Welcome to my course on Introduction to Abrasive Machining and Finishing Processes andmyself Doctor Mamilla Ravi Sankar. I am an Assistant Professor in the Department ofMechanical Engineering in IIT, Guwahati ok. So, the first and foremost thing that I am goingto deal with is, what I am going to talk about in this particular course and in a summary wayas well as in an elaborative way. So, that you can choose whether you want to take this courseor not, or why this course is important, other things ok. Coming to the overview of the class, in particularly what I am going to talk, just I would liketo acknowledge those people who are helping me from the background or who are helpingtechnically, non technically, and all those things, and then why and who can study thiscourse. So, reference materials which are also a part of this course.So, that you can refer to the books and papers relevant to this particular course, Introductionto Manufacturing, because abrasive machining and finishing process comes under a categoryof manufacturing. So, just a glimpse why manufacturing is important and other things I willstudy, other things I will explain. Overview of the syllabus in a normal way, what are theoverview content and all those things and I am also going to talk about in an elaborative waythe same things. So, introduction to abrasive particles, before you are going to study aboutthis particular course what is an abrasive particle, how can you measure the size, what are thevarieties, what about the cutting edges, what are the rectangles and all those thingsThe manufacturing of abrasive particles, how these abrasive particles are fabricated and thesize and shape of an abrasive particle, how do you determine the size of abrasive particle andI conclude this particular class with a summary of the class, what I am going to talk in thisparticular class. So, the acknowledgment goes. I am very thankful for Professor Khijwania,he is the Head, Centre for Education Technology and who gave me this opportunity toexplain this particular course or disseminate my knowledge about this particular course onIntroduction of Abrasive Machining and Finishing Process. He is the person who iscontrolling all these things, ok. I am very thankful for the staff who tirelessly worked for theediting, taking the video and preprocessing, post-processing and other things, who are there atthe Centre for Education Technology. Head of the Department of Mechanical Engineering,where I belong, to Professor Dwivedy Ji. And thanks to the MOOCs and IIT Guwahati in broad spectrum, thank you for those who arehelping hands for me in this particular course my TAs Jayanth Reddy, Abhishek Gupta,Mandeep Saini and Rawat these are the people. Apart from all these people I would like toacknowledge one person who helped me technically, he is Narayan Reddy, he is no more. So,he is a very good friend of me he helped me in many ways. So, technically he helped me a lotcoming to the course on overview of my course on introduction to abrasive machining andfinishing processes.Who can study this course ? So, normally this is particularly very helpful for mechanical engineers, productionengineering people, aerospace, material science, and metallurgy people. And moreover, it canalso helpful for other departments who want to learn about manufacturing and all thosethings. In the intended audience, it can be useful for the B Tech students- where you can learnbasics, M Tech and Ph.D. students- you can learn a basic as well as you can take up some ofthe course contents as your research topics, faculty who teaches manufacturing in particularlyabout the machining processes.So, as you know this particular course comes under the subtractive manufacturing. So, thenumber of hours is 20 hours course. So, I am going to take this particular course in 20 hours.List of the reference books. So, the first and foremost book that you can refer is Principles of Abrasive processing by M CShaw. Also, you can go through ,Professor V K Jain, Micromanufacturing Process, becausein advance abrasive finishing processes, you can take from this particular course andelaboratively if you want to understand the mechanics, if you want to understand the what isin-depth knowledge and all those if you want, you can go for Nano finishing Science andTechnology where you can study analytically and all those things.As this course is an introductory course you will only understand how this process works andI will give you a glimpse of overview, I am not touching the mechanics and other things. So,I am not going to teach you any mathematics or something, I will touch some of themathematics, not in deep mathematics. In case if you want to understand so, you can see thisparticular book like, Nano finishing Science and Technology by Professor VK Jain andJoseph McGeough, is another book where you can study about the Advanced Methods inMachining. Professor G K Lal book I am following for the grinding operation andconventional machining and finishing operations, and Professor Ghosh and Malik’s book inManufacturing Science which gives you an overview of abrasive machining and some of thefinishing process also and Astakhov. So, I am also teach in this particular course aboutgrinding fluids and ecological aspects of grinding fluids in all those things it also called as acutting fluid, but same thing hold good for the single point cutting tool and multi-pointcutting tool, cutting