Conventional machining uses tools, such as lathes, milling machines, boring machines, drill presses, or others, with a sharp cutting tool to remove material to achieve the desired geometry. In sequential combination of micro-EDM and EMM, the micro-EDM is used as a shaping process, whereas, the same μEDM process is used as a finishing process in sequential combination of laser and micro-EDM. 7.30. The machined surface integrity and surface quality that are significantly distinct from conventional machining due to the shallow depth of cut and high cutting speed are employed in HSM, which results in the elimination of BUE formation, burr-free edges, stress-free components, and extremely good surface finish. In this case, a high cutting speed results in small kerf width and the amount of assisting gas passing through the kerf lessens which, in turn, prevents the suppression of the high-temperature oxidation reaction in the region close to the kerf exit. It is especially more indispensable for machining the parts without rotational symmetry. b) milling It should be noted that in the mathematical model, a uniform thermal conductivity is assumed in the substrate material. 6.13). Drilling was also investigated by Lin, Lin, and Chen (2000). For milling, coated carbide inserts were used and once again a shorter tool life in comparison to milling conventional metals was observed. Furthermore, high ductility of NiTi is responsible for large exit burrs. Bekir Sami Yilbas, in The Laser Cutting Process, 2018. Burrs, as a result of the high ductility of NiTi alloys, are reduced when an emulsion is used in comparison to dry cutting. Micro turning followed by micro-EDM. In the non-conventional process, this is not the case. The laser beam machining generates surface with high speed, but being a thermal process, it forms recast layer which is piled up surrounding the cut area, as shown in Fig. Weinert and Petzoldt (2004) also discuss the effect of cutting fluids on chip breaking and the formation of burrs. The observation of the drilled surface morphology reveals numerous wavy tracks that are the result of the action of a blunt tool, adhesion and abrasive deformation which lead to vibration and damage of the twist drill. a) conventional machining Figure 7.37 shows the comparison of machining time taken when the EMM and micro-EDM processes applied independently and sequentially [106]. Whereas, moderate surface integrity and quality have been found in conventional machining because of high depth of cut, moderate cutting speed, heat affected zone, BUE, and burr formation. Therefore, nonuniform structure of the fibers in the substrate material (un-woven fabric) results in nonuniform thermal conductivity in the substrate material at high cutting speeds. The cutting mechanism of HSM differs from conventional machining due to the thermal softening effect of workpiece over work’s strain hardening. This means that transparent glass can only be machined either by CO2, UV lasers, or ultrashort lasers. Machining of the MEDM tool took place on the OMAX type 2652A/20HP abrasive water jet cutting system powered by a Böhler Ecotron 403 hydraulic intensifier capable of reaching water pressures up to 410 MPa. Fig. Other investigations propose cryogenic cooling as being advantageous in comparison to dry and minimum quantity lubrication conditions regarding tool wear and surface quality (Kaynak, Karaca, Noebe, & Jawahir, 2013; Kaynak, Tobe, Noebe, Karaca, & Jawahir, 2014). Kevlar is a material that burns at high temperatures. a) true 3D models developed for DMLS. This combination is useful in milling where maximum material is removed by EMM process initially. From the machining point of view, most of the material from the part to be generated is removed by laser ablation process. Conventional machining is very limited in producing molding components with contouring channels. (A) Using conventional machining technologies—from left to right: the cavity, the core, the mold with the plastic part in blue and (B) Using AM technologies—from left to right: the exterior of the cavity, the bottom of the core, and the mold with the plastic part in blue. Micro-EDM plus EMM sequential machining process. It was found that direct laser etching when material resides at focal point produces rough channel surfaces and may not be suitable for many applications. 7.35 depicts the sequencing operation procedure. This means that only 2.5 D tools for MEDM can be produced with this technology. On the other hand, the round/spherical end shape can be used to fabricate microholes or structures with minor taper. b) 3 View Answer, 7. Whereas, the conventional cutting of ductile material results in the formation of continuous chips [16,17]. c) none of the mentioned Figure 21 shows the central part of the machined work surface for flat-end and round-end tools. Which of the following is conventional machining process? CNC machining is a manufacturing process that is suitable for a wide range of applications and industries such as military, aerospace, agricultural, automotive and more. Fig. Some of the most commonly used tool materials are platinum, tungsten, titanium, stainless steel, and molybdenum. The sequential combination of EMM and micro-EDM for milling the cavity by die sinking and formation of groove is also implemented successfully. 