• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.7-13
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• 2015

The production processes were reviewed through the injection analysis of the shift lever as a core component of an auto lever installed in the automatic transmission of cars. The injection analysis was carried out for the shift lever and rod among the components in a shift lever module. The shift lever and rod are designed for injection molding with the insertion of a tube, a pin cable plate, and a steel rod for securing the strength of the product. The charging time, failure of injection molding, weld line, air trap, and deformation were reviewed according to this insert. Analyses on various gate positions were carried out for reviewing the cultivation and deformation of fiber around major components, such as the generation section of manipulation feeling and assembly section, so that optimal gate conditions might be reviewed and reflected in the mold design. Finally, we plan to compare the analysis results with the production of trial products.

• Design & Manufacturing
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• v.6 no.1
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• pp.12-17
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• 2012

In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, a full-3d simulation based on solid elements has been reported as a reliable approach. The present work covers three-dimensional injection molding simulation and relevant deformation analysis of an injection molded plastic lens based on 3d solid elements. Numerical analyses have been applied to the injection molding processes of three aspheric lenses for an image sensing module of a mobile phone. The reliability of the proposed approach has been verified in comparison with the experimental results.

• Design & Manufacturing
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• v.11 no.1
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• pp.14-18
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• 2017

Recently, the injection-molded products are lighter, and thinner than ever. In this work, Injection molding simulation was conducted to analysis the filling pattern imbalance in high speed injection molding process for thin-wall injection component, 8 inches LGP. Numerical analysis shows that shear heated polymer near the side wall causes filling imbalance between center and side of cavity. Short shot experiments were conducted and compared with simulation results. Filling imbalance ratio showed a tendency to increase for wider fan gate.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.771-772
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• 2006

Mechanical properties of metal injection molded titanium and titanium alloy parts were investigated in this study. Material powders with low oxygen content and spherical shape were obtained by electrode induction-melting gas atomization which could melt and atomize titanium and titanium alloy bars with no touch on crucible or tundish. Tensile specimens were fabricated from obtained powders by metal injection molding process. Tensile strength of the specimens increases with increasing oxygen content. This result corresponds to a tendency of wrought metal.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.773-774
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• 2006

Gas surface treatment is considered to be effective for titanium because of its high reactivity. In this study, we investigated the gas nitriding mechanism in titanium sintered parts produced by metal powder injection molding (MIM) process. The microstructure and nitrogen content of sintered MIM parts were greatly affected by nitriding conditions. Nitriding process strongly depended on the specimen size, for example, the size of micro metal injection molding (${\mu}-MIM$) product is so small and the specific surface is so large that the mechanical and functional properties can be modified by nitriding.

• Design & Manufacturing
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• v.11 no.3
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• pp.13-18
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• 2017

The injection molding analysis of VCM (Voice Coil Motor) housing for smart phone cameras were performed. We conducted the analysis in terms of injection molding pressure, the formation of weld lines, flow marks, and flow patterns. The goal of the analysis was targeted for the prediction of the optimal gate locations. Because the quality of VCM housing is strongly dependent on the precise control of the camera lens by its nature, we focused on the lens guiding lanes in the VCM housing. We first calculated the maximum injection molding pressure in terms of the filled volumes. The injection molding pressure were calculated within 146MPa at about 90% volume filled. We also investigated the possibility of the occurrence of design-related defects such flow marks, weld lines. Filling patterns regarding the design of the gate locations were delineated to find the weld lines. Throughout the simulations, the final deformations of the lens guiding lanes for the VCM housing were calculated. The deformations distribute ranging from $0.5{\mu}m$ to $2.50{\mu}m$, which were used to find the optimal design of the gates.

• Textile Coloration and Finishing
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• v.34 no.1
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• pp.46-57
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• 2022

In this study, the relationship between fiber orientation and mechanical properties with the injection pressure of polyamide-6/glass fiber composite materials manufactured by the injection molding process was investigated. Also, an actual experimental data and finite element model-based simulation data were analyzed. Specimens were manufactured through the injection molding process setting the injection pressure differently to 700, 800, 900, and 1000 bar, respectively. A morphological analysis and orientation of the PA6/GF composite material were observed using Optical microscope. Through tensile and flexural strength tests, the mechanical properties of the PA6/GF composite materials with the injection pressure were studied. As a result, it was confirmed that the mechanical properties were the superior under the injection pressure of 900 bar molding conditions. In addition, the mechanical properties of the actually manufactured specimen (PA6/GF) and virtual engineering S/W((Digimat, Abaqus) were used to compare and analyze the analysis results for the mechanical properties, and based on the reliable DB, the physical properties of the PA6/GF composite characteristics were studied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.771-777
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• 2014

Injection-compression molding was used for film insert molding of an automotive door grip using films with three-dimensional embossed patterns. A vacuum mold was fabricated for vacuum-assisted thermoforming of the film, and an injection-compression mold was developed for film insert molding. Three pressure transducers were installed inside the mold cavity to measure cavity pressures. Injection-compression molding experiments under various compression strokes and toggle speeds were performed to investigate their effects on the cavity pressure and heights of the embossed patterns. The compression stroke of 0.9mm and low toggle speed resulted in a higher degree of conservation of embossed patterns. Additionally, the processing conditions for the maximum heights of embossed patterns were almost similar to those for minimum integral value of cavity pressures. The injection-compression molding process presents the opportunity to impart a soft-touch feeling of plastic parts printed with embossed patterns.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.157-162
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• 2001

Rheological characteristics of Sm-Co type plastic magnet compound for powder injection molding process were investigated with the variation of the magnetic powder size, their relative contents and volume fraction using the mixture of fine and coarse powder. Shear viscosity of Sm-Co type compound was decreased with increasing the size of coarse powder due to the increase of powder packing density. However, the smaller the average size of fine powder resulted in the higher viscosity of compound due to the increase of agglomeration force. In case of mechanically milled Sm-Co type powder, the viscosity of compound with the mixture of coarse powder of 125∼75 ㎛ and fine powder of average size of 4.9 ㎛ greatly depends on their relative contents and shows a minimum value at the 60 % coarse powder fraction. This means that the compound shows a maximum packing density at the 60% coarse powder fraction. Compound viscosities satisfied well the rheological model with the volume fraction of magnetic powder, and maximum volume fraction of magnetic powder in Sm-Co type compound for powder injection molding was about 66%.

• Design & Manufacturing
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• v.9 no.2
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• pp.30-33
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• 2015

In injection molding, many kinds of defects have occurred because of a characteristic of plastics injection molding. Weld line is one of the defects is formed when separated melt fronts recombine together during the mold filling stage. That is one of problems in injection molding. Weld lines in the appearance of plastics parts can deteriorate visible quality. And most importantly, the local mechanical strength in the weld line area can be significantly weaker. It could be one of the most problems for structural applications. In this study, the mold available two-shot-molding of same polymers have been designed, and a series of experiment about tensile strength in weld line area has been conducted using Taguchi's design of experiment to optimize injection molding conditions decreasing of weld strength and find out a factors affected weld strength in two-shot- molding.