Thermoviscoelastic Behavior of Film‐Insert‐Molded Parts Prepared under Various Processing Conditions

Abstract

Film‐insert‐molded (FIM) tensile specimens were prepared under various molding conditions to investigate the effects of wall temperature and packing pressure on the residual stress distribution and thermoviscoelastic deformation. The warpage of the specimen increased with increasing mold‐wall temperature difference and decreased with increasing packing pressure. The FIM specimens produced with unannealed films showed the warpage reversal phenomenon (WRP) during annealing and the degree of WRP was affected significantly by the molding conditions and thermal shrinkage of the film. The warpage of the specimen was predicted by three‐dimensional flow and stress analyses and the prediction was in good agreement with the experimental results.magnified image

Plasmonic Colors: Toward Mass Production of Metasurfaces

“…Film Insert Molding (also known as in‐mold decorating/labeling, IMD/IML) is a well‐known industrial technique used to apply surface coatings or decorations onto components to enhance durability and aesthetic value . The one‐step decoration technique is often favored due to its simplicity over multistep processes, such as silk‐screen printing and painting .…”

Residual stresses and thermoviscoelastic deformation of laminated film prepared for film insert molding

“…It is well known that residual stresses are developed in the FIM parts due to nonuniform temperature and pressure distribution during cooling. Residual stress distribution of the film has been predicted by thermal stress analysis considering thermal shrinkage and viscoelastic properties [12–16]. It was assumed in this study that the laminated film is transversely isotropic, and the viscoelastic behavior satisfies the assumption of the thermorheological simplicity.…”

“…It is well known that asymmetric deformation is induced by the difference in thermal expansion coefficient (CTE) and thermal shrinkage between the laminated film and the polymeric resin used in FIM parts [13, 14]. Since the films were produced by biaxial orientation and annealing, they showed anisotropic properties.…”

Development of a retention mechanism for minimizing defective overlap in film-insert molding

“…Nowadays, FIM technique has been widely used in automotive industry [3,7,[11][12] for decorating interior and exterior automotive parts such as bumper, roof module, instrument panel, rocker panel and radiator grill. This technique has been developing in parallel with coating technique since the requirement of decreasing manufacturing cost and environmental problem are seriously considered.…”

“…As a result, the defective rate of molded part increases. In literature, the studies on film insert molding techniques mainly focus on film thickness distribution [2], residual stress [6], thermoviscoelastic [7] and interfacial characteristics of film insert [8][9][10]. In our research, we concentrated on another practical aspect of FIM related to the…”