knowledge about the friction and reduce the heat or friction

1. DEPARTMENT OF MECHANICAL
ENGINEERING
Presented by: Presented to:
Rajat yadav Dr. Vijay kumer Dwivedi
M.Tech

2. How does friction affect object?
Work piece Die interface (friction)
reduce the friction using lubricant

3. What Causes Friction?
 The amount of friction depends on:
 Roughness of the surfaces (type of surface)
 Motion of the surfaces
 Force pushing the surfaces together

6. Contd…..
 Friction acts in a direction opposite to the direction of the
object’s motion.
 Without friction, a moving object might not stop until it strikes
another object.

7.  Try rubbing your hands together at a quick
pace.. You should feel heat!
 Friction between surfaces produces heat
 Friction causes the molecules on the surface
of your hands to move faster.
 As the molecules move faster, the
temperature of the object increases.
Friction and Heat

8. Types of Friction
 Kinetic friction occurs when force is applied to an object and
the object moves.
 Examples:
Sliding Friction: pushing an object across a surface
Rolling Friction: between wheels and a surface
Fluid Friction: opposes the motion of objects traveling
through a fluid (air or water)

9. Static Friction
 The friction that acts on objects that are not moving is called
static friction.
 For example, think about what happens when you try to push a
heavy desk across a floor.
 If you push on the desk with a force less than the force of
static friction between the desk and the floor, the desk will not
move.
 To make the desk move, you must exert a force greater than
the force of static friction.
 Once the desk is moving, there is no longer any static friction.

10. Sliding Friction
 Sliding friction occurs when two solid surfaces slide over each
other.
 For example, you can spread sand on an icy path to improve
your footing.
 Ballet dancers apply a sticky powder to the soles of their ballet
slippers so they won’t slip on the dance floor.
 And when you stop a bicycle with hand brakes, rubber pads
slide against the tire surfaces, causing the wheels to slow and
eventually stop.
 On the other hand, sliding friction is a problem if you fall off
your bike and skin your knee!

11. Rolling Friction
 When an object rolls across a surface, rolling friction occurs.
 Rolling friction is easier to overcome than sliding friction for
similar materials.
 This type of friction is important to engineers who design
certain products.
 For example, skates, skateboards, and bicycles need wheels
that move freely.

12. Contd…..
 So engineers use ball bearings to reduce the friction between
the wheels and the rest of the product.
 These ball bearings are small, smooth steel balls that reduce
friction by rolling between moving parts.

14. Fluid Friction: Air Resistance
 Most objects falling through air experience a type of fluid
friction called air resistance.
 Air resistance is not the same for all objects.
 The greater the surface area of the object the greater the air
resistance.
 However, since the elephant has more mass, it has more
downward force of gravity and falls faster.

15. Workpiece die interface

16. Reducing Friction
 To reduce the amount of friction, apply a lubricant between two
surfaces.
 Motor oil, wax, and grease are examples.
 Friction can also be reduced by rolling, rather than pushing, an object.

17. Increasing Friction
 Friction increases as surfaces are made rougher.
 Friction increases when the force between two objects is
increased.

18.  Reduces friction and wear between moving parts
 Transfers heat away from engine parts
 Cleans the inside of the engine
 Cuts power loss and increases fuel economy
 Absorbs shock between moving parts
Lubrication system function

19.  Components:
 engine oil
 oil pan
 pressure relief valve
 oil filter
 oil galleries
Lubrication system operation

20. Typical Lubrication System

21. System Components

22. Operation
 Oil pump pulls oil out of the pan
 Pickup screen removes large particles
 Pump pushes oil through the oil filter and galleries
 Oil filter removes very small particles
 Filtered oil flows to camshaft, crankshaft, lifters, rocker
arms and other moving parts

23. Engine Oil
 Keeps moving parts from making direct contact
 Reduces friction
 Refined from petroleum (crude oil)
 Synthetic oils are made from substances other than crude
oil

24. lubricant Film
lubricant film separates engine parts, preventing
metal-on-metal contact

25. Bearing Types

26. Oil Viscosity (Weight)
 Thickness or fluidity of engine oil
 High viscosity number - SAE 30
 thick oil
 Low viscosity number - SAE 5
 thin oil
 Viscosity number is printed on container (standardized by
SAE)

27. Temperature Effects
 Cold oil is very thick and resists flow
 When heated, oil thins and becomes runny
 If it becomes too hot and thin, the oil film can break down
and part contact can result

28. Single and Multi-viscosity Oils
 Single viscosity—SAE 20, 30 or
40
limited range of operating
temperatures
not as stable as multi-viscosity
oil
 Multi-viscosity—SAE 10W-30,
20W-50
exhibits characteristics of a thin
light oil when cold and a
thicker, heavy oil when hot

29. Scope of tribology in engg. application
They considered the four main energy consuming
sectors: transport, manufacturing, power generation, and residential. The
following were concluded:
• In total, ~23% of the world’s energy consumption originates from
tribological contacts. Of that, 20% is to overcome friction and 3% to
remanufacture worn parts and spare equipment due to wear and wear-related.
• Implementing advanced tribological technologies can also reduce
global carbon dioxide emissions by as much as 1,460 metric tons of carbon
dioxide equivalent (MtCO2) and result in 450,000 million Euros cost savings
in the short term. In the long term, the reduction could be as large as 3,140
MtCO2 and the cost savings 970,000 million Euros.

30. Schematic of diamond nanoparticles during grinding
and polishing

31. Conclusion
 Control of friction processes is extremely difficult, or
even impossible because of the complexity and
diversity of phenomena occurring on a standard
dynamic contact.

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