A Project Report on

DESIGN AND MANUFACTURE OF MASTER PIECES OF

ROLLER HOOK BY USING CNC TECHNIQUES AND SAND

CASTING PROCESS

Submitted to

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD, HYDERABAD.

In partial fulfillment of the requirements for the award of the degree of

BACHELOR OF TECHNOLOGY In

Mechanical Engineering

By

CHADA PRADEEP REDDY (138P1A0306)

POLKAMPALLY PRANAY KUMAR (138P1A0326)

T VINOD KUMAR (138P1A0333)

KARNAVATH ANAND NAIK (138P1A0309)

Under the Guidance of

Mr. B.SHRAVAN KUMAR

Asst. Professor

AAR MAHAVEER ENGINEERING COLLEGE

(Approved by AICTE, Affiliated to JNTUH, Hyderabad.)

Vyasapuri, Bandlaguda, post: Keshavagiri, Hyderabad, 500005

i

CERTIFICATE

This is to certify that the project entitled Design and Manufacture of

Master Pieces of Roller Hook by Using CNC Techniques and Sand Casting

Process submitted by Chada Pradeep Reddy, Polkampally Pranay Kumar,

T Vinod Kumar, Karnavath Anand Naik in the partial fulfillment of the

requirement for the award of B.Tech degree in Mechanical Engineering,

AAR Mahaveer Engineering College, Bandlaguda, is a record of the student’s

own work carried out by them under my supervision. The matter embodied in

this project report is original and has not been submitted for the award of any

other degree.

INTERNAL GUIDE

Mr. B. SHRAVAN KUMAR Mr. A.NARAYANA

Asst. Professor HOD (Mechanical)

EXTERNAL EXAMINAR

ii

DECLARATION

This is to certify that the Project entitled Design and Manufacture of

Master Pieces of Roller Hook by Using CNC Techniques and Sand Casting

Process. which is submitted by us in partial fulfillment of the requirement for the

award of B.Tech degree in Mechanical Engineering, AAR Mahaveer

Engineering College, Bandlaguda, comprises only our original work and due

acknowledgement has been made in the text to all other material used.

We, hereby, further declared that in case of any legal dispute in relation to

our B.Tech project, we shall be solely responsible for the same.

Date: Name of Students

Chada Pradeep Reddy (138P1A0306)

Polkampally Pranay Kumar (138P1A0326)

T Vinod Kumar (138P1A0333)

Karnavath Anand Naik (138P1A0309)

iii

ACKNOWLEDGEMENT

We are indeed very happy to greatly acknowledge the numerous

personalities involved in lending their help to make our project on “Design and

Manufacture of Master Pieces of Roller Hook by Using CNC Techniques

and Sand Casting Process” a successful one.

We take this opportunity to express our deep sense of gratitude to our

honorable Principal Dr. B.V.RAMANA MURTHY, for providing excellent

academic environment in the college that made this endeavors possible.

We have whole hearted administration and deep sense of gratitude to Mr.

B. Shravan Kumar, Asst. Professor of the Mechanical Engineering Department,

AAR Mahaveer Engineering College for his inspiration, valuable guidance,

encouragement, suggestions and overall help throughout, for successful

completion of this project.

We would like to express our sincere gratitude and thanks to all the faculty

members and the lab staff of the Department of Mechanical Engineering of AAR

Mahaveer Engineering College, who assisted or provided any kind of support

and encouragement in our project work.

Chada Pradeep Reddy (138P1A0306)

Polkampally Pranay Kumar (138P1A0326)

T Vinod Kumar (138P1A0333)

Karnavath Anand Naik (138P1A0309)

iv

ABSTRACT

Hooks are one of the repeatable components with mass production in lifting of

loads. For overhanging load pulley mechanisms are optimize to get maximum

lifting loads with less effort. Casting is a predominant and reliable process of

manufacturing components with low cost. For production purpose, better quality

of samples has to prepare by using CNC machining techniques. Hooks are

prepared by CNC machining Techniques and casting process. In this we increase

the performance of the load.

In the present project we are designing a hook, manufacture the masters

with CNC milling and casting masters will be submitted.

v

CONTENTS

Page No.

Title Page

Certificate i

Declaration ii

Acknowledgment iii

Abstract iv

Contents v-vi

List of Figures vii-viii

List of Tables ix

Chapter 1 Introduction 1

1.1 Sand Casting 1

1.2 Basic Steps In Making Sand Castings 2

Chapter 2 Literature Survey 4

2.1 About Casting 4

2.2 Types of Castings 5

2.3 Sand Casting 6

2.4 Important Considerations for Casting 7

Chapter 3 Types of Metals Used for Casting Production 14

3.1 Different Metals Used for Casting Production 14

3.2 Pattern Material Properties of Aluminium (AL) 15

3.3 Cast Iron Properties 18

3.4 Types of Cast Irons 18

Chapter 4 Introduction To CAD 22

vi

Chapter 5 Introduction To Unigraphics 24

5.1 Scientific Computing 24

5.2 Design Considerations of Roller Hook Pattern 25

Chapter 6 Introduction To Manufacturing 29

6.1 Introduction to CAM 29

6.2 Introduction to CNC Machining 30

6.3 Some of the CNC machines 31

6.4 Electric Discharge Machining 32

6.5 CNC Machine Programming 33

Chapter 7 Introduction To Program 34

7.1 G-codes 34

7.2 M-codes 36

7.3 Computer Numerical Control Machine 37

7.4 Tooling 38

Chapter 8 Introduction To DELCAM 40

8.1 Raw Material Specifications 40

8.2 Pattern Manufacturing Process 41

8.3 Generation of CNC Program for Tool Paths 45

8.4 Finishing Tool Path 48

8.5 Results 50

Conclusion 53

References 54

vii

LIST OF FIGURES

Fig. No. Particulars Page No

1.1 schematic showing steps of the sand casting process 3

2.1 work flow in typical sand-casting foundries 6

2.2 taper in design 7

2.3 design components of a mould showing chaplets 8

2.4 Shell mould casting 9

2.5 hot and cold chamber die casting 12

2.6 centrifugal casting schematic 13

5.1 2D drawing in sketcher 25

5.2 3D development by extruding 25

5.3 2d-layout 26

5.4 3d-layout 26

5.5 direction of usage 27

5.6 pattern layout 28

7.1 five-axis machining center with rotating table and

computer interface 37

7.2 high speed steel with cobalt end mills used for cutting

operations in a milling machine 38

7.3 a CAT-40 tool holder 39

7.4 a boring head on a Morse taper shank 39

viii

8.1 raw material actors 41

8.2 DELCAM starting 41

8.3 file importing 41

8.4 work plane and raw material block creation 42

8.5 tool path generation 42

8.6 creating tool path for finishing 43

8.7 surfacing tool path 43

8.8 tool path simulations 44

8.9 master print machining 51

8.10 assembly of hook with masters 51

8.11 core box assembly components 52

ix

LIST OF TABLES

Table No. Page No

2.1 Types of casting, advantages, disadvantages and examples 5

3.1 Different metals used for casting production 15

3.2 Various shapes and sizes of Aluminium 16

Design & Manufacture of Master Pieces of Roller Hook By CNC Techniques & Sand Casting

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CHAPTER-1

INTRODUCTION

Housing is one of the accurate components to keep the bearing reliability and safety.

A new generation of bearing protectors is now available that can help maintain lubricant

cleanliness, prevent loss of lubricants, and prolong the life of your rotating equipment.

Depending upon the design of a shaft or housing, the shaft may be influenced by an unbalanced

load or other factors which can then cause large fluctuations in bearing efficiency. For this

reason, it is necessary to pay attention to the following when designing shaft and housing:

Bearing arrangement selection; most effective fixing method for bearing arrangement

Selection of shoulder height and fillet radius of housing and shaft.

