Forging - Introduction

FORGING

INTRODUCTION 

In forging the parts are shaped by heating them in an open fire or hearth and shaping them through applying compressive forces using hammers. Forging is defined as the plastic deformation of metals at elevated temperatures into a predetermined size or shape using compressive forces exerted through some means of hand hammers, small power hammers, die, press or upsetting machine.

Forging consists essentially of changing or altering the shape and section of metal by hammering at a temperature of about 980°C, at which the metal is entirely plastic and can be easily deformed or shaped under pressure. The shop in which the various forging operations are carried out is known as the smithy or smith’s shop.   Forging processes may be classified into hot forging and cold forgings and each of them possesses their specific characteristics, merits, demerits and applications.

Black-smithy is a process by which metal may be heated and shaped to its requirements by the use of blacksmith tools either by hand or power hammer. In smithy small parts are shaped by heating them in an open fire or hearth. Shaping is done under hand control using hand tools. 

Forging by machine involves the use of forging dies and is generally employed for mass production of accurate articles. In drop forging, closed impression dies are used and there is drastic flow of metal in the dies due to repeated blow or impact which compels the plastic metal to conform to the shape of the dies. The final shape of the product from raw material is achieved in a number of steps. 

Advantages of forging

Some common advantages of forging:

1. Forged parts  offer great resistance to impact and fatigue loads.

2. Forging refines the structure of the metal.Forging distorts the previously created unidirectional fiber as created by rolling and increases the strength by setting the direction of grains.

3. It results in considerable saving in time, labor and material as compared to the production of similar item by cutting from a solid stock and then shaping it.

4. The reasonable degree of accuracy may be obtained in forging operation.

5. The forged parts can be easily welded.

Disadvantages of forging

1. Rapid oxidation in forging of metal surface at high temperature results in scaling which wears the dies.

2. Forging is limited to simple shapes and has limitation for parts having undercuts etc.

3. The initial cost of forging dies and the cost of their maintenance is high.

Applications of forging

Almost all metals and alloys can be forged.

The low and medium carbon steels are readily hot forged without difficulty, but the high-carbon and alloy steels are more difficult to forge and require greater care. Forging is generally carried out on carbon alloy steels, wrought iron, copper-base alloys,  Stainless steels in ferrous materials.

In non ferrous group, alumunium alloys, and magnesium alloys.  nickel-based super-alloys are forged. Titanium components are forged especially for aerospace uses.

Producing of crank shaft of alloy steel is a good example which is produced by forging. Forging processes are among the most important manufacturing techniques utilized widely in manufacturing of small tools, rail-road equipments, automobiles and trucks and components of aeroplane industries. These processes are also extensively used in the manufacturing of the parts of tractors, shipbuilding, cycle industries, railroad components, agricultural machinery etc.

FORGEABILITY 

The ease with which forging is done is called forgeability. The forgeability of a material can also be defined as the capacity of a material to undergo deformation under compression without rupture. Forgeability increases with temperature up to a point at which a second phase, e.g., from ferrite to austenite in steel, appears or if grain growth becomes excessive.  Certain mechanical properties are also influenced by forgeability. Metals which have low ductility have reduced forgeability at higher strain rate whereas highly ductile metals are not so strongly affected by increasing strain rates. The pure metals have good malleability and thus good forging properties. The metals having high ductility at cold working temperature possesses good forgeability.

The main alloys for cold forging or hot forging are mostly aluminium and copper alloys, including the relatively pure metals.  Aluminium alloys are forged between 385°C and 455°C or about 400°C. Aluminium alloys do not form scale during hot forging operations, die life is thus excellent.

Copper and brasses with 30% or less zinc have excellent forgeability in cold working operations.
High zinc brasses can be cold forged to a limited extent but are excellent hot forging alloys.

Magnesium possessing hexagonal close packed (HCP) structure has little ductility at room temperature but is readily hot forged. Magnesium alloys are forged on presses at temperature above 400°C. At higher temperatures, magnesium must be protected from oxidation or ignition by an inert atmosphere of sulphur dioxide.

Carbon steels with 0.25 % carbon or less are readily hot forged or cold-headed. High carbon and high alloy steels are almost always hot forged.

FORGABLE MATERIALS 

Forgeable metals are purchased as hot-rolled bars or billets with round or rectangular cross the sections. Forgeable materials should possess the required ductility and proper strength. Some forgeable metals are given as under in order of increasing forging difficulty.


1. Aluminium alloys
2. Magnesium alloys
3. Copper alloys.
4. Carbon and low alloy steels
5. Martensitic stainless steels

6. Austenitic stainless steels
7. Nickel alloys
8. Titanium alloys
9. Columbium alloys
10. Tantalum alloys

11. Molybdenum alloys
12. Tungsten alloys
13. Beryllium.

ADVANTAGES OF FORGING IN COMPARISON TO CASTING AND
MACHINING 

Because of inherent improvement in the grain size and introduction of un-interrupted grain flow in the structure of finished forged component forging has the following advantages in comparison to casting and machining. Some of such advantages are given as under.

(i) Greater strength and toughness.
(ii) Reduction in weight of the finished part.
(iii) Saving in the material.
(iv) Elimination of internal defects such as cracks, porosity, blowholes, etc.
(v) Ability to withstand unpredictable loads during service.
(vi) Minimum of machine finish to be carried out on the component especially when it
is forged in dies.

EFFECT OF FORGING ON METAL CHARACTERISTICS

A continuous and uninterrupted grain flow in a forged component results in higher strength and toughness. In a cast part, there is no grain flow. Cast part is having random orientation of grains so it has weak crystalline structure.

The original crystals are deformed during forging operation and many of the constituents
are precipitated at high temperatures which again become soluble in the solid iron on freezing,
thus increasing the local homogeneity of the metal. The properties, like elastic limit, tensile
strength of metal are improved due to the grain flow.


Forging is generally employed for those components which require high strength and
resistance to shock or vibrations. It provides fine crystalline structure to the metal, improves
physical properties, closes all voids and forms the metal to shapes. It enhances the mechanical
properties of metals and improves the grain flow which in turn increases the strength and
toughness of the forged component.

But there may be certain defects also, like scale inclusions on the surface, misalignment
of the dies, crack, etc. These defects can be controlled.

All forgings are covered with scale and hence they require cleaning operation. It is done by
pickling in acid, shot peening or tumbling depending upon the size and composition of the
forgings. If some distortion has occurred in forging, a sizing or straightening operation may
be required. Controlled cooling is usually provided for large forgings. Heat treatment may
also be required to provide certain physical properties.

Choice of Forging Process

Parts made using cast iron tend to need to be bulky and are used where they will not be subjected to high stresses. Typical examples are machine bases, cylinder blocks, gear-box housings etc.

Besides other  factors, cost is a  major consideration in deciding whether to cast a component or to forge it. An I.C. engine connecting rod is a very good example of where a forging will save machining time and material, whereas the cylinder block of the same engine would be very expensive if produced by any process other than casting. Big or small complex shapes can easily be cast. Small parts can directly be machined out from regular section materials economically.

A part machined out from the rolled steel stock definitely possesses better mechanical properties than a conventionally cast part. Sometimes the shape and size of a part would mean removing a large amount of material by machining. It is sometimes more economical to forge the part, thereby reducing the machining time and the amount of material required.

