiberized by an alkaline digestion process. The changes in the pulp mold making process and the properties of pulp mold by the addition of the rice husk were investigated. The addition of rice husk fiber to the pulp mold made with OCC or UBKP resulted in the increase in drainage at the pulp mold forming process. In case of UBKP pulp mold, the addition of rice husk fiber increased the drying efficiency after pulp mold forming since the structure of pulp mold became more bulkier by the addition of the rice husk fiber. Those results showed the rice husk fiber could be applied to the pulp mold manufacturing as one of the eco-friendly natural fiber resources.

• Journal of the Korean Society of Safety
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• v.17 no.1
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• pp.72-78
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• 2002

Among the disposal techniques of inorganic wastewater sludges from industries most of sludges were dealed with buring underground inefficiently. But we have tried to recycle the resources that exhausted inorganic sludges were properly blended to certain ratioes to make lightweight aggregate, that means manufacturing of it can be possible through blending of various components, drying, sintering, cooling and crushing to certain sizes that are needed by consumers. As disposal method of inorganic wastewater sludge is changed to environmentally fraternative method, this method could be very useful to make lightweight aggregates for decoration of building and the other so many purposes of those usages. That could be economically useful due to expected income for buring costs of ordinary disposal method form industries and sales income after manufacturing it. The second important profit is saving foreign currency from purchasing self-developed lightweight aggregate insteas of importing expensive foreign product. This product will be also very impressive to user because of the fraternative lightweight to be composed of apatite structure that is important part of human body.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.7-12
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• 2013

In Die casting process, the problem of die degradation is often issued. In oder to increase of die life the material degradation of die steel was investigated using test core pins. Three test core pins were positioned in front of the gate entry and observed washout and soldering resistance during Mg die casting process. The test parameters are set as different commercial die materials, coatings condition and hardness of die surface. Usign 220t magnesium die casting machine was employed to cast AZ91 magnesium alloys. After 150 shots, macroscopic observation of die surface was carried out. Additional 50 cycles later, test pins were chemically cleaned with 5% HCl aqueous solution to find out the existence of washout and soldering layers. Microstructural characterization of die surface and the die roughness measurement were performed together. Computational simulation using AnyCasting program was also beneficial to correlate the extent of die damage with the position of test pin inside die cavity. As results, the optimal combination of die steel with productive coating as well as its hardness was drawn out. it will be helpful to decide the material and condition considering increasing of tool life.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.3
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• pp.55-65
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• 2005

In recent manufacturing systems, most jobs may have several process plans, such as alternative sequence of operations, alternative machine etc. A few researches have addressed the necessity for the integration of process planning and scheduling function for efficient use of manufacturing resources. But the integration problem is very difficult and complex. Many prior researches considered them separately or sequentially. It introduces overlapping or partial duplications in solution efforts. In this paper, Integration problem of jobs with multiple process plans in a job shop environment Is addressed. In order to achieve an efficient integration between process planning and scheduling by taking advantage of the flexibility that alternative process plans offer, we designed GA(Genetic Algorithm)-based scheduling method. The performance of proposed GA is evaluated through comparing integrated scheduling with separated scheduling in real world company with alternative machines and sequences of operations. Also, a couple of benchmark problems are used to evaluate performance. The integrated scheduling method in this research can be effectively epplied to the real case.

• Journal of the Korean Society of Safety
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• v.25 no.4
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• pp.76-83
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• 2010

As one of crucial industries, the service industry occupies a large part of economy in Korea poor in natural resources. However, prevention of industrial disasters has been promoted mainly in manufacturing and construction industries where the frequencies of such disasters and victims are high. Research on the evaluation of workplace safety climate has been conducted centering on traditional industries like manufacturing and construction, and few studies have been made for service businesses. The objective of this study was to evaluate workplace safety climate perceived in the field by workers engaged in service businesses and to contribute to the establishment of industrial safety and health policies in consideration of the characteristics of each business category. Using research variables safety knowledge, safety attitude, safety motivation, safety participation, safety compliance, and safeness of work environment, we evaluated comprehensive workplace safety climate based on the causal relations among the variables. In the results of analyzing data from a questionnaire survey of service business employees, statistically significant effect relations among the variables were identified, and the fitness of the model with approved reliability and validity was verified.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.104-108
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• 2012

Recently, small scale hydropower needs to be developed due to its clean, renewable and abundant energy resources. However, suitable draft of hydro-turbine body in combination with differences in wheel blade shapes is not determined yet in the range of small hydropower and it is necessary to study for the effective draft in combination with type. Therefore, watermill shaped of 250mm diameter. hydro-turbine aiming 20 watt class generator is adopted in this study because of its simple structure and high possibility of applying to small hydropower. The result shows that effective draft for the turbine body is variable concerning the size of turbine and flow rate of water. Thus, the difference of water depth between fore and aft turbine body contributes to the increase of torque, angular momentum and power output.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.2
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• pp.186-193
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• 2014

This paper presents characteristic analysis of underwater bearing for canned type electric water pump. Characteristic analysis of underwater bearing was performed using self-developed performance tester, which capable of torque change, noise change, motor speed change and abrasion loss test with respect to temperature change of underwater bearing. The performance tester can be monitored in real time by designing the control unit using the Labview program. The performance experiment was performed through comparison of the silicon carbide (SIC) and the carbon bearing. From the experiment results, performance of SIC bearing was better than carbon bearing at the abrasion and temperature experiment.