This machining uses ultrasonic waves to produce high frequency force of low amplitude, which act as driving force of abrasive. In USM process, the tool, made of softer material than that of the workpiece, is oscillated by the Booster and Sonotrode at a frequency of about 20 kHz with an amplitude of about 25.4 um (0.001 in). Description: Ultrasonic drilling is a non-traditional, loose abrasive machining process.In this the mirror image of a shaped tool can be created in hard, brittle materials. Process: Ultrasonic machining is a mechanical type non-traditional machining process. • Dynamic impacts of particles on the target increase the average erosion rate. In this work, cavitation refers to the formation, growth and collapse of inertial cavitation bubbles. Diamond and rubies are cut by diamond powder. A comparative assessment of machining of B 4 C with that of glass and brass has also been carried out by drilling microholes using USM. With a decrease in power rating an improvement in surface finish was observed as shown in Figure 2. Ultrasonic Homogenization is a technique of dispersions processing, which utilizes ultrasonic waves for homogeneous distribution of the dispersed phase by the following actions: reducing the sizes of the dispersed particles/droplets (breaking); disintegrating the dispersed particles agglomerates; blending the dispersed phase in the liquid. They are important because Introduction They can be used on all types of materials ranging from soft metals to hardened steels and hard nonmetallic materials such as ceramics and silicon. When very frequency vibrations are applied on to the tool, the tool is vibrating at a very high frequency. • USM M = Ultrasonic micro machining 1. The amplitude of vibration 0.0005 - 0.002” (13 – 50 μm). The amplitude of vibration 0.0005 - 0.002” (13 – 50 μm). Ultrasonic machining (UM) of ceramics is the machining method using the action of a slurry containing abrasive particles flowing between the workpiece and a tool vibrating at an ultrasonic frequency. Keywords: Ultrasonic machining,direct impact,abrasive grains,material re-moval rate. The shape and the dimensions of the workpiece depend on those of the tool. Fluidic modeling is performed to study interaction among the vibrating micro-tool tip, workpiece, and the slurry. Micro-cavitation. Abrasive waterjet (AWJ) micro-machining is a precision processing technology with some distinct advantages. The use of abrasives to shape parts is probably the oldest material removal process. However, as the process goes on, abrasive particles will be driven out of the machining area owing to the ultrasonic vibration of the micro-tool or work-piece and the … It is found that three types of impressions are formed which are craters, micro-dents and scratches. Chapter 2 Ultrasonic Machining: A Total Mechanical Machining Technology Using Loose Abrasive Particles Jingsi Wang Additional information is available at the end of the chapter Ultrasonic Micro-Drilling With Abrasive Slurry Cavitation . • It contributes to relatively uniform distribution of erosion area on the target. Alumina wears out very fast and loses its cutting power very fast. Answer: b Explanation: During ultrasonic machining, as the tool vibrates over the workpiece, the abrasive particles act as the indenters and indent both the work material and the tool. Cavitation erosion is one of the material removal mechanisms involved in ultrasonic machining (USM). Silicon finds maximum applications. Ultrasonic machining is able to effectively machine all materials harder than HRc 40, whether or not the material is an electrical conductor or an insulator[2]. Principle of Micro ultrasonic Machining Water is used as the slurry medium due to its good property for transferring ultrasonic wave. When a high frequency sinusoidal ultrasonic pressure wave is induced in a liquid medium, cavitation occurs. ). 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. The unit removal (UR) which is defined as the part of a work piece removed during one cycle of removal action, can be realized in MUSM when the submicron particles are available for use as abrasive. Patil et al. Ultrasonic machining (UM) of ceramics. Alumina is used for machining ceramics, glass and germanium. This process makes use of an abrasive jet with high velocity, to remove material and provide smooth surface finish to hard metallic work pieces. Material removal is by 3 mechanisms: Hammering of grit against the surface by the tool. processes, such as ultrasonic machining [11] and scale deposit removal [12]. Principle of Machining In the process of Ultrasonic Machining, material is removed by micro-chipping or erosion with abrasive particles. Material removal is achieved by the direct and indirect hammering of abrasive particles against a workpiece. The tool that is vibrated at ultrasonic frequency drives the abrasive to create a brittle breakage on the workpiece surface. The required UR for micro-ultrasonic machining (USM) can be realized by using submicron abrasive particles and microtools that are manufactured by micro-EDM. The first experiment was conducted on a grade 5 Ti-64 alloy using a 40kHz ultrasonic set up and two material removal mechanisms were identified under pure cavitation condition. Ultrasonic machining process schematic. Ultrasonic Machining In ultrasonic machining, a tool of desired shape vibrates at an ultrasonic frequency (19 ~ 25 kHz) with an amplitude of around 15 – 50 μm over the workpiece. The vibration frequency is 19 ~ 25 kHz. In case of brittle materials, the material is removed by crack initiation. 13 In this process a spiral rod was rotated inside the workpiece through a specially … Boron silica carbide is also used, and it is 8–12% more abrasive than boron carbide. The machining rate is reduced by keeping the micro-tool tip at a fixed distance from the workpiece and vibrating it at a small amplitude. Material removal is achieved by the direct and indirect hammering of abrasive particles against a workpiece by means of an ultrasonically vibrating tool. CFD-based erosion model in abrasive slurry jet micro-machining is presented. One such technique is ultrasonic machining (USM), in which a tool and free abrasive particles are utilized to remove material from the workpiece. In order to enhance the performance of the process, the travelling velocity of abrasive particles was increased by a combination of centrifugal force-assisted abrasive flow machining (CFAAFM) and DBG-AFF to form a new hybrid AFM process known as spiral flow-assisted AFM (SFAAFM). In the early stage of machining, abrasive particles are distributed uniformly in the machining area. This has been done by conducting a series of experiments with both machining fluid with and without micro abrasive particles. The tool, which is a negative of the workpiece, is vibrated at around 20KHz with and amplitude of between 0.013mm and 0.1mm in abrasive slurry at the workpiece surface. Ultrasonic machining is a low material removal rate (MRR), loose abrasive machining process in which the mirror image of a shaped tool can be created in hard, brittle materials. To understand the machining process, the erosion mechanism is presented and discussed when micro-particle impacting on a quartz crystal specimen. There is no direct contact between the tool and workpiece during the process. Ultrasonic machining of ceramics . The motion of the tool takes place vertically or orthogonal to the surface of the part. Impact of free abrasive grit particles (erosion). Ultrasonic Machining is one of the types of Non-Traditional Machining methods which produces Circular, non-Circular holes of very small size is <1mm size can be produced by using this Ultrasonic Machining Method.. This energy induces greater damage by indenting inside the workpiece and forming larg e sized craters. Ultrasonic machine generates high frequency vibrating wave of frequency about 20000 to 30000 Hz and amplitude about 25-50 micron. Abrasive machining involves material removal by the action of hard, abrasive particles. 17. In addition, no surface or subsurface thermal damage is induced into the machined feature. The vibration frequency is 19 ~ 25 kHz. Surface of the work piece is cleaned automatically in this process with water as medium. In order to fabricate micro shapes, micro tools are needed. Ultrasonic Machining Process description. Abrasive Water Jet Machining is an unconventional machining process used to remove unwanted material from a given work piece. Ultrasonic machining, or strictly speaking the "", is a subtraction manufacturing process that removes material from the surface of a part through high frequency, low amplitude vibrations of a tool against the material surface in the presence of fine abrasive particles.