LUBRICANT-COOLANT-LUBRICATION-FITTER ONLINE NOTE

LUBRICANT-COOLANT-LUBRICATION

i)- With the movement of two mating parts of the machine, heat is generated. 

ii)- If it is not controlled the temperature may rise resulting in total damage of the mating parts. 

iii)- Therefore a film of cooling medium with high viscocity is applied between the mating parts which is known as a ‘lubricant’.

iv)- A ‘lubricant’ is a substance having an oily property is available. 

v)- The property available in the form of fluid, semi-fluid, or solid state. 

vi)- lubricant is the lifeblood of the machine.

vii)- It is keeping the vital parts in perfect condition and prolonging the life of the machine. 

viii)- It saves the machine and its parts from corrosion, wear and tear, and it minimizes friction.

Purposes of using lubricants:-

1)- Reduces friction. 2)- Prevents wear. 3)- Prevents adhesion. 4)- Aids in distributing the load. 5)- Cools the moving elements. 6)- Prevents corrosion. 7)- Improves machine efficiency.

Properties of lubricants

a)- Viscosity, b)- Oiliness, c)- Flash point, d)- Fire point, e)- Pour point.

a)- Viscosity

i)- It is the fluidity of an oil by which it can withstand high pressure or load without squeezing out from the bearing surface.

ii)- The viscosity thickness of oil can be checked by this. 

iii)- More the thickness of oil means more viscosity and less thickness of oil has less viscosity.

iv)- In this property of oil is indicated by numbers like SAF -30, SAF-40 etc.

v)- It is checked by visco-meter.

b)- Oiliness

i)- It is that property of a lubricant in which thin layer of oil film is formed in between two moving parts 

ii)- Oiliness refers to a combination of wettability, surface tension and slipperiness. (The capacity of the oil to leave an oily skin on the metal.)

c)- Flash point:-

 It is a that property of an oil in which lubricant at certain special temperature inverted into steam known as its flash point. 

Each oil has separate flash point therefore selection of an oil for bearings, 

the flash point of oil should be less than the working temperature of bearing. 

Thus there is no chance of fire.

d)- Fire point 

i)- It is the temperature at which the oil catches fire and continues to be in flame.

ii)- It is that temperature at which oil vapor catches fire. 

iii)- This temperature is 15 degree to 20 degree higher than flash point .

iv)- during selection of an oil it should be remembered that working temperature of lubricant should be less than flash and fire point.

e)- Pour point 

i)- The temperature at which the lubricant is able to flow when poured.

ii)- It is that temperature at which on cooling it become thick and stop to flow. 

iii)- It's importance is seen in ice making  machines, refrigerator etc.

f)- Emulsification: 

i)- Good quality of an oils do not dissolve in water. 

ii)- When oil comes in contact widh water is called Emulsification like steam turbine, steam engine or hydraulic turbine etc.

g)- Acidity: 

i)- An acid should not have quantity in oil but if it is there it will badly effect on bearing metal.

h)- Oxidation: 

i)- When lubricant comes in contact with hot air it oxidized with the result oil becomes thick thus reduce the flow of oil.

i)- Votatility: 

i)- There should be less emulsification of an oil otherwise fuel consumption will be more.

j)- Specific Gravity: 

i)- It is that property of an oil at which its weight is compared with water at 30" F.

k)- Co-lour: 

i)- Normally oils are available in different colaurs like yellow, red., green, black and brown etc. 

ii)- As per thmb-rule lubricants with high boiling point have dark colour.

Classification of Lubricants: 

Normally lubricants are classified into three groups:

1. Liquid lubricants, 2. Semi solid lubricants, 3. Hard lubricants.

1. Liquid Lubricants: 

i)- The lubricants available in liquid form are called liquid lubricants like mobile oil, spindle oil etc. 

ii)- Some lubricants are available in thick form and some in thin form as below:

1)- Vegetable oils, 2)- Animal fat oils, 3)- Mineral oils, 4)- Synthetic oils

1)- Vegetable oils: 

i)- These oils are extracted from fruits, vegetables, trees, plants, and seeds. 

ii)- These are having two types (a) Drying oils, (b) Non-drying oils

(a) Drying oils: 

i)- Those oils which vaporized at low temperature are used to stop the oiliness and dry the moisture like Turpin oil etc.