Forging Process - Heating for Forging  

Hearths and Furnaces for Heating

Forgeable metals are heated either in a hearth or in a furnace. The hearths are widely used for heating the metals for carrying out hand forging operations.

Furnaces are also commonly used for heating metals for heavy forging. The forging job is always heated to the correct forging temperature in a hearth  or in a furnace located near the forging arrangements.

Gas, oil or electric-resistance furnaces or induction heating classified as open or closed hearths can be used. Gas and oil are economical, easily controlled and mostly used as fuels.

The formation of scale, due to the heating process especially on steel creates problems in forging. A non-oxidizing atmosphere should, therefore, be maintained for surface protection. Special gas-fired furnaces have been developed to reduce scaling to minimum. Electric heating is the most modern answer to tackle scaling and it heats the stock more uniformly also.

 In some cases, coal and anthracite, charcoal containing no sulphur and practically no ash are the chief solid fuels used in forging furnaces.

Forge furnaces are built raise temperatures up to 1350°C in their working chambers. They
should be sufficiently large to allow proper combustion of the fuel, and to obtain uniform
heating of the forging jobs.

Each heating furnace consists of parts including firebox, working chamber, chimney, flues, re-cuperator or regenerator, and various auxiliary arrangements.

Fuels used in forging shop

The fuels used in forging shop are classified as solid, liquid and gaseous fuels which are discussed as under.

Solid fuels: Wood, coal, anthracite, peat, charcoal, coke, pulverized fuel etc.

Liquid fuels: Crude oil, petroleum, kerosene, tar oil etc.

Gaseous fuels: Natural gas and some artificially produced gases are used generate heat.

CONTROL OF HEATING DEVICES 

For good control of heating devices such as hearth or forging furnace, the following points are should always be considered.

1. The nozzle pointing into the centre of the hearth is called the tuyre and is used to direct a stream of air into the burning coke. The air is supplied by centrifugal blower.

2. As the hottest part of the fire is close to the tuyre opening, therefore, the tuyre is provided with a water jacket to prevent it from burning away.

3. The hood provided at the top of hearth collects smoke, fumes etc., and directs them away from the workplace through the chimney in form of exhaust.

4. The fuel for the fire may be either black-smithing coal or coke. To light the fire, either use paper and sticks or preferably a gas poker.

5. Impurities will collect as clinker and must be removed from the bottom of the fire when the fire cools.

6. The blowers are used to control the air supply using forced draught. Regulators control the draught and the temperature of the fire.

7. Blower delivers to forge adequate supply of air at proper pressure which is very necessary for the combustion of fuel.

8. A centrifugal blower driven by an electric motor is an efficient means of air supply in forging hearth.

9. Fire tools such as rake, poker and slice are generally used to control or manage the fire and theses tools are kept nearby the side of the hearth. Rake is used to take heated workpiece out of the fire. Poker is a steel rod which is used to poke (stir) fire in the hearth.

10. The place of the metal to be heated should be placed just above the compact centre of a sufficiently large fire with additional fuel above to reduce the heat loss and atmospheric oxidation.

FORGING TEMPERATURES 

The temperature to start the forging for soft, low carbon steels is 1,250 to 1,300°C, the
temperature to finish forging is 800 to 840°C. The corresponding temperatures for high carbon
and alloy steels which are hard in nature are 1100 to 1140°C and 830 to 870°C. Wrought iron
is best forged at a temperature little below 1,290°C. Non ferrous alloys like bronze and brass
are heated to about 600 to 930°C, the aluminium and magnesium alloys to about 340 to 500°C.

The temperature of heating steel for hand forging can be estimated by the color of
heat and which color of the light emitted by the heated steel. For accurate determinations of
forging temperatures of the heated part, the optical pyrometers are generally used.

FORGING METHODS 

The forging methods  are generally classified into two categories namely hand forging and power forging.

Hand forging

Hand forging is performed in the black smithy shop. The job is heated at the forging temperature in hearth and it is then brought on anvil using tong. It is then forged using hand hammers and other hand forging tools for imparting specific shape.

COMMON HAND FORGING TOOLS 

For carrying out forging operations manually, certain common hand forging tools are employed.
These are also called blacksmith’s tools, for a blacksmith is one who works on the forging
of metals in their hot state. The main hand forging tools are as under.


1 .Tongs

2.Flatter

3. Swage

4. Fuller

5. Punch

6. Rivet header

7. Hot chisel

8. Hammers

9. Anvil

10. Swage block

11. Drift

12. Set-hammer

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14. Brass scale

15. Brass

16. Black smith’s gauge

17. Heading tool


The applications of some of the hand forging tool are described as under.

Tongs

The tongs are generally used for holding work while doing a forging operation.

1. Flat tongs are used for mainly for holding work of rectangular section.

2. Straight-lip fluted tongs are commonly used for holding square, circular and hexagonal bar stock.

3. Rivet or ring tongs are widely used for holding bolts, rivets and other work of circular section.

4. Gad tongs are used for holding general pick-up work, either straight or tapered.

Flatter

Flatter is  is commonly used in forging shop to give smoothness and accuracy to articles which have already been shaped by fullers and swages.

Swage

Swage is used for forging work which has to be reduced or finished to round, square or hexagonal form. It is made with half grooves of dimensions to suit the work being reduced. It consists of two parts, the top part having a handle and the bottom part having a square shank which fits in the hardie hole on the anvil face.

Fuller

Fuller  is used in forging shop for necking down a forgeable job. It is made in top and bottom tools as in the case of swages. Fuller is made in various shapes and sizes according to needs, the size denoting the width of the fuller edge

Punch

Punch is used in forging shop for making holes in metal part when it is at forging heat.


Rivet header: Rivet header is used in forging shop for producing rivets heads on parts.


Chisels

Chisels are used for cutting metals and for nicking prior to breaking. They may be hot
or cold depending on whether the metal to be cut is hot or cold. A hot chisel generally used
in forging shop.  The main difference between the two is in the edge. The edge of a cold chisel is hardened and tempered with an angle of about 60°, whilst the edge of a hot chisel is 30° and the hardening is not necessary. The edge is made slightly rounded for better cutting action.

Hand hammers

There are two major kinds of hammers are used in hand forging: (1) the hand hammer
used by the smith himself and (2) the sledge hammer used by the striker. Hand hammers
 may further be classified as (a) ball peen hammer, ( b ) straight peen hammer, and
(c) cross peen hammer. Sledge hammers  may further be classified as (a) Double
face hammer, ( b ) straight peen hammer, and (c) cross peen hammer. Hammer heads are made
of cast steel and, their ends are hardened and tempered. The striking face is made slightly
convex. The weight of a hand hammer varies from about 0.5 to 2 kg where as the weight of
a sledge hammer varies from 4 to 10 kg.


Set hammer

A set hammer generally u is used for finishing corners in shouldered work where the flatter would be inconvenient. It is also used for drawing out the gorging job.