fluids are same. So, we can use those cutting fluids as the metalworkingfluids in this particular course ok. Not only this course content is from these particulartextbooks only, but I have also taken some of the research papers, latest research papers and Ihave a compiled in this one. So, the content is, not only the part of these particular books, youcan also refer to the latest papers in this particular area. Coming to this introduction of this particular course which is a part of manufacturing that iswhy I am going to talk about a little bit about manufacturing. What is manufacturing?Successful creation of Man’s Material Welfare depends mainly on the ability of naturalresources, and exertion of human efforts both physically and mentally and development useof power tools and machine tools ok. So, in a broad view manufacturing is nothing, but theconversion of raw materials using certain energy to a finished product. Assume that I have abox side material, I want to make it an aluminium sheet for a car, I have to use certainexternal energy and then I have to prepare a final product. This particular process of conversion of raw materials into the final product is nothing, butthe manufacturing. Importance of manufacturing just you can see for the auspiciousness ofthis particular course I just gave you a glimpse this is a temple where they have fabricatedusing subtractive manufacturing processes like machining, finishing and other things ok. Importance of manufacturing I said we have the machining as well as finishing. So, I have araw material that converting using machining and other processes not only machining herethere are other processes. So, you can fabricate a car structure and all those things. Anotherone finishing applications if you see the gold ore from that ornaments you can goldornaments and other. This is the importance of manufacturing and the manufacturing if thecountries manufacturing is most developed; that means, that that country can become one ofthe superpowers, for example, China. China’s manufacturing is so good and we should aim asIndians, we should also equally good compared to China so, that we can also becomesuperpowers. So, that means, that I request all the people that manufacturing is one of thegood courses, which can make India a good country. So, most of the manufacturing industriesare there in India. So, you gain the knowledge and you work for those manufacturingcompanies and make India great ok. Coming to the syllabus of this course on introduction to abrasive machining and finishingprocesses, the overview of the syllabus chapter 1 deals with the introduction to abrasiveparticles classification of abrasive processes and the other things, second one I am dividing aparticular chapter into 3 classes I am mentioning 3 classes, it may sometimes go beyond 3classes or it may end in 2 classes itself ok.So, for the particular plan is concerned I am having the 3 divisions. The first division ischapter 1a Introduction to Abrasive Particles and Classification Abrasive Processes; thesecond one is Grinding Process and its Classifications, Applications, grinding fluids, and theother things, the third one you will see the Grinding Process, Tribological aspects, GrindingFluids and sustainable grinding and other things.Then comes to the conventional abrasive finishing processes like honing process, wirebrushing process, lapping process, buffing, super finishing and other things we also studyabout what is surface integrity. The surface integrity refers to surface metallurgy, surfacemorphology, and many other practical conventional finishing processes we will study in thisparticular chapter 2. In chapter 3 we study advanced abrasive machining processes. So, I amtalking about machining as well as finishing sometimes I am talking about machiningsometimes I am talking about finishing. So, you will understand what the difference in thelater slides is. So, in the chapter 3, advanced abrasive machining processes, we study about the abrasive jetmachining, abrasive water jet machining, ultrasonic machining followed by elastic emissionmachining.In chapter 4 we study about hybrid advanced abrasive machining processes such as electricdischarge grinding, electric discharge diamond grinding, electrochemical grinding, andchemo-mechanical polishing these are the hybrid advanced abrasive machining process wewill be studying. Then we go ahead with the latest trends in the abrasive finishing processes such as polymerassisted abrasive finishing process, where we will study about abrasive flow finishingprocess; advances in abrasive flow finishing process and applications and allied processes ofabrasive flow finishing process. Some of the papers whenever you go through it is alsomentioned as abrasive flow machining process also because in olden days people were usingabrasive flow machining applications like abrasive flow, deburring process, and other things,nowadays people are using for finishing that is why this is named as abrasive flow finishingprocess.Then we will go for magnetic field-assisted abrasive machining processes and finishingprocesses, that is called magnetic abrasive finishing, vibration-assisted magnetic abrasivefinishing, chemo-mechanical magnetic abrasive finishing, magnetic abrasive deburringmagnetic jet polishing and other things here it is written machining and you can correct it as afinishing. In chapter 7 we go for Magnetorheological abrasive