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Video 1: Need for Cutting Fluid in MachiningSo, what is the need of the cutting fluid in themachining? Just you see here. The basic problem in machining is heat generation.As we have seen thermal aspects of machining. So, during the machining of metals are ahnon metals or something considerable heat is generated when the conservation of mechanicalenergy converts into the heat energy ok. Saviour plastic deformation will takes place. Youcan see this the primary shear zone, saviour plastic deformation is taking place wherethe mechanical energy is converting into the heat energy.So, there is a 3 zones where the heat generates one is heat in shearing zone which is a majoramount of the heat generated for which you are using the cutting fluid to extract theheat. Heat in chip tool interface, heat we have already seen the heat takes place inthe chip tool interface because of two things, one is chip is carrying the plastic deformation,zones temperature at the same time frictional heat between tool rake surface and chip bottomside will also causes two things. So, this two will be there and heat in work piece interfacetool work piece interface tool work piece interface will have a fictional rubbing actionwhere dominated by abrasion action that I also causes interference. At the same timework piece also carry three to five percent if you see in all metal working the plasticdeformation is involved. I am saying you the plastic deformation is involved which is Ican even say that it is a saviour plastic deformation because it is taking into thesaviour zone where the material feel you take place. As I asked already telling you thatmetal forming process and metal machining process for failure is not required in themetal deformation processes, but failure is required in the ah metal cutting operationsthen only the metal shearing takes place ok. The energy dissipated in the cutting convertedinto heat which is in terns raises the temperature machining. How it will raises? Just I mighthave already shown this video, but since it is an apt video for this cutting fluid applicationthat is I will just go and show you again you see how the fireworks will takes placein this one. If you see here what is happening, the machining is taking place at the extremeconditions on a hard machine work piece. So, what is happening here is if you see in thisvideo what you can clearly see is the lot of heat is generating, not only heat is generatingthe chips are coming like firing bullet us. At the same time if you clearly see thereis a accumulation of hot a chips which is a continuous chip in that location that isvery harmful because your final product is coming in this direction. If you are finalproduct is coming in this direction if a chip is intended there it is disturbing my finalsurface roughness which is coming as a product plus it is also giving some heat input becausemy chip is red hot chip which giving the heat to the work piece which damage the micro structuralon the surface of the work piece. That is two disadvantages for how to overcome allthese things we will see in the cutting fluid applications ok.So, further we proceed. You can clearly see the video. Now you can see the lump is comingout where the continuous chip red hot chip is coming and you can clearly see in thisregion, red hot chip is coming and it is disturbing the machining process. At the end also thesame thing is clearly visible there is continuous red hot chip is there in this type of chipsare presented this disturb the surface morphology as well as metallurgy which we have studiedin the last week courses. How to eradicate all these things or how to minimise thesethings for that purpose we will use the cutting fluids or you can go for another alternativethat is called alternative what you can go for it is hard cutting tools which may increasethe cost of the production. So, the cheapest way or the economical wayhow you can go ahead is cutting fluids ok. So, that is why that is a need of the cuttingfluid ok. Proper method whenever these type of things are there how you have to utilizeif you have a cutting fluid ok. You cannot throw it like a mad person ok youshould use fully utilise how to send if you see here figure a this is a good way and thisis poor way. Why? So, the heat is generated in this region where chip tool interface isthere. At the same time in the good way also if it would have been done at certain degreesrecently their studies shows that if you send at 45 degrees that will be better. That wasthe some of the researchers has conveyed ok. So, it may be better. Whatever is given isa good. So, what we can you can go ahead is better. So, this would be better. I am notsaying the best, but it would be better. The poor, why it is poor? Because ah the cuttingfluid is falling ahead of my measuring region which is not for which is not required forus. At the same time if you see in the group there is a cutting fluid application fromthe flank surface side also where the work piece rubs against the cleaning surface flanksurface of the real relieve surface ok. Here what normally you will send is a lubricantbased, cutting fluid you will send in the flank surface here in the good one where youchoose and the chip tool interface there coolant type you will send ok. Because the temperatureextraction should be there from the top side and the operation is dominating in the bottomside that is why you always go for a better lubricant. So, that the lubrication will bedone as you have seen the tribological lubrication and all those thing.In the milling operation the good one is like in the milling cutting region I will cometo the milling in the upcoming whenever I am going to talk to you about the multi pointcutting tool and all those things. Anyhow in some of you know what is milling, whatis up milling, what is down milling ok and all those things. So, anyhow I will