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        검색결과 130

        22.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the injection pressure of 31 MPa and clamping force of 1,000 kN toggle electric injection molding machine were used to measure the load transmitted to the frame during injection molding and to use it as the design basis data. In general, the toggle structure is composed of a movable plate, tie bars, crossheads, toggle links, toggle pins, base plates, etc and The material is spherical graphite cast iron(FCD 400). In this study, it was found that there was a 1.3% safety factor by calculating the clamping force in the structure of the five-point toggle link system. In addition, Expected static bottom load, Expected dynamic additional load, Maximum expected additional load, and Maximum weight load were measured using tensile measurements and presented as important basic design data of the assembly.
        4,000원
        23.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Macro-porous carbon foams are fabricated using cured spherical phenolic resin particles as a matrix and furfuryl alcohol as a binder through a simple casting molding. Different sizes of the phenolic resin particles from 100– 450 μm are used to control the pore size and structure. Ethylene glycol is additionally added as a pore-forming agent and oxalic acid is used as an initiator for polymerization of furfuryl alcohol. The polymerization is performed in two steps; at 80oC and 200oC in an ambient atmosphere. The carbonization of the cured body is performed under Nitrogen gas flow (0.8 L/min) at 800oC for 1 h. Shrinkage rate and residual carbon content are measured by size and weight change after carbonization. The pore structures are observed by both electron and optical microscope and compared with the porosity results achieved by the Archimedes method. The porosity is similar regardless of the size of the phenolic resin particles. On the other hand, the pore size increases in proportion to the phenol resin size, which indicates that the pore structure can be controlled by changing the raw material particle size.
        4,000원
        25.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Injection molding is extensively used for mass production of plastic products. Over the years, the plastic products have been manufactured in a variety of colors, materials and mechanical properties to fulfill the market demand. The purpose of this study is to identify the relation between the color of resin and the product quality. To proceed this study, different colored PBT specimens have injection molded, and mechanical properties were compared. Tensile tests and bending tests have carried out to study mechanical properties of the specimens, and differentials have occurred in tensile strength, bending strength and tensile elongation by their respective color. And the red specimens were broken during the bending test. The experimental results reveal that the color of the resin influences the mechanical strength of the injection molded product. As a result, the color of resin should be considered when setting parameters for injection molding in order to improve the product quality.
        4,000원
        26.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to the development of plastic materials, injection molding products are limitlessly used. The colours of the plastic material also, have been developed to meet the needs of customers. The purpose of the present study is to verify the shrinkage of the injection-molded PC and PBT specimens in different colours. In this study, red, white, black and transparent colours were selected for PC resin. Also blue, red and black colours were selected for PBT resin. 50 specimens were produced per each colour, and measured after cooling-off. The P-value, the test statistic of the measurements in every direction of PC and PBT specimens were below 0.05 except the PBT specimen’s thickness. The rate of shrinkage for the length and thickness of PC specimens were 0.48% and 3.9% that obtained 4.4 times as big as the gap those between those two rates. The shrinkage in PBT were about 1.45% for the length and 5.08% for the thickness which had 3.6 times as big as the gap. This experimental results obtained that the colour of the resin (PC and PBT) effects its shrinkage. Consequently, the colour of the resin must be concerned in the event of injection-molding.
        4,000원
        33.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanopowders provide better details for micro features and surface finish in powder injection molding processes. However, the small size of such powders induces processing challenges, such as low solid loading, high feedstock viscosity, difficulty in debinding, and distinctive sintering behavior. Therefore, the optimization of process conditions for nanopowder injection molding is essential, and it should be carefully performed. In this study, the powder injection molding process for Fe nanopowder has been optimized. The feedstock has been formulated using commercially available Fe nanopowder and a wax-based binder system. The optimal solid loading has been determined from the critical solid loading, measured by a torque rheometer. The homogeneously mixed feedstock is injected as a cylindrical green body, and solvent and thermal debinding conditions are determined by observing the weight change of the sample. The influence of the sintering temperature and holding time on the density has also been investigated. Thereafter, the Vickers hardness and grain size of the sintered samples have been measured to optimize the sintering conditions.
        4,000원
        34.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Smart phones are currently the most popular electronic devices with high volume production activities driven by high demand and requirements for rapid turnaround time. The changes of displacement were analyzed according to a variable of the gate size and runner system. The radial type and gate with large size were shown that better results in displacement. While the design and production of lenses, the key component of a camera, still need to be improved, the current technology has run into its limit with regard to trends in size and weight reduction. In this study, an injection molding analysis was performed on plastic lenses that are widely employed for smart phone cameras. Specifically, the displacement of lenses at the time of injection molding was studied by varying the gate size and runner system.
