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This comparative study investigated how early childhood education and care practitioners in South Korea and Norway perceive the concept of children’s well-being and their own roles in supporting an...

Injection mold filling process was analyzed for a rectangular plate with micro patterns on the surface. For products with micro patterns whose dimensions are much larger than the dimensions of the micro patterns, numerical analysis may require a prohibitively large number of numerical grids. In order to solve this problem, anlaysis was done by separating the global flow through the base plate from the filling of the micro patterns. Global flow was analyzed using the generalized Hele-Shaw (GHS) model, while local flow for micro patterns was simulated by the Navier-Stokes equation. The boundary conditions, such as pressure and temperature, for the local analysis were obtained using the results of the global analysis. The proposed method was validated by experiments. Experimental observation showed good agreement with the numerical results. Effect of process parameters on the transcription fidelity was further examined. The numerical approach presented in this paper would enable a more efficient analysis and provide better understanding of filling behavior during injection molding of parts with micro patterns on the surface.

Poor filling occurs during the injection molding process of micro- or nano- scale patterns mainly because the hot polymer melt rapidly cools and its skin quickly solidifies upon contact with the mold surface. In this study, it is proposed to use Polyethylene terephthalate (PET) film coated with patterned polyurethane acrylate (PUA) as an effective thermal bar- rier. It can significantly hinder heat transfer into the mold during the molding process and thus may keep the melt viscosity low for longer duration. As a result, the replication would be improved not only during the filling phase but also during the packing phase. In order to verify the validity of the use of polymeric stamper, the melt-film interface temperature was eval- uated by numerical simulation. Experimental results indicated that patterns possessing widths within the range of one to tens of micrometers and a height of approximately 10 !m were successfully filled and demolded.