teachyou, but; however, just to show from the cutting fluid point of view this is a good way toapply the cutting fluid and if you are throwing on the tool top side where the cooling isalready done by the atmospheric air to make you are just wasting the cutting fluid.If you see the grinding normally teeth grinding and all those thinks this is a good way andif you see in the drilling normally you should send along the fluids. So, that that willbe better rather than cooling the surface of the work piece at substance certain differentlocations where it may not be required. May be required, but thing is that is that theheat conductivity to the surface may not be required that is why this is not a preferablechoice. So, if you can send through the fluids are in the machining region. What will happen?It will lubricate it will cool as well as additional effect in the drilling processis it will try to evacuate the chips that is a beauty and the third function of thecutting fluid ok. In detail functions will come across in this lecture about the cuttingfluid and its requirements and all those things. As just now I was telling. So, now we comeacross about the purpose of the cutting fluids and it are none other than its function. So,the first and foremost function is normally depend on the manufacturing process that youare choosing either it can be lubricant function or cooling function this has a equal choicesor equal importance basically because if you are going for lower speeds lubricant typeis required if you are going for a high speeds normally the coolant type is required ok.So, lubricant type normally it will reduce the friction and where in the machining regionabout the I am talking about the tool ok. If at all I am using the coolant what willhappen it will cool the machining region; that means, that it will try to cool the chip,it will try to cool the tool and it will try to cool the work piece also which is carryingcertain amount of heat. So, if you are cooling and all those things if you are doing whatwill happen the another benefit that you are going to achieve is reduce the forces. Ifyou reduce the forces the energy consumption will be less that is what is F c into V normalit will go down. So, your energy requirement or power input will be obviously, will godown ok. Protect their mechanical surface from theenvironmental corrosion. What do you mean by this? If at all what I am talking is aboutthe corrosion environmental corrosion. Environmental corrosion comes from where your environmentcontains oxygen, nitrogen, and many many chemicals it is all elements it is having. Nowadaysif you see lot of pollution is there, so many elements are there ok many elements are there.Whenever the machining operation is going to take place lot of ah heat is generatedthe surface is very hot in that circumstances if these environmental aspects come into elementscome into picture it will have corrosion on the surface especially in terms of iron basedcomponents there will be a conscious. So, in order to protect all those things you tryto use the rust inhibiters are corrosion preventers ok. If you are cutting fluid contains a particularpart of this rust inhibitors as a ingredient of the cutting fluid then you can preventthe environmental corrosion.
Video 2: Types of Cutting Fluids in MachiningNow, you can see the types of cutting fluids used in a machining this slide I am goingto elaborately touch in next class. Since I am going to talk about for the additiveslet me slightly say that on y axis you have a cooling properties on x axis if you havea lubricating property. Just now I told you if you have a cutting fluid you always addwater to it ok whenever you are adding water you are improving the cooling properties.Why? The proof here from the literature is that water is a better cooling property liquidand mineral oil or the lubricant whatever you are getting from the market is a betterlubricant. So, if at all you want better. So, you have to make the emulsions ok. So,what you do is mineral oil you take and you add H 2 O to it you are going to get the emulsions.We will have optimum cooling properties as well as optimum lubricating properties. Thiswill have cooling properties plus lubricating properties both. If you choose mineral oilit will have a lubricating property if you choose water it will have a cooling propertythat is why to optimise both things if I required in the my machining operation both coolingand lubrication then I am going to use emulsions ok, cooling plus lubrication.So, emulsions hm contains water if emulsions contains water whenever the high temperaturemachining is taking place the water will react with the iron based work pieces and causesrust for that purse always had some additives. You can see here always there is additives,mineral oil with additives, emulsions with additives, water with additives and other.What are these additives that was the major thing that we are going to see here? Someof the additives are biocides helps in a preventing the microorganisms rust inhibitor. So, rustingit helps as we have seen the previous slide. Anti wear additives it will help better lubrication,extreme pressure additives at extremely ah high loads your additives will provide thelubricity for proper lubrication and all these things.The pressure are much much high in terms of broaching operation and others at that pressureshow much additives are going to help for better lubrication in all those things that we willcome and see ok. So, regarding this as I said we will see again this slide in the upcomingclasses because this is the graph that have great importance from the point of lubricationas well as cooling. The cutting fluid types normally one is theoil types where ever you see petroleum. Nowadays if you see the companies like servo they willsupply servo cut s is one of the oils ok, these are all mineral oils ok. So, animal,vegetable, compound lot of oils are