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Optimal process conditions of thin-wall injection molding of a cellular phone cover were investigated with the consideration of interaction effects between process parameters. [L.sub.27] experimental tests based on Taguchi's method were performed, and then Cyclone Scanner, PolyCAD and PolyWorks were used to measure the shrinkage and warpage of the thin-wall injected parts to determine the optimal process conditions. Based on the results of the analysis of variables and the F-test, interaction effects for each observed factor were determined. The results indicated that the packing pressure was the most important process parameter affecting the shrinkage and warpage of the thin-wall part. The optimal process conditions were different for the shrinkage and the warpage. This was because during the injection process, the mechanisms affecting shrinkage or warpage were different. Compared with the results obtained with simplified thin-wall parts in the literature, it was found that the geometry of a real commercial part did affect the optimal process conditions and the order of influence of process parameters. The optimal process conditions determined by Taguchi's method for reducing the shrinkage and warpage were verified experimentally in this work. Polym. Eng. Sci. 44:917-928, 2004., INTRODUCTION Because of the aggressive competition for lighter weight and miniaturization, 3C products (computers, communication devices and consumer electronics) have been requiring thin-wall covers. In general, a part with a [...]

The structural and optical characteristics of ZnTe epilayers grown on GaAs substrates with ZnSe/ZnTe strained superlattices buffer layers were investigated. Photoluminescence spectra clearly differentiated the strong free exciton peaks, weak donor-acceptor pair, Y lines and oxygen-bound exciton peaks, indicating the high quality of the films. Differences between the computed and the experimental values suggested that the residual mismatch-induced strain and the thermally induced strain in ZnTe epilayers during cooling may be simultaneously taken into account.

The mechanical properties of isotactic polypropylene can be enhanced in one direction by a combination of rolling and drawing in a rolling mill. The longitudinal strength and modulus of the oriented polypropylene (OPP) increases with an increase in draw ratio; however, the transverse properties remain relatively unchanged. In this study, multidirectional OPP laminates (with [(O).sub.2], [(O/90).sub.s] and [(O/[+ or -] 45).sub.s] lay-ups) were made to obtain sheet materials with improved properties in more than one direction in the plane. A hot-plate welding technique was used to produce these translucent and recyclable laminates. The in-plane properties of the laminates were successfully predicted with classical laminate theory (CLT), which is commonly used to predict the properties of fiber reinforced materials. These laminates can be quasi-isotropic and were found to have improved modulus (up to 6 GPa for [(0/90).sub.s] laminates) and strength (up to 150 MPa for [(0/90).sub.s] laminates) as well as exceptionally good impact toughness.

A proposed model for describing the output behavior of n-channel silicon on isolator metal oxide semiconductor (MOS) field effect transistor devices is presented. Developed to consider the bipolar and MOS structures, it estimates the snapback effect of such devices with body bonded to the source or floating depending on its configuration or material characteristics. Results indicate the predominance of the bipolar-induced snapback voltage with channel lengths more than eight micrometers.

Focuses on the optical and structural characteristics of zinc compound thin films on a gallium compound substrate. Examination of the crystal quality and dislocation density in the epilayer; Performance of modulation spectroscopy; Determining whether the epilayer is under tensile strain.