[0:04]INDIAN INSTITUTE OF TECHNOLOGY GUWAHATI.
[0:13]NPTEL, NPTEL ONLINE CERTIFICATION COURSE. An Initiative of MHRD.
[0:30]Welcome to my course on Introduction to Abrasive Machining and Finishing Process. Myself, Dr. Mamilla Ravi Shankar. I am Assistant Professor in Department of Mechanical Engineering at IIT Guwahati. So, the first and foremost thing that I am going to deal with is what I am going to talk about in this particular course and in a summary way as well as in the elaborative way, so that you can choose whether you want to take this course or not or why this course is important, other things. Coming to the overview of the class, in particularly what I am going to talk, just I acknowledge those people who are helping from the background or who are helping technically non-technically and all those things. And the why and who can study this course. 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. Introduction to Manufacturing, because Abrasive Machining and Finishing Process comes under the category of manufacturing, so, just a glimpse why manufacturing is important and other things I will study, other things I will explain. Overview of the syllabus in a normal way, what are the overview, content and all those things and I am also going to talk about in a elaborative way the same things. So, introduction to abrasive particles before you are going to study about this particular course, what is an abrasive particle, how can you measure the size, what are the varieties, what about the cutting edges, what are the rake angles and all those things. The manufacturing of abrasive particles, how these abrasive particles are fabricated and the size and shape of abrasive particle, how do you determine the size of abrasive particle and I conclude this particular class with a summary of the class, what I am going to talk in this particular class. So, the acknowledgement goes, I am very thankful for Professor K. Khijwania, he is the Head, Centre for Education Technology and who gave me this opportunity to explain this particular course or disseminate my knowledge about this particular course on Introduction of Abrasive Machining and Finishing Process. He is the person who is controlling all these things. Okay. I am very thankful for the staff who tirelessly working for the editing, taking the video and pre-processing, post-processing and other things who are there at the Centre for Education Technology. Head of the Department of Mechanical Engineering where I belongs to Professor. Dwivedy ji.
[3:26]And thanks to MOOCs and IIT Guwahati in broad spectrum. Okay. Thank you for those who are helping 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 to acknowledge one person who helped me technically, he is Narayan Reddy, he is no more. So he is very good friend of me. He helped me in many ways. So, technically he helped me a lot. Coming to the course on overview of my course on Introduction to Abrasive Machining and Finishing Process. Who can study this course? So, normally this is particularly very helpful for Mechanical Engineers, Production Engineering people, Aerospace, Material Science and Metallurgy people. And moreover, it can also helpful for other departments who want to learn about manufacturing and all those things. In the intended audience, it can be useful for the B. Tech students where you can learn the basics, M. Tech and PhD students, you can learn the basic as well as you can take up some of the courses as your research topics, faculty who teaches manufacturing.
[4:49]So, as you know, this particular course comes under the subtractive manufacturing. So, number 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.C. Shaw. So Professor V. K. Jain, Micromanufacturing Processes, because advanced abrasive finishing processes, you can take from this particular course. And elaboratively if you want to understand the mechanics, if you want to understand the what is in in-depth knowledge and all those things if you want, you can go for Nanofinishing Science and Technology, by Professor V. K. Jain.
[5:58]And Joseph McGeough is another book where you can study about the advanced methods in machining. Professor G. K. Lal book I am following for the grinding operation and conventional machining and finishing operations. And Professor Ghosh and Professor Malik's book in Manufacturing Science which gives you overview of abrasive machining and some of the finishing processes also. And Astakhov. So, I am also teaching in this particular course about grinding fluids and ecological aspects of grinding fluids and all those things. It also called as a cutting fluids, but same thing holds good for the single point cutting tool and multipoint cutting tool, cutting fluids are same. So, we can use those cutting fluids as a metal working fluids in this particular course. Okay. Not only this course content is from this particular textbooks only, I have taken some of the research papers, latest research papers and I have compiled in this one. So, content is not only the part of this particular books, you can also refer to the latest papers in this particular area. Okay. Coming to this introduction of this particular course which is a part of manufacturing, that's why I am going to talk about a little bit about the manufacturing. What is manufacturing? Okay. Successful creation of men's material welfare depends mainly on the ability of natural resources and extention of human efforts, both physical and mental and development use of power tools and machine tools. Okay. So, in a broad view, manufacturing is nothing but conversion of raw materials using certain energy to a finished product. Assume that I have an bauxite material, I want to make it a aluminum sheet for a car. I have to use certain external energy and then I have to prepare a final product. This particular process of conversion of raw materials into the final product is nothing but the manufacturing. Importance of manufacturing. Just you can see for the auspiciousness of this particular course, I just gave you a glimpse. This is a temple where they have fabricated using subtractive manufacturing process like machining, finishing and other things. Okay. Importance of manufacturing. I said we have the machining as well as finishing. So, I have a raw material that converting using machining and other processes, not only machining here, many other processes, so, you can fabricate a car structure and all those things. Another one, finishing applications. If you see the gold ore from that, ornaments, you can gold ornaments and all the things. This is the importance of the manufacturing. And the manufacturing if the country's manufacturing is most developed, that means that that country can become one of the superpowers. For example, China. China's manufacturing is so good. And we should aim as an Indians, we should also equally good compared to China, so that we can also become superpowers. So, that means that I request all the people that manufacturing is one of the good courses which can makes India a good country. Most of the manufacturing industries are there in India. So, you gain the knowledge and you work for those manufacturing companies and make India great. Okay. Coming to the syllabus of this course on Introduction to Abrasive Machining and Finishing Process. The overview of the syllabus. Chapter 1 deals with the Introduction to Abrasive Particles, Classification of Abrasive Processes and other things. Second one, I am dividing a particular chapter into three classes. I am mentioning three classes, it may sometimes go beyond three classes or it may end in two classes itself.