Anvil

An anvil is a most commonly tool used in forging shop.  It acts as a support for blacksmith’s work during hammering. The body of the anvil is made of mild steel with a tool steel face welded on the body, but the beak or horn used for bending curves is not steel faced. The round hole in the anvil called pritchel hole is generally used for bending rods of small diameter, and as a die for hot punching operations. The square or hardie hole is used for holding square shanks of various fittings. Anvils in forging shop may vary up to about 100 to 150 kg and they should always stand with the top face about 0.75 mt. from the floor. This height may be attained by resting the anvil on a wooden or cast iron base in the forging shop.



Swage block

Swage block generally used in forging shop.  It is mainly used for heading, bending, squaring, sizing, and forming operations on forging jobs. It is 0.25 mt. or even more wide. It may be used either flat or edgewise in its stand.


Drift

Drift generally used in forging shop.  It is a tapered rod made of tool steel. Holes are opened out by driving through a larger tapered punch called a drift.


Hardie

Hardie is a type of chisel used in forging shop.  Its taper head is fixed into the hardie hole of the anvil, the cutting edge being upward. The part to be cut is kept over the cutting edge of the fixed hardie on anvil and another chisel is placed over the job and the cutting is performed by hammering.


Shovel

Shovel generally used in forging shop to place coal or coke in the furnace. It is also used to set coal pieces in furnace and remove ash from furnace.

Poker

Poker  is employed for removing clinker from the furnace and to loose the
compact coal pieces in the furnace.


Rake

Rake is used to put coal pieces on tuyres.


Beak Iron

Beak iron  is also known as small anvil and is made of forged steel. Its upper front end consists of horn and upper back end comprises of flat tail. Its taper shank is inserted into the hardie hole of the anvil. It is commonly used as anvil for small forge work.

The hand forging operations  are:


1. Upsetting 2. Bending

3. Drawing down 4. Cutting

5. Setting down 6.Punching

7. Flattening 8. Fullering

9. Forge Welding 10. Swaging



(i) Drawing out

Drawing out is used to reduce the thickness of a bar and to increase its length. It may be carried out by working the metal over the horn the anvil , then by hammering it on the anvil face.

The rounded horn of the anvil acts as a blunt edge, which forces the metal to flow lengthwise when struck by the hammer. For drawing down very heavy work, fuller may be used for drawing down a bar over the horn (round portion) of anvil.


(ii) Fullering

Fullering operation  involves heating the stock in the black smith hearth. Then heated stock is placed on the fuller fixed on anvil. A fuller is put over the sock and hammering is done to reduce the cross section of job at required point.

(iii) Upsetting

Upsetting is also known as jumping operation which is carried out to increase the
thickness (or diameter) of a bar and to reduce its length. Generally, the increase in thickness
is only local, for example, when forming a bolt head. This operation is an operation just
opposite to drawing and involves increasing the cross-sectional area usually by hammering or
pressing in a direction parallel to the ingot axis. The length of the ingot decreases and
following the path of least resistance it spreads out. The required shape is given the ingot
by spreading it between two dies. Only that portion of the bar which is to be upset is heated
locally. Or, the whole bar is heated and except for the portion to be upset, the rest is quenched
in water so that upset will form only on the hot portion of the bar. In one method of upsetting,
the bar is held in the tong and supported vertically on the anvil. The top edge of the bar is
then hammered to form the upset on the bottom hot end of the bar. For upsetting, the blow
of the hammer must be in line with the bar to prevent bending of the bar.

(iv) Bending

Bending is a very commonly used forging operation in forging shop to give a turn to a
metal rod or plate. It is accompanied by spreading of the metal in the inside of the bend and
narrowing at outside. The simplest method of bending a piece of metal in hand forging is to
support it on the anvil and to strike its free end with a hammer When bent, the metal of
the workpiece thins out round bend causing weakness. This can be overcome by upsetting the
bar prior to bending.

(v) Cutting

Cutting is a main forging operation to cut out a metal rod or plate into two pieces with
the help of a chisel and hammer when the metal is in red hot condition. A hot or cold cut
(chisel) is used for cutting heated metal bars in a smithy shop. The hot set does not require
hardening and tempering. Its cutting edge is keener than that of a cold set. Hot sets are
manufactured from a tough variety of steel in order that they may cut through relatively soft
red-hot metal with ease. While cutting, it is best to cut half through the workpiece to turn
it over and cut through from the other end.

(vi) Punching

Punching is a main forging operation used for producing hole in metal plate by using a
tool known as punch. The metal plate is placed over the hollow cylindrical die and punch is
placed above it at required location where hole is being made. For punching a hole, the metal
job must be at near welding heat and the punch is driven part way through the job with
hammer blows. The work is then turned over and the hole is completed from the other side.
The above said practice is adopted for thicker jobs.

(vii) Forge Welding

It is a process of joining two metal pieces to increase the length by pressing or hammering
them when they are at forging temperature. It is performed in forging shop and hence
sometimes it is called as forge welding.

Power Forging

To have heavy impact or blow for more plastic deformation, power hammers generally classified as spring hammer and drop hammers are used. The capacity of these hammers is given by the total weight. A 100 kg hammer will be one of which the falling pans weigh 100 kg. The heavier these parts and greater the height from which they fall, the higher will be intensity of blow the hammer will provide. Power hammers are of different types e.g. spring power hammers, pneumatic power hammers etc. These hammers are named due to their construction, according to their way of operation.  

Spring Hammer

Spring hammer is commonly used for small forgings. It is light type of power hammer. The oscillation of the spring is responsible for the up and down movement of the tup thus, the required blows are provided on the job to be forged. A hand lever is also equipped with this mechanical kind of hammer to adjust the stroke of the connecting rod and, hence the intensity of blows.

Eccentric type of spring hammer is the one in which a rotating eccentric disc is used for
producing vibrations in the spring. It can be operated by means of a foot ring, known as
treadle provided at the bottom and is connected to the shaft at the top through a vertical bar
having a clutch at its end. The shaft at the top of hammer carries a pulley and a solid disc
at the end. The pulley is driven by means of a belt from the line shaft or an electric motor.
The solid disc, at the, end of the shaft, carries a crank connected eccentrically to it which has
a laminated spring at its lower end. The nip carrying the weight is suspended on a toggle joint
connecting the two ends of the laminated spring. When the foot treadle is pressed the clutch
engages with the shaft and the disc carrying the crank starts rotating which in turn produces
fluctuations in the toggle joint of the machine. It makes the tup to move and down in vertical
direction. The speed of blows entirely depends upon the speed of the driving pulley.

Spring hammers may be made available in various capacities having the tup weights
from 30 to 250 kg. Those having top weights 50 to 100 kg and speed of blows up to 300 per
minute are in generally used in forging shop. These hammers have a common drawback in
their springs getting broken very frequently due to severe vibrations during forging of the
jobs in the forging shop.

Drop Hammers

Drop hammers are operated hydraulically and are widely used for shaping parts by drop hammering a heated bar or billet into a die cavity.  A drop forging raises a massive weight and allows it to fall under gravity on close dies in which forge component is allowed to be compressed. The die incorporates its shape on to the hot work piece. Drop hammers are commonly used for forging copper alloys and steel.

HEAT TREATMENT OF FORGING 

Heat treatment is carried out for releasing the internal stresses arising in the metal during forging and cooling of work piece. It is used for equalizing the granular structure of the forged metal and improving the various mechanical properties. Generally forged parts are annealed, normalized and tempered to obtain the desired results.

