Unconventional Machining Process
A Course Material onUnconventional machining processByMr. M.MANIKANDAN, M.E.ASSISTANT PROFESSORDEPARTMENT OF MECHANICAL ENGINEERINGSASURIE COLLEGE OF ENGINEERINGVIJAYAMANGALAM – 638 056
QUALITY CERTIFICATEThis is to certify that the e-course materialSubject CodeSubjectClass: ME2026: Unconventional machining process: III Year MECH A & Bbeing prepared by me and it meets the knowledge requirement of the university curriculum.Signature of the AuthorName: M.MANIKANDAN.M.EDesignation: Assistant professorThis is to certify that the course material being prepared by Mr.M.Manikandan is of adequate quality.He has referred more than five books among them minimum one is from abroad author.Signature of HDName: E.R.SIVAKUMAR.M.E (PhD)SEAL
CONTENTChapterTopicPage no.UNIT I INTRODUCTION1.1Introduction11.1.1The Major Characteristics Of ConventionalMachining11.1.2Material Removal Processes21.2Need For Unconventional Machining Processes21.3Classification Of UCM Processes21.4Brief Overview3UNIT II MECHANICAL ENERGY BASED PROCESSES2.1Abrasive Jet Machining82.1.1Process Parameters and MachiningCharacteristics102.1.2Modeling of material removal102.1.3Modeling has been done with the followingassumptions102.2Water Jet Machining112.3Abrasive Water-Jet Machining122.4Ultrasonic Machining15UNITIII ELECTRICAL BASED PROCESSES3.1Electrical Discharge Machining (EDM)213.1.1Application Of EDM223.1.2Working Principle Of EDM23
ChapterTopicPage no.3.1.3Limitations Of EDM233.1.4Dielectric Fluids243.1.5Design Considerations For EDM Process243.2Wire Cut Electrical Discharge Machining24UNIT-IV CHEMICAL AND ELECTRO CHEMICAL ENERGY BASEDPROCESSES4.1Chemical Machining304.2Chemical Milling314.3Electrochemical Machining324.4Electrochemical Honing344.5Electrochemical Grinding344.5.1Surface Finishes Can Be Achieved WithElectrochemical Grinding364.5.2Materials Can Be Cut With Electrochemical Grinding374.5.3Advantages Of Electrochemical Grinding375.1UNIT-V THERMAL ENERGY BASED PROCESSESLaser–Beam Machining415.1.1Applications425.2Laser beam cutting (milling)425.3Electron Beam Machining435.4Plasma Arc Machining455.5Plasma Arc Welding465.6Plasma Arc Machining48
ME2026 UNCONVENTIONAL MACHINING PROCESSES(COMMON TO MECHANICAL AND PRODUCTION)LTPC3003OBJECTIVE:To learn about various unconventional machining processes, the various processparameters and their influence on performance and their applicationsUNIT I INTRODUCTIONUnconventional machining Process – Need – classification – Brief overview.5UNIT II MECHANICAL ENERGY BASED PROCESSES10Abrasive Jet Machining – Water Jet Machining – Abrasive Water Jet Machining UltrasonicMachining. (AJM, WJM, AWJM and USM). Working Principles – equipment used –Process parameters – MRR-Variation in techniques used – Applications.UNIT III ELECTRICAL ENERGY BASED PROCESSES8Electric Discharge Machining (EDM)- working Principle-equipments-Process ParametersSurface Finish and MRR- electrode / Tool – Power and control Circuits-Tool Wear –Dielectric –Flushing – Wire cut EDM – Applications.UNIT IV CHEMICAL AND ELECTRO-CHEMICAL ENERGY BASED PROCESSES 12Chemical machining and Electro-Chemical machining (CHM and ECM)-Etchantsmaskanttechniques of applying maskants-Process Parameters – Surface finish and MRRApplications. Principles of ECM-equipments-Surface Roughness and MRR-Electricalcircuit- Process Parameters-ECG and ECH - Applications.UNIT V THERMAL ENERGY BASED PROCESSES10Laser Beam machining and drilling (LBM), plasma arc machining (PAM) and ElectronBeam Machining (EBM). Principles – Equipment –Types - Beam control techniques –Applications.Total: 45OUTCOMES: Upon completion of this course, the students can able to demonstrate differentunconventional machining processes and know the influence of difference processparameters on the performance and their applications.TEXT BOOKS:1.Vijay.K. Jain “Advanced Machining Processes” Allied Publishers Pvt. Ltd., New Delhi, 20072.Pandey P.C. and Shan H.S. “Modern Machining Processes” Tata McGraw-Hill, NewDelhi,2007.REFERENCES:1.Benedict. G.F. “Nontraditional Manufacturing Processes”, Marcel Dekker Inc., NewYork,1987.2.Mc Geough, “Advanced Methods of Machining”, Chapman and Hall, London, 1998.3.Paul De Garmo, J.T.Black, and Ronald.A.Kohser, “Material and Processes inManufacturing Prentice Hall of India Pvt. Ltd., 8thEdition, New Delhi , 2001.
