Industrial boilers are used in numerous fields, and heat efficiency enhancement is a major topic of study. A double-pipe boiler is a simply structured industrial boiler having a high thermal efficiency. Baffles are specially installed in the doublepipe boiler for increasing the heating time. The baffles determine the heat efficiency of the double-pipe boiler. However, it is theoretically difficult to design a baffle and locate its optimal position, solely by considering the fluid flow of heated air, and the heat exchange between water and heated air. To confirm the correct positioning of baffles, fluid flow and heat transfer simulations were conducted on the boiler. Our results showed that at some points, there was insufficient circulation of heated air. To overcome this problem, baffles were added at these points, by referring to the simulation results. The changing of baffles resulted in an increase in efficiency of heat transfer in the double-pipe boiler.

To evaluate the quality of the cross section of Ni alloy thin plate cut by laser, we have proposed an analysis method using SEM image to measure surface roughness of cross section. The surface roughness of the cut area of the thin plate is considerably difficult to analyze using conventional measurement technique such as profile measurement with a probe. When the SEM image is used, the roughness value can be collected quantitatively while judging the surface status qualitatively. A Hastelloy C-276 thin plate with a thickness of 50 μm coated with HTS was cut by Nd:YAG laser, and the state of the cross section was analyzed by applying the proposed method in this research. The optimum laser cutting process condition could be found for the lowest surface roughness.

Inconel 718, a typical ultraheat-resistant alloy, is recognized as a useful component in aircraft parts owing to its high-temperature strength and good chemical stability. Although many studies have been conducted to determine the proper drill shape to overcome the poor machinability when drilling into Inconel 718, most have involved a cutting process program known as AdvantEdge, as an experimental approach requires much time and money. In this study, our purpose is to optimize the drill shape for efficient drilling by conducting a trust force and temperature analysis using AdvantEdge. In order to achieve this purpose, the reliability of the results of the analysis was verified and by applying design of experiment an analysis of the geometric parameters of the drill shape considering the thrust force and temperature was conducted.

Fuel used in the steel metallurgy industry is stored in huge stage systems called SILO. Fuel is released by RDM (Rotary Discharge Machine), at the place of utilization. RDM is located in the Silo, and is constituted of a main frame, driving part, discharging part and control part. RDM is combined to a direct motion on the rail in tunnel, having a rotary motion enabled by a motor. In this paper, we calculate the theoretical discharging capacity of RDM to confirm the correlation between design element and discharging capacity of RDM. Also, through structure analysis, we confirm the vulnerable point of RDM when it discharges the storage materials. We hope to apply these results to design a more efficient RDM.

Induction heating has been applied to the preheating process in various industrial fields. It has been used as a simple device structure, limiting the heating zone through controlled variables, and free-welding positions. It would be helpful to weld thick plates with arc welding such as GMAW. The induction heating process is well suited to this process. In this study, in order to find suitable induction heating parameters, a simulation was conducted with multi physics S/W. Three kinds of material were heated by induction coils designed specially for thick plate. Consequently, steel and nimonic alloy were the most efficient materials for preheating by induction. It can be concluded that the induction heating process is a good method for preheating the thick plate.

Hastelloy C-276 composed of Cr, Mo, and Ni is a versatile, corrosion-resistant alloy with numerous industrial applications including its use in nuclear reactors, general chemical plants, and as a superconducting base material. Of especial significance, it can be used as a thin-sheet type whereby lap-joint welding is occasionally necessary. The main welding problems for thinsheet metals are deformation and burn-through from an excessive heat input. Laser welding can minimize these problems because it has a high energy density and low heat effect on the base material. In this study, the laser-welding characteristics of lap-joint Hastelloy C-276 sheet metal were determined. The criteria of the laser-welding variables were chosen using a heat-conduction analysis, and the optimal welding parameters were selected by experimenting with an Nd:YAG laser.

