Non-conventional Machining: ULTRASONIC MACHINING BY T.ROHITH KUMAR Roll.NO. B14ME031

Department of Mechanical EngineeringKAKATIYA INSTITUTE OF TECHNOLOGY AND SCIENCE(Autonomous Institute under Kakatiya University, Warangal)

ULTRASONIC MACHINING

Presented By T. ROHITH KUMAR Roll. No. B14ME031 III YR ME-1

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ULTRASONIC MACHINING

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INTRODUCTION

Manufacturing industries like aviation, nuclear, missile, tool and die making now use newly developed hard and difficult-to-machine materials demanding high precision and surface finish. Difficulty in simultaneously achieving high degree of precision and surface finish in the traditional methods of machining has led to the development of some new machining techniques.Material removal processes can be divided into two groups: a. Conventional Machining Processes b. Unconventional Machining processes3

CLASSIFICATION OF NON-CONVENTIONAL MACHINING PROCESSES:

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NEED FOR UNCONVENTIONAL MACHINING PROCESS:

The main reason for using unconventional machining process are :To machine high strength alloys eg., Inconel, Titanium alloys, etc.To produce complex surfaces.To achieve high accuracies and surface finish.Machining of composites.Deep hole with small hole diameter. Difficult to machine material.

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ULTRASONIC MACHINING PROCESS:

Ultrasonic machining is a non-traditional machining process, grouped under the mechanical group NTM processes. USM is mechanical material removal process used to erode holes or cavities on hard or brittle work piece by using shaped tools, high frequency mechanical motion and an abrasive slurry. 6

PRINCIPLEThe time spent onultrasonic machineentirely depends on the frequency of the vibrating tool, size of grains of the abrasive slurry, the rigidity and the viscosity as well. The shaped tool under the actions of mechanical vibration causes the abrasive particles dipped in slurry to be hammered on the stationary workpiece. This causes micro-indentation fracture on the material.7

WORKING

Schematic representation of Ultrasonic machining process

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Continue

Schematic representation of material removal mechanism

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EQUIPMENTUltrasonic Machining consists of: Power supplyTransducer a. Piezoelectric Transducer: b. Magneto-strictive Transducer Tool Holder Amplifying tool holders, copper washersTool HornAbrasive slurryWork piece Different Horns used in USM

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PROCESS PARAMETERSAmplitude of vibration (15 to 50 m) Frequency of vibration (19 to 25 kHz) Feed force (F) related to tool dimensions Abrasive size and Abrasive material: Al203, SiC, B4C, DiamondSlurry Contact area of the tool Volume concentration of abrasive in water slurry Work material

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PROCESS CAPABILITIESCan Machine work piece harder than 40 HRC to 60 HRC like carbides, ceramics, glass that cannot be machined by conventional methods. Tolerance range 7 micron to 25 microns. Holes up to 76 micron have been drilled.Hole depth of 152mm deep is achieved by special flushing techniques. Linear material removal rate: 0.025 to 25mm/min. Surface finish: 0.25 micron to 0.75 micron.

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ADVANTAGESUSM effectively machines precise features in hard, brittle materials such as glass, engineered ceramics, quartz, etc. Produces fine finished and structured results.Unlike conventional machining methods, ultrasonic machining produces no heat affected zone.Ultrasonic machining does not thermally damage the workpiece or appear to introduce significant levels of residual stress, which is important for the survival of brittle materials in service.Can drill circular or non circular holes on hard materials.

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DISADVANTAGES

High tooling cost.Low material removal rate.High power consumption.The initial equipment cost is higher than conventional machine tools.It is difficult to machine softer materials.It is difficult to drill deep holes, as slurry movement is restricted.

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APPLICATIONSUsed for machining hard, brittle materials like glass, ceramics, carbides, diamond, etc. Used in machining of dies for wire drawing, punching and blanking operations. USM enables a dentist to drill a hole of any shape on teeth without any pain.USM can be used to cut industrial diamonds.USM is used for grinding Quartz, Glass, ceramics. Coining and engraving applications.

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CONCLUSIONUltrasonic machining (USM) is of particular interest for the machining of conductive, non-conductive, brittle materials such as engineering ceramics. USM process is purely depends on the work material properties mainly hardness and fracture toughness, tool properties, abrasive properties and process settings.The machining of materials such as Glass, super alloys, ceramics, Tungsten carbide etc. to their final dimension by conventional methods is extremely tough and generally not possible. To overcome such kind of problems USM can be utilized. 17

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