Shape precision and dimensions of fitting; area run out tolerance of shoulder.

Machining precision and mounting error of housing and shaft suitable for allowable alignment

angle and inclination of bearing.

1.1 Sand Casting

Sand casting, also known as sand moulded casting, is a metal casting process characterized by

using sand as the mould material. It is relatively cheap and sufficiently refractory even for steel

foundry use. A suitable bonding agent (usually clay) is mixed or occurs with the sand. The

mixture is moistened with water to develop strength and plasticity of the clay and to make the

aggregate suitable for moulding. The term "sand casting" can also refer to a casting produced via

the sand casting process. Sand castings are produced in specialized factories called foundries.

Over 70% of all metal castings are produced via a sand casting process.

Molds made of sand are relatively cheap, and sufficiently refractory even for steel

foundry use. In addition to the sand, a suitable bonding agent (usually clay) is mixed or occurs

with the sand.

The mixture is moistened, typically with water, but sometimes with other substances, to

develop the strength and plasticity of the clay and to make the aggregate suitable for molding.

The sand is typically contained in a system of frames or mold boxes known as a flask.

The mold cavities and gate system are created by compacting the sand around models,

or patterns, or carved directly into the sand.

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1.2 Basic Steps In Making Sand Castings

The basic steps involved in making sand castings are:

1. Patternmaking: Patterns are required to make moulds. The mould is made by packing

moulding sand around the pattern. The mould is usually made in two parts so that the pattern

can be withdrawn.

In horizontal moulding, the top half is called the cope, and the bottom half is called the

drag.

In vertical moulding, the leading half of the mould is called the swing, and the back half

is called the ram.

When the patterns withdrawn from the moulding material (sand or other), the imprint of

the pattern provides the cavity when the mould parts are brought together. The mould

cavity, together with any internal cores as required, is ultimately filled with molten metal

to form the casting.

2. If the casting is to be hollow, additional patterns, referred to as core boxes, are needed to

shape the sand forms, or cores, that are placed in the mould cavity to form the interior surfaces

and sometimes the external surfaces as well of the casting. Thus the void between the mould and

core eventually becomes the casting.

3. Moulding: is the operation necessary to prepare a mould for receiving the metal. It consists of

ramming sand around the pattern placed in support, or flask, removing the pattern, setting cores

in place, and creating the gating/feeding system to direct the metal into the mould cavity created

by the pattern, either by cutting it into the mould by hand or by including it on the pattern, which

is most commonly used.

4. Melting and pouring are the processes of preparing molten metal of the proper composition

and temperature and pouring this into the mould from transfer ladles.

5. Cleaning includes all the operations required to remove the gates and risers that constitute the

gating/feeding system and to remove the adhering sand, scale, parting fins, and other foreign

material that must be removed before the casting is ready for shipment or other processing.

Paths for the entrance of metal into the mold cavity constitute the runner system and

include the sprue, various feeders which maintain a good metal 'feed', and in-gates which attach

the runner system to the casting cavity.

Gas and steam generated during casting exit through the permeable sand or

via risers, which are added either in the pattern itself, or as separate pieces.

Design & Manufacture of Master Pieces of Roller Hook By CNC Techniques & Sand Casting

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Fig: 1.1 schematic showing steps of the sand casting process

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CHAPTER-2

LITERATURE SURVEY

2.1 About Casting

2.1.1 Casting methods

Metal casting process begins by creating a mould, which is the ‘reverse’ shape of the part we need. The mould is made from a refractory material, for example, sand. The metal is heated in an

oven until it melts, and the molten metal is poured into the mould cavity.

The liquid takes the shape of cavity, which is the shape of the part. It is cooled until it

solidifies. Finally, the solidified metal part is removed from the mould.

A large number of metal components in designs we use every day are made by casting. The

reasons for this include:

(a) Casting can produce very complex geometry parts with internal cavities and hollow sections.

(b) It can be used to make small to very large size parts

(c) It is economical, with very little wastage: the extra metal in each casting is re-melted and re

used

(d) Cast metal is isotropic – it has the same physical/mechanical properties along a ny direction.

2.1.2 Common Examples

The solidified part is also known as a casting, which is ejected or broken out of the mold to

complete the process. Casting materials are usually metals or various cold setting materials that

cure after mixing two or more components together; examples are epoxy, concrete, plaster and

clay.

Door Handles, Locks, The outer casing or housing for motors, pumps, etc., wheels of

many cars. Casting is also heavily used in the toy industry to make parts, e.g. toy cars, planes,

and so on.

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2.2 Types of Castings

Summarizes different types of castings, their advantages, disadvantages and examples.

Process Advantages Disadvantages Examples

Sand Wide range material

sizes, shapes ,low

cost

Poor finishing ,wide

tolerance

Engine blocks and

cylinder heads

Shell mould Better accuracy,

higher production

rate

Limited part size Connect rods ,gear

housings

Expandable patterns Wide range of metals Pattern have low

strength

Cylinder heads, break

components

Plaster mould Complex shapes

,high accuracy ,good

finishing

Non-ferrous metals

low production rate

Prototype of

mechanical

components

Ceramic mould Complex shape ,high

accuracy

Small sizes Impellers ,induction

mould tooling

Permanent mould Good finishing ,low

porosity ,high

production rate

Costly moulds

,simpler shapes only

Gears, gear housings

Die Excellent

dimensional ,high

production rate

Costly moulds ,small

parts, non

Ferrous metals

Precession gears

,camera bodies ,car

wheels

Centrifugal Large cylindrical

parts ,good quality

Expensive or limited

shapes

Pipes boilers ,fly

wheels

Table: 2.1 types of casting, advantages, disadvantages and examples

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2.3 Sand casting

Fig: 2.1 work flow in typical sand-casting foundries

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Sand casting uses natural or synthetic sand (lake sand) which is mostly a refractory material

called silica (SiO2). The sand grains must be small enough so that it can be packed densely;

however, the grains must be large enough to allow gasses formed during the metal pouring to

escape through the pores. Larger sized moulds use green sand (mixture of sand, clay and some

water). Sand can be re-used, and excess metal poured is cut-off and re-used also.

2.4 Important considerations for casting

(a) How do we make the pattern?

Usually craftsmen will carve the part shape by hand and machines to the exact size.

(b) Why is the pattern not exactly identical to the part shape?

- You only need to make the outer surfaces with the pattern; the inner surfaces are made by

the core

- You need to allow for the shrinkage of the casting after the metal solidifies

(c) If you intersect the plane formed by the mating surfaces of the drag and cope with the cast

part, you will get a cross-section of the part. The outer part of the outline of this cross section is

called the parting line. The design of the mould is done by first determining the parting line

(why?)

(d) In order to avoid damaging the surface of the mould when removing the pattern and the

wood-pieces for the vents, pouring cup and spur, risers etc., it is important to incline the vertical

surfaces of the part geometry. This (slight) inclination is called a taper. If you know that your

part will be made by casting, you should taper the surfaces in the original part design.

Fig: 2.2 taper in design

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(e) The core is held in position by supporting geometry called core prints (see figure below). If

the design is such that there is insufficient support to hold the core in position, then metal

supports called chaplets are used. The chaplets will be embedded inside the final part.

Fig: 2.3 design components of a mould showing chaplets

(f) After the casting is obtained, it must be cleaned using air-jet or sand blasting

(g) Finally, the extra metal near the gate, risers and vents must be cut off, and critical surfaces

are machined to achieve proper surface finish and tolerance.

2.4.1 Shell-mould casting

Shell-mould casting yields better surface quality and tolerances. The process is described

as follows:

The 2-piece pattern is made of metal (e.g. aluminium or steel), it is heated to between

175°C-370°C, and coated with a lubricant, e.g. silicone spray.

