• Design & Manufacturing
• /
• v.13 no.2
• /
• pp.1-5
• /
• 2019

In this study, micro cellular injection molding of automobile head lamp housing with uneven thickness structure was performed to obtain improvement on deformation and light-weight of the part. The thickness of the presented model was uniformly modified to control the deformation of the molded part. In order to maximize the lightweight ratio, the model having an average thickness of 2.0 mm were thinly molded to an average thickness of 1.6 mm. GFM(Gas Free Molding) and CBM(Core Back Molding) technology were applied to improve the problems of the conventional foam molding method. Equal Heat & Cool system was also applied by 3D cooling core and individual flow control system. Warpage of the molded parts with even cooling was minimized. To improve the mechanical properties of foamed products, complex resin containing nano-filler was used and variation of mechanical properties was evaluated. It was shown that the weight reduction ratio of products with light-weighted injection molding was 8.9 % and the deformation of the products was improved from the maximum of 3.6 mm to 2.0 mm by applying Equal Heat & Cool mold cooling system. Also the mechanical strength reduction of foamed product was less than 12% at maximum.

• Journal of Powder Materials
• /
• v.9 no.4
• /
• pp.227-234
• /
• 2002

For the austenitic stainless steel (304L) manufactured by metal injection molding(MIM), the effects of copper content and sintering temperature on the mechanical properties, antibacterial activities, corrosion resistance, and electric resistances were investigated. The specimens were prepared by injection molding of the premixed powders of water-atomized 304 L and Cu with poly-acetyl binders. The green compacts were prepared with various copper contents from 0 to 10 wt.% Cu, which were debound thermally at 873 K for 7.2 ks in $N_2$gas atmosphere and subsequently sintered at various temperatures from 1323 K to 1623 K for 7.2 ks in Ar gas atmosphere. The relative density and tensile strength of the sintered compacts showed the minimum values at 5 and 8 wt.% Cu, respectively. Both the relative density and the tensile strength of the specimen with 10 wt.% Cu sintered at 1373 K showed the highest values, higher than those of copper-free specimen. Antibacterial activities investigated by the plastic film contact printing method for bacilli and the quantitative analysis of copper ion dissolved in water increased as the increase of the copper content to stainless steels. It was also verified by the measurement of pitting potential that the copper addition in 304 L could improve the corrosion resistance. Furthermore the electric conductivity increased with the increase of copper content.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.219-220
• /
• 2006

To understand the effect of powder characteristics on the thermal debinding behavior, PIM parts produced with powders with different particle sizes and particle shapes were examined to determine their weight losses during thermal debinding. The results show that the average diameter of the pore channel in the compact increased when the temperature increased and when coarse powders were used. However, the weight loss rates did not increase proportionally with the pore size. This suggests that the different powders that are frequently used in PIM parts do not affect the thermal debinding rate significantly. This is because the pore size is much larger than the mean free path of the decomposed gas molecules. Thus, the diffusion rates of the gases are not rate-controlling in thermal debinding. The controlling mechanism of the thermal debinding rate is the decomposition of the backbone binder in the PIM parts.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1219_1220
• /
• 2009

In recent years, the companies of electric power equipment for MV, HV class trend to develop that the eco-friendly insulated(solid, eco-gas, air etc.) switchgear replace with existent SF6 gas insulated switchgear by environmental problems such as global warming and soon. This paper introduces the Solid Insulated Switchgear(SIS) which is the epoxy of eco-friendly insulation material. The characteristic of SIS to introduce in this paper is as following. 1) Eco-friendly. (SF6 gas free) 2) The structure of flexible system. (Expansion) 3) The optimum design. (The Analysis of electrical & mechanical) 4) An Interface treatment between epoxy and insert. (Molding technology) This paper described about some technology for development of SIS.

• Journal of the Korean Institute of Gas
• /
• v.18 no.1
• /
• pp.46-51
• /
• 2014

The purpose of this paper is to study of the vehicle lamp manufacturing system composing ultrasonic waves connection process. Making lamp assembly plant, it was produced in the separate process as the injection molding, ultrasonic waves bonding, annealing in the constant temperature, lamp assembling and packing. But the improvement method producing the lamp was added with one-step process by one automation technique. As a result, welding with ultrasonic waves process, the method decreased the energy consumption and noise during ultrasonic waves welding. Therefore, this method used the mathematics modeling for checking validity, it selected the stability and suitable controller using transfer function of plant and bode chart. In this study, the $180^{\circ}$ revolution control system to turn injection part upside down was $M_{eq}\;lcos{\theta}(t)$ because of gravity influence. It effected to unstable condition a system. For solving this problem, it aimed the linearization and stabilization of system by elimination $M_{eq}\;lcos{\theta}(t)$ as applying Free-forward control technique.

• Applied Chemistry for Engineering
• /
• v.27 no.4
• /
• pp.380-385
• /
• 2016

Nanocelluloses, mainly cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC, i.e., defect-free, rod-like crystalline residues after acid hydrolysis of fibers), have been the subject of recent interest. Due to the presence of hydroxyl groups on the surface of nanocelluloses, their surfaces are reactive, making them suitable candidates for reinforcing materials for manufacturing polymer composites. In this study, CNF was used as a reinforcing material for manufacturing cement composites. CNF was prepared by TEMPO (2,2,6,6,-tetramethyl piperidine-1-oxyl radical) oxidation procedure combined with extensive homogenization and ultrasonication. Transmission electron microscopy (TEM) analysis of the suspension showed the width of CNF between 10 and 15 nm. The compressive strength of cement composites containing 0.5% CNF was comparable to that of conventional cement composites. On the other hand, the tensile and flexural strength were improved by 49.7% and 38.8%, respectively, compared to those of conventional cement composites. Also, at an ambient condition, the degree of self-shrinkage reduction reached to 18.9% in one day, followed by 5.9% in 28 days after molding.