[10:00]Okay. So, for the particular plan is concerned, I am having the three divisions. The first division is Chapter 1a: Introduction to Abrasive Particles and Classification Abrasive Processes. Second one is Grinding Process and its classifications, applications, grinding fluids and other things. The third one, you will see the Grinding Process Tribology, grinding fluids and sustainable grinding and other things. Then comes to the Conventional Abrasive Finishing Processes like Honing Process, Wire Brushing Process, lapping Process, buffing, superfinishing and other things.
[10:41]We also study about what is surface integrity, the surface integrity refers to surface metallurgy plus surface morphology and many other practical conventional finishing processes we will study in this particular Chapter 2. In Chapter 3 we study Advanced Abrasive Machining Processes. So I am talking about machining as well as finishing. Sometimes I am talking about machining, sometimes I am talking about finishing. So, you will understand what is the difference in the later slides. So, in the Chapter 3 Advanced Abrasive Machining Processes, we study about the Abrasive Jet Machining, Abrasive Water Jet Machining. Ultrasonic Machining, followed by Elastic Emission Machining. In the Chapter 4, we study about Hybrid Advanced Abrasive Machining Processes such as Electric Discharge Grinding, Electric Discharge Diamond Grinding, Electrochemical Grinding and Chemomechanical Polishing. These are the hybrid advanced abrasive machining processes we will study. Then we go ahead with the latest trends in the Abrasive Finishing Processes such as Polymer Assisted Abrasive Finishing Process where we study about Abrasive Flow Finishing (AFF) Process. Advances in Abrasive Flow Finishing and Applications of AFF and its Allied Processes. Some of the papers whenever you go through, it is also mentioned as Abrasive Flow Machining Process also. Because in olden days, people were using for Abrasive Flow Machining applications like Abrasive Flow Deburring Process and other things. Nowadays people are using for finishing, that's why this is named as Abrasive Flow Finishing Process. Then we will go for Magnetic Field Assisted Abrasive Machining Processes and Finishing Processes. That is called Magnetic Abrasive Finishing, Vibration Assisted MAF, Chemomechanical MAF, Magnetic Abrasive Deburring, Magnetic Jet Polishing and other things. Okay. Here it is written machining and you can correct it as a Finishing.
[12:41]In the Chapter 7, we go for Magnetorheological Abrasive Finishing Processes. In the previous case, normally you will have the particles. Here you will have a magnetic slurry. So, you go through the Magnetorheological Abrasive Flow Finishing Process, Magnetorheological Finishing Process, Magnetorheological Float Polishing and other Magnetic Assistive Process. You will go through in Chapter 7. In the Chapter 8, you will go with Hybrid Abrasive Machining Processes or Hybrid Abrasive Finishing Processes. Chemomechanical MRF. Finishing of Advanced Materials like biomaterials. Latest Updates in Abrasive Machining and Finishing Processes. Abrasive Finishing Processes that are there in the latest trends. From the research papers, I will explain to you. Coming to the Classification of Manufacturing Process, there are Machining Process, Forming Process, Joining Process, Casting Process, Powder Metallurgy, Sheet Metal Processing and Finishing Process. Among these, Machining and Finishing Processes are the ones that comes under the abrasive processes. Okay. Normally abrasives are used for machining as well as finishing which are nothing but the subtractive manufacturing processes. Introduction to Machining and Finishing, we will study about Importance of Machining and Finishing. Basic Approaches in Manufacturing. What are the difference between Machining and Finishing and Importance of Machining and Finishing, why machining is important in manufacturing, why finishing is important, what are the conventional and advanced finishing processes, towards sustainable and all those things. This point 4 we come across in the later cases, but 1, 2, 3 we will come across now and study of the surface integrity about surface morphology and metallurgy we will come in few classes later. Okay. First and foremost, why you have to study this particular course? Okay. So, that is the basic question that you will always have. Okay. So, this is before and after. You can see the surface here.