Ch.14 Rajinder Singh

WYMAN-GORDON 50,000-TON FORGING PRESS. 1955. NORTH ... The Mesta Machine Co. of Pittsburgh was contracted to build the press.

https://www.asme.org/wwwasmeorg/media/ResourceFiles/AboutASME/Who%20We%20Are/Engineering%20History/Landmarks/89-wyman-gordon-50000-ton-hydraulic-forging-press.pdf

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5.MANUFACTURINGPROCESSES

Product Design Guide For Forging

5. FORGING - MANUFACTURING PROCESSES
    5.1 Forging Machinery
        5.1.1 Hammers
        5.1.2 Presses
    5.2 Forging Processes
        5.2.1 The Open Die Process
        5.2.2 The Impression Die Process
            5.2.2.1 Conventional Impression Die Forging
            5.2.2.2 Flashless (Enclosed Impression Die) Forging
            5.2.2.3 Net and Shape Forging
            5.2.2.4 Hot Die and Isothermal Forging
        5.2.3 The Ring Rolling Process
        5.2.4 The Cold Forging Process
            5.2.4.1 Alloys Used for Cold Forging
            5.2.4.2 Cold Forging Processes
            5.2.4.3 Product Advantages of Cold Forging
        5.2.5 The Warm Forging Process
    5.3 Secondary Operations
        5.3.1 Heat Treating
        5.3.2 Machining
        5.3.3 Finishing Operations

https://www.forging.org/forging/design/5-manufacturing-processes-0.html

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Cost Drivers for Forging

https://www.forging.org/forging/design/331-materials-cost.html

https://www.forging.org/forging/design/332-tooling-costs.html

https://www.forging.org/forging/design/333-manufacturing-cost.html

More in:

https://www.forging.org/forging/design/3-design-and-development-products-made-forgings.html

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3.THEDESIGNANDDEVELOPMENTOFPRODUCTSMADEFROMFORGINGS

3. THE DESIGN AND DEVELOPMENT OF PRODUCTS MADE FROM FORGINGS

3.1 Concurrent Engineering
3.2 Design Parameters for Forgings

• 3.2.1 Service Loads
• 3.2.2 Service Temperatures
• 3.2.3 Alloys Forged
• 3.2.4 Interfacing Structural Components
• 3.2.5 Accidental Unanticipated Conditions

3.3 Cost Drivers

• 3.3.1 Material Cost
• 3.3.2 Tooling Cost
• 3.3.3 Manufacturing Cost
• 3.3.4 Secondary Operations
• 3.3.5 Quantities Produced

3.4 Process Tradeoffs

• 3.4.1 A Comparison of Open Die, Impression Die, Rolled Ring and Cold Forging Processes
• 3.4.2 Forging Processes Compared With Alternate Processes
• 3.4.2.1 Sheet Metal Stamping
• 3.4.2.2 Weldments
• 3.4.2.3 Foundry Casting
• 3.4.2.4 Investment Casting
• 3.4.2.5 CNC Machined Bar and Plate
• 3.4.2.6 Powder Metallurgy
• 3.4.2.7 Reinforced Plastics and Composites

3.5 Designing Products Made from Forgings

• 3.5.1 Development of a Typical Shape
• 3.5.2 Selecting a Forging Company
• 3.5.3 Selecting the Optimum Forging Alloy
• 3.5.4 Product design Guidelines
• 3.5.4.1 Design Rules for Parts Made From Impression Die Forgings
• 3.5.4.2 Design Rules For Parts Made From Upset Forgings
• 3.5.4.3 Design Rules for Parts Made From Open Die Forgings
• 3.5.4.4 Design Rules for Parts Made From Rolled Rings
• 3.5.4.5 Design Rules for Parts Made by Cold and Warm Forging

3.6 Predicting, Developing and Maintaining Properties in Forgings

• 3.6.1 Physical Properties
• 3.6.2 Mechanical Properties
• 3.6.3 Developing and Maintaining Product Performance

3.7 Specifying Heat Treating

• 3.7.1 Heat Treating Steel
• 3.7.1.1 Annealing Processes for Steel
• 3.7.1.2 Hardening Treatments for Steel
• 3.7.2 Heat Treating Stainless Steels
• 3.7.3 Heat Treating Aluminum Alloys
• 3.7.4 Heat Treating Titanium Alloys
• 3.7.5 Heat Treating Heat Resistant Alloys

3.8 Prototyping

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Industrial Engineering and Productivity Improvement of Forging Operations

https://www.researchgate.net/publication/312316702_Productivity_Improvement_in_Forging_Industry_Using_Industrial_Engineering_Techniques

https://www.springerprofessional.de/en/industrial-engineering-and-ergonomics/manufacturing/scientists-are-developing-ergonomic-forging-tongs/16909142

About forging on IISE site
https://www.iise.org/details.aspx?id=2712

Enhancing tool availability in the forging industry by adjusting PPC and tool maintenance
2011 IEEE International Conference on Industrial Engineering and Engineering Management
https://ieeexplore.ieee.org/document/6117886


Forging Companies

https://www.bharatforge.com/worldwide/national

UD 21 May 2021
Pub 12 August 2019

Sheet Metal Components Production

Sheet Metal Working
Chapter 20 of  Fundamental of Modern Manufacturing
Mikell P. Groover

Contents

20.1 Cutting Operations
20.1.1 Shearing, Blanking, and Punching
20.1.2 Engineering Analysis of Sheet-Metal Cutting
20.1.3 Other Sheet-Metal-Cutting Operations

20.2 Bending Operations
20.2.1 V-Bending and Edge Bending
20.2.2 Engineering Analysis of Bending
20.2.3 Other Bending and Forming Operations

20.3 Drawing
20.3.1 Mechanics of Drawing
20.3.2 Engineering Analysis of Drawing
20.3.3 Other Drawing Operations
20.3.4 Defects in Drawing

20.4 Other Sheet-Metal-Forming Operations
20.4.1 Operations Performed with Metal Tooling
20.4.2 Rubber Forming Processes

20.5 Dies and Presses for Sheet-Metal Processes
20.5.1 Dies
20.5.2 Presses

20.6 Sheet-Metal Operations Not Performed on Presses
20.6.1 Stretch Forming
20.6.2 Roll Bending and Roll Forming
20.6.3 Spinning
20.6.4 High-Energy-Rate Forming

20.7 Bending of Tube Stock

Sheet metalworking includes cutting and forming operations performed on relatively thin sheets of metal. Typical sheet-metal thicknesses are between 0.4 mm (1/64 in) and 6 mm (1/4 in). When thickness exceeds about 6 mm, the stock is usually referred to as plate.   The most commonly used sheet metal is low carbon steel (0.06%–0.15% C typical). Its low cost and good formability, combined with sufficient strength for most product applications, make it ideal as a starting material.

Industrial products that include sheet or plate metal parts: automobile and truck bodies, airplanes, railway cars, locomotives, farm and construction equipment, appliances, office furniture,

and more. These products have sheet-metal exteriors and many internal sheet metal components .

Sheet metal parts are generally characterized by high strength, good dimensional accuracy, good surface finish, and relatively low cost.

Most sheet-metal operations are performed on machine tools called presses.  The term stamping press is used to distinguish these presses from forging and extrusion.

