6.17b. 4. • The rate of material removal, in USM, depends, on the frequency of tool vibration, static pressure, the size of the machined area, and the abrasive and workpiece material. Relation (6.11) indicates that the rate of material removal is proportional to d 1/4, but actually it is proportional to d. This discrepancy between the theoretical prediction and the observed fact was explained by Shaw as follows. Electric Discharge Machining (EDM) has metal removal rate of about 10-20 mm 3 /s. Ultrasonic Machining USM Process Parameters and Factors Affecting Ultrasonic Machining Rate, Working of ultrasonic machining equipment, USM applications, advantages and limitations, Types of Pattern Material - Application, Advantages And Limitation, 3-2-1 Principle of Location (Six Point Principle) Degree Of Freedom Controlled By 3-2-1 Location Principle - With Image, Different Types of Cutting Tools Materials and Their Properties, Basic Components of IC Engine and Their Function, Design and Working Principle of Simple Carburetor. The characteristic of variation of Δt, given by –. To avoid this, the work piece made of a brittle material is fastened to a base usually made of glass. a) 25% b) 50% c) 75% d) 100% View Answer. 4. 7. (iv) The chemical action associated with the fluid used. 6.18a. Figure 6.9 shows the indentation caused by such an impact at an instant of time. Cutting speed may or may not be a factor given to you by the toolmaker, it will depend on the material of the tool and the material of the part to be machined. Disclaimer 8. ____ can be used as abrasive carrying medium. In Ultrasonic Machining (USM) the material removal rate would (a) increase (b) decrease (c) increase and then decrease (d) decrease and then increase with increasing mean grain diameter of the abrasive material. Let us now consider the impact of a rigid, spherical abrasive grain of diameter don the work surface. The tool travels vertically or orthogonal to the surface of the part at amplitudes of 0.05 to 0.125 mm (0.002 to 0.005 in. 6.17a. Thus, a further increase in the concentration does not help. In USM dominant in material removal is ____. The basic USM process involves a tool (made of a ductile and tough material) vibrating with a very high frequency and a continuous flow of an abrasive slurry in the small gap between the tool and the work surface. In USM process, the mechanism of material removal can be described as the effect of the impact indentation and fracture phenomena. (ii) The impact of the free abrasive particles on the work surface. The machining time can be controlled easily because the process is stable when a suitable feed rate is selected 14.3 Abrasive Micromachining 14.3.1 Microgrinding Diamond microgrinding at the ductile mode is used for machining of brittle materials such as ceramics using a grinding wheel speed of 30-60 m/s, workpiece speed of 0.1-1.0 m/min. Comparing the values of hw and h’w under normal conditions, we see that h’w is very small as compared with hw, and so it can be concluded that most of the material is removed by the directly impacting abrasive grains. If the distance travelled by the tool from the position A to the position B is h (the total indentation), then-, Since the flow stress σ and the Brinell hardness H are the same, equations (6.6) and (6.7) yield –. Material Removal Rate 15. 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