ME2026UNCONVENTIONAL MACHINING PROCESSUNIT I INTRODUCTION1.1 INTRODUCTIONUnconventional manufacturing processes is defined as a group of processes that removeexcess material by various techniques involving mechanical, thermal, electrical or chemical energyor combinations of these energies but do not use a sharp cutting tools as it needs to be used fortraditional manufacturing processes.Extremely hard and brittle materials are difficult to machine by traditional machiningprocesses such as turning, drilling, shaping and milling. Nontraditional machining processes, alsocalled advanced manufacturing processes, are employed where traditional machining processes arenot feasible, satisfactory or economical due to special reasons as outlined below. Very hard fragile materials difficult to clamp for traditional machining When the work piece is too flexible or slender When the shape of the part is too complexSeveral types of non-traditional machining processes have been developed to meet extrarequired machining conditions. When these processes are employed properly, they offer manyadvantages over non-traditional machining processes. The common non- traditional machiningprocesses are described in this section.Manufacturing processes can be broadly divided into two groups)a) Primary manufacturing processes: Provide basic shape and sizeb) Secondary manufacturing processes: Provide final shape and size with tighter control ondimension, surface characteristicsMaterial Removal Processes Once Again Can Be Divided Into Two Groups1. Conventional Machining Processes2. Non-Traditional Manufacturing Processes or Unconventional Machining processesConventional Machining Processes mostly remove material in the form of chips by applyingforces on the work material with a wedge shaped cutting tool that is harder than the work materialunder machining condition.SCE1Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESS1.1.2 THE MAJOR CHARACTERISTICS OF CONVENTIONAL MACHINING ARE: Generally macroscopic chip formation by shear deformation Material removal takes place due to application of cutting forces – energy domain can beClassified as mechanical Cutting tool is harder than work piece at room temperature as well as under machiningConditionsNon-conventional manufacturing processes is defined as a group of processes that removeexcess material by various techniques involving mechanical, thermal, electrical or chemical energyor combinations of these energies but do not use a sharp cutting tools as it needs to be used fortraditional manufacturing processes. Material removal may occur with chip formation or even nochip formation may take place. For example in AJM, chips are of microscopic size and in case ofElectrochemical machining material removal occurs due to electrochemical dissolution at atomiclevel.1.2. NEED FOR UNCONVENTIONAL MACHINING PROCESSES Extremely hard and brittle materials or Difficult to machine material are difficult toMachine by traditional machining processes. When the work piece is too flexible or slender to support the cutting or grindingForces when the shape of the part is too complex.1.3. CLASSIFICATION OF UCM PROCESSES:1. Mechanical Processes Abrasive Jet Machining (AJM) Abrasive Water Jet Machining (AWJM) Water Jet Machining (WJM) Ultrasonic Machining (USM)SCE2Department of Mechanical Engineering
ME20262. Electrochemical Processes Electrochemical Machining (ECM) Electro Chemical Grinding (ECG) Electro Jet Drilling (EJD)UNCONVENTIONAL MACHINING PROCESS3. Electro-Thermal Processes Electro-discharge machining (EDM) Laser Jet Machining (LJM) Electron Beam Machining (EBM)4. Chemical Processes Chemical Milling (CHM) Photochemical Milling (PCM)1.4. BRIEF OVERVIEW1 ULTRA SONIC MACHININGUSM is a mechanical material removal process in which the material is removed byrepetitive impact of abrasive particles carried in liquid medium on to the work surface, by ashaped tool, vibrating at ultrasonic frequency.2 ABRASIVE JET MACHININGIt is the material removal process where the material is removed or machined by theimpact erosion of the high velocity stream of air or gas and abrasive mixture, which is focusedon to the work piece.3. LASER BEAM MACHININGLaser-beam machining is a thermal material-removal process that utilizes a high- Energy,Coherent light beam to melt and vaporize particles on the surface of metallic and non- Metallic workpieces. Lasers can be used to cut, drill, weld and mark. LBM is particularly suitable for makingaccurately placed