[15:00]Okay. The welding is done, but you cannot directly use it because the surface morphology is different, and at the same time surface metallurgy is different. In order to sell your product into the market, you need good aesthetic appeal, you need perfect tolerances and other things. For that purpose, you should go for machining and finishing of these particular things and you can clearly see here how the things are achieved. This is the beauty about abrasive machining and finishing processes. If at all you want to go for advanced finishing of implants. Okay. If at all you can see the knee surgery or totally replacement other things, if you see you need to go for a finishing of knee implants. This is the casted product and this is a finished product.
[15:58]Okay. Assume that you are going to keep the casted product directly inside the knee, what will happen? The surface roughness is very high, metallurgical aspects are different. So, there will be a corrosion effect, there will be a friction. So, lot of problems will come. For that, to overcome that you need to go for abrasive based machining and finishing processes. In the case 1, that is the pipe and welding and machining, you can go for the abrasive based grinding processes, but you cannot go for the knee implant. So, you have to go for abrasive finishing processes. So, in the case 1 you need abrasive machining processes, in the case 2 you need to go for advanced abrasive finishing processes. Okay. What are the two approaches in manufacturing? Normally there are top-down approach. Top-down approach means I have a material. And I have to do the machining and take out the useful product. That is called object that I want. This is called top-down approach. I have a shape, big shape out of which I want to make a small component. Then I am doing a machining process. I am doing a machining process to make a component. That is called top-down approach. I am coming from top to the bottom. Okay. In the bottom-up approach, normally I have powders and I am making a component. Like Powder Metallurgy is a bottom-up approach. I have powders, I am going to compact it, sinter it and and I make a component. In a first case, I do the machining operation. Okay. So, there is some problem in the top-down approach such as material waste will be there in terms of chips and all those things.
[17:47]And this particular course is followed top-down approach. And mostly people who are sitting maybe a B.Tech student or starting of M.Tech students, other students, you may not know what is the difference between a machining and a finishing. Okay. Some many of you may know. Okay. So, you should understand machining and finishing 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 finishing applications. So, you should know what is a machining and what is a finishing. In a machining process, if you see how much material I am removing from particularly this component is important. That is my major criteria. In a finishing process, my major criteria is not about how much material I am removing. I am, whether I got the particularly required surface finish or not. That is the most. Even though I remove less material, if I am getting a surface finish in a good way, that means that surface roughness in a very low value, that means that that is my finishing process. Okay. So, you think about what the surface roughness that I want so that I can sell this particular product in the market. That if that is the criteria, then you have to go for finishing process. If your criteria is machining, so you just go for the material removal criteria. Okay. Assume that in a 10 minutes time I want to remove 10 mm thickness. So, when the material removal takes place? Normally if you see the abrasive machining process which is a top-down approach in a grinding process or in a lathe process and other processes, normally the machining takes place after the yielding point. That means that that's why these machining processes are called as severe plastic deformation processes. Okay. So, once the after this one only the material start sharing from the workpiece. Okay. So, we don't bother about much about the elastic limit and other things, we directly go for failure. In this particular slide, it is failure but the thing for a machining people and a finishing people, you need to remove the chip. That means that you have to delaminate or you have to dislodge that particular chip from the surface. That means that you are fracturing or you are shearing. That means that this particular thing will start after this point F. Okay. So, don't think in a negative way that we are fracturing the particular component or not. It is not the fracturing, we are taking out the chip from the workpiece. What I am going to teach in this particular course like Introduction to Machining and Finishing Process. You have seen summary, but in a elaborative way how I am going to teach this particular course. This particular thing will help you whether you are really liking the course or whether really it will help you in your future or really you are going to gain the knowledge or something. That you can decide by seeing this elaborative way of this particular course. In the course 1, I have already taught you what you are going to study. That is Introduction to Abrasive Particles. Bonded, unbonded, superabrasives. When you call it as a superabrasive, when you call it as a bonded abrasive, when you call it as an unbonded abrasive and other things, you will study about this one. Then you go about the conventional abrasive finishing processes and grinding other things. Among, you know, what is grinding and other conventional finishing processes. But you may not know what is the difference between bonded abrasive and unbonded abrasive. This is called unbonded and this is called bonded. Okay. Whatever the abrasive particles individually you see in a market or if you want to purchase, if it is individual particles, that means called it is unbonded. Whenever you see a grinding wheel where vitrified bond, rubber bond, shellac bond is bonded. That means that you know, if you see a abrasive particle in a grinding wheel that is called a bonded abrasive particle. Okay. So, this is the surface of a grinding wheel. The last figure is the surface of a grinding wheel, but if you see unbonded, these are the individual particles. It is individual particle. So, Chapter 1 also deals with grinding process. So, we study about the grinding, wheel specification, classification of grinding processes. What is the surface integrity? That means that how do you divide into two things that is surface metallurgy and surface morphology. Okay.