finishing processes, in a previous casenormally you will have the particles. Here you will have a magnetic slurry. So, you gothrough the magnetorheological abrasive flow finishing process, magnetorheologicalfinishing process, magnetorheological float polishing and other magnetorheological ormagnetic abrasive finishing processes you will go through in chapter 7. In chapter 8 you willgo with hybrid abrasive machining processes are hybrid abrasive finishing processes. Chemomechanical magnetorheological finishing process finishing of advanced materials likebiomaterials like implant materials finishing and other things and latest updates in abrasivefinishing processes. Abrasive finishing processes that are there in the latest trends from theresearch papers I will explain to you. Coming to the classification of manufacturing processes, there is a machining processforming process, joining process, casting process, powder metallurgy sheet metal processingand finishing processes. Among these so, machining and finishing processes are the ones thatcome under the abrasive processes.Normally abrasives are used for machining as well as finishing, which are nothing, but thesubtractive manufacturing processes. Introduction to machining and finishing we will study about the importance of machining andfinishing. Basic approaches in manufacturing what are the difference between machining andfinishing, and importance of machining and finishing why machining is important whyfinishing is important, what is the conventional and advanced finishing processes towards asustainable and all those things this 0.4 we come across in the later cases, but 1 2 3 we willcome across now and study of the surface integrity about surface morphology and metallurgywe will come in few classes later ok. First and foremost, why you have to study this particular course ok? So, that is a basicquestion that you will always have ok. So, this is a before and after you can see the surfacehere the welding is done, but you cannot directly use it, because the surface morphology isdifferent at the same time surface metallurgy is different. In order to sell your product into themarket, you need good aesthetic appeal, you need perfect tolerances and other things for thatpurpose you should go for machining and finishing of this particular things and you canclearly see here how the things are achieved. This is the beauty about abrasive machining andfinishing processes if at all you want to go for advanced finishing of implants.If at all you can see the knee surgery are totally replacement other things if you see you needto go for the finishing of the knee implant. This is the casted product and this is the finishedproduct ok. Assume that you are going to keep the casted product directly inside the kneewhat will happen? The surface roughness is very high metallurgical aspects are different. So,there will be a corrosion effect there will be friction. So, lot of problems will come for that toovercome that you need to go for abrasive based machining and finishing processes. In thecase 1 that is the pipe and welding and machining, you can go for the abrasive based grindingprocesses, but you cannot go for a knee implant. So, you have to go for abrasive finishingprocesses. So, in the case 1 you need abrasive machining processes in the case 2 you need togo for advanced abrasive finishing processes ok. What are the 2 approaches in manufacturing normally there is a top-down approach? The topdown approach means I have a material and I have to do the machining and take out theuseful product that is called an object the tie bond this is called the top-down approach. I havea shape big shape out of which I have I want to make a small component, then I am doing amachining process to make a component that is called top-down approach I am coming fromtop to the bottom ok. In the bottom-up approach normally I have a powder and I am making acomponent like powder metallurgy is a bottom-up approach, I have powders I am going tocompact it synthetically and I make a component in a first case I do the machining operation.So, there is some problem in the top-down approach such as material waste will be there inthumps up chips and all those things, and this particular course is followed a top-downapproach. And most people who are sitting maybe a B Tech student or starting of M Techstudents other students; you may not know what is a difference between in machining andfinishing some many of you may know ok. So, you should understand machining andfinishing, because this particular course is abrasive machining as well as finishing. So,abrasives are constant, and you are using for machining applications as well as finishingapplications. So, you should know what is machining and what is a finishing. In a machining process ifyou see how much material I am removing from particularly this component is important thatis my major criteria. In a finishing process, my major criteria is not about how much materialI am removing I am whether I got the particularly required surface finished or not that is themost. Even though I remove less material if I am getting a surface finish in a good way; thatmeans, that surface roughness in a very low value; that means, that that is my finishingprocess ok. So, you think about what the surface roughness that I want so, that I can sell thisparticular product in the market. What if that is the criteria then you have to go