holesSCE3Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESS4. ELECTRON EAM MACHININGIt is the thermo-electrical material removal process on which the material isremoved by the high velocity electron beam emitted from the tungsten filament made toimpinge on the work surface, where kinetic energy of the beam is transferred to the workpiece material, producing intense heat, which makes the material to melt or vaporize itlocally.5. ELECTRO CHEMICAL MACHININGIt is the controlled removal of metals by the anodic dissolution in an electrolytic medium, wherethe work piece (anode) and the tool (cathode) are connected to the electrolytic circuit, which is kept,immersed in the electrolytic medium6. ELECTO CHEMICAL GRINDINGECG is the material removal process in which the material is removed by the combination ofElectro- Chemical decomposition as in ECM process and abrasive due to grinding.7. PLASMA ARC MACHININGPlasma is defined as the gas, which has been heated to a sufficiently high temperature toBecome ionized.8. WATER JET MACHININGWater jet cutting can reduce the costs and speed up the processes by eliminating or reducingexpensive secondary machining process. Since no heat is applied on the materials, cut edges are cleanwith minimal burr. Problems such as cracked edge defects, crystallization, hardening, reducedwealdability and machinability are reduced in this process.9. ELECTRICAL DISCHARGE MACHININGEDM is the controlled erosion of electrically conductive materials by theInitiation of rapid and repetitive spark discharge between the electrode tool to the cathode and work toanode separated by a small gap kept in the path of dielectric medium. ThisProcess also called spark erosion.SCE4Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESSUNIT II MECHANICAL ENERGY BASED PROCESSES2. MECHANICAL PROCESSES Abrasive Jet Machining (AJM)Abrasive Water Jet Machining (AWJM)Water Jet Machining (WJM)Ultrasonic Machining (USM)2.1 ABRASIVE JET MACHINING (AJM)In Abrasive Jet Machining (AJM), abrasive particles are made to impinge on the workmaterial at a high velocity. The high velocity abrasive particles remove the material by microcutting action as well as brittle fracture of the work material.In AJM, generally, the abrasive particles of around 50 μm grit size would impinge on the workmaterial at velocity of 200 m/s from a nozzle of I.D. of 0.5 mm with a standoff distance of around 2mm. The kinetic energy of the abrasive particles would be sufficient to provide material removaldue to brittle fracture of the work piece or even micro cutting by the abrasives.Skematic Arrangement Of AjmSCE8Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESSSCE9Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESS2.1.1. Process Parameters and Machining CharacteristicsAbrasive: Material – Al2O3 / SiC / glass beadsShape – irregular / sphericalSize – 10 50 μmMass flow rate – 2 20 gm/minCarrier gas: Composition – Air, CO2, N2Density – Air 1.3 kg/m3Velocity – 500 700 m/s Pressure – 2 10 barFlow rate – 5 30 lpmAbrasive Jet : Velocity – 100 300 m/sMixing ratio – mass flow ratio of abrasive to gasStand-off distance – 0.5 5 mmImpingement Angle – 60 90Nozzle: Material – WCDiameter – (Internal) 0.2 0.8 mmLife – 10 300 hours2.1.2. Modeling of material removalMaterial removal in AJM takes place due to brittle fracture of the work material due to impactof high velocity abrasive particles.2.1.3. Modeling has been done with the following assumptions:(i) Abrasives are spherical in shape and rigid. The particles are characterized by the mean gritdiameter(ii) The kinetic energy of the abrasives are fully utilized in removing material(iii) Brittle materials are considered to fail due to brittle fracture and the fracture volume isconsidered to be hemispherical with diameter equal to choral length of the indentation(iv) For ductile material, removal volume is assumed to be equal to the indentationvolume due to particulate impactSCE10Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESS2.2. WATER JET MACHINING (WJM)2.2.1. IntroductionWater jet cutting can reduce the costs and speed up the processes by eliminating orreducing expensive secondary machining process. Since no heat is applied on the materials, cutedges are clean with minimal burr. Problems such as cracked edge defects, crystallization,hardening, reduced wealdability and machinability are reduced in this process.Water jet technology uses the principle of pressurizing water to extremely high pressures,and allowing the water to escape through a very small opening