Each heated half-pattern is covered with a mixture of sand and a thermo set resin/epoxy

binder. The binder glues a layer of sand to the pattern, forming a shell. The process may

be repeated to get a thicker shell.

The assembly is baked to cure it.

The patterns are removed, and the two half-shells joined together to form the mould;

metal is poured into the mould.

When the metal solidifies, the shell is broken to get the part.

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Fig: 2.4 shell mould casting

2.4.2 Expendable-pattern casting

The pattern used in this process is made from polystyrene (this is the light, white packaging

material which is used to pack electronics inside the boxes). Polystyrene foam is 95% air

bubbles, and the material itself evaporates when the liquid metal is poured on it.

The pattern itself is made by moulding – the polystyrene beads and pentane are put inside an

aluminium mould, and heated; it expands to fill the mould, and takes the shape of the cavity. The

pattern is removed, and used for the casting process, as follows:

- The pattern is dipped in slurry of water and clay (or other refractory grains); it is dried to get a

hard shell around the pattern.

- The shell-covered pattern is placed in a container with sand for support, and liquid metal is

poured from a hole on top.

- The foam evaporates as the metal fills the shell; upon cooling and solidification, the part is

removed by breaking the shell.

The process is useful since it is very cheap, and yields good surface finish and complex

geometry. There are no runners, risers, gating or parting lines – thus the design process is

simplified. The process is used to manufacture crank-shafts for engines, aluminium engine

blocks, manifolds etc.

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2.4.3 Plaster-mould casting

The mould is made by mixing plaster of Paris (CaSO4) with talc and silica flour; this is a fine

white powder, which, when mixed with water gets a clay-like consistency and can be shaped

around the pattern (it is the same material used to make casts for people if they fracture a bone).

The plaster cast can be finished to yield very good surface finish and dimensional accuracy.

However, it is relatively soft and not strong enough at temperature above 1200°C, so this method

is mainly used to make castings from non-ferrous metals, e.g. zinc, copper, aluminium, and

magnesium.

Since plaster has lower thermal conductivity, the casting cools slowly, and therefore has more

uniform grain structure (i.e. less war page, less residual stresses).

2.4.4 Ceramic mould casting

Similar to plaster-mould casting, except that ceramic material is used (e.g. silica or powdered

Zircon ZrSiO4). Ceramics are refractory (e.g. the clay hotpot used in Chinese restaurants to cook

some dishes), and also have higher strength that plaster.

- The ceramic slurry forms a shell over the pattern;

- It is dried in a low temperature oven, and the pattern is removed

- Then it is backed by clay for strength, and baked in a high temperature oven to burn off any

volatile substances.

- The metal is cast same as in plaster casting.

This process can be used to make very good quality castings of steel or even stainless steel; it is

used for parts such as impellor blades (for turbines, pumps, or rotors for motor-boats).

2.4.5 Permanent mould casting

Here, the two halves of the mould are made of metal, usually cast iron, steel, or refractory alloys.

The cavity, including the runners and gating system are machined into the mould halves. For

hollow parts, either permanent cores (made of metal) or sand-bonded ones may be used,

depending on whether the core can be extracted from the part without damage after casting. The

surface of the mould is coated with clay or other hard refractory material – this improves the life

of the mould. Before moulding, the surface is covered with a spray of graphite or silica, which

acts as a lubricant. This has two purposes – it improves the flow of the liquid metal, and it allows

the cast part to be withdrawn from the mould more easily. The process can be automated, and

therefore yields high throughput rates. Also, it produces very good tolerance and surface finish.

It is commonly used for producing pistons used in car engines, gear blanks, cylinder heads, and

other parts made of low melting point metals, e.g. copper, bronze, aluminium, magnesium, etc.

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2.4.6 Die casting

Die casting is a very commonly used type of permanent mould casting process. It is used for

producing many components of home appliances (e.g. rice cookers, stoves, fans, washing and

drying machines, fridges), motors, toys and hand-tools – since Pearl river delta is a largest

manufacturer of such products in the world, this technology is used by many HK-based

companies. Surface finish and tolerance of die cast parts is so good that there is almost no post-

processing required. Die casting moulds are expensive, and require significant lead time to

fabricate; they are commonly called dies. There are two common types of die casting: hot- and

cold-chamber die casting.

• In a hot chamber process (used for Zinc alloys, magnesium) the pressure chamber connected to the die cavity is filled permanently in the molten metal.

The basic cycle of operation is as follows: (i) die is closed and gooseneck cylinder is

filled with molten metal; (ii) plunger pushes molten metal through gooseneck passage and nozzle

and into the die cavity; metal is held under pressure until it solidifies; (iii) die opens and cores, if

any, are retracted; casting stays in ejector die; plunger returns, pulling molten metal back through

nozzle and gooseneck; (iv) ejector pins push casting out of ejector die. As plunger uncovers inlet

hole, molten metal refills gooseneck cylinder.

The hot chamber process is used for metals that (a) have low melting points and (b) do

not alloy with the die material, steel; common examples are tin, zinc, and lead.

• In a cold chamber process, the molten metal is poured into the cold chamber in each cycle. The operating cycle is (i) Die is closed and molten metal is ladled into the cold chamber

cylinder; (ii) plunger pushes molten metal into die cavity; the metal is held under high pressure

until it solidifies; (iii) die opens and plunger follows to push the solidified slug from the cylinder,

if there are cores, they are retracted away; (iv) ejector pins push casting off ejector die and

plunger returns to original position. This process is particularly useful for high melting point

metals such as Aluminium, and Copper (and its alloys).

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Fig: 2.5 hot and cold chamber die casting

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2.4.7 Centrifugal casting

Centrifugal casting uses a permanent mould that is rotated about its axis at a speed between 300

to 3000 rpm as the molten metal is poured. Centrifugal forces cause the metal to be pushed out

towards the mould walls, where it solidifies after cooling. Parts cast in this method have a fine

grain microstructure, which is resistant to atmospheric corrosion; hence this method has been

used to manufacture pipes. Since metal is heavier than impurities, most of the impurities and

inclusions are closer to the inner diameter and can be machined away.

Surface finish along the inner diameter is also much worse than along the outer surface

Fig: 2.6 centrifugal casting schematic

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CHAPTER-3

TYPES OF METALS USED FOR CASTING PRODUCTION

3.1 Different Metals Used For Casting Production

The metals cast by foundries can be sub-divided into several main groups as shown in Table

below.

Main Group Sub-sets Further divisions and Alloy Constituents

Ferrous

Iron

Grey: Containing > 95% iron with carbon, silicon and

manganese.

Ductile: Iron with carbon, silicon and magnesium.

Malleable: Constituents as grey iron. Cast in chill

condition, graphite aggregated through heat treatment

Alloy: Containing up to 30% each of chromium and/or

nickel to provide additional hardness and heat-treat

ability.

Steel

Carbon steel: Contains carbon levels up to 1.7%

(typically 0.1 to 0.5%) and

Manganese up to 1.6%.

Low alloy steel: A low carbon (0.35%maximum) iron

alloy containing 3 to

5% chromium and 2 to 8% nickel.

Stainless steel: Iron base alloy containing up to 30%

chromium and/or up to 40% nickel. Corrosion resistance

increases with Cr/Ni content.

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Non-ferrous

Aluminium

Various alloys usually containing silicon, copper and/or

magnesium.

Copper

Pure copper: > 99% pure

Brass: an alloy of copper and zinc (up to 45%),

sometimes with up to 2% lead and 1% tin.

Bronze: an alloy of copper and tin (up to 12%).