(b) Non-drying oils: 

i)- Those oils having oiliness and dry quickly like mustard oil, sunflower oil, linseed oil, cocomut oil, olive oil and neem oil etc. 

ii)- These are good lubricants

(2) Animal fat oils: 

i)- These oils are produced from flash and fat of an animals like lard oil, tallow oils, whale and seal etc. 

ii)- These oils are used in light and heavy machines for lubricants.

(3) Mineral oils: 

i)- This oil is available from earth in liquid mineral form.

ii)- These oil after purification it is divided into many class like kerosene oil., petrol, diesel, mobile oil, spindle oil. gear oil etc. 

iii)- These are cheaper and do good work. 

iv)- Now-a-days these are mostly used.

(4) Synthetic oil: 

i)- This oil is not available from nature.

ii)- It produces in refinery. 

iii)- Then their properties resemble with minerals oil. 

iv)- These are normally made from coal, sand etc. and these are the mixture of following chemical compound 

Synhetic asters, silicones, organo - phosphate esters, silicate esters, poly silkiness glycol etc.

v)- These are mostly used for high temperature and speed like engine of an aeroplane or chance of quick hot to cold or cold to hot but it is costly.

2. Semi solid lubricants: 

i)- These lubricants have oily base.

ii)- Its thickness is more than others oils. Grease comes in this class,

iii)- There are two main types of grease:

(a) Soft grease, (b) Hard grease.

(a) Soft Grease: 

i)- This is used in such places where due to high temperature liquid lubricant not resist (stand) and not possible to lubricate every day. 

ii)- Grease is filled up in cup with the result lubricant automatically reaches in the parts of moving machine.

iii)- Grease is a mixture of artificial oil and petroleum in which some another materials are mixed to make semi-solid .

iv)- Soft grease has 65% to 90% mineral oil and rest another materials.

v)- According to use of grease divided into following these classes.

(a) Sodium base grease: It is used on machines running at high speed.

(b) Calcium base grease: It is used on machines running at low speed.

(c) Aluminium base grease: This type of grease is used on flat surfaces slide on each other.

b)- Hard Grease: 

It is used for sharp edge tools to protect long life milling cutlers from rust because it does not melt on normal temperature. 

There are so many types of grease like tallow, petro leum etc.

3. Hard Lubricants: 

i)- Hard lubricants are used in such places where liquid or semi liquid not resist on pressure or temperature.

ii)- The best lubricants in hard lubricant are graphite, wax, tallac etc. 

iii)- Which self act as lubricant.

Lubricator: 

i)- The method by which lubricant reaches in the machine parts known as lubricators. 

ii)- Some special lubricators are a)- Lieuvains glass lubricators, b)- Wick Lubricators, c)- Ring oiling system, d)- Tell tale lubricators, e)-Cylinder oil cup system, f)- Hand pressure grease lubricator, g)- Motor pump pressure.

Methods of lubrication: 

The following methods are used to give oil (lubricant) in the machines.

1)- Gravity Feed System: 

i)- In this system due to gravity of earth oil itself reaches to parts of a machine. 

ii)- In this system oil is filled in the glass bottle and place it on high place and reaches up to machine parts drop by drop with the help of cotton pads.

iii)- In this lieutenant's glass lubricators are only used. 

2. Force Feed System: 

i)- This is the best system for continuous flow of oil in machine parts. 

ii)- In this, force is applied for lubricant to reach up to machine parts like oil-cane, oil gun, grease gun, grease cup, oil pump etc.

3. Splash Feed System: 

i)- In this system a ring is placed near the bearing fitted on shaft . 

ii)- The oil filled vessels placed below the ring. 

iii)- So when shaft rotate then it will also rotate the ring and ring with jumping of an oil reaches in bearing. 

iv)- This is the one of the best method of lubrication because there is no chance of oil littering out.