there. Then emulsions, if you just I will show youthe emulsion emulsions are nothing, but the mixture of oil and water along with additivesthat you have seen in the previous slide. Good for operations where the temperaturerises significant because it will also. Semi synthetic is are the chemical emulsions basicallywhich contains mineral oil diluted in water with additives and reduce the particle sizeok. These are the chemical emulsions. The above ones are mineral oil based waterbased emulsion these are chemical based synthetic chemicals with additives. Basically here emulsionsare used in the semi synthetic, here directly chemicals are used along with the additivesok and you can even dilute with water or without oil also ok. So, you can do that. So, if yousee a range of cutting fluids as you have seen in the previous slide water is a bettercooling, cooling fluid ok. So, soluble oils normally soluble oils which easily mix withwater that is why it is called soluble oils. Straight oils normally whose chain is verybig, normally you if you see the chains like a large chain, small chain, medium chain theseare the chemical compositions like alkanes alkenes alkynes if the chain is goes beyondthe c 13 normally. These are main branch is dominating at the same time the sister branchesare the side branches will be not donating much. So, this type of oils are one of thestraight oils. This is a mixed oils you can mix with 2 3 varieties of oils. Chemical additiveoil, as I said semi synthetic oil is normally are called as a semi synthetic where you canadd chemical synthesized oils along with the mineral oil, chemical compounds directly asI said ah synthetic oils are completely chemical compounds where you can add water to it makeslightly emulsion and the solid lubricants. Solid lubricants are normally nano particlesor micro particles ok, nano particles where you used the or micro particles also you cansay micro particles also plus compressed air. With this you will send to the machining regionand you will get the lubricant. If here basically the lubricant action is dominated comparedto the cooling, whatever the air that you are sending assume that you are sending youcold compressed air that will be better here ok. So, whenever somebody want to take theresearch work in this area. So, solid lubricant you can take along withthat cooling fluid that is cooling gas are normally the air. Cooled air you can impregnatewith the solid ah nano particles ah which are better lubricants and you can send tothis one. So, your cooling fluid will extract the heat because it is at the low temperatureat the same time being a air it can penetrate into the region. So, people very less workis done in this area. So, people who are working in the soil lubricants for machining applicationsyou can try with low temperature high pressure air mixing with solid lubricants and you cansend it to the machining region and you can check. And you can even compare with normallyand solid lubricant particles also you can vary. So, you sometimes the problem is wheneveryou are going for nano particles agglomeration is a problem. So, you have to optimise theparticle size how much volume of the particles was sending, it is discharge so much you think.You can play with the volume amount or the discharged at the same time particle size,at the temperature of the fluid that is air that you are sending. So, you can play air,pressure air pressure and all those things will play on the volume discharge.So, lot of interaction factors and all those things are there. So, if somebody is interestedyou can get a very good PhD topic out of this one. So, please ah work in this area ok asI was saying you know this is not only the course for beginners like second year B.Tech,it also good for the first year M.Tech and a PhD also. So, my topic any B.Tech studentslikes it this topic you can take it M.Tech student or free to take ok are you can goto my website and you can write to us at this is what we were looking any suggestions youwant to and all those things and we can always help you see as we work in this area. So,we have slightly better knowledge. So, we can help you and spreading knowledge is whatwe are here for ok. So, the cutting fluid method application theflow rates are normally if you see the flood cooling. If you see the flood cooling whatare the method application, is there are many types of techniques where one of the commonlyused technique in in India nowadays in the industry especially small scale industriesah flood cooling ok, where the cutting fluid falls a 10 meter per minute. Normally it istoo high, but whatever ah the text books refers is a 400 to 600 ml per minute is the one.So, this is slightly I because we have taken from some of the old textbooks. So, it maybe at the same time the basic problem here is a poor visibility ok. I can say that thiswill be like a 400 effectively nowadays people are working in the range of 400 ml to 600ml per minute ok. So, on an average you can say it is around 500 ml per minute. This isaverage value ok, the basic problem is poor visibility.As you have seen the cutting fluid is ah extremely milky type. So, it will cover if the fluidcontent is very high what will happen? You cannot see the measuring region ok that isthe basic problem at the same time cutting fluid is very high, so emissions is also veryhigh. So, emissions whenever you see in the next classes you will really see what is thebasic problems. So, second one is a mist one where you have a better visibility what Imean to say better visibility does not mean that ah it is transparent or something.Here you will mix the cutting fluid with gas and you send the atomize as you have seenin the MQL, is one of the other names are the synonyms for minimum quantity lubricationwhere you send the air plus cutting fluid and you just circulate into the grinding operationor machining operation, new type of machine operation ok.