Variations: leaded bronze (9 to 22% lead), gun metal (3

to 5% lead & 2 to 8% zinc), aluminium bronze (with 6 to

9% aluminium, 0 to 5% nickel, 0.5 to 5% iron), phosphor

bronze.

Zinc

Zinc-based alloys with up to 4% aluminium and trace

amounts of copper, magnesium, etc.

Super

alloys

Nickel or cobalt-based alloys in combination with

chromium, iron, manganese, molybdenum, etc.

Magnesium

Magnesium alloyed with aluminium, zinc and thorium.

Other metals can be added in trace amounts.

Titanium

Pure titanium: > 99% pure α/β alloys with aluminium,

vanadium, zinc, molybdenum and zirconium.

Table: 3.1 different metals used for casting production

3.2 Pattern Material Properties of Aluminium (AL)

Aluminium is the most commonly used and commercially available metal. Its light weight and

high strength-to-weight ratio make it a good choice for everything from aircraft to flashlights to

jigs to just about anything else you can make out of metal. Pure aluminium, primarily seen in the

1xxx series of wrought aluminium alloys, has little strength, but possesses high electrical

conductivity, reflectivity, and corrosion resistance. For this reason, a wide variety of aluminium

alloys have been developed.

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Here is six alloys of aluminium in various shapes and sizes:

2011 Aluminium Available in Hex, Round

2024 Aluminium Available in Plate, Rectangle, Round, Sheet, Square, Tube

5052 Aluminium Available in Sheet

6061 Aluminium Available in Angle, Channel, I-Beam, Pipe, Plate, Rectangle, Round,

Sheet, Square, Tube

6063 Aluminium Available in Angle, Channel, Rectangle Tube, Square Tube

7075 Aluminium Available in Plate, Round, Sheet

Table: 3.2 various shapes and sizes of aluminium

2011 Aluminium

2011(AL) is the most machinable of the commonly available aluminium alloys.

Machining this alloy can produce excellent surface finishes on your product, and small,

broken chips.

Weldability, strength, and anodizing response are all rated as average at best, and this

alloy does not have a high degree of corrosion resistance.

If the ability to make your part quickly is important to you, and strength is not the

primary desire, 2011(AL) represents a good choice if you're using aluminium.

2024 Aluminium

Copper is the main alloying ingredient in 2024(AL).

It is very strong compared to most aluminium alloys, and has average machinability, but

the copper component of this alloy makes it susceptible to corrosion (many items in this

alloy are produced with a clad surface to protect the underlying material.)

In addition, 2024(AL) is not considered to be wieldable.

Finally, the fatigue resistance of 2024(AL) make it a primary choice when the

application is expected to be under stress or strain for prolonged periods. It is commonly

used in aerospace applications.

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5052 Aluminium

5052(AL). is the alloy most suited to forming operations, with good workability and

higher strength than that of the 1100(AL). or 3003(AL). Alloys that are commercially

available.

5052(AL). is not heat-treatable, but is stronger than most of the 5xxx series of alloys.

5052(AL). has very good corrosion resistance, and can be easily welded.

5052(AL). is not a good choice for extensive machining operations, as it has only a fair

machinability rating.

6061 Aluminium

6061 Aluminium is, by most any measure, the most commonly used aluminium alloy.

It is specified in most any application due to its strength, heat treatability, comparatively

easy machining, and weldability.

If that were not enough, it is also capable of being anodized, adding a layer of protection

for finished parts.

The main alloy ingredients of 6061 aluminium are magnesium and silicon.

6063 Aluminium

6063 is often called architectural aluminium for two reasons

First, it has a surface finish that is far smoother than the other commercially available

alloys.

Second, its strength is significantly less (roughly half the strength of 6061), making it

suited for applications where strength is not the foremost consideration.

6063 is rated as "Good" for forming and cold working operations, "Excellent" for

anodizing, and "Fair" for machining.

7075 Aluminium

7075 is "aircraft grade" aluminium.

Its principal alloying ingredients are Zinc and copper, which make it one of the highest-

strength aluminium alloys that are available. In fact, its typical strength in the T6 temper

is higher than most mild steels.

7075 also has average-to-good ratings for machinability, corrosion resistance, and

anodizing response. Like 2024, however, it is not considered to be weldable.

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3.3 Cast Iron Properties

Cast iron is iron or a ferrous alloy which has been heated until it liquefies, and is then

poured into a mould to solidify. It is usually made from pig iron. The alloy constituents affect its

colour when fractured: white cast iron has carbide impurities which allow cracks to pass straight

through Grey cast iron has graphitic flakes which deflect a passing crack and initiate countless

new cracks as the material breaks.

Carbon (C) and silicon (Si) are the main alloying elements, with the amount ranging from 2.1–4 wt% and 1–3 wt%, respectively. Iron alloys with less carbon content are known as steel. While

this technically makes these base alloys ternary Fe–C–Si alloys, the principle of cast iron

solidification is understood from the binary iron–carbon phase diagram. Since the compositions

of most cast irons are around the eutectic point of the iron–carbon system, the melting

temperatures closely correlate, usually ranging from 1,150 to 1,200 °C (2,100 to 2,190 °F),

which is about 300 °C (572 °F) lower than the melting point of pure iron.

Cast iron tends to be brittle, except for malleable cast irons. With its relatively low melting point,

good fluidity, castability, excellent machinability, resistance to deformation and wear resistance,

cast irons have become an engineering material with a wide range of applications and are used in

pipes, machines and automotive industry parts, such as cylinder heads (declining usage), cylinder

blocks and gearbox cases. It is resistant to destruction and weakening by oxidation

Cast iron is made by re-melting pig iron, often along with substantial quantities of scrap iron,

scrap steel, lime stone, carbon (coke) and taking various steps to remove undesirable

contaminants. Phosphorus and sulphur may be burnt out of the molten iron, but this also burns

out the carbon, which must be replaced. Depending on the application, carbon and silicon

content are adjusted to the desired levels, which may be anywhere from 2–3.5% and 1–3%

respectively. Other elements are then added to the melt before the final form is produced by

casting. Iron is sometimes melted in a special type of blast furnace known as a cupola, but more

often melted in electric induction furnaces or electric arc furnaces.[citation needed]

After melting is

complete, the molten iron is poured into a holding furnace or ladle.

3.4 Types of Cast Iron

Cast iron's properties are changed by adding various alloying elements, or alloyants. Next to

carbon, silicon is the most important alloyant because it forces carbon out of solution. Instead the

carbon forms graphite which results in a softer iron, reduces shrinkage, lowers strength, and

decreases density. Sulphur, when present, forms iron sulphide. , which prevents the formation of

graphite and increases hardness. The problem with sulphur is that it makes molten cast iron

sluggish, which causes short run defects. To counter the effects of sulphur, manganese is added

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because the two form into manganese sulphide. instead of iron sulphide. The manganese

sulphide is lighter than the melt so it tends to float out of the melt and into the slag. The amount

of manganese required to neutralize sulphur is 1.7 × sulphur content + 0.3%. If more than this

amount of manganese is added, then manganese carbide forms, which increases hardness and

chilling, except in grey iron, where up to 1% of manganese increases strength and density.

Nickel is one of the most common alloying elements because it refines the pearlite and graphite

structure, improves toughness, and evens out hardness differences between section thicknesses.

Chromium is added in small amounts to the ladle to reduce free graphite, produce chill, and

because it is a powerful carbide stabilizer; nickel is often added in conjunction. A small amount

of tin can be added as a substitute for 0.5% chromium. Copper is added in the ladle or in the

furnace, on the order of 0.5–2.5%, to decrease chill, refine graphite, and increase fluidity.