        4,000원
        35.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to explore olfactory sensitivity of odors from injection molding processing. To do this, the experiment was carried out in an injection molding factory, and participants were exposed to the environment where odor-substances (Formaldehyde, Benzene, Toluene, Ethylbenzene, Xylene, Styrene) exist. In addition, we used the subjective scale using semantic adjectives as an olfactory sensitivity. As a result, the assessment structure of olfactory sensitivity was composed of eight factors (irritant, thermal, tense, unique, like-dislike, active, stable, masculine), and the main factor which was irritant characteristics explained 20% of the total olfactory sensibility. These results suggested that odors from injection molding processing would cause more negative emotional responses than the flavor which is mainly used in olfactory sensitivity. This study, as a basic study of the improvement in a factory environment for the efficiency of work, has limits in that it was conducted to the extent of identifying the olfactory sensitivity structure of those who were at a laboratory and who were exposed to the environment of odor substance induced in the injection molding processing. Therefore, for the method of removing malodorous substance, the effect of materials which can neutralize it, and the comparison of a direct performance in the environment where negative sensitivity structure exists, a series of studies which aim to improve the environment of injection molding factories, such as performance assessment in the environment of a factory and an office need to be conducted. It is expected that when these studies are put together, the improvement guidelines will be provided as a type that can maximize the effectiveness of work in the factory environment where injection molding processing is done.
        4,000원
        36.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An injection unit is the important part which guide the melted resine into the mold. Once injection molding is performed, there will be a pressure of 33 MPa built up inside of injection cylinder body. It was confirmed that the crack occurs by internal stress on the 9 mm material when the machine is used for long time. Because the cylinder rod has material thickness of 9~12 mm during manufacturing process on the cylinder body, there would be 3 mm thickness differences. In this experiment, IDEAS, a computer aided structure analysis software, is used to present the optimized design condition. Insert rod with inner diameter of 9 mm was set as a normal and vary 3 mm in x, y axis direction. When the internal pressure of 33 MPa occurs at the injection unit, fix the x and y direction and find out the stress acting only in z axis. It was confirmed that the stress of 45~82 N/mm 2 was built up when the left of cylinder body had been set 9 mm by using a structure analysis. Also, it has been verified the thickness of the material on the left need to be greater and equal than 12 mm to prevent a material crack by an internal stress.
        4,000원
        38.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A powder injection molding process is developed and optimized for piezoelectric PAN-PZT ceramics. Torque rheometer experiments are conducted to determine the optimal solids loading, and the rheological property of the feedstock is evaluated using a capillary rheometer. Appropriate debinding conditions are chosen using a thermal gravity analyzer, and the debound specimens are sintered using sintering conditions determined in a preliminary investigation. Piezoelectric performance measures, including the piezoelectric charge constant and dielectric constant, are measured to verify the developed process. The average values of the measured piezoelectric charge constant and dielectric constant are 455 pC/N and 1904, respectively. Powder injection molded piezoelectric ceramics produced by the optimized process show adequate piezoelectric performance compared to press-sintered piezoelectric ceramics.
        4,000원
        39.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Powder injection molding (PIM), which combines the advantages of powder metallurgy and plastic injection molding technologies, has become one of the most efficient methods for the net-shape production of both metal and ceramic components. In this work, plasma display panel glass bodies are prepared by the PIM process. After sintering, the hot isostatic pressing (HIP) process is adopted for improving the density and mechanical properties of the PIMed glass bodies. The mechanical and thermal behaviors of the prepared specimens are analyzed through bending tests and dilatometric analysis, respectively. After HIPing, the flexural strength of the prepared glass body reaches up to 92.17 MPa, which is 1.273 and 2.178 times that of the fused glass body and PIMed bodies, respectively. Moreover, a thermal expansion coefficient of 7.816 × 10−6/oC is obtained, which coincides with that of the raw glass powder (7.5-8.0 × 10−6/oC), indicating that the glass body is fully densified after the HIP process.
        4,000원
        40.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently as the manufacturers want competitiveness in dynamically changing environment, they are trying a lot of efforts to be efficient with their production systems, which may be achieved by diminishing unplanned operation stops. The operation stops and maintenance cost are known to be significantly decreased by adopting proper maintenance strategy. Therefore, the manufacturers were more getting interested in scheduling of exact maintenance scheduling to keep smooth operation and prevent unexpected stops. In this paper, we proposedan integrated maintenance approach in injection molding manufacturing line. It consists of predictive and preventive maintenance approach. The predictive maintenance uses the statistical process control technique with the real-time data and the preventive maintenance is based on the checking period of machine components or equipment. For the predictive maintenance approach, firstly, we identified components or equipment that are required maintenance, and then machine parameters that are related with the identified components or equipment. Second, we performed regression analysis to select the machine parameters that affect the quality of the manufactured products and are significant to the quality of the products. By this analysis, we can exclude the insignificant parameters from monitoring parameters and focus on the significant parameters. Third, we developed the statistical prediction models for the selected machine parameters. Current models include regression, exponential smoothing and so on. We used these models to decide abnormal patternand to schedule maintenance. Finally, for other components or equipment which is not covered by predictive approach, we adoptedpreventive maintenance approach. To show feasibility we developed an integrated maintenance support system in LabView Watchdog Agent and SQL Server environment and validated our proposed methodology with experimental data.
        4,000원
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