[23:00]Grinding fluids which is a important one because this is an important whenever you go as an engineer to a certain company, people are using cutting fluids or the grinding fluids. How these cutting fluid fall in the machining region or the grinding region. How it will emit the emissions. How it is going to affect the particular operator and surrounding environment and other things. By studying about the grinding fluid emissions and its consequences, how to resolve this particular problem. So, sustainable grinding and you also study about the micro grinding process. When you call it as a micro grinding, when you call it as a macro grinding and applications of various grinding processes, you will study. So, you can see here, this is called a surface grinder and how material is removed from the surface grinding process. Okay. This is how the surface is material is removed from the surface grinding process. The conventional abrasive finishing processes, we will study about the belt grinding process, honing process, wire brushing process.
[24:26]You will also study about the latest things like pitch polishing. What is pitch polishing and other things. And you study about the sand blasting, micro blasting and vibratory finishing, drag finishing, these are the common conventional finishing processes where mass production or batch production is used. Coming to the advanced abrasive machining processes as you know, you are going to study about abrasive jet machining where abrasives are getting assistance from a compressed air.
[25:04]Because the air is a carrier medium here and abrasive particles will follow the path of injecting the air, but the air has a drawback that is it can diverge easily because of which the dimension that I want to get maybe disrupted. For that purpose, people have gone for advanced version, that is called abrasive water jet machining where you will get a highly compressed or pressurized water jet mixed with abrasive particles will go. Here, compared to abrasive jet machining, you are going to get better and narrow, precise structure or whatever you want, compared to abrasive jet machining. And you will also study about ultrasonic machining where piezoelectric transducer will give ultrasonic vibrations and you will have a abrasive slurry which is passed from slurry nozzle where you will have abrasive particles and this particular thing will reciprocate and you will get a whatever the shape is there, converse shape you will generate. We will also study about elastic emission machining which is one of the latest trends of machining and you can also call it as a finishing operation because you can remove the material in a very, very minute amount. We will in the Chapter 4, we study about Advanced Abrasive Machining Processes which are hybrid. Normally hybrid means, you are clubbing one conventional machining process, that is grinding process. You are mixing with some of the advanced machining process like EDM, Electrical Discharge Machining, then these both are clubbed, then it is called hybrid. So, one of the common process is electric discharge grinding where electrical discharge machining and grinding process are clubbed each other. That's why this is called electric discharge grinding. So in a electric discharge grinding, you will have a discharge and you will have a machining with abrasive particle. Okay. So, discharge, normally if at all I want to grind the ceramic particles. Like silicon carbide or alumina or bioceramics like Hydroxyapatite, bioglass and all those things. What you cannot do with a slightly higher abrasive particles? For that purpose you have to go for Electrical Discharge Grinding Process where your discharge will help to make this particular process soften. This particular thing will become soft and your abrasive particle will remove it. That is the beauty about this particular process. Similarly, Electrical Discharge Diamond Grinding where you will you are going to use diamond as abrasive particle and there is another technology called wire EDG, that is called instead you here, the people are clubbing the grinding with wire EDM and you can have a wire EDG process. Another process is Electrochemical Grinding, similar technology where you club electrochemical machining with grinding process and Chemomechanical Polishing are some of the papers also call it as Chemomechanical Planerization. Okay. So, whatever you are seeing here is wire EDG and whatever you are seeing here is EDG or Electric Discharge Diamond Grinding. If the abrasive particle is silicon carbide or alumina, it is called EDG. If the abrasive particle is diamond, then it is called as Electric Discharge Diamond Grinding. Then comes to the Chapter 5 where you are going to study about Polymer Assisted Abrasive Finishing Process which is a good process for complex surface finishing and other things. There are three varieties. One is one-way abrasive process and two-way abrasive process and orbital. Okay. So, in one-way process, you are just injecting the here, the medium is most important. In this particular chapter, you study about the machine assets, the machine structure, medium, tooling and other things. In one-way, you are just pushing the medium, that is polymer plus abrasives plus rheological additives. You are pushing in this direction and you are component is here and you are finishing and again it is coming here. In a two-way, your component is here, this is the component and you are reciprocating from two directions. This direction it is goes. Whenever it is upward direction, this also goes