called “orifice” or “jewel”.Water jet cutting uses the beam of water exiting the orifice to cut soft materials. This method isnot suitable for cutting hard materials. The inlet water is typically pressurized between1300 –4000 bars. This high pressure is forced through a tiny hole in the je el, hich is typically 0.18 to0.4 mm in diameter. Picture of water jet chining process.SCE11Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESS2.2.2. ApplicationsWater jet cutting is mostly used to cut lower strength materials such as wood, plastics andaluminium. When abrasives are added, (abrasive water jet cutting) stronger materials such assteel and tool steel.2.2.3. Advantages Of Water Jet Cutting There is no heat generated in water jet cutting; which is especially useful for cutting toolsteel and other metals where excessive heat may change the properties of the material. Unlike machining or grinding, water jet cutting does not produce any dust or particles thatare harmful if inhaled. Other advantages are similar to abrasive water jet cutting2.2.4. Disadvantages of water jet cutting One of the main disadvantages of water jet cutting is that a limited number of materialscan be cut economically. Thick parts cannot be cut by this process economically and accurately Taper is also a problem with water jet cutting in very thick materials. Taper is when the jetexits the part at different angle than it enters the part, and cause dimensional inaccuracy.2.3. ABRASIVE WATER-JET MACHINING (AWJM)2.3.1. IntroductionAbrasive water jet cutting is an extended version of water jet cutting; in which the waterjet contains abrasive particles such as silicon carbide or aluminium oxide in order to increasethe material removal rate above that of water jet machining. Almost any type of materialranging from hard brittle materials such as ceramics, metals and glass to extremely softmaterials such as foam and rubbers can be cut by abrasive water jet cutting. The narrow cuttingstream and computer controlled movement enables this process to produce parts accurately andefficiently. This machining process is especially ideal for cutting materials that cannot be cut bylaser or thermal cut. Metallic, non-metallic and advanced composite materials of variousthicknesses can be cut by this process. This process is particularly suitable for heat sensitivematerials that cannot be machined by processes that produce heat while machining.The schematic of abrasive water jet cutting is shown in Figure 15 which is similar to water jetcutting apart from some more features underneath the jewel; namely abrasive, guard and mixingtube. In this process, high velocity water exiting the jewel creates a vacuum which sucksabrasive from the abrasive line, which mixes with the water in the mixing tube to form a highvelocity beam of abrasives.SCE12Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESS2.3.2.ApplicationsAbrasive water jet cutting is highly used in aerospace, automotive and electronicsindustries. In aerospace industries, parts such as titanium bodies for military aircrafts, enginecomponents (aluminium, titanium, and heat resistant alloys), aluminium body parts and interiorcabin parts are made using abrasive water jet cutting.In automotive industries, parts like interior trim (head liners, trunk liners, and door panels)and fiber glass body components and bumpers are made by this process. Similarly, inelectronics industries, circuit boards and cable stripping are made by abrasive water jet cutting.2.3.2.Advantages of abrasive water jet cutting In most of the cases, no secondary finishing requiredNo cutter induced distortionLow cutting forces on work piecesLimited tooling requirementsLittle to no cutting burrTypical finish 125-250 micronsSmaller kerf size reduces material wastagesNo heat affected zoneLocalises structural changesNo cutter induced metal contaminationEliminates thermal distortionNo slag or cutting drossPrecise, multi plane cutting of contours, shapes, and bevels of any angle.2.3.3.Limitations of abrasive water jet cutting Cannot drill flat bottomCannot cut materials that degrades quickly with moistureSurface finish degrades at higher cut speeds which are frequently used for rough cutsSCE13Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESSThe major disadvantages of abrasive water jet cutting are high capital costand high noise levels during operation.A component cut by abrasive water jet cutting is shown in Figure .As it canbe seen, large parts can but cut with very narrow kerfs