Remembered during the use of lubricant.

i)- There should be knowledge of oil or grease point.

ii)- In Select proper lubricant.

(iii) Select proper lubricant instrument.

(iv) Use lubricant.

COOLANT

Coolant is a such type of mixture which is used to reduce the heat produce by friction during cutting of job by cutting tool.

There are two types of coolant.

1. Coolant having lard oil and fish oil in it.

2. Coolant having quantity of water in it as water, it self is a good coolant because it has more capacity to bear heat as compared to another liquid materials but due to some disadvantages it is not used in place of coolant because fear of rust on machine with its use.

To protect from this some cutting oil is added in the water. 

There are following types of coolant:

1. Air: 

i)- Air also act as coolant. 

ii)- Normally machining on jobs made of cast iron compressed air is used. 

iii)- In addition to it fan is provided with engine or motor for air with force is applied for cooling the engine.

2. Cutting oil: 

i)- To get good finish on different metals during working at high speed different types of an oils are used in place of coolant .

ii)- Kerosene oil is used as oil coolant during operation on cast iron .

iii)- But working on hard steel Mobil oil, lard oil, soluble oil is used.

3. Soluble oil: 

It is cheap and mostly used coolant and used by mixing with water and the quantity of soluble oil in mixture.

It should be according to manufacturing company and during its preparation it should be properly mixed.

The following three types of soluble oils are available from Indian oil corporation:

(a) Servo cut 'S

b)- in Servo cut "XL'

c)- Servo cut clear

a) Servo cut "S" : 

i)- It has good capacity of cooling and lubricant and give good surface and tool-wear. 

ii)- For normal works 5% water is added but for grinding thin solution is made. 

iii)- It gives milky co-lour on mixing with water and used for both ferous and non ferrous metals.

(b) Servo cut 'XL': 

i)- It is best quality soluble oil. 

ii)- It can also dissolve in hard water.

iii)- It give mud type co-lour on mixing with water.

c)- Servo cut clear: 

i)- When this coolant mix in water it is transparent ie., job and tool can be seen during machining. 

ii)- It has good property of cooling and lubricating thus life of tool increases and gives fine finish.

Note: Remember servosynth cutting oil should not be used on non-ferrous metals.

Properties of good coolant: Good coolant has following good properties:

(a) Coolant should have such property that it should not be effected by atmosphere like it should not freeze in winter.

(b) Coolant should not have such an element which effect the health of the worker and job.

(c) Coolant should have property to flow so that it can maximum used on job and cutting tool.

d)- It should have property to bear heat.

e)- It should be oily.

f) It should have strength to quickly cocl the job and tool.

g) The machine and job should not be rusty with its use.

h) It should help to have fine finish.

(i) It should be easily soluble in water.

j) It should protect the metals from welding.

k) It should be cheap and easily available.

l) It should not produce fume and steam.

System of application of coolant: 

There are three main types of application of coolant:

i)- Drip cane method

ii)- in Pump drip method

iii)- General distribution method

Drip cane method: 

i)- In this system a tank is fitted at the top of machine with nut-bolt having pipe below the tank with nozzle in the front of pipe. 

ii)- It can be set at any where over the tool so that coolant fall on tool.

iii)- In this system has disadvantage that coolant cannot be reuse.

pump drip method: 

i)- In this system a tank is fitted below the base of a machine having electric motor pump. 

ii)- The coolant is replace over the job and tool with the help of flexible pipe fitted with this pump and the same coolant is brought back with the help of pipe into tank so this can be used again and again.

General distribution Method: 

i)- Where the numbers of machines are in line and to bring coolant at every machine this system is used.

ii)- It has big tank having electric motor pump. 

iii)- The pipe is connected with the pump having small pipes which bring the coolat to each machine the coolant which fell down after cooling the job and tool again entered into tank by these pipes thus same coolant can be reused.