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Sustainable Polishing of Directed Energy Deposition–Based Cladding Using Micro-Plasma Transferred Arc
Published in Kishor Kumar Gajrani, Arbind Prasad, Ashwani Kumar, Advances in Sustainable Machining and Manufacturing Processes, 2022
Pravin Kumar, Neelesh Kumar Jain, Abhay Tiwari
This is one of the processes used for improving surface finish and reducing surface waviness. In this process, ultrasonic vibration is utilized to cause an impact on the surface, causing surface modification. The process considers variable parameters such as static load, amplitude of vibration, number of impacts per unit area, and ball-tip diameter [6]. It imparts additional advantages of grain refinement, hardness improvement, wear resistance, and gain in fatigue strength. Similarly, ultrasonic cavitation abrasive finishing is also used for surface modification. In this process, the manufactured DED part is immersed in deionized water mixed with hard abrasive. An ultrasonic horn tip is maintained at a specific height above the workpiece surface, and an ultrasonic wave of high frequency is generated in the solution to cause cavitation (development, growth, collapse of bubbles). A schematic diagram of the ultrasonic cavitation abrasive finishing process is also shown in Figure 18.1. Cavitation produces micro-jets with velocities ranging from 200–700 m/s, and the available abrasive particles in the solution finish the surface. It results in improvement of surface roughness in the range of a few microns (1–5 μm) [7]. The previously discussed processes are suitable for finishing up to a few microns and are successfully being used to finish the parts manufactured by a laser-based DED.
Industrial Applications
Published in Suresh C. Ameta, Rakshit Ameta, Garima Ameta, Sonochemistry, 2018
Anil Kumar Chohadia, Yasmin, Neelam Kunwar
Progress has been made in the past few years in the size of plastic parts that can be welded ultrasonically, particularly using higher-power equipment and improvement in ultrasonic horn. Such improvements in joint design have extended the area of ultrasonic welding to more difficult plastics and shapes. The development in ultrasonic welding process has been mainly affected by ultrasonic staking, spot welding and inserting of metal parts into plastics.
Multiphysics modeling of ultrasound-assisted biomass torrefaction for fuel pellets production
Published in IISE Transactions, 2023
The vibration amplitude generated by piezoelectric ceramics is usually small and requires amplification through an ultrasonic horn as shown in Figure 1 (Rouquette, 2004). An ultrasonic horn is usually a tapered metal rod, which has a transitional section with a longitudinal cross-section profile that converges toward the output end. Thus, the ultrasonic vibration is greatly amplified at the output end of the ultrasonic horn, contributing sufficient ultrasound energy for operations such as ultrasonic welding and machining (Rouquette, 2004; Nad, 2010). Another function of the ultrasonic horn is to efficiently transfer the ultrasound energy from the piezoelectric disks onto the treated medium, which, in this research, is a volume of biomass. Most of the ultrasound energy is absorbed locally by the medium, resulting in the generation of heat. This thermal effect converts biomass into torrefied materials with better fuel characteristics for combustion and gasification applications (Kambo and Dutta, 2014).