LATHE MACHINE

MACHINING OPERATIONS AND MACHINE TOOLS

1. Turning and Related Operations

2. Drilling and Related Operations

3. Milling 4. Machining & Turning Centers

5. Other Machining Operations

6. Shape, Tolerance and Surface Finish

7. Machinability

8. Selection of Cutting Conditions

9. Product Design Consideration

1. Turning & Related Operations

•Turning –a machining process in which a single-point tool remove material from the surface
of a rotating work piece. (Lathe)
Other Lathes & Turning Machine

•Tool room Lathe and Speed Lathe

•Turret Lathe –The tailstock is replaced with a turret

•Chucking Machines –No tailstock

•Automatic Bar Machine –Similar to chuck machine but with a collet –A single-and multiple-
spindle bar machines

•NC Lathe

1 Boring Machining
•Boring –Cutting is done inside diameter of the work material

Horizontal Boring Machining Vertical Boring Machining

There are many different types of internal combustion engines. They can be classified by:

1. Application: Automobile, truck, locomotive, light aircraft, marine, portable power system,
power generation

2. Basic engine design: Reciprocating engines (in turn subdivided by arrangement of cylinders:
e.g., in-line, V, radial, opposed), rotary engines

3. Working cycle: Four-stroke cycle: naturally aspirated (admitting atmospheric air),

4. Valve or port design and location: Overhead (or I-head) valves, under head (or L-head) valves,
rotary valves, cross-scavenged porting (inlet and exhaust ports on opposite sides of cylinder at
one end), loop-scavenged porting (inlet and exhaust ports on same side of cylinder at one end),
through- or inflow- scavenged (inlet and exhaust ports or valves at different ends of cylinder)
 5. Fuel. Gasoline (or petrol), fuel oil (or diesel fuel), natural gas, liquid pet- roleum gas, alcohols
(methanol, ethanol), hydrogen, dual fuel

6. Method of mixture preparation. Carburetion, fuel injection into the intake ports or intake
manifold, fuel injection into the engine cylinder

7. Method of ignition. Spark ignition (in conventional engines where the mixture is uniform and
in stratified-charge engines where the mixture is non-uniform), compression ignition (in
conventional diesels, as well as ignition in gas engines by pilot injection of fuel oil)

8. Combustion chamber design: Open chamber (many designs: e.g., disc, wedge, hemisphere,
bowl-in-piston), divided chamber (small and large auxiliary chambers; many designs: e.g., swirl
chambers, pre-chambers

9. Method of load control. Throttling of fuel and air flow together so mixture composition is
essentially unchanged, control of fuel flow alone, a com- bination of these

10. Method of cooling. Water cooled, air cooled, uncooled (other than by natural convection
and radiation)

ENGINE OPERATING CYCLES

Cost of this book is about reciprocating engines, where the piston moves back and forth in a
cylinder and transmits power through a connecting rod and crank mechanism to the drive shaft
as shown in Fig. 1-1. The steady rotation of the crank produces a cyclical piston motion. The
piston comes to rest at the top center (TC) crank position and .bottom-center (BC) crank
position when the cylinder volume is a minimum or maximum, respective1y.t The minimum
cylinder volume is called the clearance volume V,.
The volume swept out by the piston, the difference between the maximum or total volume L
(and the clearance volume, is called the displaced or swept volume V. The ratio of maximum
volume to minimum volume is the compression ratio typical values of r, are 8 to 12 for SI
engines and 12 to 24 for CI engines. The majority of reciprocating engines operate on what is
known as the four-stroke cycle. Each cylinder requires four strokes of its piston-two revolutions
of the crankshaft-to complete the sequence of events which produces one power stroke. Both
SI and CI engines use this cycle which comprises (see Fig. 1-2):

1. An intake stroke, which starts with the piston at TC and ends with the piston at BC, which
draws fresh mixture into the cylinder. To increase the mass inducted, the inlet valve opens
shortly before the stroke starts and closes after it ends.

2. A compression stroke, when both valves are closed and the mixture inside the cylinder is
compressed to a small fraction of its initial volume. Toward the end of the compression stroke,
combustion is initiated and the cylinder pressure rises more rapidly.

3. A power stroke, or expansion stroke, which starts with the piston at TC and ends at BC as the
high-temperature, high-pressure, gases push the piston down and force the crank to rotate.
About five times as much work is done on the piston during the power stroke as the piston had
to do during compression

4 An exhaust stroke, where the remaining burned gases exit the cylinder: first, because the
cylinder pressure may be substantially higher than the exhaust pressure: then as they are swept
out by the piston as it moves toward TC. As tile piston approaches TC the inlet valve opens. Just
after TC the exhaust value closes and the cycle starts again.

ENGINE COMPONENT
ENGINE COMPONENTS

Labeled cutaway drawings of a four-stroke SI engine and a two-stroke CI engine are shown in
Figs. 1-4 and 1-5, respectively. The spark-ignition engine is a four- cylinder in-line automobile
engine. The diesel is a large V eight-cylinder design with a inflow scavenging process. The
function of the major components of these engines and their construction materials will now be
reviewed. The engine cylinders are contained in the engine block. The block has traditionally
been made of gray cast iron because of its good wear resistance and low cost. Passages for the
cooling water are cast into the block. Heavy-duty and truck engines often use removable
cylinder sieves pressed into the block that can be replaced when worn. These are called wet
liners or dry liners depending on whether the sleeve is in direct contact with the cooling water.
Aluminum is being used increasingly in smaller SI engine blocks to reduce engine weight. Iron
cylinder liners may be inserted at the casting stage, or later on in the machining and assembly
process. The crankcase is often integral with the cylinder block. The crankshaft has traditionally
been a steel forging; nodular cast iron crankshafts are also accepted normal practice in
automotive engines. The crank- shaft is supported in main bearings. The maximum number of
main bearings is one more than the number of cylinders; there may be less. The crank has
eccentric portions (crank throws); the connecting rod big-end bearings attach to the crank pin
on each throw. Both main and connecting rod bearings use steel- backed precision inserts with
bronze, Babbitt, or aluminum as the bearing materials. The crankcase is sealed at the bottom
with a pressed-steel or cast aluminum oil pan which acts as an oil reservoir for the lubricating
system.

Pistons are made of aluminum in small engines or cast iron in larger slower-speed engines. The
piston both seals the cylinder and transmits the combustion-generated gas pressure to the
crank pin via the connecting rod. The connecting rod, usually a steel or alloy forging (though
sometimes aluminum in small engines), is fastened to the piston by means of a steel piston pin
through the rod upper end. The piston pin is usually hollow to reduce its weight.
 WIELDING PROCESSING
Wielding: is the permanent joining of two or more metal material together.
NAME: BALOGUN TAIBAT OMOLOLA
DEPARTMENT: CIVIL ENGINEERING
MATRIC NO:CVE/2015/0023
COURSE CODE:MEE208
DATE:19/06/2017