• Polymer(Korea)
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• v.27 no.2
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• pp.152-158
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• 2003

Two commercial processing methods have been used to produce poly(methyl methacrylate) (PMMA) marbles; cell molding method and belt molding method. Cell molding method has low productivity and belt molding method has high equipment cost as well as high production cost. A new production method far PMMA marbles using plastic films as molds was studied in this investigation to overcome the shortcomings of cell molding and belt molding method. As plastic film molds for producing PMMA marbles, poly(vinyl acetate) film was used. A methyl methacrylate compound, which has good processability in film molding and shows good mechanical properties after curing, was prepared and used to produce PMMA marbles by film molding method. Properties of the PMMA marbles produced by film molding method were similar to, or higher than, those of commercial PMMA marbles produced by cell molding and belt molding method respectively. The film molding method is considered to have high possibility in commercial application.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.281-284
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• 2008

Film insert melding is one of the surface processes that enhances functional or aesthetic qualities of an existing product's surface. In general, film insert molding consists of three processes including thermoforming, trimming and injection molding. Thermoforming, which is the first process of film insert molding, is the most important process because the variation of film thickness has an effect on the mold design and process conditions for the subsequent processes, that are, trimming and injection molding. This study is focused on predicting the film thickness distribution through film insert thermoforming process using commercial FEM code. In order to describe rheological behavior of thermoplastic film (ABS), G'Sell's viscoelastic constitutive law was adopted. The numerical model of film insert thermoforming was established, and the simulation to predict film thickness distribution was performed. Comparison between the results of simulation and experiment was made to validate the proposed finite element analysis.

• Journal of computational fluids engineering
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• v.18 no.3
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• pp.20-25
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• 2013

In various manufacturing industries, an in-mold decoration (IMD) process for plastic objects is widely utilized because a film forming and an injection molding processes run simultaneously. In the present study, the deformation of polymer film and filling of resin in the IMD process were numerically investigated to evaluate the quality of the plastic object formed by the IMD process, which consists of thermoforming and injection molding processes. To obtain the initial shape of the polymer film during the injection molding process, the deformation of the polymer film in the thermoforming process was pre-formed using the vacuum conditions to attach the film to a cavity. Since the properties and deformation of polymer film are greatly affected by the behavior of polymer resin being injected into a mold cavity, numerical simulations for the injection molding and film forming were performed with one-way coupling method. The results showed that the injected resin could lead to the tearing of the polymer film in local regions near the corners. In order to verify the proposed numerical methodology, the numerical results of the deformation patterns printed on the initial polymer film were compared with the experimental data. The proposed methodology to couple film forming analysis with injection molding analysis can be used to predict the deformation of film in IMD process.

• 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 Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.472-479
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• 2013

We carried out research into an environmentally friendly injection molding process that involves filling the mold with polymer after thin films are fixed into the cavity, without the coating, plating process. Film insert injection molding is a new technique in which molten plastic resin is injected into the cavity after films are precisely attached to the side of the mold wall. In the film insert injection molding process, the insert film is moved by the flow of the molten plastic resin. Overlap defects cause a decline in the productivity and the quality of the manufactured goods. To reduce overlap defects, new injection mold parts are proposed to produce automotive exterior parts using thin films. It is suggested that the best possible method would be to fix the thin films to one side of the mold wall, and develop interior pins to fix the films in the mold. Based on this new pin fixing system, the problem of the film being moved by the flow of the molten resin was improved.

• Transactions of Materials Processing
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• v.20 no.3
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• pp.250-256
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• 2011

Vacuum-assisted thermoforming is one of the critical steps for the successful application of film insert molding(FIM) to parts of complex shapes. If the thickness distribution of the formed film is non-uniform, cracking, deformation, warping, and wrinkling can easily occur at the injection molding stage. In this study, the effects of processing parameters, which include the film heating time, plug depth, plug speed and vacuum delay time, on film thickness distribution were investigated. It was found that the film thickness at the part sidewall decreases with increasing the film heating time and plug depth, but the thickness at the bottom was found to exhibit the opposite behavior. The film thickness of the sidewall was observed to increase at higher plug speed and vacuum delay time of 0 ~ 0.3sec.

• Transactions of Materials Processing
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• v.21 no.1
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• pp.30-35
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• 2012

FIM(Film Insert Molding) is an innovative method of producing decorated parts for a wide range of products. Because it requires fewer steps when compared to conventional production methods, the time and cost of manufacturing high quality components can be reduced considerably. In this paper, the effects of processing conditions on the warpage of film-insert molded plate were investigated by using a design of experiments. The dominant factors affecting warpage were mold temperature and holding pressure. Warpage increased with the temperature difference between stationary mold and fixed one. Even when the mold temperature difference was zero, the plate with a film was bent after ejection such that the film side protruded. As holding pressure increased, warpage decreased significantly. In addition warpage increased with time increment for the film-insert molded plates.

• Design & Manufacturing
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• v.14 no.1
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• pp.15-21
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• 2020

Smart systems in different application areas such as automotive, medical and consumer electronics require a novel manufacturing method of electronic, optical and mechanical functions into products. Traditional methods including mechanical assembly, bonding of plastic and electronic circuit cause the problems in large size of products and complicated manufacturing processes. In this study, thermoforming and film insert molding were applied to fabricate a dome shaped plastic part embedded with electronic circuits. The deformation of patterns printed on PET film was predicted by thermoforming simulation using T-SIM, and the results were compared with those by experiment. In order to decrease spring-back after thermoforming, the Taguchi method of design of experiment was used. Through ANOVA analysis, it was found that mold temperature was the most dominant parameter for spring-back. By using flow analysis, gate design was performed to decrease injection pressure. During film insert molding, the wash-out of ink printed on film occurred for Polycarbonate. When the resin was changed to PMMA, the wash-out disappeared due to low melt temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.10
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• pp.812-816
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• 2011

An optical lens is usually produced in the manner of high temperature compression molding with tungsten carbide alloy molding cores, it is necessary to develop and study technology for super-precision processing of molding cores and coating the core surface. As main methods used in surface improvement technologies using thin film, DLC present high hardness, chemical stability, and outstanding durability of abrasion to be extensively applied in various industrial fields. In this study, the effect of DLC coating of a thin film by means of the FVAS (filtered vacuum arc source) analyzed the characteristics of thin film. Surface roughness before and after DLC coating was measured and the result showed that the surface roughness was improved after coating as compared to before coating. In conclusion, it was observed that DLC coating of the ultra hard alloy core surface for molding had an effect on improving the surface roughness and shape of the core surface. It is considered that this will have an effect on improving abrasion resistance and the service life of the core surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1191-1192
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• 2010