Chiefly, the metal wire-feed and laser additive manufacturing (AM) is a deposition process to produce larger mechanical parts required for aerospace, shipbuilding, automobile, and mold repair industries. The principal advantage of metal wire-feed AM is the high deposition rate compared to an assisted metal powder-feed AM, and metal powder-based fusion AM. During the wire-feed deposition process, the feed orientation is a critical parameter managed at all stages of processing. A better surface finish is attained when the melted wire flows smoothly through the process, and a wire feed direction that is utilized opposite to the deposition direction yields the best results. To improve the surface quality of metal 3D printing, we designed a rotating wire feeder, the feed direction of which varies with the direction of deposition; all free-form lines which thus exhibit identical surface qualities. Here, we use a rotating stage to orient the wire-feed direction according to the bead direction, a slip ring to supply electrical power to the feeder motor, and utilized two rotating channels on a plate to supply Ar gas and extract fumes safely during the processing stage. We evaluated the rotating wire feeder by building various parts as needed to the equipment.

In this work, we introduce various bonding technologies for 3D package and suggest Insert-Bump bonding (ISB) process newly to stack multi-layer chips successively. Microstructure of Insert-Bump bonding (ISB) specimens is investigated with respect to bonding parameters. Through experiments, we study on find optimal bonding conditions such as bonding temperature and bonding pressure and also evaluate in the case of fluxing and no-fluxing condition. Although nofluxing bonding process is applied to ISB bonding process, good bonding interface at 270℃ is formed due to the effect of oxide layer breakage.

Paradigm shift to 3-D chip stacking in electronic packaging has induced a lot of integration challenges due to the reduction in wafer thickness and pitch size. This study presents a hybrid bonding technology by self-alignment effect in order to improve the flip chip bonding accuracy with ultra-thin wafer. Optimization of Cu pillar bump formation and evaluation of various factors on self-alignment effect was performed. As a result, highly-improved bonding accuracy of thin wafer with a 50μm of thickness was achieved without solder bridging or bump misalignment by applying reflow process after thermo-compression bonding process. Reflow process caused the inherently-misaligned micro-bump to be aligned due to the interface tension between Si die and solder bump. Control of solder bump volume with respect to the chip dimension was the critical factor for self-alignment effect. This study indicated that bump design for 3D packaging could be tuned for the improvement of micro-bonding quality.

To overcome many defects such as the high product cost, large energy consumption, and big space capacity in conventional mechanical machining, the miniaturization of machine tool and micro factory systems has been envisioned recently. The object of this paper is to research the effect of dynamic characteristic parameters in bolted-joint beams, which is widely applied to the joining of mechanical structures in order to identify structural system characteristics and to predict dynamic behavior according to scale-down from macro to micro system as the development of micro/mesoscale machine tool and micro factories. Modal parameters such as the natural frequency, damping ratio, and mode shape from modal testing and dynamic characteristics from finite element analysis are extracted with all 12 test beam models by materials, by size, and by joining condition, and then the results obtained by both methods are compared.