up. Whenever this goes down, this also goes down. Okay. So, this is called two-way and orbital, you will have a orbital motion where if at all I want to finish the complex blind holes and other things you can do by orbital finishing, but here also medium is reciprocated. So, medium will come, again this piston will move up. So, normally on an average, if you club these motions, you will have a this particular motion. Similarly, in the two-way also you will have a this particular motion. It it goes up and comes down. Goes up and comes down in a two-way. Similarly in the orbital also. Magnetic Field which is another field of interest to many of the masters and PhD students along with the polymer rheology. You can also study about magnetorheological fluids. Here magnetic abrasive finishing. Vibration Assisted MAF and Chemomechanical Magnetic Abrasive Finishing, Magnetic Abrasive Deburring and Magnetic Jet Polishing, other things you will study in this particular course. You can see here, this is the North Pole and this is the South Pole. In between you will form a magnetic brush where magnetic brush consists of carbonyl iron particles which are iron particles basically which in a pure form, at the same time abrasive particles. Whenever you have a electromagnetic field, these particles will form a chain. Carbonyl Iron Particles form a chain. That is carbonyl iron particles will form a chain where in abrasive particles will held. At the same time, some of the people will also use bonded abrasives where they will sinter the abrasive particles on to a iron particles. That is what you can see in this particular things. These are all one type of bonded abrasive particles. In the Chapter 7, you will study about magnetorheological fluids where it is a slurry basically. These fluids are used for sophisticated applications like contact lens polishing and other things. Okay. So, magnetorheological abrasive flow finishing process, magnetorheological finishing process, magnetorheological float polishing and magnetic assist other processes we will see. Whatever you are seeing here is MRF, that is called magnetorheological finishing process where you can also see the video, how the magnetorheological finishing process works. Whenever magnetic fluid is put on to the disk where the electromagnetic field is there, it forms the stiff fluid and the polishing will take place. The stiffness is a function of your composition and the field strength. That is magnetic field strength.
[32:51]At last and the last chapter, we will study about hybrid abrasive machining processes and finishing processes. One is Chemomechanical MRF we will study. Normally how the chemical aspects of this particular process also come into picture and along with the magnetorheological finishing process. Finishing of advanced materials like biomaterials, electronic materials, aerospace materials, wherever required. Normally the complex surfaces of knee implant which is a biomaterial, you have to finish and you you the components like which are used in fighter jets, which are used in the other aerospace applications, component and defence applications and silicon based electronic things also. Components also we will see how to finish and latest updates if possible time is there and if the what are the latest updates in this particular abrasive machining as well as finishing and we will summarize this particular course.
[34:33]Particularly summary of this particular course. I have acknowledged to the many of the people from the CET Head Professor K. Khijwania to Professor Narayan Reddy who helped me technically and Professor K. Khijwania helps in terms of providing the facilities and providing the staff. I am thankful to him and Professor Narayan Reddy who is very good friend of me and he is no more. He gave me a lot of knowledge from the technical point of view. I always thankful for Professor Narayan Reddy. And course, who study and why this course is helpful. I have already explained and reference materials. I am again telling you this particular course not only depend on the books or the reference books or the reference materials. I am also following some of the latest research papers. So, clearly if you can understand, you can easily answer the assignments as well as you can easily answer the examinations. Okay. To understand the questions, to understand the assignments, you please understand the course and strictly follow the courses, so that you can easily gain the knowledge as well as the marks. Introduction to manufacturing, overview of the syllabus, what I am going to teach in this course (elaborative way) and Introduction to Abrasive Particles. Manufacturing of Abrasive Particles.
[36:44]Size and shape. Size is random normally. You can see it, but the shape, normally the cutting edges are randomly oriented and the shape is also random. Abrasive particle may be like this, another abrasive particles may be like this, another abrasive particles may be like this. So, the shape is random. And at the same time, you can see the cutting edges. This particular cutting edge, this particular cutting edge and this particular cutting edge, cutting edges are also random. So, if randomness increases, the surface roughness will give better and better. That means that surface roughness value will be low and low. Okay. And at the last, I am summarizing this particular class. Thank you for your kind attention in this particular class. And in elaborative way about this particular course and content. We will come up and hope you gain a great knowledge from this course. Thank you.
