Lubricant and coolant

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1. GOVT INDUSTRIAL TRAINING INSTITUTE SALEM-636007. S.SANKARAN A.T.O,FITTER.

2. OBJECTIVES INTRODUCTION LUBRICANT LUBRICATION LUBRICATOR DEFINITION ABOUT LUBRICANT KINDS OF LUBRICANT PROPERTIES OF LUBRICANT LUBRICATION METHODS LUBRICATORS DISTINGUISH BETWEEN LUBRICANT AND COOLANT

3. INTRODUCTION LUBRICANTS: When friction takes place between two parts made of metal they generate heat. Due to this heat these parts expand little bit in size and some interruption in their smooth movement. Such friction in a machine causes noise as well as the parts start getting worn out. There is therefore, need for making a thin layer of some sticky and greasy substance. These substances are known as lubricants.

4. CLASSIFICATION OF LUBRICANTS Lubricants are classified in three levels 1. Liquid lubricant 2. Semi solid lubricant 3. Solid lubricant

5. DIFINITION ABOUT CLASSIFICATION OF LUBRICANT 1. LIQUID LUBRICANT: Lubricants in the form of liquids like Oils are called liquid lubricants. In this category the following three kinds of oils are included. a) Vegetable oil b) Mineral oil c) Fat oil a) Vegetable oil : The oils extracted from fruits, vegetable and seeds. In this category two types of oils are available. i) Drying oil ii) Non drying oil

6. Vegetable oil types and its Definition Drying oil: Drying oil means, it becomes dry in normal temperature and their greasiness ends, called drying oil. These oils are used to protect precision measuring instrument from moisture. Example : Turpentine oil is generally used in this oil. Non drying oil : Non drying oil means, it which do not get dried easily and their greasiness remains in tact are non drying oil. These oils are used in light duty machines Example :Coconut oil, Mustard oil, Cotton seed oil, Caster oil, Olive oil, Palm oil etc;

7. l b) Mineral oil : These are natural oils. Such oils are extracted from mines like other minerals. These mineral oils are purified in the refineries and different kinds of oils are produced. Such as petrol, diesel, kerosene and gear oil. c) Fat oil : Oils are extracted from fats of water animals and other animals are called fat oils. These oils are used in all kinds of machines. Mainly fats oil is extracted from fats of fish and pigs etc;

8. 2. SEMI SOLID LUBRICANT: Grease and Vaseline are often termed as semi-solid lubricants. Grease in a thick substance which contains stickiness and greasiness. This can be generally divided into two parts. i) Soft grease ii) Hard grease Soft Grease : Soft grease is used at such places where it is difficult to make a film from other lubricants or where it is difficult to do lubrication daily. For lubrication with soft grease, grease cap and nipple are used. Grease is made from mixture of mineral oils and other substances.

9. The quantity of mineral oils in soft grease from 65 ⸓ to 90⸓ Grease is specially prepared for different purpose of lubrication, for example bearing grease, chassis lubrication grease etc; ii) Hard grease : It is used to protect precision instruments, and small cutting tools from rust. Hard grease also of different types. After melting it is applied to the tools and machine parts is allowed to get dry. This grease does not melt at normal temperature and remains stuck to the machine parts and tools.

10. 3. SOLID LUBRICANT: Where liquid and semi solid lubricants cannot be used solid lubricants are used. Wax, graphite, mica etc; come under this category. These substances are good lubricants itself. PROPERTIES OF LUBRICANT All types of lubricant mentioned above have their own properties. Lubricants should be chosen on the basis of their following properties. 1. Viscosity 5.Pour point 2. Oiliness 6.Emulsification 3. Flash point 7. Acidity 4. Fire point 8.Specific gravity

11. DEFINITION ABOUT PROPERTIES OF LUBRICANT Viscosity : The property of flow in a liquid is called viscosity. The thin liquids have low viscosity and thick oils have more viscosity. The viscosity of lubricants is reduced due to temperature in the operation of machines. According to machine, lubricant of appropriate viscosity should be used. If the lubricant is of low viscosity, it would flow out as a thin layer between two parts of a machine. If the lubricant with high viscosity is used it would not be able to reach between the two parts of a machine.

12. Viscosity is known by numbers. Example Light machine oil – 180,210 Engine oil - 260 Compressor oil – 275 Cylinder oil – 2000, 3500 Pump oil – 300, 375 Motor oil – 1200, 3000 Diesel oil – 600, 900 Oiliness : The property of making the surface wet and producing greasiness is called Oiliness. That is why it creates a layer of greasiness between two parts.

13. Flash Point : Temperature at which oil turns into steam and evaporates is called Flash Point. Fire Point : The point at which the steam oil starts burning is called Fire Point. It is usually more than the Flash point by 15º to 20º. Pour Point : Temperature at which oil stops flowing and starts freezing is known as Pour Point. It is important in air conditioners and refrigerators.

14. Emulsification : If a lubricant or oil gets mixed with water it is against the properties of a lubricant. The oil must have the quality of not dissolving in the water. Acidity: Any kind of acidity in oil is against its properties. There should be no acid in water else it would have an adverse impact on the jobs. Specific gravity: The property of oil which enables it to gain weight and remain below the water when it is mixed with water, is known as specific gravity

15. LUBRICATION METHODS Lubrications between two parts of a machine is done in various ways. Some of the methods are as under: 1. Gravity feed method 2. Oil hole method 3. Splash method 4. Sight feed method. 5. Force feed method

16. The sources with whose help lubricant is supplied between the two parts in operation are called lubricators. Generally the following lubricators arrangement is done. 1. Gravity feed method / Wick feed method Under this system, oil is kept in a container at a height from the machine. This lubricant is supplied with the help of cotton wicks through the principle of gravity. There are some machines and its parts, which need constant lubrication drop by drop. These wicks are made of woolen stuff and remains dipped in oil from one end. Oil gets absorbed in the wick and falls in drops from the other end on shaft or other parts.

