This paper reports a simple and effective method to fabricate microlens arrays with the ultraviolet-curable resins, and a soft mold of micro-holes array. During capillary forming operation, the surface of the soft mold of micro-holes array is being pressed against the ultraviolet-curable resin layer coated on the plastic substrate. An array of convex lense can be formed in the circular holes of...

The design of injection molding systems for plastic parts relies heavily on experience and intuition. Recently, mold makers have been compelled to shorten lead times, reduce costs and improve process performance due to global competition. This paper presents a framework, based on a Multidisciplinary Design Optimization (MDO) methodology, which tackles the design of an injection mold by integrat...

Plastic injection molding is discontinuous and a complicated process involving the interaction of several variables for control the quality of the molded parts. The goal of this research was to investigate the optimal parameter selection, the significant parameters, and the effect of the injection-molding parameters during the post-filling stage (packing pressure, packing time, mold temperature...

A new metal mold material for pulsed current sintering (PCS) methods at high temperatures with higher electrical resistivity than cemented carbide molds, was fabricated using mechanical milling and PCS. The constituent (100 1 x)(WC­10 or 30FeAl) + xC (x = 0­8; mass%) hard material with dispersed spherical carbon particles were synthesized via mechanical milling of the source powders and PCS. Th...

A three-step molding softlithographic process has been developed for the construction of a sharp Y-junction structure formation in a 1 × 2 Y-branch plastic optical fiber (POF) coupler design. The 1×2 Y-branch POF coupler is based on a Y-junction splitter which requires that the splitting part is constructed with sharp infinitesimal junction. The softlithographic process enables a PDMS mold to b...

Purpose – The purpose of this paper was to study the combined effect of hygro and thermo-mechanical behavior on a plastic encapsulated micro-electro-mechanical systems (MEMS) package during the reflow process after exposed to a humid environment for a prolonged time. Plastic encapsulated electronic packages absorb moisture when they are subjected to humid ambient conditions. Design/methodology/...

A combination of silicon anisotropic etch and mechanical hot embossing techniques is used to demonstrate the feasibility of manufacturing plastic micropyramids. These micropyramids have the desirable optical characteristics to enhance the brightness of LCD (liquid crystal displays) in battery-powered laptop computers, personal TVs and camcorders. Silicon mold inserts, 4-inch in diameter, are fi...

The solidification process during squeeze casting is analyzed based on the classical solidification and plastic deformation theory. The linear relationship between punch velocity and the solidification rate is established if the density change of molten meals is neglected. To obtain defect-free castings, the punch velocity should be larger than the solidification rate. The densification mechani...

The ability to fabricate periodic structures with sub-wavelength features has a great potential for impact on integrated optics, optical sensors, and photovoltaic devices. Here, we report a programmable nanoreplica molding process to fabricate a variety of sub-micrometer periodic patterns using a single mold. The process utilizes a stretchable mold to produce the desired periodic structure in a...

The presence of thermal mismatch between different materials of plastic IC packages was found to cause reliability and moldability issues such as delamination and warpage phenomenon. Delamination and warpage between the mold compound and die attach adhesive material were evaluated for Quad Flat No-lead (QFN) package. Evaluation was conducted on two set of different materials combination of epox...