This study details a method of determining suitable cutting conditions without using a database. In a previous work, a system that derived the cutting conditions from the drilling conditions was constructed by considering energy efficiency. This energy efficiency was estimated as the ratio of the supplied energy to removed volume. However, the derivation of the limit feed rate, using energy efficiency, has two main limitations. The first problem is that the results of the measured removed volume and the removed volume immediately after penetration are different. The second issue is cutting energy efficiency is difficult to predict. In this report, in order to solve two problems, a method for finding the energy efficiency of drilling below the minimum set time and a model for finding the energy efficiency of cutting were constructed. The predicted value of the limit feed rate is closer to the measured value than the method proposed in the previous work. The same result was obtained when different materials were used. It is thus concluded that the method proposed in this report can be applied to various materials.

In recent years, Laser Metal Deposition (LMD), in which metal powders are injected into the molten pool created by laser irradiation and overlay welding is performed, has been attracting attention as a new technology for metal 3D printers. However, it is difficult to select the conditions for obtaining good quality in LMD using high-speed tool steel powder, and internal defects such as blowholes and lack of fusions are likely to occur. Therefore, laser remelting process was attempted to remove these internal defects in the overlay layer of high-speed tool steel. The purpose of this study is to perform laser remelting after LMD using the same equipment and to select remelting conditions that can remove internal defects. In the remelting process using the overlay layer of high-speed tool steel, the inter-pass temperature at which blowholes and lack of fusions could be removed without irregular surfaces was about 300～400℃. The remelting conditions were 2 kW laser power, 4 mm/s scanning speed, and 5 passes of laser irradiation × 4 times. Furthermore, the average hardness increased from 588 HV to 702 HV, and the non-uniformity of hardness was reduced.

In the contact phenomenon on the die surface during forging, it is essential to equalize the reaction force. In recent years, improvements in additive manufacturing technology have made it possible to form a lattice structure inside a structure. In this study, we aim to achieve uniformity of the surface reaction force at contact by optimizing the combination of lattices inside a structure that mimics a mold. The lattice is treated as a bulk material with effective stiffness, and the effective stiffness is calculated by the homogenization method. The effective stiffness is calculated using the homogenization method. Multiple types of lattice structures are combined with increasing the range of feasible stiffness. The lattice shape inside the structure is updated by referring to the concept of fully stressed design, in which the proposed design is updated by an updating equation based on arbitrarily set stresses. Finally, a finite element analysis is performed to model the detailed lattice geometry and to verify the performance of the obtained optimal structure. As a result, the gap between the maximum and minimum surface reaction force is less than one-eighth of the conventional design, and it is confirmed that the proposed method is effective in equalizing the surface reaction force.