major project1.pptx

7/28/2019 major project1.pptx

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INTRODUCTION

Surface roughness has become the most significanttechnical requirement and it is an index of product quality. Inorder to improve the mechanical properties like :-

Fatigue strength

Corrosion resistanceA reasonably good surface finish is desired. Nowadays,the manufacturing industries specially are focusing theirattention on dimensional accuracy and surface finish. In orderto obtain optimal cutting parameters to achieve the best

possible surface finish, manufacturing industries have resortedto the use of handbook based information and operatorsexperience. This traditional practice leads to improper surfacefinish and decrease in the productivity due to sub-optimal useof machining capability.


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OPERATION

Turning operations

Turning is the removal of metal from the outer

diameter of a rotating cylindrical work piece. Turningis used to reduce the diameter of the work piece,

usually to a specified dimension, and to produce a

smooth finish on the metal.


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Turning is the most commonly used method

for metal cutting. Turning operations are

evaluated based on the performance

characteristics such as :-

Surface Roughness

Material Removal Rate

Tool Wear

Tool life

Cutting force.


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PARAMETER

These performance characteristics are strongly

correlated with cutting parameter such as :-

Cutting Speed

Feed Rate

Depth of cut.It is an important task to select cutting

parameter for achieving high cutting performance.

There is need to operate this machines are efficiently as

possible in order to obtained required payback.

Achieving desire surface quality is of great importance

for the functional behavior of the mechanical parts.


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Adjustable Parameters in Turning

Operation

In turning operation a piece of material

(wood, metal, plastic, or stone) is rotated and

a cutting tool is traversed along 2 axes of

motion to produce precise diameters and

depths. Turning can be either on the outside

of the cylinder or on the inside (also known as

boring) to produce tubular components tovarious geometries.


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The turning processes are typically

carried out on a lathe, considered to be theoldest machine tools, and can be of four

different types such as :-

Straight Turning Taper Turning

Profiling or External Grooving


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Those types of turning processes can

produce various shapes of materials such as:- Straight

Conical

Curved

Grooved work piece.

Turning is the process whereby a single

point cutting tool is parallel to the surface. Itcan be done manually, in a traditional form oflathe.


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Conventional Lathe:

A lathe is a machine tool used principallyfor shaping pieces of metal, wood, or othermaterials by causing the work piece to be held

and rotated by the lathe while a tool bit isadvanced into the work causing the cuttingaction. Lathes can be divided into three types foreasy identification:

Engine lathe Turret lathe

Special purpose lathes.


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EssentialFeatures of The Lathe

Bed and Ways :- The bed is the base forthe working parts of the lathe. The mainfeature of the bed is the ways which are

formed on the bed's upper surface and whichrun the full length of the lathe. The tailstockand carriage slide on the ways in alignmentwith the headstock. The headstock is normally

permanently bolted at one end (at theoperator's left).


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Headstock:- The headstock carries the headspindle and the mechanism for driving it. In the

belt-driven type headstock, the driving mechanismconsists merely of a cone pulley that drives thespindle.

Tailstock:- The primary purpose of the tailstock

is to hold the dead center to support one end ofthe work being machined between centers.However, it can also be used to hold live centers,tapered shank drills, reamers, and drill chucks. The

tailstock moves on the ways along the length ofthe bed to accommodate work of varying lengths.It can be clamped in the desired position by thetailstock clamping nut.


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EngineLathes.

The engine lathe is intended for generalpurpose lathe work and is the usual lathe foundin the machine shop. The engine lathe may bebench or floor mounted The engine lathe consists

mainly of :- Headstock

Tailstock

Carriage

and a bed upon which the tailstock and

carriage move.


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Most engine lathes are back-geared and

high torque, which is required for machining

large diameter work pieces and taking heavy

cuts. The usual engine lathe has longitudinal

power and cross feeds for moving the

carriage. It has a lead screw with gears to

provide various controlled feeds for cutting


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Bench-Type Engine Lathe

The bench-type engine lathe is the most

common general purpose screw cutting lathe

normally found in a small shop. It commonly

has an 8 to 12 inch swing and a 3 to 5 foot bed

length, the size being limited by the

practicality of bench mounting. The bench

upon which the lathe is mounted may be astandard wood-topped shop bench or a

special metal lathe


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Carriage:- The carriage carries the crossfeed slide and the compound rest which in

turn carries the cutting tool in the tool post.

