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Powder-Based Additive Manufacturing Systems
Published in G.K. Awari, C.S. Thorat, Vishwjeet Ambade, D.P. Kothari, Additive Manufacturing and 3D Printing Technology, 2021
G.K. Awari, C.S. Thorat, Vishwjeet Ambade, D.P. Kothari
The LaserCUSING process offers many advantages, such as those listed below: Green technology: The LaserCUSING process is a production method that produces almost no waste. Metal powder which has not been melted can be fully reused without the loss of any material for further processing. In fact, the laser process is almost emission-free. Due to the high degree of performance of the laser systems used at Concept Laser, the energy that is applied is efficiently transformed into working power.Freedom of geometry: Complex geometry of components or geometry of components that cannot be generated by traditional means without the use of laser melting devices. There are no restrictions on the production of hollow or grid parts on the inside with this technology.Near net shape: The design of components with close-net or ready-to-install geometry reduces manufacturing time and saves costs.
Environment-Friendly Machine Tools and Operations
Published in Helmi Youssef, Hassan El-Hofy, Non-Traditional and Advanced Machining Technologies, 2020
In considering a clean machining process, the interaction between economy, ecology, and technology has to be considered, as shown in Figure 10.1. Conflicts may arise among these three factors and a good compromise has to be made. To improve the quality of the machining processes, it is essential to adopt innovative methods that achieve the minimum environmental contamination in addition to their stability, reliability, and acceptable economic conditions. In this regard, the application of near net shape technology to manufacture parts with complex shapes by substituting cutting operations with forming activities provides advantages such as reduced chip volumes, lower cutting forces, reduced volumes of cutting fluids and cutting fluid losses, and simpler machine tools with lower power requirements.
Nanoscintillators
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Santosh K. Gupta, Yuanbing Mao
The synthesis of OTCs requires highly pure ceramic nanopowders, which are consolidated into a “green body” by pressing or casting. The “green body” is then sintered to near full density and subsequently hot pressed by isostatic method to make them nonporous. OTCs have the combination of scintillation superiority of single crystals along with the ruggedness and processability of glass. Ceramics offer the following prospective advantages compared with single-crystal scintillators: Increased flexibility in scintillator composition since precursor powders can be tailored to provide specific needed properties.Lower processing temperatures, since a melt, typically required for crystal growth, is avoided, potentially lowering costs by increasing yields.Faster processing cycles, hours compared to days.Near net shape fabrication, reducing machining costs and providing the ability to produce complex shapes if required.
Cyclic oxidation and hot corrosion performance of direct metal laser sintered and wrought alloy 718 at 800°C in air and molten salts containing Na2SO4, V2O5 and NaCl
Published in Corrosion Engineering, Science and Technology, 2023
S. M. Muthu, Dhinakaran Veeman, Shiladitya Paul, M. Prem Kumar
In the recent decades, the fabrication of complex parts via additive manufacturing (AM) has become an attractive and cost-effective production method. One such method, direct metal laser sintering (DMLS) is a modified version of selective laser melting (SLM), and it is suitable for fabricating titanium, steels and superalloys in a layer-by-layer process [3,4]. In the DMLS process, the gas atomised powder particles were sintered by ytterbium laser power source. DMLS process extensively utilised for producing the different shaped parts in various sectors and offers a good dimensional accuracy and production flexibility. It can produce the near-net shape parts without any secondary machining process which could eliminate the materials wastages, tool cost and machining time. DMLS-produced parts offer a unique microstructure as compared to conventional manufactured parts due to high cooling rate [3–5]. Smith et al. [6] produced the alloy 718 parts via DMLS method and further carried out the heat treatment to enhance the properties. The authors compared the microstructure and mechanical properties of the DMLS-built alloy with conventional produced alloy. Sumanth et al. [7] fabricated the alloy 718 by DMLS with different scanning orientation strategies and further discussed their impacts on microstructural and mechanical properties.
Surface hardenability studies of the die steel machined by WEDM
Published in Materials and Manufacturing Processes, 2018
Eswara Krishna Mussada, Choo Chee Hua, Ayyagari Kameswari Prasada Rao
Hard and brittle materials, such as hardened steels, ceramics, super alloys, fiber-reinforced composites, soft elastomers, tissues, and metal matrix ceramic composites, are most demanded functional materials in several industries owing to their exceptional mechanical, thermal, corrosion resistant properties, etc. Unfortunately, conventional machining methods can no longer be employed for such materials, efficiently; hence, they are normally categorized as difficult-to-machine materials. There are several processes that machine materials by evaporation, melting, electrical energy, chemical reaction, and/or hydraulic power conjointly referred to as the unconventional (or nontraditional) machining process. These machining techniques are unaffected by the brittleness and hardness or the softness of the workpiece materials. Some of these processes are useful in near-net-shape machining of the difficult-to-machine materials to the final component, thus discovering applications in automotive, electronics, aerospace, die, and mold industries. Electrical discharge machining (EDM) is one of the nonconventional manufacturing processes that erodes materials with the help of electric discharge pulses generated between the workpiece and electrode. These discharge pulses generate a plasma channel, which in turn rises the temperature up to 20,000°C at the electrode-workpiece gap in a short span [1]. This temperature rise is enough to melt and evaporate materials irrespective of their hardness and melting points.
On the compressibility of metal powders
Published in Powder Metallurgy, 2018
J.M. Montes, F.G. Cuevas, J. Cintas, F. Ternero, E.S. Caballero
Powder compaction is a production method commonly used in the manufacturing industry today. One of the multiple compaction modalities, the cold die compaction, is widely used in powder metallurgy, combined with a subsequent sintering process that takes place at high temperatures. This manufacturing technique provides a method for near net shape parts fabrication where subsequent finishing operations are minimised or eliminated. The high importance of the compaction process is due to the fact that the compact’s green porosity (the green properties referring to those after compaction but before sintering) influences the subsequent densification during sintering. In order to minimise experiments and to optimise serial production, several methods to analyse the powder compaction process have been studied. One of the most important issues is the compaction equation or compaction law, which describes the relationship between porosity (or relative density) and the applied pressure during compaction.