One of the factors that influence the dynamic characteristics of machining systems is the cutting tool. Cutting tools are very diverse, and receptance coupling substructure analysis (RCSA) is essential for analyzing the dynamic characteristics of each tool. For RCSA, a full receptance matrix of the equipment and tools is essential. In this study, rotational degree-of-freedom receptance was estimated and analyzed using translational receptance. Displacement/moment receptance was analyzed according to the distance of the response point using the first-and second-order finite difference methods. The rotation/moment receptance was estimated according to the distance of the response point. Rotation/moment receptance was analyzed using Schmitz’s method and compensation strategies. The limitations of these strategies were analyzed, and the rotation/moment receptance for the beam under free-free boundary conditions was predicted using the second compensation strategy.

In semiconductor inspection equipment, a chuck used to hold a wafer is equipped with a cooling or heating system for temperature uniformity across the surface of the wafer. Surface temperature uniformity is important for increasing semiconductor inspection speed. Triply periodic minimal surfaces (TPMSs) are proposed to enhance temperature uniformity. TPMSs are a topic of increasing research in the field of additive manufacturing and are a type of metamaterial inspired by nature. TPMSs are periodic surfaces with no intersections. Their continuous curve offers self-support during the additive manufacturing process. This structure enables the division of a single space into two domains. As a result, the heat transfer area per unit volume is larger than that of general lattice structures, leading to a superior heat transfer performance. This paper proposes a new structure called a double-wall TPMS. The process of creating a double-walled TPMS by adjusting the thickness of the sheet TPMS was investigated, and its thermal performance was studied. Finally, a double-wall TPMS was applied to the chuck. The optimal designs for the diamond and gyroid structures exhibited a difference in surface temperature uniformity of 0.23 °C and 0.66 °C, respectively. Accordingly, the models optimized with the double-wall TPMS are proposed.

절대절점좌표계는 1990년대 중반 탄성 다물체 동역학 해석을 위해 개발된 기법으로 대변위, 대회전 그리고 대변형의 표현이 가능하다. 이러한 장점에도 불구하고 자유도의 증가로 인한 해석시간의 증가라는 단점이 존재한다. 해석시간을 줄이는 방안들 중 하나로 무차원 운동방정식이 적용되어 왔다. 본 연구에서는 절대절점좌표계에서 박판에 대한 무차원 운동방정식을 활용하여 그 효율성을 확인하였다. 무차원 질량행렬과 힘벡터를 유도하는 과정은 생략하였으며, 무차원 강성행렬을 유도하는 과정에 대해 설명하였다. 중력장에서 구 조인트로 체결된 박판의 거동을 확인하였으며, 요소수가 증가할수록 차원 운동방정식 대비 무차원 운동방정식의 해석시간이 단축되는 것을 확인하였다.

Recent advances in additive manufacturing have provided more freedom in the design of metal parts; hence, the prototyping of fluid machines featuring extremely complex geometries has been investigated extensively. The fabrication of fluid machines via additive manufacturing requires significant attention to part stability; however, studies that predict regions with a high risk of collapse are few. Therefore, a novel algorithm that can detect collapse regions precisely is proposed herein. The algorithm reflects the support span over the faceted surface via propagation and invalidates overestimated collapse regions based on the overhang angle. A heat exchanger model with an extremely complex internal space is adopted to validate the algorithm. Three samples from the model are extracted and their prototypes are fabricated via laser powder bed fusion. The results yielded by the fabricated samples and algorithm with respect to the sample domain are compared. Regions of visible collapse identified on the surface of the fabricated samples are predicted precisely by the algorithm. Thus, the supporting span reflected by the algorithm provides an extremely precise prediction of collapse.

This paper presents an optimization method for achieving temperature uniformity in the heat exchanger of semiconductor-heating devices with an approach based on a surrogate model. The technique developed in this study simplifies the conjugate heat transfer in the channel network of the heat exchanger. A body-centred cubic (BCC) lattice core was adopted for local augmentation of the heat transfer performance within the internal channel of the heat exchanger. To reveal the effects of flow speed and lattice column diameter on pressure drop and heat transfer, a CFD simulation was implemented with Reynolds number and diameter ratio varied in the ranges of 3078–23852 and 0.0869–0.313, respectively, using a central composite design. The surrogate model was defined after a dimensional analysis of a single channel and the surrogate circuit analogy. A particle swarm optimization algorithm was adopted to determine the optimal column diameters of each lattice structure based on the surrogate model. The reliability of the optimization of the heat exchanger of the semiconductor-heating device model was assessed by comparing it to a model that consisted of only identical lattices in each position. The results showed prominent enhancement that the deviation in temperature was reduced by 83.4%.

To address overhang sagging in laser powder bed fusion (L-PBF) of meso-scale film-cooling holes, this study proposes a 777TD hybrid geometry combining the nominal 7° diffuser features of a 777 hole with a pointed, self-supporting roof. Ideal smooth-wall computational fluid dynamics (CFD) calculations compared cylindrical, teardrop, 777, and 777TD holes with diameters of 0.5–0.8 mm at a blowing ratio of 1.0 and a density ratio of 1.5. At D = 0.8 mm, the predicted area-averaged adiabatic film-cooling effectiveness was 0.3308 for 777TD and 0.3208 for 777, a nominal relative increase of 3.1%. Separately, Haynes 230 specimens were fabricated at build orientations of 30° and 60° and evaluated by X-ray computed tomography (CT). At D = 0.8 mm and a 30° build orientation, the in-tolerance proportion in the selected outlet region was 93% for 777TD and 76% for 777, an increase of 17 percentage points under a ±0.1D deviation criterion. These results support further evaluation of the hybrid geometry for meso-scale cooling hole manufacture. The CFD comparison and CT conformity assessment provide complementary evidence; the cooling performance of the as-built holes has not been experimentally validated.