Molybdenum is added on the order of 0.3–1% to increase chill and refine the graphite and

pearlite structure; it is often added in conjunction with nickel, copper, and chromium to form

high strength irons. Titanium is added as a degasser and deoxidizer, but it also increases fluidity.

0.15–0.5% vanadium are added to cast iron to stabilize cementite, increase hardness, and

increase resistance to wear and heat. 0.1–0.3% zirconium helps to form graphite, deoxidize, and

increase fluidity.

In malleable iron melts, bismuth is added, on the scale of 0.002–0.01%, to increase how much

silicon can be added. In white iron, boron is added to aid in the production of malleable iron; it

also reduces the coarsening effect of bismuth

3.4.1 Grey cast iron

Grey cast iron is characterised by its graphitic microstructure, which causes fractures of the

material to have a grey appearance. It is the most commonly used cast iron and the most widely

used cast material based on weight. Most cast irons have a chemical composition of 2.5–4.0%

carbon, 1–3% silicon, and the remainder is iron. Grey cast iron has less tensile strength and

shock resistance than steel, but its compressive strength is comparable to low and medium

carbon steel.

3.4.2 White cast iron

It is the cast iron that displays white fractured surface due to the presence of cementite. With a

lower silicon content (graphitizing agent) and faster cooling rate, the carbon in white cast iron

precipitates out of the melt as the metastable phase cementite, Fe3C, rather than graphite.

The cementite which precipitates from the melt forms as relatively large particles,

usually in a eutectic mixture, where the other phase is austenite (which on cooling might

transform to martensite). These eutectic carbides are much too large to provide precipitation

hardening (as in some steels, where cementite precipitates might inhibit plastic deformation by

impeding the movement of dislocations through the ferrite matrix).

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Rather, they increase the bulk hardness of the cast iron simply by virtue of their own

very high hardness and their substantial volume fraction, such that the bulk hardness can be

approximated by a rule of mixtures. In any case, they offer hardness at the expense of toughness.

Since carbide makes up a large fraction of the material, white cast iron could reasonably be

classified as a cermet.

White iron is too brittle for use in many structural components, but with good

hardness and abrasion resistance and relatively low cost, it finds use in such applications as the

wear surfaces (impeller and volute) of slurry pumps, shell liners and lifter bars in ball mills and

autogenous grinding mills, balls and rings in coal pulverisers, and the teeth of a backhoe's

digging bucket (although cast medium-carbon martensitic steel is more common for this

application).

It is difficult to cool thick castings fast enough to solidify the melt as white cast iron all the way

through. However, rapid cooling can be used to solidify a shell of white cast iron, after which the

remainder cools more slowly to form a core of grey cast iron. The resulting casting, called a

chilled casting, has the benefits of a hard surface and a somewhat tougher interior.

High-chromium white iron alloys allow massive castings (for example, a 10-tonne impeller) to

be sand cast, i.e., a high cooling rate is not required, as well as providing impressive abrasion

resistance. These high-chromium alloys attribute their superior hardness to the presence of

chromium carbides.

The main form of these carbides are the eutectic or primary M7C3 carbides, where

"M" represents iron or chromium and can vary depending on the alloy's composition. The

eutectic carbides form as bundles of hollow hexagonal rods and grow perpendicular to the

hexagonal basal plane. The hardness of these carbides are within the range of 1500-1800HV

3.4.3 Malleable cast iron

Malleable iron starts as a white iron casting that is then heat treated at about 900 °C (1,650 °F).

Graphite separates out much more slowly in this case, so that surface tension has time to form it

into spheroidal particles rather than flakes. Due to their lower aspect ratio, spheroids are

relatively short and far from one another, and have a lower cross section vis-a-vis a propagating

crack or phonon.

They also have blunt boundaries, as opposed to flakes, which alleviates the stress

concentration problems faced by grey cast iron. In general, the properties of malleable cast iron

are more like mild steel.

There is a limit to how large a part can be cast in malleable iron, since it is made from

white cast iron.

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3.4.4 Ductile cast iron

A more recent development is nodular or ductile cast iron. Tiny amounts of magnesium or

cerium added to these alloys slow down the growth of graphite precipitates by bonding to the

edges of the graphite planes. Along with careful control of other elements and timing, this allows

the carbon to separate as spheroidal particles as the material solidifies. The properties are similar

to malleable iron, but parts can be cast with larger sections.

Ductile iron is not a single material but part of a group of materials which can be

produced with a wide range of properties through control of their microstructure. The common

defining characteristic of this group of materials is the shape of the graphite. In ductile irons,

graphite is in the form of nodules rather than flakes as in grey iron. Whereas sharp graphite

flakes create stress concentration points within the metal matrix, rounded nodules inhibit the

creation of cracks, thus providing the enhanced ductility that gives the alloy its name.

Nodule formation is achieved by adding nodulizing elements, most

commonly magnesium (magnesium boils at 1100 °C and iron melts at 1500 °C) and, less often

now, cerium (usually in the form of mischmetal). Tellurium has also been used. Yttrium, often a

component of mischmetal, has also been studied as a possible nodulizer.

Austempered Ductile Iron (ADI) was discovered in the 1950s but was commercialized

and achieved success only some years later. In ADI, the metallurgical structure is manipulated

through a sophisticated heat treating process. The "aus" portion of the name refers to austenite.

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CHAPTER-4

INRODUCTION TO CAD

Computer-aided design (CAD) is the use of computer systems to assist in the creation,

modification, analysis, or optimization of a design. CAD software is used to increase the

productivity of the designer, improve the quality of design, improve communications through

documentation, and to create a database for manufacturing. CAD output is often in the form of

electronic files for print, machining, or other manufacturing operations.

Computer-aided design is used in many fields. Its use in designing electronic systems is

known as Electronic Design Automation, or EDA. In mechanical design it is known

as Mechanical Design Automation (MDA) or computer-aided drafting (CAD), which includes

the process of creating a technical drawing with the use of computer software.

CAD software for mechanical design uses either vector-based graphics to depict the

objects of traditional drafting, or may also produce raster graphics showing the overall

appearance of designed objects. However, it involves more than just shapes. As in the

manual drafting of technical and engineering drawings, the output of CAD must convey

information, such as materials, processes, dimensions, and tolerances, according to application-

specific conventions.

CAD may be used to design curves and figures in two-dimensional (2D) space; or curves,

surfaces, and solids in three-dimensional (3D) space.

CAD is an important industrial art extensively used in many applications, including

automotive, shipbuilding, and aerospace industries, industrial and architectural

design, prosthetics, and many more. CAD is also widely used to produce computer

animation for special effects in movies, advertising and technical manuals, often called

DCC Digital content creation.

The design of geometric models for object shapes, in particular, is occasionally

called computer-aided geometric design (CAGD).

While the goal of automated CAD systems is to increase efficiency, they are not

necessarily the best way to allow newcomers to understand the geometrical principles of Solid

Modeling. For this, scripting languages such as PLSM (Programming Language of Solid

Modeling) are more suitable.

Below are some of the commercial packages in the present market.

AutoCAD and Mechanical Desktop are some low-end CAD software systems, which are

mainly used for 2D modelling and drawing.

NX, Pro-E, CATIA and I-DEAS are high-end modelling and designing software systems

that are costlier but more powerful. These software systems also have computer aided

manufacturing and engineering analysis capabilities.

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Ansys, Abaqus, Nastran, Fluent and CFX are packages mainly used for analysis of

structures and fluids. Different software are used for different proposes. For example,

Fluent is used for fluids and Ansys is used for structures.

Alibre and Collab CAD are some of the latest CAD systems that focus on collaborative

design, enabling multiple users of the software to collaborate on computer-aided design over the

Internet.