TYPE OF PRESSES

Presses are classified based upon the method of operation method of power source method of activation of slide and number of slides in action.

1. Method of Operation

(i) Arbor Press. It is a hand operated press. It combines the principle of lever with pinions to a related rack build into the ram. They are used where a very limited no. of production of parts is required.

(ii) Foot Press. It is also manual operated press. Most of the presses have foot action in their operating mechanism.

(iii) Open back inclinable press. It is a power operated press. They are having bench or floor models.



2. Method of Power Sources

(i) Manual presses

(ii) Mechanical power presses

(iii) Hydraulic presses.

(iv) Pnuematic presses



3. Method of Activation of Slide

(i) Crank shaft presses
(ii) Knuckle joint presses
(iii) Toggle presses

4. Number of Slides in Action

(i)  single action presses
(ii) Double action presses
(iii Triple action

NPTEL Lecture 7 - PRESSES FOR SHEET METAL WORKING
NPTELMechanical EngineeringManufacturing Processes
https://nptel.ac.in/courses/112107144/7

Lecture 4 - FORMABILITY OF SHEET METAL
https://nptel.ac.in/courses/112107144/4

Lecture 6 - SHEET METAL PROCESSES
https://nptel.ac.in/courses/112107144/6

Lecture 8 - DIE AND PUNCH
https://nptel.ac.in/courses/112107144/8


Metal Press Work - YouTube Video
Uploaded by Engineering Education Channel
_______________

_______________
https://www.youtube.com/watch?v=aUhvo0om1q0


PRESS OPERATION

Sheet metal process  planner has to know certain fundamentals specifications of press machine. Some of them are press tonnages, stroke of the press, die area, shut height etc.,

Press tonnage

The tonnage of a mechanical press is equal to the shear strength of the crankshaft metal multiplied by the area of the crankshaft bearings.

The tonnage of a hydraulic press is the area multiplied by the oil pressure in the cylinder.

It indicates the amount of pressure in tonnes that a press exerts on  work safely and is used for rating a press. The press may exist in various capacities of tonnes varying from 5, 10, 20, 32, 50, 75, 200, 500 tons to tackle the sheet metal operation using proper die in press.

Press stroke:
It is the reciprocating motion of a press slide. It is adjustable on a hydraulic press.

Die area: It is the available surface for mounting punches and die components

Shut height

It is the distance from the top of the bed to the bottom of the slide when stroke down and the adjustment up. The shut height of the die must be equal to or less than the shut height of the press.

Die shut height = Punch shoe thickness + Die show thickness + Die steel height + Punch
steel Height-bypass of steels.

The by-pass of steels may be taken as from 3 mm to 6 mm.

Sheet Metal Operations  

1. Shearing. It takes place in the form of a cut when punch strikes and enters in the sheet placed on die. The quality of the cut surface is greatly influenced by the clearance between the two shearing edges of the punch and dies.

2. Cutting. It means severing a piece from a strip or sheet with a cut along a single line using suitable punch and die of press tool in press machine.

3. Parting. It signifies that scrap is removed between the two pieces to part them using suitable punch and die of press tool in press machine.


4. Blanking. It is a operation in which the punch removes a portion of material called blank from the strip of sheet metal of the necessary thickness and width using suitable punch and die of press tool in press machine.

5. Punching. It is the operation of producing circular holes on a sheet metal by a punch and die. The material punched out is removed as waste. Piercing, on the other hand, is the process of producing holes of any desired shape in the part or sheet using suitable punch and die of press tool in press machine.

6. Notching. It is a process to cut a specified shape of metal from the side or edge of the stock using suitable punch and die.

7. Slitting. When shearing is conducted along a line, the process is referred to as slitting. It cuts the metal sheet lengthwise using suitable punch and die of press tool in press machine.

8. Lancing. It makes a cut part way across a sheet and creates a bend along the cut using suitable punch and die.

9. Nibbling. It is an operation of cutting any shape from sheet metal without special tools. It is done on a nibbling machine.

10. Trimming. It is the operation of cutting away excess metal in a flange or flash from a sheet metal part using suitable punch and die of press tool in press machine.

11. Bending. Bending is the operation of deforming a sheet around a straight axis. The neutral plane lies on this straight axis. In bending all sheet material are stressed beyond the elastic limit in tension on the outside and in compression on the inside of the bend. There is only one line, the natural line that retains its original length. The neutral axis lies at a distance of 30 to 50% of thickness of the sheet from the inside of the bend. Stretching of the sheet metal on the outside makes the stock thinner. Bending is sometimes called as forming, which involves angle bending, roll bending, roll forming, seaming and spinning.

MACHINES USED IN SHEET METAL SHOP

The machines, which are in use to perform different operations on metal sheets, are as follows:

1. Shearing machine
2. Bending machine
3. Folding machine
4. Grooving machine
5. Peining machine
6. Beading machine
7. Swaging machine
8. Burring machine
9. Double seaming machine

Many  special purpose machines are developed and fabricated to suit  particular kinds of work for mass production of identical parts at lower cost.

Shearing machine

A shearing machine consists of a base or frame, which can be conveniently fixed on a bench in any position as desired. Two shearing blades are provided in the machine. One called the fixed blade is rigidly fixed with the frame whereas the other known as movable blade is operated by means of the hand lever provided at the rear. In operation, the metal sheet is placed between the shear blades in such a way that the markings of the layout come exactly under the cutting edge of the upper blade. Out of the two blades one is fixed and the other moveable. When the lever is pulled by the operator the lower blade rises and thus the metal sheet is cut. This particular provision enables the metal sheet to be locked against the upper blade during the operation on account of the circular motion of the hand lever. With the result, the metal sheet is prevented from being distorted.

Folding machine
Folding machines are used for bending and folding the edges of metal plates to form
the joint at the seam. Bending machines or bending rollers, as they are better known, are
used for shaping metal sheets into cylindrical objects. The machine consists of three rollers.
These rollers have different adjustments indifferent types of machines. In some-machines
two rollers at the bottom have fixed position and the third one (top roller) can be adjusted
in vertical direction to adjust the pressure and give the required curvature to the sheet.
A still better control is obtained by having two rollers exactly one over the other, out of
which the bottom roller is fixed and the top roller can be adjusted vertically to suit the
thickness of the sheet and the pressure required for rolling. The third roller, called radius
roller can be moved up and down to provide the desired curvature. Improved designs of
these machines are available which contain the rollers, which have grooves of various
shapes and sizes to form corresponding shapes in metal sheets. Conical shaped rollers are
used for tapered cylindrical articles. Similarly other machines named above are used to
perform different operations after which they are named.

Burring machine
Burring machine is used to make a burr on the edges of the bottom and covers. Burr is the starting of the seam. Double seaming machine is used for double seaming flat bottoms on straight or flared cylindrical pieces.

Various types of press machines with different capacities are used for mass production of sheet metal components. These are equipped with different kind of press tools or dies. These are commonly employed for fast and accurate processing of sheet metal work.

