Analisis Proses Blanking Dengan Simple Press Tool

Blanking production process will be required for mass production due to good product quality and lower production costs. For mini wrench products, blanking process can be done with a simple press tool. This analysis starting with design, manufacturing and than analysis. It's concluded that the construction of simple press tool are Plate Material (ST 60), Pillar Material (ST 60), Punch and Dies Material (SKD 11 with 15 mm thickness and 0.108 mm clearance), stripper material (ST 37), the punch holder material (ST 37), and the stopper material (ST 37). Forces acting on the machine press tool are cutting force (37 kN), clamping force (371 N), and power press machine (8.5 kW)

Simulating the sintering of powder particles during the preheating step of Electron Beam Melting process: Review, challenges and a proposal

The powder bed preheating before melting is a distinctive manufacturing step of the Electron Beam Melting (EBM) process. During preheating slight sintering occurs and small necks are formed between neighbouring particles. The necks improve the heat transfer and the powder bed strength allowing a reduction of supports structures and the neutralisation of the so-called smoke. However, preheating may represent over 50% of the total production time. This work investigates the major strategies in literature for preheating phase optimisation and proposes a numerical simulation approach to evaluate the neck growth and the corresponding sintering level

A phase-field study of neck growth in electron beam powder bed fusion (EB-PBF) process of Ti6Al4V powders under different processing conditions

Traditional sintering processes are carried out to achieve complete material densification. In an electron beam powder bed fusion (EB-PBF) process, the same sintering mechanisms occur but only with the aim to form small connections between the particles (necks). A proper neck formation is central for the EB-PBF process because, among other effects, ensures the thermal stability of the process and helps to avoid smoke phenomena. This work presents a numerical study of neck formation under the EB-PBF processing conditions. A new type of modelling is introduced for the temperature sintering load and included in a phase-field model, which simulates the neck growth during the EB-PBF process of Ti6Al4V powders. The model was validated with an ad-hoc experiment, which provided a deviation with respect to the estimated neck diameter of about 9%. The deviation was investigated by reasonably varying the processing conditions. The results showed that the thermal history, the process time scale (including also the cooling phase), and the geometrical characteristics of the particles significantly affected the sintering rate and neck radius

A multiscale framework for the evaluation of thermal conductivity of sintered powder at the powder bed fusion with electron beam conditions

The thermal conductivity of the powder bed during the electron beam powder bed fusion (PBF-EB) process strongly influences the process conduction and the quality of the components produced. The evaluation of this property is challenging. The models currently available in the literature cannot provide values of the thermal conductivity that consider the temperature evolution typical of the preheating step. This work presents a novel computational framework to evaluate the thermal conductivity of a powder bed for the PBF-EB process. The framework combines the thermal conditions of the PBF-EB process with information on the geometrical features of the powder bed and an analytic method to calculate the thermal conductivity and its variation with temperature and time. The proposed numerical framework is applied to the body centred structure (BCC), a typical arrangement that can emulate the PBF-EB conditions. The numerical framework is multiscale by nature, providing information about the whole powder bed starting from geometrical information about the neck among the powder particles

Studi Kesehatan Ekosistem Terumbuk Karang Di Perairan Pulau Ketawai Kabupaten Bangka Tengah

Ekosistem terumbu karang memiliki fungsi sebagai feeding ground, nursery ground dan spawning ground bagi organisme pendukung yang bersimbiosis di ekosistem perairan. Tujuan penelitian ini adalah mengetahui kesehatan ekosistem terumbu karang dengan menggunakan metode purposive sampling dan Underwater Photo Transect (UPT) di perairan Pulau Ketawai Kabupaten Bangka Tengah. Penelitian ini dilaksanakan pada bulan April sampai Oktober 2021 sebanyak 4 (empat) titik di perairan Pulau Ketawai, Bangka Tengah. Hasil penelitian menunjukan ekosistem pada terumbu karang perairan pulau ketawai termasuk dalam kondisi baik dengan nilai tutupan Terumbu Karang berkisar 50,20% hingga 66,20%. Tingkat keanekaragaman bentuk pertumbuhan paling banyak terdapat pada stasiun 01 dengan dominansi bentuk pertumbuhan Coral Foliose (CF) sebesar 32,53% dan tingkat keanekaragaman bentuk pertumbuhan paling rendah terdapat pada stasiun 04 di dominansi oleh pertumbuhan Coral Heliopora (CHL) dengan persentase 32,47

Observation of electro-activated localized structures in broad area VCSELs

We demonstrate experimentally the electro-activation of a localized optical structure in a coherently driven broad-area vertical-cavity surface-emitting laser (VCSEL) operated below threshold. Control is achieved by electro-optically steering a writing beam through a pre-programmable switch based on a photorefractive funnel waveguide.Comment: 5 Figure

Effect of the Sintering Conditions on the Neck Growth during the Powder Bed Fusion with Electron Beam (PBF-EB) Process

A distinctive characteristic of the powder bed fusion with electron beam (PBF-EB) process is the sintering of the powder particles. For certain metallic materials, this is crucial for the success of the subsequent step, the melting, and, generally, the whole process. Despite the sintering mechanisms that occur during the PBF-EB process being similar to well-known powder metallurgy, the neck growth rates are significantly different. Therefore, specific analyses are needed to understand the influence of the PBF-EB process conditions on neck growth and neck growth rate. Additionally, some aspects, such as the rigid body motion of the particles during the sintering process, are still challenging to analyze. This work systematically investigated the effects of different particle diameters and particle diameter ratios. Additionally, the impact of the rigid body motion of the particles in the sintering was analyzed. This work demonstrated that the sintering results significantly depended on the EB-PBF process conditions