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Mechanics and Material Removal Modeling and Design of Velocity Transformers in Ultrasonic Machining
Published in Satya Bir Singh, Prabhat Ranjan, Alexander V. Vakhrushev, A. K. Haghi, Mechatronic Systems Design and Solid Materials, 2021
V. Dhinakaran, Jitendra Kumar Katiyar, T. Jagadeesha
In ultrasonic machining, a tool made of ductile and tough material and of the desired shape vibrates at ultrasonic frequency (19 to 25 kHz) with an amplitude of 15–50 microns over the workpiece. Generally, the tool is pressed down with a feed force F. Between the tool and work, the machining zone is flooded with hard abrasive particles generally in the form of a water-based slurry. As the tool vibrates over the workpiece, abrasive particles act as indenter and indent both work and tool material. Abrasive particles, as they indent, the work material would remove the material from both the tool and workpiece. In ultrasonic machining, material removal is due to crack initiation, propagation, and brittle fracture of the material. USM is used for machining hard and brittle materials, which are poor conductors of electricity and thus cannot be processed by electro-chemical machining (ECM) or electro-discharge machining (EDM).
Mechanical Energy-based Machining Processes
Published in Zainul Huda, Machining Processes and Machines, 2020
USM Process.Ultrasonic machining (USM), also called ultrasonic vibration machining, is a mechanical-energy-based non-traditional material removal process that involves the erosion of holes or cavities on a hard or brittle workpiece by using shaped tools, high-frequency mechanical vibration, and an abrasive slurry. In USM, a low-frequency electrical signal is applied to a transducer which converts the electrical energy into high-frequency mechanical vibration with a frequency in the range of 20–40 kHz. This high-frequency mechanical energy is then transmitted to a horn-and-tool assembly, which results in a unidirectional vibration of the tool at the ultrasonic frequency with a known amplitude in the range of 15–50 μm (see Figure 14.1a). A constant stream of abrasive slurry is also passed between the tool and workpiece. The abrasive hard particles in slurry are accelerated toward the surface of the workpiece by a tool oscillating at a frequency up to 40 kHz through repeated abrasions; the tool machines a cavity of a cross-section identical to its own (Figure 14.1b).
Engineering Problem Optimized Using Genetic Algorithm
Published in Kaushik Kumar, Divya Zindani, J. Paulo Davim, Optimizing Engineering Problems through Heuristic Techniques, 2020
Kaushik Kumar, Divya Zindani, J. Paulo Davim
The working of ultrasonic machining process involves the conversion of higher frequency electrical energy to mechanical vibrations. The conversion takes place via transducer/booster combination. The converted energy is transmitted to energy focusing as well as amplifying device: horn/tool assembly. Vibration of the tool takes place at ultrasonic frequency with an amplitude ranging 12–50 μm. A feed force is required to press the tool. The machining zone is flooded with the abrasive slurry that is generally in the form of water-based slurry. The tool material vibrates over the workpiece and the indenting operation is performed by the abrasive particles that indents the workpiece material. Material removal process is therefore achieved through the crack initiation and propagation mechanism as a result of brittle fracture. The power rating ranges 100–1,000 W. Abrasive slurry in the form of silicon carbide, aluminum oxide and boron carbide suspended in certain medium is pumped in the gap between the tool and the workpiece material. The tool is pushed on the workpiece with some static load. The abrasive particles are continuously indented by the hammer with the kinetic energy imparted by the vibrating tool. Continuous flushing of the abrasive slurry, refreshes the abrasive particles in the machining zone and at the same time also removes the debris from the machining area.
Development of cutting force prediction model for carbon fiber reinforced polymers based on rotary ultrasonic slot milling
Published in Machining Science and Technology, 2018
Muhammad Amin, Songmei Yuan, Muhammad Zubair Khan, Chong Zhang, Qi Wu
In the last two decades, various machining processes (cutting, grinding, drilling, milling, etc.) have been developed and also applied for composite materials (Sheikh-Ahmad, 2009; Kalla et al., 2010; Chen et al., 2011; Liu, et al., 2012). However, with the development of advanced composite materials like polymer matrix composites (PMC), ceramic matrix composites (CMC) and metal matrix composites (MMC), the conventional machining processes have not shown adequate results (Groover, 2010). Later, some nontraditional machining processes have been developed like abrasive water jet machining, electric discharge machining, ultrasonic machining, vibration-assisted machining, and rotary ultrasonic machining (RUM) that have shown the improved results for such materials (Lau et al., 1990; Pei et al., 1995; Xu et al., 2014; Yuan et al., 2015; Alberadi et al., 2016). The ultrasonic energy was applied for the first time in a material removal process in 1927 by Wood and Loomis and the static ultrasonic machining was carried out for the machining of materials with hardness greater than 40 HRC (Thoe et al., 1998; Singh and Singhal, 2016). The lower material removal rates (MRR) and some geometrical errors (due to the loose abrasive particles in a slurry) have been reported for ultrasonic machining process (Gilmore, 1991; Halm and Schulz, 1993; Kataria et al., 2016). The ultrasonic-assisted grinding was carried out with smaller cutting depths (e.g., 0.1, 1.0 and 30 µm), and lower cutting forces (along with better surface integrity) were investigated (Denkena et al., 2008; Lauwers et al., 2010). However, the machining process can be carried out with increased cutting depths and higher MRR through RUM.
A review on the conventional, non-conventional, and hybrid micromachining of glass
Published in Machining Science and Technology, 2019
Muhammad Pervej Jahan, Asma Perveen, Ann M. Rumsey
Ultrasonic machining (USM) is widely used in industries for micromachining of hard and brittle materials irrespective of its conductivity. Being a non-thermal and non-chemical process, USM offers very little changes in microstructure of machined surface. In USM, removal of materials takes place by the abrasive grit suspended in the slurry due to the vibrating effect of tool that excites the abrasive against the workpieces. This process of material removal is done due to the impact action of abrasive against workpiece surface as well as the cavitation induced due to the ultrasonic vibration of the tool in the fluid (Kainth et al., 1979). The direct hammering may contribute up to 80% of material removal for brittle material like glass. Another minor mechanism known as cavitation effect originated from abrasive slurry and chemical action of slurry is responsible for rest of the material removal (Shaw, 1956). Soundararajan and Radhakrishnan (1986) also investigated with the help of mild steel tool with boron carbide abrasive on material removal mechanism of high-speed steel, WC, and glass plate, and concluded that removal is mostly due to the hammering. Kainth et al. (1979) investigated on mechanics of material removal which considered direct impact of abrasive on workpiece as well as probabilistic distribution of abrasive diameter. They validated their model against glass materials and mild steel. At the end of the process, workpiece produces reverse shape of the tool. Tool material is usually chosen to be ductile in order to reduce the tool wear (Kremer, 1995). Due to the presence of abrasive in-between tool wall and workpiece wall, overcut is the usual phenomenon of USM, which is the function of abrasive size. On top of that, surface finish and material removal rate are also affected by the abrasive size (Komaraiah and Reddy, 1993).
A comparative assessment of micro drilling in boron carbide using ultrasonic machining
Published in Materials and Manufacturing Processes, 2020
Ahmad Haashir, Tapas Debnath, Promod Kumar Patowari
The world is changing due to the promising technological advances. This has led to the increased demand for miniaturized components and devices which has further realized the need for ultra-precision machining and micro-fabrication techniques. Ultrasonic machining (USM) is a non-chemical, non-thermal and non-electrical machining process utilized for machining of hard and brittle materials such as ceramics, carbides, and composites. The minimal metallurgical and physical changes in work material make it a unique technique for precision machining applications.