Industrial Engineering - Productivity Science

Process parameters in sheet-metal cutting are clearance between punch and die, stock thickness, type of metal and its strength, and length of the cut.  (Groover, Section 20.1.2)


Die Basics 101: Intro to stamping
https://www.thefabricator.com/article/stamping/die-basics-101-intro-to-stamping

Getting to Production Faster with 3D-Printed Press Brake Tooling
A case study from Centerline Engineered Solutions demonstrates that a 3D-printed die and punch can withstand press brake forces, providing a cheaper, faster path to production.
https://www.additivemanufacturing.media/blog/post/getting-to-production-faster-with-3d-printed-press-brake-tooling
https://www.additivemanufacturing.media/blog/post/getting-to-production-faster-with-3d-printed-press-brake-tooling

Sheet Metal Stamping Dies and Processes - SME Training Guide - You can download
https://www.sme.org/study-guides


Punch Press Dies – Set Up and Working
https://www.eigenengineering.com/punch-press-dies-set-up-and-working-in-the-manufacturing-industry/
(+91) 80 61111300| info@eigenengineering.com
Eigen – USA
Address - 1:
4201 Military Highway
McAllen, Texas 78503 USA.
Phone : +1 248 933 4593.

Address - 2:
409 Rivanna Lane
Greenville, SC 29607.
Phone : +1 248 933 4593
Eigen
KDDL Ltd. Unit Eigen
No.55-A, Hunachur Village, Jala Hobli,
Yelahanka Taluk, Bangalore North
Near Kiadb Aerospace Park
Bangalore, Karnataka 562149
Phone: (+91) 80 61111300
Ext: 312
Email: info@eigenengineering.com

What is metal stamping? - The Basics of Metal Stamping
https://www.esict.com/what-is-metal-stamping/

Understanding Metal Stamping
https://www.thomasnet.com/articles/custom-manufacturing-fabricating/understanding-metal-stamping/


Updated on 8 Jan 2021 12 August 2019, 1 August 2019

Milling Machine And Operations

 MILLING

1. INTRODUCTION

2 PRINCIPLE OF MILLING

3 MILLING METHODS - UP and Down

4. TYPES OF MILLING CUTTERS

5. TYPES OF MILLING MACHINES

6. SIZE OF MILLING MACHINE

7. CUTTING PARAMETERS 

8 INDEXING AND DIVIDING HEADS

9 OPERATIONS OF MILLING MACHINE

1. INTRODUCTION

A milling machine is a machine tool that removes metal as the work is fed against a rotating multipoint cutter. The milling cutter rotates at high speed and it removes metal with the help of multiple cutting edges. Milling machine is used for machining flat surfaces, contoured surfaces, surfaces of revolution, external and internal threads, and helical surfaces of various cross-sections. In many applications, due to its higher production rate and accuracy, milling machine has replaced shapers and slotters.

2 PRINCIPLE OF MILLING

In milling machine, the metal is cut by means of a rotating cutter having multiple
cutting edges. The workpiece is fed against the rotary cutter. As the
workpiece moves against the cutting edges of milling cutter, metal is removed in form chips
of trochoid shape.  The work to be machined is held in a vice, a rotary table, a three jaw chuck, an index head, between centers, in a special fixture or bolted to machine table. The cutting speed of the cutting tool and the feed rate of the workpiece depend upon the type of material being machined and the tool being used.

3 MILLING METHODS

There are two distinct methods of milling classified as follows:

1. Up-milling or conventional milling, and

2. Down milling or climb milling.

1 UP-Milling or Conventional Milling Procedure

In the up-milling or conventional milling,  the metal is removed  by a cutter rotating against the direction of travel of the workpiece. In this type of milling, the chip thickness is minimum at the start of the cut and maximum at the end of cut. As a result the cutting force  varies from zero to the maximum value per tooth movement of the milling cutter. The major disadvantages of up-milling process are the tendency of cutting force to lift the work from the fixtures and poor surface finish
obtained. But being a safer process, it is commonly used method of milling.




2 Down-Milling or Climb Milling

Down milling is also known as climb milling. In this method,
the metal is removed by a cutter rotating in the same direction of feed of the workpiece. The
effect of this is that the teeth cut downward instead of upwards. Chip thickness is maximum
at the start of the cut and minimum in the end. In this method,  there is less friction involved and consequently less heat is generated on the contact surface of the cutter and workpiece. Climb milling can be used advantageously on many kinds of work to increase the number of pieces per sharpening and to produce a better finish. With climb milling, saws cut long thin slots more satisfactorily. Another advantage is that slightly lower power consumption is obtainable by climb milling, since there is no need to drive the table against the cutter.

4. TYPES OF MILLING CUTTERS

(1) Plain milling cutters,

(2) Side milling cutters,

(3) Face milling cutter,

(4) Angle milling cutters,

(5) End milling cutter,

(6) Fly cutter,

(7) T-slot milling cutter,

(8) Formed cutters,

(9) Metal slitting saw,

Milling cutters may have teeth on the periphery or ends only, or on both the periphery
and ends. Peripheral teeth may be straight or parallel to the cutter axis, or they may be
helical, sometimes referred as spiral teeth.

5. TYPES OF MILLING MACHINES

Milling machine rotates the cutter mounted on the arbor of the machine and at the same
time automatically feed the work in the required direction.


According to general design, the distinctive types of milling machines are:


1. Column and knee type milling machines

(a) Hand milling machine

( b ) Horizontal milling machine

(c) Universal milling machine

(d) Vertical milling machine

2. Planer milling machine

3. Fixed-bed type milling machine

(a) Simplex milling machine.

( b ) Duplex milling machine.

(c) Triplex milling machine.

4. Machining center machines

5. Special types of milling machines

(a) Rotary table milling machine.
( b ) Planetary milling machine.
(c) Profiling machine.
(d) Duplicating machine.
(e) Pantograph milling machine.
(f) Continuous milling machine.
( g ) Drum milling machine
(. h ) Profiling and tracer controlled milling machine

Some important types of milling machines are discussed as under.

1 Column and Knee Type Milling Machine

 In this type of milling machine the table
is mounted on the knee casting which in turn is mounted on the vertical slides of the main
column. The knee is vertically adjustable on the column so that the table can be moved up
and down to accommodate work of various heights.

The principal parts of a column and knee type milling machine are described as under.

Base

It is a foundation member for all the other parts, which rest upon it. It carries the
column at its one end. In some machines, the base is hollow and serves as a reservoir for
cutting fluid.

Column

The column is the main supporting member mounted vertically on the base. It is box
shaped, heavily ribbed inside and houses all the driving mechanism for the spindle and table
feed. The front vertical face of the column is accurately machined and is provided with
dovetail guideway for supporting the knee.

Knee

The knee is a rigid grey iron casting which slides up and down on the vertical ways of
the column face. An elevating screw mounted on the base is used to adjust the height of the
knee and it also supports the knee. The knee houses the feed mechanism of the table, and
different controls to operate it.

Saddle

The saddle is placed on the top of the knee and it slides on guideways set exactly at 90°
to the column face. The top of the saddle provides guide-ways for the table.

Table

The table rests on ways on the saddle and travels longitudinally. A lead screw under the
table engages a nut on the saddle to move the table horizontally by hand or power. In
universal machines, the table may also be swiveled horizontally. For this purpose the table
is mounted on a circular base. The top of the table is accurately finished and T -slots are
provided for clamping the work and other fixtures on it

Overhanging arm

It is mounted on the top of the column, which extends beyond the column face and serves
as a bearing support for the other end of the arbor.