CAD systems enable the application of concurrent engineering and can have significant

influence on final product cost, functionality, and quality. The role of the CAD is in aiding

him/her by providing:

Accurately generated and easily modifiable graphical representation of the

product. The user can nearly view the actual product on screen, make any

modifications to it, and present his/her ideas on screen without any prototype,

especially during the early stages of the design process.

Perform complex design analysis in short time. Implementing Finite Elements

Analysis methods the user can perform.

Static, Dynamic and Natural Frequency analysis, Heat transfer analysis, Plastic

analysis, Fluid flow analysis, Motion analysis, Tolerance analysis, Design

optimization.

Record and recall information with consistency and speed. In particular the use of

Product Data Management (PDM) systems can store the whole design and

processing history of a certain product, for future reuse and upgrade.

CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of

physical components, but it is also used throughout the engineering process from conceptual

design and layout of products, through strength and dynamic analysis of assemblies to definition

of manufacturing methods of components. It can also be used to design objects.

Furthermore, many CAD applications now offer advanced rendering and animation

capabilities so engineers can better visualize their product designs. 4D BIM is a type of virtual

construction engineering simulation incorporating time or schedule related information for

project management.

CAD has become an especially important technology within the scope of computer aided

technologies, with benefits such as lower product development costs and a greatly shortened

design cycle. CAD enables designers to layout and develop work on screen, print it out and save

it for future editing, saving time on their drawings.

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CHAPTER-5

INTRODUCTION TO UNI-GRAPHICS

Unigraphics software is one of the world’s most advanced and tightly integrated CAD/CAM/CAE software package developed by Siemens PLM Software, offers several pre-

packaged Mach Series solutions for NC machining. Available in a range of capability levels,

these solutions accelerate programming and improve productivity for a variety of typical

manufacturing challenges, from basic machining to complex, multiple-axis and multi-function

machining, as well as mould and die manufacturing it also merges solid and surface modelling

techniques into one powerful tool set. The packages include complete capabilities for geometry

import, CAD modelling and drafting, full associatively to part designs, NC tool path creation,

verification and post processing, along with productivity tools that streamline the overall

machining process.

5.1 Scientific Computing

The mathematical description of processes in science and engineering with continuous

models has been a very successful technique for a long time. In general this technique leads to a

set of coupled partial differential equations that can only be solved numerically. The numerical

solution of partial differential equations is at the heart of a new interdisciplinary discipline

called Scientific Computing

The efficient simulation of a given process requires knowledge from the application

discipline (natural sciences or engineering), from mathematics (analysis and numerical

mathematics) and from computer science. A number of very successful techniques for the

solution of partial differential equations (PDEs), especially adaptive mesh refinement and

multigrid methods have been developed by mathematicians in the past decades. The enormous

advancement of computer technology, especially the development of large parallel computers

leads to new possibilities.However, the usage of all these techniques in complex applications has

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not been so easy. This is due to the enormous complexity and the interdisciplinary knowledge

that is required to combine all these methods. Finally the software implementation became

increasingly complex to the order that it cannot be managed by a single person.

5.2 Design Considerations of Roller Hook Pattern

5.2.1 Pattern Model Design

Starting NX

Fig: 5.1 2D drawing in sketcher

Toolbars and tools

Fig: 5.2 3D development by extruding

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Fig: 5.3 2d – layout

Fig: 5.4 3d - layout

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Fig: 5.5 direction of usage

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Fig: 5.6 pattern layout

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CHAPTER-6

INTRODUCTION TO MANUFACTURING

6.1 Introduction to CAM

Computer-integrated manufacturing (CIM) is the manufacturing approach of using computers to

control the entire production process. This integration allows individual processes to exchange

information with each other and initiate actions. Through the integration of computers,

manufacturing can be faster and less error-prone, although the main advantage is the ability to

create automated manufacturing processes. Typically CIM relies on closed-loop control

processes, based on real-time input from sensors. It is also known as flexible design and

manufacturing.

The term "computer-integrated manufacturing" is both a method of manufacturing and the name

of a computer-automated system in which individual engineering, production, marketing, and

support functions of a manufacturing enterprise are organized. In a CIM system functional areas

such as design, analysis, planning, purchasing, cost accounting, inventory control, and

distribution are linked through the computer with factory floor functions such as materials

handling and management, providing direct control and monitoring of all the operations.

As a method of manufacturing, three components distinguish CIM from other manufacturing

methodologies:

Means for data storage, retrieval, manipulation and presentation;

Mechanisms for sensing state and modifying processes;

Algorithms for uniting the data processing component with the sensor/modification

component.

CIM is an example of the implementation of information and communication

technologies (ICTs) in manufacturing.

CIM implies that there are at least two computers exchanging information, e.g. the controller of

an arm robot and a micro-controller of a CNC machine.

Some factors involved when considering a CIM implementation are the production volume, the

experience of the company or personnel to make the integration, the level of the integration into

the product itself and the integration of the production processes. CIM is most useful where a

high level of ICT is used in the company or facility, such as CAD/CAM systems, the availability

of process planning and its data.

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6.2 Introduction to CNC Machining

Numerical control (NC) is the automation of machine tools that are operated by precisely

programmed commands encoded on a storage medium, as opposed to controlled manually via

hand wheels or levers, or mechanically automated via cams alone. Most NC today is computer

numerical control (CNC), in which computers play an integral part of the control.

In modern CNC systems, end-to-end component design is highly automated

using computer-aided design (CAD) and computer-aided manufacturing (CAM) programs. The

programs produce a computer file that is interpreted to extract the commands needed to operate a

particular machine via a post processor, and then loaded into the CNC machines for production.

Since any particular component might require the use of a number of different tools drills, saws,

etc. Modern machines often combine multiple tools into a single "cell". In other installations, a

number of different machines are used with an external controller and human or robotic

operators that move the component from machine to machine. In either case, the series of steps

needed to produce any part is highly automated and produces a part that closely matches the

original CAD design.

CNC like systems are now used for any process that can be described as a series of

movements and operations. These include laser cutting, welding, friction stir welding, ultrasonic

welding, flame and plasma cutting, bending, spinning, hole-punching, pinning, gluing, fabric

cutting, sewing, tape and fiber placement, routing, picking and placing (PnP), and sawing.

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6.3 Some of the CNC Machines

Mills:

CNC mills use computer controls to cut different materials. They are able to translate

programs consisting of specific number and letters to move the spindle to various locations and

depths.

Many use G-code, which is a standardized programming language that many CNC

machines understand, while others use proprietary languages created by their manufacturers.

These proprietary languages while often simpler than G-code are not transferable to other

machines.

Lathes:

Lathes are machines that cut spinning pieces of metal. CNC lathes are able to make fast,

precision cuts using index able tools and drills with complicated programs for parts that normally

cannot be cut on manual lathes.

These machines often include 12 tool holders and coolant pumps to cut down on tool

wear. CNC lathes have similar control specifications to CNC mills and can often read G-code as

well as the manufacturer's proprietary programming language.

Plasma cutters:

Plasma cutting involves cutting a material using a plasma torch. It is commonly used to

cut steel and other metals, but can be used on a variety of materials. In this process, gas (such

as compressed air) is blown at high speed out of a nozzle; at the same time an electrical arc is

formed through that gas from the nozzle to the surface being cut, turning some of that gas

to plasma.

The plasma is sufficiently hot to melt the material being cut and moves sufficiently fast to

blow molten metal away from the cut.

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6.4 Electric Discharge Machining

Electric discharge machining (EDM), sometimes colloquially also referred to as spark

machining, spark eroding, burning, die sinking, or wire erosion, is a manufacturing process in

which a desired shape is obtained using electrical discharges (sparks).

Material is removed from the work piece by a series of rapidly

recurring current discharges between two electrodes, separated by a dielectric fluid and subject to

an electric voltage. One of the electrodes is called the tool-electrode, or simply the ‘tool’ or ‘electrode’, while the other is called the work piece-electrode, or ‘work piece’.

