Compared with synthesis of nanomaterials, fabrication of structures with nano-scale feature size is more challenging. Laser micro-nanofabrication has appeared as a versatile approach to reach this end due to its intrinsic three-dimensional (3D) processing capability and sub-100 nm spatial resolution. Different from conventional planar UV lithography widely used in the semiconductor industry, a technology based on pattern definition by photomask and linear exposure of resists, the ３D laser approach relies on light-matter nonlinear interactions and directly depicts complex patterns in three dimensions. Considering that compositions of various performances could be induced into photopolymers or transparent solids used for the fabrication, the technology as a new generation high precision manufacturing tool, is quite promising for ３D functional micronanophotonic, optoelectronic and mechanical devices and their integrated systems.

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The addition of fillers, which come in various sizes and shapes, provides an effective means for improving various properties of plastics. In injection molding of fiber-filled plastics, warpage is often caused by anisotropic shrinkage due to filler orientation. Generally, to decrease warpage, particulate fillers are used in place of fibers, however, mechanical properties (modulus and strength) may suffer.
In the research reported in this paper, the warpage behavior using glass fibers and flakes and the anisotropic shrinkage at ribbed sections were examined. We have clarified the following: 1) Warpage decreases with decreasing fiber content. 2) The amount of warpage in fiber filled composites was unrelated to the rib-thickness. However, in glass flake-filled composites, rib-thickness depended strongly on the glass flake content. 3) The glass flakes, which were very small compared to the glass fibers, had a much smaller aspect ratio, and acted more like particulate fillers with minimal anisotropic shrinkage. 4) The relationship between the anisotropy and filler type and orientation was empirically determined.

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The precise measurement of three dimensional shrinkage at different locations within molded parts is seldom reported. In this research, we compared the measured shrinkage (relating the difference between the dimensions of the metal mold and the resultant molded plastic parts) with calculations based on PVT measurements for parts made from AS and ABS resins. With increasing packing pressure, the shrinkage was minimized in the normal direction (ND) more than in the melt flow (MF) and transverse (TD) directions. The ND shrinkage was proportional to the volume shrinkage, while those of the other directions were proportional to less than the 1/3 power of volume shrinkage. The TD shrinkage was larger than the MD shrinkage. With increasing packing pressure, the gate seal time increased for ABS, but hardly changed for AS. The molecular orientation, obtained from birefringence measurements, increased with packing pressure.

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