Front brace

It is an extra support, which is fitted between the knee and the over-arm to ensure
further rigidity to the arbor and the knee.

Spindle

It is situated in the upper part of the column and receives power from the motor through
belts, gears, and clutches and transmit it to the arbor.

Arbor

It is like an extension of the machine spindle on which milling cutters are securely
mounted and rotated. The arbors are made with taper shanks for proper alignment with the
machine spindles having taper holes at their nose. The draw bolt is used for managing for
locking the arbor with the spindle and the whole assembly.

The arbor assembly consists of the following components.
1. Arbor

2. Spindle

3. Spacing collars

4. Bearing bi

5. Cutter

6. Draw bolt

7. Lock nut

8. Key block

9. Set screw



2 Planer Type Milling Machine

It is a heavy duty milling machine. It resembles a planer and like a planning machine
it has a cross rail capable of being raised or lowered carrying the cutters, their heads, and
the saddles, all supported by rigid uprights. There may be a number of independent spindles
carrying cutters on the rail as two heads on the uprights. The use of the machine is limited
to production work only and is considered ultimate in metal re-moving capacity.

3 Special Type Milling Machines

Milling machines of non-conventional design have been developed to suit special purposes.
The features that they have in common are the spindle for rotating the cutter and provision
for moving the tool or the work in different directions.

6. SIZE OF MILLING MACHINE

The size of the column and knee type milling machine is specified by

(1) The dimensions of the working surface of the table, and

(2) Its maximum length of longitudinal, cross and vertical travel of the table.

In addition to above, number of spindle speeds, number of feeds, spindle nose taper,
power available, floor space required and net weight of machine will also be required for
additional specification.

7. Cutting Speed, Feeds and DEPTH OF CUT

The depth of cut in milling is defined as the thickness of the material removed in one
pass of the work under the cutter. Thus it is the perpendicular distance measured between
the original and final surface of the workpiece, and is expressed in mm.

8 INDEXING AND DIVIDING HEADS

Indexing is the operation of dividing the periphery of a piece of work into any number
of equal parts. In cutting spur gear equal spacing of teeth on the gear blank is performed by
indexing. Indexing is accomplished by using a special attachment known as dividing head or
index head as shown in Fig. 24.8. The dividing heads are of three types:

(1) Plain or simple dividing head,

(2) Universal dividing head and

(3) Optical dividing head.


1 Plain or Simple Dividing Head

The plain dividing head comprises a cylindrical spindle housed on a frame, and a base
bolted to the machine table. The index crank is connected to the tail end of the spindle
directly, and the crank and the spindle rotate as one unit. The index plate is mounted on the
spindle and rotates with it. The spindle may be rotated through the desired angle and then
clamped by inserting the clamping lever pin into anyone of the equally spaced holes or slots
cut on the periphery of the index plate. This type of dividing head is used for handling large
number of workpieces, which require a very small number of divisions on the periphery.

1. Swiveling block 2. Live centre

3. Index crank 4. Index plate.

9 OPERATIONS PERFORMED ON MILLING MACHINE

Unlike a lathe, a milling cutter does not give a continuous cut, but begins with a sliding
motion between the cutter and the work. Then follows a crushing movement, and then a
cutting operation by which the chip is removed. Many different kinds of operations can be
performed on a milling machine but a few of the more common operations will now be
explained. These are:

Plain milling or slab milling

 It is a method of producing
a plain, flat, horizontal surface parallel to the axis of rotation of the cutter.

Face milling

 It is a method of producing a flat
surface at right angles to the axis of the cutter.

Side milling

 It is the operation of production of a
flat vertical surface on the side of a work-piece by using a side milling cutter.

Angular milling

 It is a method of producing a flat
surface making an angle to the axis of the cutter.

Gang-milling

 It is a method of milling by means of
two or more cutters simultaneously having same or different diameters mounted on the arbor
of the milling machine.

Form milling

 It is, a method of producing a surface
having an irregular outline.

End milling

 It is a method of milling slots, flat surfaces,
and profiles by end mills.

Profile milling

 It is the operation of reproduction of an
outline of a template or complex shape of a master die on a workpiece.

Saw milling

 It is a method of producing deep slots and
cutting materials into the required length by slitting saws.

T-slot milling



Keyway milling


Gear cutting milling



Helical milling



Flute milling

It is a method of grooving or cutting of flutes on drills, reamers, taps, etc,


Straddle milling

It is a method of milling two sides of a piece of work by employing two side-milling
cutters at the same time.

Thread milling

It is a method of milling threads on dies, screws, worms, etc. both internally and
externally. As an alternative to the screw cutting in a lathe, this method is being more
extensively introduced now a day in modern machine shops.






Define the following terms used in milling operation.

(а) Cutting speed

(b) Feed

(c) Depth of cut

(d) Machining time.


____________ ____________
____________ ____________
____________ ____________
____________ ____________

SmithyCo Videos  total 50 are there


Updated on 14 March 2020
14 May 2012

Introduction to Lathe - Turning Operations

An engine lathe is the most basic and simplest form of the lathe.  Besides the simple turning operation,  lathe can be used to carry out other operations  such as drilling, reaming, boring, taper turning, knurling, screw-thread cutting, grinding etc.

TYPES OF LATHE

1. Speed lathe

(a) Wood working
( b ) Spinning
(c) Centering
(d) Polishing


2. Centre or engine lathe

(a) Belt drive
( b ) Individual motor drive
(c) Gear head lathe

3. Bench lathe

4. Tool room Lathe

5. Capstan and Turret lathe

6. Special purpose lathe

(a) Wheel lathe
( b ) Gap bed lathe
(c) Duplicating lathe
(d) T-lathe

7. Automatic lathe

SPECIFICATION OF LATHE 

The size of a lathe is generally specified by the following means:

(a) Swing or maximum diameter that can be rotated over the bed ways

( b ) Maximum length of the job that can be held between head stock and tail stock centres

(c) Bed length, which may include head stock length also

( d ) Maximum diameter of the bar that can pass through spindle or collect chuck of capstan lathe.


(i) Maximum swing over bed
(ii) Maximum swing over carriage
(iii) Height of centers over bed
(iv) Maximum distance between centers
(v) Length of bed
(vi) Width of bed
(vii) Morse taper of center
(viii ) Diameter of hole through spindle
(ix) Face plate diameter
(x) Size of tool post
(xi) Number of spindle speeds
(xii) Lead screw diameter and number of threads per cm.
(xiii) Size of electrical motor
(xiv) Pitch range of metric and inch threads etc.



Introduction to lathe - Monash University Video
_________________

_________________



CUTTING SPEED

Cutting speed for lathe work may be defined as the rate in meters per minute at which
the surface of the job moves past the cutting tool. Machining at a correct cutting speed is
highly important for good tool life and efficient cutting. Too slow cutting speeds reduce
productivity and increase manufacturing costs whereas too high cutting speeds result in
overheating of the tool and premature failure of the cutting edge of the tool. The following
factors affect the cutting speed:

(i) Kind of material being cut,

(ii) Cutting tool material,

(Hi) Shape of cutting tool,

(iv) Rigidity of machine tool and the job piece and

(v) Type of cutting fluid being used.