for thefinishing process if your criteria are machining so, you just go for the material removalcriteria ok. Assume that in a ten minutes time I want to remove 10 mm thickness. So, youhave to go to the machining process. So, when the material removal takes place normally if you see the abrasive machiningprocess, which is a top-down approach in a grinding process or in a late process and otherprocesses. Normally the machining takes place after the yielding bind; that means that that iswhy these machining processes are called as severe plastic deformation processes ok. So,once the after this one only the material start shearing from the work piece ok.So, we do not bother about much about the elastic limit and the other things, we directly gofor failure. In this particular slide it is failure, but the thing for a machining people and afinishing people you need to remove the chip, that means that you have to delaminate or youhave to dislodge that particular chip from the surface; that means, you are fracturing or youare shearing; that means, that this particular thing we will start after this point F ok. So, donot think in a negative way that we are fracturing the particular component are it is not thefracturing we are taking out the chip from the workpiece.  What I am going to teach in this particular course like an introduction to machining andfinishing process, you have seen a summary, but in an elaborative way how I am going toteach this particular course. This particular thing will help you whether you are really likingthe course or whether really it will help you in your future or really you are going to gain theknowledge or something that you can decide by seeing this elaborative way of this particularcourse. In course 1 I have already taught you what you are going to study that is an introduction toabrasive particles, bonded, unbonded super abrasives when you call it a super abrasive. Whenyou call it as a bonded abrasive, when you call it as an unbonded abrasive and other thingsyou will study about this one then you go about conventional abrasive finishing processes andgrinding other things. Among you know what is grinding and other conventional finishingprocesses, but you may not know what a difference between bonded abrasive is andunbonded abrasive; this is called unbonded abrasives and this is called bonded ok.What about the abrasive particles individually you see in a market or if you want to purchaseif it is individual particles; that means, called it is unbounded. Whenever you see a grindingwheel where vitrified bond rubber bond shellac bond is bonded; that means, that you know ifyou see an abrasive particle in a grinding wheel, that is called a bonded abrasive particle ok.So, this is a surface of a grinding wheel the last figure is a surface of a grinding wheel, but ifyou see unbonded these are the individual particles it is an individual particle. So, chapter 1 also deals with the grinding process. So, we study about the grinding wheelspecification classification of grinding processes; what is surface integrity; that means thathow would you divide into 2 things that are surface metallurgy and surface morphology.Grinding fluids which is a important one because this is important whenever you go as anengineer to a certain company, people are using cutting fluids or the grinding fluids how thiscutting fluid fall in the machining region or the grinding region or it will emit the emissions,how it is going to affect the particular operator and surrounding environmental (Refer Time:23:26) sinks by studying about the grinding fluid emissions and its consequences, how toresolve this particular problems.So, sustainable grinding and you also study about the micro-grinding process when you call itas a micro-grinding when you call it as a macro grinding and applications of various grindingprocesses you will study. So, you can see here this is called a surface grinder and how thematerial is removed you can see in this particular picture ok. This is how the surface ismaterial is removed from the surface grinding process. The conventional abrasive finishing processes you will study about the belt grinding process,honing process, wire brushing process you will also study about the lapping process.Normally lapping process follows the 3 body abrasion, the grinding process will follow the 2body abrasion and these are all things you will study in the tribological aspects of grinding.You will also study about the latest things like pitch polishing, what are pitch polishing andthe other things. And you study about the sandblasting, micro blasting and vibratory finishingand drag finishing these are the common conventional finishing processes where you massproduction or batch production is used. Coming to the advanced abrasive machining processes as you know, you are going to studyabout abrasive jet machining where abrasives are getting assistance from a compressed air,because the air is a carrier medium here and an abrasive particles will follow the path ofinjecting the air, but the air has a drawback that is it can diverge easily because of which thedimension that I want to get may be disrupted.For that purpose people have gone for a advanced version that is called abrasive water jetmachining, where you will get a highly compressed or pressurized water jet mixed withabrasive particles , here compare to abrasive jet machining you are going to get better andnarrow