When the distance between the two electrodes is reduced, the intensity of the electric

field in the space between the electrodes becomes greater than the strength of the dielectric (at

least in some point(s)), which breaks, allowing current to flow between the two electrodes. This

phenomenon is the same as the breakdown of a capacitor. As a result, material is removed from

both the electrodes.

Wire EDM

Also known as wire cutting EDM, wire burning EDM, or travelling wire EDM, this

process uses spark erosion to machine or remove material with a travelling wire electrode from

any electrically conductive material. The wire electrode usually consists of brass or zinc-coated

brass material.

This process is used to cut plates and to make punches, tools, and dies from any

conductive material, including hard metals that are too difficult to machine with other methods,

such as; metal allows, graphite, carbide and diamond.

Water jet cutters

A water jet cutter, also known as a water jet, is a tool capable of slicing into metal or

other materials (such as granite) by using a jet of water at high velocity and pressure, or a

mixture of water and an abrasive substance, such as sand. It is often used during fabrication or

manufacture of parts for machinery and other devices.

Water jet is the preferred method when the materials being cut are sensitive to the high

temperatures generated by other methods. It has found applications in a diverse number of

industries from mining to aerospace where it is used for operations such as cutting, shaping,

carving, and reaming.

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6.5 CNC Machine Programming

The way an operator tells the machine what exactly to do is through specialized

programming. The program is written with a bunch of sentence like commands.

Every single command is composed of particular CNC words which have both a letter

and number element. The letter describes the “kind” and the number describes the “value.” These instructions are literally step-by-step guidelines on what the machine should do at any given

point in the machining process.

Someone called a CNC programmer must first visualize the entire process as it would

happen during implementation. Then they would need to insert those steps into the program via

the different available commands/words.

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CHAPTER-7

INTRODUCTION TO PROGRAM

7.1 G-codes

G-code is the common name for the most widely used numerical control (NC)

programming language, which has many implementations. Used mainly in automation, it is part

of computer-aided engineering. G-code is sometimes called G programming language.

Rapid move (transport the tool through space to the place where it is needed for cutting;

do this as quickly as possible).

Controlled feed move in a straight line or arc.

Series of controlled feed moves that would result in a hole being bored, a workpiece cut

(routed) to a specific dimension, or a profile (contour) shape added to the edge of a

workpiece.

Set tool information such as offset.

Switch coordinate systems.

Here are the most common G-codes with their function called out.

G00 Rapid positioning

G01 Linear interpolation

G02 Circular/helical interpolation (clockwise)

G03 Circular/helical interpolation (counter clockwise)

G04 Dwell

G10 Coordinate system origin setting

G17 XY plane selection

G18 XZ plane selection

G19 YZ plane selection

G20 Inch system selection

G21 Millimetre system selection

G40 Cancel cutter diameter compensation

G41 Start cutter diameter comp. left

G42 Start cutter diameter comp. right

G43 Tool length offset (plus)

G49 Cancel tool length offset

G53 Motion in machine coordinate system

G54 Use preset work coordinate system 1

G55 Use preset work coordinate system 2

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G56 Use preset work coordinate system 3

G57 Use preset work coordinate system 4

G58 Use preset work coordinate system 5

G59 Use preset work coordinate system 6

G59.1 Use preset work coordinate system 7

G59.2 Use preset work coordinate system 8

G59.3 Use preset work coordinate system 9

G80 Cancel motion mode (includes canned)

G81 Drilling canned cycle

G82 Drilling with dwell canned cycle

G83 Chip-breaking drilling canned cycle

G84 Right hand tapping canned cycle

G85 Boring, no dwell, feed out canned cycle

G86 Boring, spindle stop, rapid out canned

G87 Back boring canned cycle

G88 Boring, spindle stop, manual out canned

G89 Boring, dwell, feed out canned cycle

G90 Absolute distance mode

G91 Incremental distance mode

G92 Offset coordinate systems

G92.2 Cancel offset coordinate systems

G93 Inverse time feed mode

G94 Feed per minute mode

G98 Initial level return in canned cycles

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7.2 M-codes

Default M codes used on most machines types. User customizable M codes will change

based on application and user definition.

Machine code

MATLAB programming language

Military GPS signal

Half of the G & M-Code programming language used in the CNC Machining Industry.

M02 End of Program

M03 Spindle On Clockwise, Laser, Flame, Power ON

M04 Spindle On Counter Clockwise

M05 Spindle Stop, Laser, Flame, Power OFF

M06 Tool Change

M08 Coolant On

M09 Coolant Off

M10 Reserved for tool height offset

M13 Spindle On, Coolant On

M30 End of Program when macros are used

M91 Readout Display Incremental

M92 Readout Display Absolute

M97 Go to or jump to line number

M98 Jump to macro or subroutine

M99 Return from macro or subroutine

M100 Machine Zero Reset

M199 Mid program start

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7.3 Computer Numerical Control Machine

Most CNC milling machines (also called machining canters) are computer controlled

vertical mills with the ability to move the spindle vertically along the Z-axis. This extra degree of

freedom permits their use in die sinking, engraving applications, and 2.5D surfaces such

as relief sculptures. When combined with the use of conical tools or a ball nose cutter, it also

significantly improves milling precision without impacting speed, providing a cost-efficient

alternative to most flat-surface hand-engraving work.

Fig: 7.1 five-axis machining center with rotating table and computer interface

CNC machines can exist in virtually any of the forms of manual machinery, like

horizontal mills. The most advanced CNC milling-machines, the multi-axis machine, add two

more axes in addition to the three normal axes (XYZ). Horizontal milling machines also have a

C or Q axis, allowing the horizontally mounted workpiece to be rotated, essentially allowing

asymmetric and eccentric turning. The fifth axis (B axis) controls the tilt of the tool itself. When

all of these axes are used in conjunction with each other, extremely complicated geometries,

even organic geometries such as a human head can be made with relative ease with these

machines. But the skill to program such geometries is beyond that of most operators. Therefore,

5-axis milling machines are practically always programmed with CAM.

The Operating system of such machines is a closed loop system and functions on

feedback. These machines have developed from the basic NC (NUMERIC CONTROL)

machines. A computerized form of NC machines is known as CNC machines. A set of

instructions (called a program) is used to guide the machine for desired operations.

CNC machine is operated by a single operator called a programmer. This machine is

capable of performing various operations automatically and economically. While reading this

article, along with collecting other information about milling machines, it is crucial for one to

understand the computerized form of such machines

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7.4 Tooling

The accessories and cutting tools used on machine tools (including milling machines) are

referred to in aggregate by the mass noun "tooling". There is a high degree of standardization of

the tooling used with CNC milling machines, and a lesser degree with manual milling machines.

To ease up the organization of the tooling in CNC production many companies use a tool

management solution.

Milling cutters for specific applications are held in various tooling configurations.

Fig: 7.2 high speed steel with cobalt end mills used for cutting operations in a milling

machine

CNC milling machines nearly always use SK (or ISO), CAT, BT or HSK tooling. SK

tooling is the most common in Europe, while CAT tooling, sometimes called V-Flange Tooling,

is the oldest and probably most common type in the USA. CAT tooling was invented

by Caterpillar Inc. of Peoria, Illinois, in order to standardize the tooling used on their machinery.

CAT tooling comes in a range of sizes designated as CAT-30, CAT-40, CAT-50, etc. The

number refers to the Association for Manufacturing Technology (formerly the National Machine

Tool Builders Association (NMTB)) Taper size of the tool.