Video 3: Properties of Cutting Fluids in MachiningNow, we will look into the properties what are the properties that I am looking. It shouldpossess good lubricating properties to reduce the friction which you have seen. Non corrosivenessthat is rust inhibitors are inbuilt should be made whenever the suppliers of this cuttingfluid supplies and natural. So, that not react chemically. So, it should be as natural aspossible. Why I am telling this some of the papers if you see people are using coconutoil people are using castor oil people are using palm oil palm oil based cutting fluidpapers you can see in Thailand based, Malaysia based many people are working in this area.So, Jatrophine these are all that people are working. So, why do not any many people arein India also working. So, you go through the literature and find the combination ofthis ions or combination of these ions along with the water or can we mix with them mineraloil because mineral oil has a better lubricity if the cooling ability of this one is betterthen why do not we mix all with the water. So, only thing is that you should choose fora right emulsifiers which can do so that most of the cutting fluid will have natural tendencyso that the chemical aspects will go down. For example, whenever you want to purchasea soap in a whenever you want to take the bath and whenever you want to purchase a soapthe first thing a person who move some of knowledge about the soap he is just to rotatethis and the back side and just check what is the t f m of this one ok. Why they willcheck? Normally t f m stands for total fat material or content of the fact which is nonchemical. For example, if you take a I am just not advertisingfor anything just let me take the advertisement of the government of India where people manypeople may not like the animal fat in it. So, the best way is going for assume thatMysore sandal soap is there. So, normally total fat material the fat material that theyare taking most of the material that they are taking is sandalwood oil. So, oils isnothing, but a fat. So, if oil content which is coming from sandalwood if it is puttingon my skin it is good for me rather than the chemicals made soaps ok. So, sorry that Iam my wish is not to advertise or something, just I am taking for example, because if youhave less chemicals and if you have more fats which are natural fats that are coming tothe plant which is good for your health that is very good.So, choose a soap not only that what a specified where the total fat material is more whichwill help you if at all the fat is coming from the plants that is still more betterbecause it is natural biodegradable everything will be there ok. That is why this point iscompletely valid where you should have a natural content. So, that the chemical reaction shouldbe very very less on the machining surface or the operator health or it should not emitany chemicals or something. It should not very easily flammable; that means, the measuringconditions will go around 300 to 1000 degrees depend on workpiece and ah tool combinationok. On this tool combination normally the temperature will be slightly increase, inthat circumstances what will happen there may be a chance of flame ability.So, your cutting fluid always should avoid all this flaming things it should not catchfire and all those things. So, it should be visa versa, it should drop or it should avoidthe firing that is all of the property. It should be stable whenever you use and andyou you can store it ok it should be completely stable it should not age with respect to thetime ok in it will have certain age are after wards expiry date will be there. So, the expirydate should not be very low that is what the statements says. It should high heat conductingif it can heat conducting ability of the this one will be very high if it falls betweenmy cutting tool and chip if it fall here what will happen it will conduct away most of theheat that is what everybody want conductivity of the fluid will be very high that will takeaway the heat ok. The harmless to the skin of the operators because whenever the workpieceassume that the still we have studied only the turning process.So, workpiece is rotating with very high speed if my cutting fluid is falling what will happen,there may be a chance of splashing it may splash on the hands it may splash on the faceit may splash on the head depend on the operators position if he is like this it may splashon this one, so many things are there. So, even though its spalshes on his face you shouldnot harm the operator ok. Low priced to the minimum production cost; that means, thatthe production cost of this one will be less. So, that you can economic price ok. Theseare all the requirements the properties a consumer looks at whenever he want to purchasethese