précised structure is whatever you want compared to abrasive jet machining here thedivergence is slightly less. And we will also study about ultrasonic machining where thepiezoelectric transducer will give ultrasonic vibrations and you will have an abrasive slurry,which is passed from slurry nozzle where you will have an abrasive particle and thisparticular thing will reciprocate and you will get a whatever the shape is there convert shapeyou will generate. We will also study about elastic emission machining, which is one of thelatest trends of machining and you can also call it as a finishing operation because you canremove the material in a very minute amount. We will in chapter 4 we study about advanced abrasive machining processes which arehybrid. Normally hybrid means you are clubbing one conventional machining process that isgrinding process, you are mixing with some of the advanced machining processes like EDMelectrical discharge machining then these both are clubbed then it is called a hybrid. So, oneof the common process is electric discharge grinding where electric discharge machining andgrinding process are clubbed each other, that is why this is called electric discharge grinding.So, in a electric discharge grinding, you will have a discharge and you will have machiningwith abrasive particle ok. So, discharge normally if at all I want to grind the ceramic particleslike silicon carbide or alumina or bio ceramics like hydroxy appetite bio glass and all thosethings what you cannot do with slightly higher abrasive particles for that purpose. You haveto go for electrical discharge grinding process, where your discharge will help to make thisparticular process to soften. This particular thing will become soft and your abrasive particlewill remove it that is a beauty about this particular process. Similarly, electric dischargediamond grinding where you will you are going to use diamond as an abrasive particle, andthere is another technology called wire EDG, that is called inset you here the people areclubbing the grinding with wire EDM and you can have a wire EDG process. Anotherprocess is electrochemical grinding similar technology where you club electrochemicalmachining with the grinding process and chemo-mechanical polishing or some of the papersalso call it as chemo-mechanical planarization ok. So, whatever you are seeing here is wireEDG and whatever you are seeing here is EDG or electric discharge diamond grinding. If theabrasive particle is silicon carbide or alumina it is called EDG, if the abrasive particle isdiamond then it is called as electric discharge diamond grinding. Then comes to chapter 5 where you are going to study polymer assisted abrasive finishingprocess, which is a good process for complex surface finishing under other things. There are3 varieties one is a one-way abrasive process and 2-way abrasive process and orbital ok. So,in the one-way process you are just injecting the here the medium is most important, in thisparticular chapter you study about the machining as such thus machine structure, medium,tooling other things. In one way you are just pushing the medium that is polymer plusabrasives plus rheological additives, you are pushing in this direction and your component ishere and you are finishing and again it is coming here. In a 2 way your component is here thisis the component and you are reciprocating from 2 directions this direction it goes wheneverit is upper direction, this also goes up whenever this goes down this also goes down ok. So,this is called 2 way and orbital you will have an orbital motion where if at all I want to finishthe complex blind holes other things you can do by orbital finishing, but here also medium isreciprocated. So, the medium will come again this piston will move up. So, normally on anaverage if you club these motions, you will have this particular motion similarly in the 2 wayalso you will have this particular motion. It goes up and comes down goes up and comesdown in 2 way, similarly in the orbital also a magnetic field which is another field of interestto many of the masters and Ph.D. students along with the polymer rheology, you can alsostudy about magnetorheological fluids. Here magnetic abrasive finishing, vibration-assistedMAF and chemo-mechanical magnetic abrasive finishing, magnetic abrasive deburring andmagnetic jet polishing other things you will study in this particular course. You can see here this is a north pole and this is a south pole, in between, you will form amagnetic brush where magnetic brush consists of carbonyl iron particles, which are ironparticles basically which is a pure form at the same time abrasive particles. Whenever youhave an electromagnetic field this particle will form a chain, CIP particles form a chain that iscarbonyl iron particles will form a chain wherein abrasive particles will be held. At the sametime, some of the people will also use bonded abrasives where they will sinter the abrasiveparticles on to an iron particle that is what you can see in this particular things these are allone type of bonded abrasive particles. In this chapter 7, you will study about magnetorheological fluids where it is slurry basically.So, these fluids are used for sophisticated applications like contact lens polishing and otherthings. So, magnetorheological abrasive flow finishing process magnetorheological floatpolishing and magnetic assistive another process we will see.