which reduces materialwastages. The complex shape part made by abrasive water jet cutting2.3.4. Abrasive water jet cutting WJM - PureWJM - with stabilizerAWJM – entrained – three phase –abrasive, water and airAWJM – suspended – two phase –abrasive and water o direct pumpingi. Indirect Pumpingii. Bypass pumpingSCE14Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESS2.4. ULTRASONIC MACHINING (USM)2.4.1. IntroductionUSM is mechanical material removal process or an abrasive process used to erode holes orcavities on hard or brittle work piece by using shaped tools, high frequency mechanical motionand an abrasive slurry. USM offers a solution to the expanding need for machining brittlematerials such as single crystals, glasses and polycrystalline ceramics, and increasing complexoperations to provide intricate shapes and work piece profiles. It is therefore used extensively inmachining hard and brittle materials that are difficult to machine by traditional manufacturingprocesses. The hard particles in slurry are accelerated toward the surface of the work piece by atool oscillating at a frequency up to 100 KHz - through repeated abrasions, the tool machines acavity of a cross section identical to its own.SCE15Department of Mechanical Engineering
ME2026UNCONVENTIONAL MACHINING PROCESSFigure : Schematic of ultrasonic machine toolUSM is primarily targeted for the machining of hard and brittle materials (dielectric orconductive) such as boron carbide, ceramics, titanium carbides, rubies, quartz etc. USM is aversatile machining process as far as properties of materials are concerned. This process is ableto effectively machine all materials whether they are electrically conductive or insulator.For an effective cutting operation, t
unconventional machining processes and know the influence of difference process parameters on the performance and their applications. TEXT BOOKS: 1.Vijay.K. Jain “Advanced Machining Processes” Allied Publishers Pvt. Ltd., New Delhi, 2007 2.Pandey P.C. and Shan H.S. “Modern Machining Processes” Tata McGraw-Hill, New Delhi,2007. REFERENCES:
There are different types of machining process used for sapphire material. The fig. 1 shows a graphical representation of sapphire machining processes i.e. laser machining process, grinding process, polishing process, lapping process, new developed machining process, compound machining process and electro discharge machining process. Fig.1.
Modern Manufacturing Methods It is not possible to produce chips by conventional machining process for delicate components like semi conductor. NON-TRADITIONAL MACHINING (NTM) Non-Traditional machining also termed unconventional machining processes. Unconventional machining processes is defined as a group of
Machining metals follows a predictable pattern with minimal creep. When machining plastics, quick adjustments must be made to accommodate substantial creep — not to mention that the material has a strong propensity for chipping and melting during machining. Simply stated, the basic principles of machining metals do not apply when machining
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Machining metals follows a predictable pattern with minimal creep. When machining plastics, quick adjustments must be made to accommodate substantial creep — not to mention that the material has a strong propensity for chipping and melting during machining. Simply stated, the basic principles of machining metals do not apply when machining
where the use of 5-axis simultaneous machining brings unequalled surface quality. Moreover, it is targeted at prototype machining, 5-axis trimming and special machining where full 5-axis machining is the requirement for quick and accurate manufacturing. Multi-Axis Surface Machining is also an add-on product to Prismatic Machining and Lathe .
a result, a new class of machining processes has evolved over a period of time to meet such demands, named non-traditional, unconventional, modern or advanced machining processes [1–3]. These advanced machining processes (AMP) become still more important when one considers precision and ultra-precision machining.
In the midst of Michel’s awakening to the sensuous, sensual existence, to the Dionysian world in nature and himself, he observes: [Marceline] led the way along a path so odd that I have never in any country seen its like. It meanders indolently between two fairly high mud walls; the shape of the gardens they enclose directs it leisurely course; sometimes it winds; sometimes it is broken; a .