17. 2. Oil hole method Under this arrangement a small gun metal cup is used. It is particularly used in vertical steam engines. It can also be fitted on other machines in case of need. Under this arrangement also imbrications is in drops and is regular.

18. 3. Splash Method Under this method oil is kept in a pot inside or outside a machine. When a certain part of machine is operated (moves) oil drops are splashed. Then splashed drops of oil reach the machine parts and perform lubrication appropriately. In this method some of the following techniques are used. a) Ring oiling method b) worm gear oil method c) Chain oiling method

19. Ring oiling method In order to lubricate the shafts of some machines, ring lubrications arrangement is used. Under this arrangement oil is filled in a container kept below the shaft. Two rings are provided near the shaft bush. These rings rotate with the shaft and bring up oil for lubrication. Worm gear oiling method In this method, oil is filled in a container. If worm gear will rotates continuously, oil drops are splashed through the gear. Then splashed drops of oil reach the machine parts and perform lubrication appropriately.

20. 4. Sight feed method This arrangement is usually used in oil engines etc. oil is filled in a container like a glass tumbler. Oil is controlled by a valve. When the engine operates valve gets opened and the oil falls on the shaft in drops. When engine is put off, the valve also closes and no oil comes out.

21. 5.ForceFeedMethod Under this method oil is kept in a container outside or inside the machine, which is regularly supplied to the different parts through the various oil channels with adequate pressure. Oil is also supplied through oil can or oil gun. Oil can arrangement Arrangement for lubrication on external parts. An oil container is used for lubrication purposes. When we press its pressure button, oil comes out from the nozzle in the desired quantity, according the pressure.

22. Oil gun arrangement It is used for lubrication of those parts where lubrication is not possible with the oil can. This oil gun is similar to an ordinary syringe, which contains a flexible nozzle. In some oil guns arrangements are made to exert pressure an oil through compressed air.

23. Grease gun arrangement At places where greasing is necessary as per a fixed schedule, greasing gun is used. It looks like a syringe. A piston and a nozzle is used in it. With this greasing can be done with proper pressure. At places where there is need for greasing with great pressure. There is providing for providing pressure of compressed air.

24. COOLANT When metal is cut with a cutting tool, because of friction between the metal and the tool, heat is produced. Although the cut chips absorb this heat yet some heat has to be borne by cutting tools and jobs. However job may not be damaged by this heat but the cutting tool can be damaged. With heat the temper of cutting tools wears out and their cutting capacity is also reduced.

25. Finishing, clean and quick cutting cannot be done with these cutting tools. Coolants are used for protecting these cutting tools. In the old days, only water was used as a coolant but on the modern age tremendous progress has been achieved in engineering. As a result a number of effective coolants have been invented which are known by the name of the cutting fluids. Cutting fluids have the following advantages in addition to being coolants.

26. ADVANTAGES OF CUTTING FLUID 1. It perform lubrication between the job and the cutting tool. 2. It keeps the jobs and the cutting tool at normal temperature and save them from burning. 3. It saves the job, tool and cutting chip from blending. 4. It saves the job from rust. 5. Increases the life of the tool. 6. Keeps the tip or edge of the tool away from the chips. 7. It brings good finishing on the job cutting 8. The rate of cutting increases.

27. KINDS OF CUTTING FLUIDS For different jobs different kinds of fluids are used. These can be divided into two parts: 1. Mineral and animal oil. 2. Soluble oil. 1. Mineral and animal oil: There are certain jobs and spaces, where the coolant water can harm the machine, instrument or the job. At such places fluid without water is used. These fluids include kerosene oil, animal oil, diesel, turpentine oil, or mobile oil. They function as coolants and lubricants.

28. Soluble oil: This type of cutting fluid is prepared from animal oils, Vegetable oils, mineral oils, and chemicals. These materials are soluble in water and these are mixed with water and used as coolants. The mixture is composed of one part of oil and 4 to 20 parts of water. The emulsion should be prepared by pouring the oil into the water and not by pouring the water into oil. To secure the best results with mixture of oils or emulsions which the consumer mixes in his own shop. Instructions from the manufacturer should be rigidly followed.

29. Oils and compounds for Different Operations The following general recommendations are followed in normal practice for machining different materials. 1. Low carbon steel: For Turning, soluble oils, straight minerals oils or lard oil is used. For Drilling and Milling soluble oil with one part of oil and 10 to 20 parts of water is most satisfactory. For tapping mineral oils are used. For Grinding, soluble oil is best. For broaching in steels, a heavy mineral oil or soluble oil emulsion is used. For thread cutting soluble oil with 1:15 is used.

30. 2. Alloy steels and high carbon steels For Turning mineral land oil or 70% mineral oil and 30% sulphur base oil is used. For milling mineral or lard oil or soluble oil with 1:19 is most suitable. For Tapping mineral or lard oil is used. For Drilling generally soluble oil with 1:15 or mineral oil is used. 3. Cast Iron It is generally worked dry or compressed air may be used as a coolant.

31. 4. Brass It is machined dry when it is a cast brass. For brass rod straight mineral of Mixture of mineral oil with 10% lard oil is used. 5. Aluminium Some of the aluminium alloys have been successfully machined dry. But to attain best results kerosene oil mixed with 10% mineral oil is used.