things ok. How to choose the choice cutting fluids whichtype of cutting fluid I want? This type of cutting fluid you do not want, this type ofcutting fluid I want and all those thing s how do you choose. You will choose based onwhich basis the cutting fluid is select just is the question.So, what is the basis for it type of operation? Whether I am going for turning operation withI am going for the broaching operations, whether I am going for the learning operation thisis one criteria. The second criteria is the rate of material whether I want to removea bulk whether I want to remove a minimal this type of thing with you if I want to goand remove a huge amount of material then I have to choose according to it. If my materialremoval rate is very fast heat temperature will be very high.So, I have to use coolant based cutting fluid my conditions are slowly remove, but largetime if the huge time. So, you go for lubricant based. So, the material of the workpiece ifthe material of the workpiece is very hard so the temperature generation is very hard.So, you have to use both the things because the it also try to upgrade the tool. So, youhave to choose a optimally at the same time material of the tool normally people talkabout the combination and a hardness ratio. Normally tool hardness to the workpiece hardnessshould be slightly higher. If it is higher normally 3 times 5 times, if it is 7 timesthat will be better ok, depend on this combination normally it will you will choose the cuttingfluid also ok. Surface finish requirement if the surface finish on my product is requiredthen I have to obviously, choose lubricant dominator because the lubricant is helps theoperation between my flank surface and the my final product ok.
Video 4: Cutting Fluid in the Machining OperationNow, the cutting fluids depending on the type of machining operation is need to may varywhich is cooling or lubricant. It is same thing that and the effectiveness of the cuttingfluid is depend on the number of factors such as type machining operation and others things.I said in the graph also water is an excellent coolant and the ah cutting fluid depend onthe severity of the particular machining operation if it is a turning operation it is not muchsaviour, but if it is a broaching operation and all those things it is high pressure thingswhere you need proper lubrication and cooling. So, for that purpose you have to use a specialtype of cutting fluids where you will have high pressure additives and all those things.Cutting fluid action normally how the action takes place in terms of heat extraction orthe lubricating. So, normally this is a capillary action just highlight first before readingthis. Cutting fluid seep from the sides of the chip through the capillary action of theinterlocking network of surface asperities at the interface; that means, whenever youare sending a cutting fluid basically it will go from higher concentration to lower concentrationby the capillary action state will go and unlock the interlocking network between chipand tool that is the action. Discontinuous cutting operations have morestraightforward mechanisms for the lubrication application, but tools are more susceptibleto thermal shock ok. What I mean to say whatever the above point this point holds good forcontinuous chips, if you are going for discontinuous chip it is takes forward because ah chip arenot entangling there it will becoming a powder form or a small small fragments. So, the properlubrication and cooling will be done in the machining region; however, this nano particlesor micro particles that are forming is a discrete particles. So, discontinuity will be therein the nano range or a micro range which may cause shocks ok.So, you have to take care about the cutting fluid appropriate cutting fluid in this isprocess. Normally if I am not using the cutting fluid what will happen? So, just let me takean example which I have taken from some other source.A machining operation is being carried out with a cutting fluid that is an effectivelubricant. What will be the changes in the mechanics of the cutting operation if thefluid is shut off? Assume that I am not using the cutting fluid, but I am using the turning.What are the problems that one can experience with operator? So, chain of events takingplace if the cutting fluid is shut off. What are the things? If you see the frictionalat the chip tool interface will increase ok. So, which will destroy the tool the shearingangle will decrease because if the shearing angle decreases what will happen? Lot of problemswill come the temperature in the plastic shearing zone will slightly increase ok. If my shearingangle is like this the line is, if it goes like this what will happen? My length will increase ok.
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