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Fig: 7.3 a CAT-40 tool holder Fig: 7.4 a boring head on a Morse taper shank

SK and HSK tooling, sometimes called "Hollow Shank Tooling", is much more common

in Europe where it was invented than it is in the United States. It is claimed that HSK tooling is

even better than BT Tooling at high speeds. The holding mechanism for HSK tooling is placed

within the (hollow) body of the tool and, as spindle speed increases, it expands, gripping the tool

more tightly with increasing spindle speed. There is no pull stud with this type of tooling.

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CHAPTER-8

INTRODUCTION TO DELCAM

Power mill is a 3D CAM (Computer-aided manufacturing) solution that runs

on Microsoft Windows for the programming of tool paths for 2 to 5 axis CNC (Computer

Numerical Control) Milling machines developed by Delcam Plc. The software is used in a range

of different engineering industries to determine optimal tool paths to reduce time and

manufacturing costs as well as reduce tool loads and produce smooth surface finishes.

The code of Power mill originates from the software DUCT which was developed in 1973

by Donald Welbourne and Ed Lambourne along with the help of Delta Metal Group, whose

funding aided the transferral of the system into industry. The advancement of mini computers

from 1982 meant that it became economically viable to design complex 3D shapes using a

computer

8.1 Raw Material Specifications

Aluminium (or aluminium) is a chemical element in the boron group with

symbol Al and atomic number 13. It is a silvery white, soft, ductile metal. Aluminium is the third

most abundant element(after oxygen and silicon), and the most abundant metal, in

the Earth's crust. It makes up about 8% by weight of the Earth's solid surface.

Aluminum is remarkable for the metal's low density and for its ability to

resist corrosion due to the phenomenon of passivation. Structural components made from

aluminum and its alloys are vital to the aerospace industry and are important in other areas

of transportation and structural materials. The most useful compounds of aluminum, at least on a

weight basis, are the oxides and sulfates.

Physical

Aluminium is a relatively soft, durable, lightweight, ductile and malleable metal with

appearance ranging from silvery to dull gray, depending on the surface roughness. It is

nonmagnetic and does not easily ignite. The yield strength of pure aluminium is 7–11 MPa,

while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has

about one-third the density and stiffness of steel. It is easily machined, cast, drawn and extruded.

Chemical

Corrosion resistance can be excellent due to a thin surface layer of aluminium oxide that

forms when the metal is exposed to air, effectively preventing further oxidation. The strongest

aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This

corrosion resistance is also often greatly reduced by aqueous salts, particularly in the presence of

dissimilar metals.

Due to above advantages we used rectangular Aluminium block with the dimensions

164x60x37 as raw material for making bearing housing patterns.

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Fig: 8.1 raw material factors

8.2 Pattern Manufacturing Process:

Fig: 8.2 DELCAM starting Fig: 8.3 File importing

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Fig: 8.4 work plane and raw material block creation

Fig: 8.5 tool path generation

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Fig: 8.6 creating tool path for finishing

Fig: 8.7 surfacing tool path

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Fig: 8.8 tool path simulations

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8.3 Generation of CNC Program for Tool Paths

ROUGHING TOOL PATH:

%

: 0001

G91 G28 X0 Y0 Z0

G40 G17 G80 G49

G0 G90 Z45.

T1 M6

G54 G90 T0

( Toolpath Name: 1 )

(Output: )

(Units: MM )

(Tool Coordinates: Tip )

(Tool Number: 1 )

(Tool Id: 1 )

(Coolant: Standard )

(Gauge Length: 40.000 )

(Block: )

(MIN X: -82.000 )

(MIN Y: -30.000 )

(MIN Z: -38.000 )

(MAX X: 82.000 )

(MAX Y: 30.000 )

(MAX Z: 0.000 )

(COORDINATE SYSTEM: Active Workplane )

(Datum - Tool Tip: )

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(X: 0.000)

(Y: 0.000)

(Z: 45.000)

(Number of Flutes: 1)

(Tool: End Mill)

(DIAMETER: 8.000)

(Safety)

(Tool Cutting Moves: Safe No Gouges)

(Tool Leads: Safe No Gouges)

(Tool Links: Safe No Gouges)

(Holder Cutting Moves: Collisions Not Checked)

(Holder Leads: Collisions Not Checked)

(Holder Links: Collisions Not Checked)

( Toolpath: Offset Area Clearance )

(STEPOVER: 5.000 )

(TOLERANCE:0.100 )

(THICKNESS:0.250 )

( Toolpath Stats: )

(LENGTH: 151773.039)

(TIME: 2/29/35)

(LIFTS: 112)

X-43.664 Y-5.307 S1500 M3

G43 Z40. H1 M8

G1 Z.5 F500

X-43.742 Y-5.711 Z.464

X-44.169 Y-7.485 Z.304

X-44.756 Y-9.213 Z.145

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X-45.247 Y-10.47 Z.027

X-45.519 Y-11.13 Z-.036

X-45.815 Y-11.78 Z-.098

X-41.422 Z-.482

X-37.029 F1000

X-37.435 Y-10.503

X-37.707 Y-9.569

G1 X-74.261 Y19.061

X-74.141 Y18.812

G0 Z45.

M9

G91 G28 Z0

G49 H0

G28 X0 Y0

M30

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8.4 Finishing Tool Path

%

:0001

G91 G28 X0 Y0 Z0

G40 G17 G80 G49

G0 G90 Z45.

T1 M6

G54 G90 T0

( Toolpath Name: 2 )

(Output:)

(Units: MM )

(Tool Coordinates: Tip )

(Tool Number: 1 )

(Tool Id: 2 )

(Coolant: Standard )

(Gauge Length: 20.000 )

(Block: )

(MIN X: -82.000 )

(MIN Y: -30.000 )

(MIN Z: -38.000 )

(MAX X: 82.000 )

(MAX Y: 30.000 )

(MAX Z: 0.000 )

(COORDINATE SYSTEM: Active Workplane )

(Datum - Tool Tip:)

( X: 0.000)

( Y: 0.000)

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Dept. of Mechanical Engineering, AARM Hyderabad Page 49

( Z: 45.000)

(Number of Flutes: 1 )

(Tool: Ball Nosed )

(DIAMETER: 4.000 )

(Safety: )

(Tool Cutting Moves: Safe No Gouges )

(Tool Leads: Safe No Gouges )

(Tool Links: Safe No Gouges )

(Holder Cutting Moves: Collisions Not Checked )

(Holder Leads: Collisions Not Checked)

(Holder Links: Collisions Not Checked )

( Toolpath: Optimised Constant Z )

( STEPOVER: 0.250 )

( TOLERANCE:0.100 )

( THICKNESS:0.000 )

( Toolpath Stats: )

( LENGTH: 106400.392 )

( TIME: 1/31/39 )

( LIFTS: 221 )

X-70.139 Y.211 S1500 M3

G43 Z40. H1 M8

G1 Z.5 F500

X-69.847 Y.233 Z.474

X-69.741 Y.042 Z.455

X-69.744 Y-.125 Z.441

X-73.26 Y20.826

X-73.336 Y20.854

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Y21.27

X-73.26 Y21.345

X-71.345 Y21.344

G0 Z45.

M9

G91 G28 Z0

G49 H0

G28 X0 Y0

M30

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8.5 Results

Fig: 8.9 master print machining

Fig: 8.10 assembly of hook with masters

Design & Manufacture of Master Pieces of Roller Hook By CNC Techniques & Sand Casting

Dept. of Mechanical Engineering, AARM Hyderabad Page 52

Fig: 8.11 core box assembly components

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Dept. of Mechanical Engineering, AARM Hyderabad Page 53

CONCLUSION

The material HE30 used for making pattern plays an important role for high production

rate.

Designing techniques are presented for sand casting patterns.

CNC programming also introduced to get high accuracy in pattern making.

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