The solid state dissimilar joining of mild steel and aluminum 5052-O alloy is successfully achieved by friction stir welding (FSW). The 2 mm thick sheets are butt welded using a convex scrolled tool made of tungsten carbide. With a constant weld speed of 75 mm/min, two different tool at rotation speeds of, 800 and 1000 rpm, were employed to determine the feasibility of the joint formation. Macroscopic observation of the cross section confirmed the formation of a sound FSW joint. However, the formation of an intermetallic in the Stir Zone (SZ) is also observed for the both sets of process parameters. Comparatively, better material mixing is observed when the parameters are set at, 1000 rpm and 75 mm/min respectively. The hardness test revealed the presence of three distinct hardness zones in the SZ for the two parameter sets.

A new method for the electrostatic suspension of disk-shaped objects is proposed which is based on a time-optimal control scheme and deploys only high-voltage power supplies that can deliver de voltages of positive and/or negative polarity. This method possesses the unique feature that no high-voltage amplifiers are needed which leads to a remarkable system simplification and objects can be suspended stably even in vacuum environment. Using this scheme, an aluminium disk used in a 3.5-inch HDD was suspended stably at an airgap of 0.3㎜.

Micro-forming is a suited technology to manufacture very small metallic parts(several mm-㎛). Micro-forming of Zr?₂Cu₁?Ni₁₃Al? bulk metallic glass(BMG) as a candidate material for this developing process are feasible at a relatively low stress in the supercooled liquid state without any crystallization during hot deformation. In this study, micro￢formability of a representative bulk metallic glass, Zr?₂Cu₁?Ni₁₃Al? , was investigated for micro-forging of U-shape pattern. Micro-formability was estimated by comparing Rj values (=A_f/A_g), where A? is cross-sectional area ofU groove, and Ar the filled area by material. Micro-forging process was simulated and analyzed by applying finite element method. FEM simulation results showed reasonable agreement with the experimental results when the material properties and simulation conditions such as top die speed, remeshing criteria and boundary conditions were tightly controlled. The micro-formability of Zr?₂Cu₁?Ni₁₃Al? was increased with increasing load and time in the temperature range of the supercooled liquid state. Also, FEM simulation using a commercial software, DEFORM was confirmed to be applicable for the optimization of micro-forming process.

This study presents the method of extracting shape design data on any aspheric lens by reverse engineering. The design formula for aspheric lenses is needed in almost all of the design, manufacture and measuring processes. The difficulty in designing the lens lies in the fact that it uses a complex formula for the aspheric surface, and many of the preliminary design values must be selected before actually inserting them into the formula. If the values could be extracted from an aspheric lens for which the structural design information is unknown and used in designing other lenses of similar characteristics, the difficulties in designing and measuring aspheric lens could be reduced. Therefore, in this study, the concept of reverse engineering was applied to demonstrate the method of extracting shape design information of aspheric lens from an arbitrary aspheric lens.