• 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 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.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.

• 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.

• 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.

• 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.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.69-73
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• 2008

본 연구에서는 고분자 플라스틱 부품의 친환경 외장성형공법인 Insert Film 사출성형공법중 첫 번째 공정인 진공성형공정에서 진공금형의 표면온도 균일화 기술에 대해 연구를 수행하였다. 진공금형의 온도분포 균일화를 위한 금형설계 및 설계된 금형에 대한 온도분포 평가를 위한 ANSYS를 이용한 유한요소열해석을 수행하였으며, 이때 정상상태 및 과도상태를 함께 평가하였다. 설계 결과를 바탕으로 금형을 제작하였으며, 생산성을 고려하여 4캐비티로 제작된 금형에 대해 금형표면의 온도분포 평가실험을 수행하였다. 또한 금형내 캐비티 온도센서 및 제어시스템을 설치하여 진공금형표면 온도분포가 항상 일정하게 유지될 수 있도록 금형시스템을 개발하였다. 결과적으로 일정한 온도범위의 금형표면온도제어가 가능하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.819-820
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• 2008

• Design & Manufacturing
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• v.12 no.2
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• pp.5-10
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• 2018

Vacuum-assisted thermoforming is one of the critical steps for successful application of film insert molding(FIM) to parts of complex shape. In this study, the simulations and experiments of thermoforming processes were performed to investigate the effects of process conditions on thickness distribution and printed pattern deformation of films in vacuum-assisted thermoforming. The film thickness uniformity increased with decreasing film heating time, whereas it increased with increasing vacuum delay time. After thermoforming of films with uniform pattern space of 5mm, the maximum space was 9.432mm. Based on the simulation, a modified pattern was calculated to obtain uniform spaces after thermoforming. In the experiments for film with the modified pattern, the maximum space appeared 5.837mm. In, addition. the predicted patterns were in good agreement with the experimental results.

• Composites Research
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• v.25 no.4
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• pp.117-125
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• 2012

Warpage of the film insert molded (FIM) part is caused by an asymmetric residual stress distribution. Asymmetric residual stress and temperature distribution is generated by the retarded heat transfer in the perpendicular direction to the attached film surface. Since warpage was not prevented by controlling injection molding conditions, glass fiber (GF) filled composites were employed as substrates for film insert molding to minimize the warpage. Distribution of short GFs was evaluated by using micro-CT equipment. Proper models for micro mechanics, anisotropic thermal expansion coefficients, and closure approximation should be selected in order to calculate fiber orientation tensor and warpage of the FIM part with the composite substrate. After six kinds of micro mechanics models, three models of the thermal expansion coefficient and five models of the closure approximation had been considered, the Mori-Tanaka model, the Rosen and Hashin model, and the third orthotropic closure approximation were selected in this study. The numerically predicted results on fiber orientation tensor and warpage were in good agreement with experimental results and effects of GF reinforcement on warpage of the FIM composite specimen were identified by the numerical results.