In this study, a new method of bonding CFRP and Al6061-T6 with epoxy adhesive after shot-peening treatment on the surface of Al6061-T6 specimens was proposed to improve bonding strength of a single lap joint between CFRP and Al6061-T6. More specifically, correlation between shot peening coverage on the Al6061-T6 surface and bonding strength with CFRP was experimentally analyzed. Experimental results showed that the surface roughness and the bonding strength increased as the peening time on the surface of Al6061-T6 increased up to a specific peening time (or coverage). However, the surface roughness and bonding strength decreased again under an over-peening condition of 480 seconds (300% coverage) or more. Therefore, it is necessary to search for the optimal peening time that can maximize bonding strength as well as the fatigue life of parts at a peening time between 320 (200%) and 480 s (300%) through additional experiments in future studies.

The objective of this study was to perform surface hardening experiments of titanium alloy using laser. The surface hardness value after laser hardening treatment was observed to increase with respect to the inflow of laser energy. However, when the laser energy exceeded the critical value, damage and cracks were observed on the surface of the material. The relationship between surface hardness values and process variables such as laser energy, scan speed, and number of laser scans was quantitatively modeled through the design of experiments and analysis of variance. Using the established mathematical model, the surface hardness value of the material can be predicted accurately with an average of 10% error over various process conditions. Analysis of the surface composition of the material using energy dispersive spectrometry showed that titanium oxide was the main cause of the increasing surface hardness. Further studies will be conducted to improve the accuracy and predictability of the model using nonlinear modeling techniques.

Generally speaking, the high speed forming process is suitable for the precise manufacturing of hard-to-form and high strength materials. This study conducted microscale embossing and punching experiments by establishing a forming system that uses a laser induced acceleration. The changes in the flyer velocity with the laser energy, flyer thickness, and flyer diameter were measured using a high speed camera, and the effects of the noted acceleration characteristics of flyers on processing performance were investigated. It is particularly important that in the case of punching, the advantages of high speed processing, in which the accuracy was improved by increasing the shear zone of the workpiece, were identified. Significantly in the case of embossing, it was observed that the formability improved by increasing the flyer velocity as the flyer diameter decreased. However, in the case when the flyer thickness was decreased, increased energy was consumed in the plastic deformation of the flyer, and the advantages of high speed forming could not be realized. For this reason, further research is needed to take advantage and optimize the forming process using the laser induced acceleration through experiments which are noted as considering the various process variables and materials.

In this paper, a real-time condition diagnosis system for the lens injection molding process is developed through the use of LabVIEW. The built-in-sensor (BIS) mold, which has pressure and temperature sensors in their cavities, is used to capture real-time signals. The measured pressure and temperature signals are processed to obtain features such as maximum cavity pressure, holding pressure and maximum temperature by the feature extraction algorithm. Using those features, an injection molding condition diagnosis model is established based on a response surface methodology (RSM). In the real-time system using LabVIEW, the front panels of the data loading and setting, feature extraction and condition diagnosis are realized. The developed system is applied in a real industrial site, and a series of injection molding experiments are conducted. Experimental results show that the average real-time condition diagnosis rate is 96%, and applicability and validity of the developed real-time system are verified.

This study investigates the effects of the size of copper sheets on the plastic deformation behavior in a microscale deep drawing process. Tensile tests are conducted on the copper sheets to study the flow stress of the materials with different grain sizes before carrying out the microscale deep drawing experiments. After the tensile tests, a novel desktop-sized microscale deep drawing system is used to perform the microscale deep drawing process. A series of microscale deep drawing experiments are subsequently performed, and the experimental results indicate that an increase in the grain size results in the reduction of the deformation load of the copper sheets due to the effects of the surface grain. The results also show that the blank holder gap improves both the formability of copper sheets and the material flow.

As demands on micro-products increase significantly with raising functional integration and increasing complexity, microfoming attracts a lot of attention in the manufacture of microproducts. Since the conventional big forming systems are not adequate to achieve sufficient tolerances of micro-scale parts, it is necessary to reduce the scale of the forming equipment and devices. In addition, understandings on the size effects, which exist in the material behavior and process characterization of microforming processes, need to be expanded. In this study, a miniaturized forming system based on the ball screw and servo motor actuator was developed for the efficient micro-parts production. In addition, tensile tests and cylindrical upsetting experiments were performed to evaluate the performance of the microforming system and to investigate the flow stress and friction size effects in microforming processes.

This paper presents a transformable track mechanism for wall climbing robots. The proposed mechanism allows a wall climbing robot to go over obstacles by transforming the track shape, and also increases contact area between track and wall surface for safe attachment. The track mechanism is realized using a timing belt track with one driving actuator. The inner frame of the track consists of serially connected 5R-joints and 1P-joint, and all joints of the inner frame are passively operated by springs, so the mechanism does not require any actuators and complex control algorithms to change its shape. Static analysis is carried out to determine design parameters which enable 90º wall-to-wall transition and driving over projected obstacles on wall surfaces. A Prototype is manufactured using the transformable track on which polymer magnets are installed for adhesion force. The size of the prototype is 628㎜Ⅹ200㎜Ⅹ150㎜ (LengthⅩWidthⅩHeight) and weight is 4㎏f. Experiments are performed to verify its climbing capability focusing on 90º wall to wall transition and driving over projected obstacle.

This study investigates the non-traditional manufacturing process of dry wire electrical discharge machining (EDM) in which liquid dielectric is replaced by a gaseous medium. Wire EDM experiments of thin workpieces were conducted both in wet and dry EDM conditions to examine the effects of spark cycle (T), spark on-time (Ton), thickness of workpieces, and work material on machining performance. The material removal rate (MRR) in the dry wire EDM case was much lower than that in the wet wire EDM case. In addition, the thickness of workpiece and workmaterial were found to be critical factors influencing the MRR for dry EDM process. The relative ratios of spark, arc and short circuit were also calculated and compared to examine the effectiveness of processes of dry and wet wire EDM.