Five-Axis machines can generate undesirable defects such as the undercutting and overcutting errors that frequently occur in the three-axis machining process. It is therefore necessary to develop a program for NC-code generation, whereby the cutter posture is considered to decrease the occurrence of defects. In previous studies, the Easy-Impeller CAM(E-ICAM), an automatic CAM program used for the five-axis machining of impellers, was developed; however, when EICAM is used to machine an impeller, it is possible to gouge the hub and blade. Therefore, the aim of this study is the establishment of a formula for each type of endmill to minimize gouging according to the cutter posture, in consideration of several factors that affect accuracy in the machining of an impeller. This study also aimed to improve the performance and accuracy of EICAM in the manufacturing of impellers.

In order to prevent crack in thick weld zones, the preheating process such as induction and gas torch heating needs to be applied. Among them induction heating is the most effective heat source because it has rare thermal effect and very rapid heating characteristics. In this paper, when the induction heating method is used to improve arc welding, the temperature distribution and magnetic field density of the welding zones are analyzed by simultaneously solving heat transfer and electromagnetic field equation. In particular, cone and flat type coils are designed and induction heating effects of each type are compared to identify heating characteristics on a V ?groove weld joint. As a result, a cone shape coil is more efficient in the preheating process. When induction heating and arc welding system is designed for thick plate with V-groove weld joint, the results in this paper could be applied.

Manufacturing processes of industrial tire are composed of mixing, extrusion, curing, trimming and inspecting. Among them curing is the most important process in the production of industrial tire. In this study the newly developed spring vent system was designed in order to solve rubber intrusion problem inside spring vent system in the curing process. After the experiment it is concluded that rubber intrusion was caused by angled stem head part. New spring vent system was manufactured and new design of spring vent system is proper to use for industrial tire curing process.

A flexible-rigid multibody analysis was performed to examine the dynamic response of a heavy handling robot system under a worst motion scenario. A rigid body dynamics analysis was solved and compared with flexible-rigid multibody analysis. The modal analysis and test were also carried out to establish the accuracy and the validation of the finite element model used in this paper. For the flexible-rigid multibody simulation, stresses in several major bodies were interested, so that those parts are flexible and other parts are modeled as rigid body in order to reduce computer resources.

Recently, many studies are being conducted to realize high quality polishing technology, but because of high dependence on field experience and insufficient research for ultra-precision polishing technology, it is difficult to establish standardization of polishing conditions. The purpose of this study is to determine high-efficiency superfinishing conditions which are applicable in the field of machining. To achieve this, we have a developed a superfinishing device and conducted a series of polishing experiments for mechanical materials such as SM45C, Brass, Al7075, and Ti, from the perspective of oscillation speed, the rotational speed of the workpiece, contact roller hardness, contact pressure, and feed rate. From the experimental results, it was confirmed that the polishable superfinishing conditions range and efficient feed rate of polishing film can be etermined.

This research introduces the efficient modeling and manufacturing method using reverse engineering combined with rotational simulation of a pair of screw and mill-turn machining realized a proposed NC program. Because previously developed model had insufficient flow measuring accuracy, we considered that matter in the aspect of method of modeling and performance test. For that reason we modified the modeling which could minimize a gab between male and female screw, and developed precise tester which consists of constant tank, flowmeter and load cell, etc., and then conducted the test for defining characteristic and accuracy of flowmeter and repeated same test 5-times. Consequently we could obtain satisfied measuring accuracy and reproducibility indicated in the catalog of master model. Hence we give our conclusion as to the validity of developing accurate screw type flowmeter using the proposed process such as reverse engineering, mill-turn machining and precise performance test.

As the industrial development is accelerated, a new machining process and system are keenly required to achieve super precision surface finish. Especially to get ground surface finish for complicated and narrow inner shape of molds, it is impossible with the existing methods so that a new method is being required to be developed. A new material; called Magic(MAGnetic Intelligent Compounds), is finally made and it is called Magic machining that uses this material. There is a way to make a material as follows, the mixture of magnetic particles, bonding material and particles of abrasive grain should be melt down by proper heat, and then this mixture put in a mold and cool down in magnetic field which has a uniform direction. This new polishing method is spotlighted as an excellent solution to the existing problems. However it hasn't reported any study about the influence of the machining conditions of polishing velocity, amplitude and polishing pressure to the surface roughness yet. This study would examine closely the influence of polishing conditions of. the Magic polishing tool to the surface finish to decide the optimum polishing condition and to standardize the Magic polishing work.