The carriage slides on the ways along the bed.

Apron:- The apron is attached to the front

of the carriage. It contains the mechanism

that controls the movement of the carriage for

longitudinal feed and thread cutting. It

controls the lateral movement of the cross-

slide.


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Floor-MountedEngine Lathe

The floor-mounted engine lathe or pedestal-typeengine lathe, is inherently more rigid than the bench-type lathe and may have a swing as great as 16 or 20

inches and a bed length as great as 12 feet, with 105inches between centers. The drive motor is located inthe pedestal beneath the lath headstock. A tensionrelease mechanism for loosening the drive belt is

usually provided so that the drive belt may be quickly

changed to different pulley combinations for speedchanges.


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SlidingGap-Type Floor-Mounted

Engine LatheThe sliding gap-type floor-mounted lathe orextension gap lathe contains two lathe beds, thetop bed or sliding bed, and the bottom bed .Thesliding bed mounts the carriage and the tailstock

and can be moved outward, away from theheadstock as desired. By extending the slidingbed, material up to 28 inches in diameter may beswung on this lathe. The sliding bed may also be

extended to accept between centers work piecesthat would not normally fit in a standard lathe ofthe same size.


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DesignofExperiments:

TaguchiMethods

Design of Experiment (DOE) has been

implemented to select manufacturing process

parameters that could result in a better

quality product. The DOE is an effective

approach to optimize the throughput in

various manufacturing-related processes. In

their study, three independent variables,


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each with three levels, had total of (33) = 27

experimental runs. Oftentimes, the optimum

metal cutting process required studying morethan three factors for the cutting parameters.

For example, if a DOE setup considered

four or five independent variables, each withat least three levels, then (34) = 81 runs or

(35) = 243 runs were required in the

experiments.


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Purposeof Study

There were two purposes of this research.

The first was to demonstrate a systematic

procedure of using Taguchi parameter design

in process control of individual lathe

machines. The second was to demonstrate a

use of the Taguchi parameter design in order

to identify the optimum surface roughnessperformance with a particular combination of

cutting parameters in a lathe operation.

Procedure and Steps of Taguchi


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Procedure and Steps of Taguchi

Parameter Design


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Orthogonal arrays have a balanced

property in which every factor setting occurs

the same number of times for every setting of

all other factors in the experiment.

Orthogonal arrays allow researchers or

designers to study many design parameterssimultaneously and can be used to estimate

the effects of each factor independent of the

other factors. Therefore, the informationabout the design parameters can be obtained

with minimum time and resource.


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Selection of Orthogonal Array

There are 18 basic types of standard OrthogonalArrays (OA) in the Taguchi parameter design(Torng, Chou, & Liu,1997). Since four factors werestudied in this research, three levels of each

factor were considered. Therefore, an L18Orthogonal Array (L18 (21 x 37)) was selected forthis study. The layout of this L18 OA is shown infig. Each run will have three data collected.

Therefore, a total of (18*3) = 54 data values werecollected, which were conducted for analysis inthis study.


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Variable factor levels

Controllable

Factors

Level 1 Level 2 Level 3

A: Depth of cut

B: Cutting speed

C: Feed rateD: Tool diameter


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Orthogonal array (L18(21 x 37))

Column No.

Trial No. 1 2 3 4 5 6

1 1 1 1 1 1 1

2 1 1 2 2 2 2

3 1 1 3 3 3 3

4 1 2 1 1 2 2

5 1 2 2 2 3 3

6 1 2 3 3 1 1

7 1 3 1 2 1 3

8 1 3 2 3 2 1

9 1 3 3 1 3 2

10 2 1 1 3 3 2

11 2 1 2 1 1 3

12 2 1 3 2 2 1

13 2 2 1 2 3 1

14 2 2 2 3 1 2

15 2 2 3 1 2 3

16 2 3 1 3 2 3

17 2 3 2 1 3 1

18 2 3 3 2 1 2

R lt T bl


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Result Table

Experimen

t No. 1

2. (A) Depth of

cut (in)

3. (B) Cutting

speed(rpm)

4 .(C)Feed Rate

(ipm)

5. (D)Back Rack

angle(0C)

Surface

Measurment

1 1

2 1

3 1

4 1

5 1

6 1

7 1

8 1

9 1

10 2

11 2

12 213 2

14 2

15 2

16 2

17 2

18 2


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Thank You

major project1.pptx

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