7.32. The micro tool manufactured by micro-EDM process has rough surface due to the formation of micro craters. © 2011-2020 Sanfoundry. Fig. Fig. Very small space is required to set up ECM process To avoid premature failure of the tool, low cutting speeds, proper tool materials, and cutting fluids are required (Ezugwu & Wang, 1997). What Are CNC Machines? WJ machining is a non-conventional machining process in which a high-speed jet of water is used as the tool to remove the workpiece material by erosion. However, as the drilled channels are straight and incapable to contour the molding surface uniformly, for the same mold volume, the number of channels is lower due to the geometrical constraints and so some degradation in the cooling performance is expected. d) none of the mentioned Whereas, the cutting forces are notably higher in conventional machining. VBm follows a 3D construction process in which metallic plates are joining by brazing in a vacuum furnace. d) rolling d) both surface finishing and metal removal This is because of the ability to produce many types of products and parts. 4.3), which are processed to create “build paths” that reproduce the models through the consolidation of powder material, layer by layer, by means of an energy source. Increase of feed rate leads to increase in surface roughness, however, very small feed rate presents high surface roughness. Bijoy Bhattacharyya, in Electrochemical Micromachining for Nanofabrication, MEMS and Nanotechnology, 2015. View Answer. Voltage and current waveforms of five basic EDM gap states. View Answer, 11. Some studies pertain to the production of microparts by micromilling (Piquard, D’Acunto, Laheurte, & Dudzinski, 2014; Weinert & Petzoldt, 2008). S.S. Joshi, D. Marla, in Comprehensive Materials Processing, 2014. The whole set of plates is then assembled and introduced into a vacuum furnace, where it is heated, keeping a uniform temperature, in a controlled atmosphere. Fig. Burrs are also favored with small feed rates, which should also be avoided due to high tool wear. View Answer, 9. It takes only a few minutes to fabricate microfluidic chip (Fu, Ju, Yang, & Wang, 2012). The methodology applied for machining is rough cutting by pulsed laser beam and then finishing precisely by micro-EDM process. 6.12). c) buffing Similarities between conventional machining and NTM. c) tumbling Because the material goes through rapid temperature cycles and steep temperature gradients occur between the successive layers, a heat treatment should be performed afterwards to reduce the thermal tensile stresses [31]. INTRODUCTION:Manufacturing processes can be broadly divided into two groups and they are primarymanufacturing processes and secondary manufacturing processes. Which of the following is not the type of nontraditional machining? The following are the characteristic of a NON-CONVENTIONAL machining, EXCEPT..... Chapter 7 Non Conventional Machining DRAFT. Abrasive Water Jet Machining. To generate an effective WJ, a specially designed nozzle with an orifice made in a sapphire insert is used. Poor chip breaking in NiTi machining results in long continuous chip which in turn results in tool wear and is not affected by the use of cutting fluids; chip breaking is noticed only in low cutting speeds where tool wear is excessive. In the Electron Beam Machining process, a high velocity focused beam of electrons are used to remove the metal from the workpiece. a) true c) mechanical energy process The traditional mechanical machining has a long history, it has played a great role in human production and material civilization. Nickel-based alloys also present high strength and are considered hard-to-machine. The final finishing and geometric accuracy of micropart is then obtained by subsequent application of controlled micro-EDM process. Various online gap control strategies can be developed to monitor and control the above mentioned discharge states. d) none of the mentioned Furthermore, it is argued that the use of coated instead of uncoated cemented carbide tools exhibits no advantage in the case of drilling. 4.1.15 shows voltage and current waveforms of the five discharge states, e.g., (i) Open circuit, (ii) Normal discharge, (iii) Transient arcing, (iv) Harmful Arcing and (v) Short circuit. Bijoy Bhattacharyya, Biswanath Doloi, in Modern Machining Technology, 2020. Which of the following is a conventional process of machining? Ignition delay is also an important indicator to maintain the stability of machining under above mentioned situations. d) 5 b) some of the material is wasted The tool follows programmed path and moves in downward direction after completion of each layer. 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