The Swiss-type automatic lathe is designed to produce small-diameter and long rods with high accuracy and efficiency. However, its unique mechanism causes the disadvantage of a large amount of waste material. This disadvantage can be solved by the use of the friction welding method. In the previous study, the authors optimized the welding conditions on a Swiss-type lathe using tensile strength evaluation of joined workpieces as an index. However, the mechanical properties such as the fatigue strength of the jointed workpiece by the automatic lathe have not been clarified. In this report, rotational bending fatigue tests were conducted on the welded specimens. It was found that the fatigue strength is weakened from the bulk material. Additionally, improvement of fatigue strength by a burnishing process was applied.

Burrs and chipping that occur after machining are a fundamental and permanent problem. Burrs and chipping are repaired in the post-process, which increases the machining cost. Previous research has mainly focused on reducing burrs and chipping, and has not addressed the prediction of edge qualities (burrs and chipping). If the edge quality after machining can be predicted, production planning such as deburring and chipping correction work can be easily planned, and machining costs can be reduced by shortening the lead time. In addition, if the edge quality after machining is displayed on the CAM simulation, toolpaths can be created with fewer burrs and chipping, and more realistic digital twinning becomes possible. In this study, we devised a method to predict burrs and chipping that occur during face milling and examined the advantages of this method. This method can check edge quality at all engagement and disengagement angles by front milling a workpiece with a diagonal groove. In this report, face milling was performed using a vertical machining center, and burrs and chipping corresponding to the engagement and disengagement angles were measured.

In this paper, the influence of oxygen concentration in the building chamber on the melt pool behavior and the mechanical properties of the built part obtained via a metal-based powder bed fusion with a laser beam (PBF-LB/M), which is one of an additive manufacturing (AM) method, was experimentally investigated. The metal powders used were two types of aluminum alloy powders; Al-Si-Mg and Al-Mg-Sc. The amount of fumes and spatter particles scattered from laser-irradiated area was calculated when the oxygen concentration was varied from 10 to 10000 ppm, and their chemical composition was evaluated. In addition, the mechanical properties of the built part obtained in different oxygen concentration and their chemical composition were also evaluated. The results showed that the amount of oxygen in the building chamber was one of the principal factor affecting the melt pool behavior. The amount of fumes scattered during the building of Al-Mg-Sc powder was significantly increased when the oxygen concentration in the building chamber was below 5000 ppm, and the amount of Mg composition included in fumes was extremely larger than the virgin powder. Aluminum alloy powders are oxygen-active, so fume generation must be minimized. It was noted that the suitable oxygen concentration during the building of Al-Mg-Sc powder in the PBF-LB/M was ranged from 3000 to 5000 ppm in order to obtain the excellent mechanical properties such as high relative density and elongation while minimizing the amount of fume generation.

Gold leaf is traditional craft in Japan. Manufacturing process of gold leaf is mostly done by hand. The aging craftsmen who produce gold leaf and the lack of their successors are serious problems. Therefore, we focus on the automation of the process “Hakuutushi”. It is the process of transferring only a sheet of gold leaf from between the stacks of gold leaves and carbon papers. This work requires a lot of concentration and delicacy. The key to automation is the handling technology for lifting and releasing the leaf. We found the electrostatic adsorption method using thread for it. We investigated the cause about why thread can adsorb leaf. It was found that the thread is charged by the transfer of electric charge through water on the surface of the threads. We also suggest the optimal shape of thread for handing the leaf.