Calculation of cutting speed Cs, in meters per minute 

Cs = ((22/7) x D x N)) /1000

Where

D is diameter of job in mm.

N is in RPM

FEED 

Feed is defined as the distance that a tool advances into the work during one revolution
of the headstock spindle. It is usually given as a linear movement per revolution of the spindle
or job. During turning a job on the center lathe, the saddle and the tool post move along the
bed of the lathe for a particular feed for cutting along the length of the rotating job.




_________________ _________________
_________________ _________________
_________________ _________________
_________________ __________________

Smithyco videos - 50 videos are there

Updated on 14 March 2020
27 October 2015

IMTMA - Modern Manufacturing India Magazine

Latest January 2020 Issue
http://www.mmindia.co.in/flipbook/jan2k20/#page/72

Case: Industry 4.0 in Godrej
Smart fixtures

Latest May 2019 Issue
https://www.imtma.in/pages/145/mmi-magazine

January 2014 Issue
http://www.imtma.in/userfiles/files/File/MMI/MMIjan2k14issue1.pdf


Companies Editorially mentioned in the issue

A
ABB Group .............. .38
Ace Micromatic Group ...... .61
ACMA ................ 32,62
Ampco Metal ............. .64
Automation Industry Association .............. .26

B
Bajaj Motors ............. .63
Batliboi Ltd .............. .61
BFW Ltd ................ .61
Bharat Electronics Ltd ...... .63
Bharat Heavy Electricals ..... .63
BorgWarner Turbo Systems
Worldwide Headquarters .... .52
Bosch Ltd ............... .61
Boschert GmbH + Co KG .... .64
Brakes India Ltd ........... .52

C
Carl Zeiss India (Bangalore) Pvt Ltd ................. .64
Claas .................. .38
Cummins India ........... .38

D
Danfoss ................. .38
Delcam Software .......... .61
Deutsche Messe. . . . . . . . . . . .24
DMG MORI ............ 26,76
DRDO .................. .63

E
EEPC India .............. .38

F
Fanuc .................. .63
Festo Controls ............ .61
Forbes Marshall ........... .48
Force Motors ............. .63
Frost & Sullivan ......... 25,26

G
Grind Master Machines ..... .64
GW Precision Tools India .... .61

H
HAESL .................. .46
Hexagon Metrology India .... .61
Hypertherm (India) Thermal
Cutting ................. .64

I
IMTMA ........ .8,10,22,60,62
Indian Railways ........... .63
International Institute of
Welding ................ .56
Inverto ................. .38
Isgec Heavy Engineering Ltd . . .65
ISRO ................... .63

J
Jinan Tianchen Machine Group .65
Jyoti CNC Automation Ltd ... .61

K
Kennametal India Limited .... .24
Kjellberg Finsterwalde Plasma
und Maschinen GmbH ...... .65
Kubota India ............. .38

L
Laser Technologies Pvt Ltd ... .65
LVD Strippit India Pvt Ltd .... .24

M
M. D. Corporation ......... .65
Metrol Corporation India . . 52,76
Micromatic Machine Tools ... .18

N
Naval Dockyard ........... .63

P
Pentair ................. .38

R
Radcam Technologies ....... .64
Renishaw Metrology Systems . .46

S
Sahajanand Laser
Technologies ........... 34,62
Salvagnini Italia ........... .62
Schuler India ........... 62,65
Sheths’ ................. .63
SIAM ................... .63
Siemens .............. 20,48
Singhal Power Press ........ .63
Sumitomo Electric ......... .24
Sundaram Finance Ltd ...... .52
T
TaeguTec India Pvt Ltd .... 8,62
TAGMA ................. .63
Titan Industries ........... .63
Toyota Kirloskar Motors ..... .63
TRUMPF ................ .63
Turbo Energy Ltd .......... .52
TVS Motors .............. .63
V
VDMA Robotik + Automation . .26
VDW-Nachwuchsstiftung .... .24
Volvo India Pvt Ltd ......... .63
Y
Yamazaki Mazak .......... .63


Updated on 29 Feb 2020,  29 July 2019, 7 March 2014

Manufacturing Processes- Technology - Engineering - Books - Bibliography

Machine Tools
Dr. R. Kesavan
Laxmi Publications, Ltd., 2010 - Machine-tools - 454 pages
https://books.google.co.in/books?id=ojUSAga14cMC


Manufacturing Technology - II
Dr. R.Kesavan, B. Vijaya Ramanath
Firewall Media, 2006 - 467 pages
https://books.google.co.in/books?id=4-I0IoGxJrAC

Metal Casting

PERMANENT MOLD OR GRAVITY DIE CASTING

This process is commonly known as permanent mold casting in U.S.A and gravity die casting in England. A permanent mold casting makes use of a mold or metallic die which is permanent. Molten metal is poured into the mold under gravity only and no external pressure is applied to force the liquid metal into the mold cavity.  The metallic mold can be reused many times before it is discarded or rebuilt.

The molds are made of dense, fine grained, heat resistant cast iron, steel, bronze, anodized aluminum, graphite or other suitable refractoriness. The mold is made in two halves in order to facilitate the removal of casting from the mold. It may be designed with a vertical parting line or with a horizontal parting line as in conventional sand molds.

The mold walls of a permanent mold have thickness from 15 mm to 50 mm. The thicker mold walls can remove greater amount of heat from the casting. For faster cooling, fins or projections may be provided on the outside of the permanent mold. This provides the desirable chilling effect.

Advantages

(i) Fine and dense grained structure is achieved in the casting. Because of rapid rate of cooling, the castings possess fine grain structure.
(ii) No blow holes exist in castings produced by this method.  Good surface finish and surface details are obtained.  defects observed in sand castings are eliminated.
(iii) The process is economical for mass production. Fast rate of production can be attained.
(iv)  Close dimensional tolerance or job accuracy is possible to achieve on the cast product.
(v) Manpower required is less.


Disadvantages

(i) The cost of metallic mold is higher than the sand mold. The process is impractical for large castings.
(ii) The surface of casting becomes hard due to chilling effect.
(iii) Refractoriness of the high melting point alloys.

Applications

(i) This method is suitable for small and medium sized casting such as carburetor bodies, oil pump bodies, connecting rods, pistons etc.
(ii) It is widely suitable for non-ferrous casting.


PRESSURE DIE CASTING

Molten metal is forced into metallic mold or die under pressure in pressure die casting. The pressure is generally created by compressed air or hydraulically means. The pressure varies from 70 to 5000 kg/cm 2 and is maintained while the casting solidifies. The application of high pressure is associated with the high velocity with which the liquid metal is injected into the die to provide a unique capacity for the production of intricate components at a relatively low cost. This process is called simply die casting in USA. The die casting machine should be properly designed to hold and operate a die under pressure smoothly. There are two general types of molten metal ejection mechanisms adopted in die casting set ups which are:

(i) Hot chamber type
(a) Gooseneck or air injection management
(b) Submerged plunger management
(ii) Cold chamber type

Die casting is widely used for mass production and is most suitable for non-ferrous metals and alloys of low fusion temperature. The casting process is economic and rapid. The surface achieved in casting is so smooth that it does not require any finishing operation. The material is dense and homogeneous and has no possibility of sand inclusions or other cast impurities. Uniform thickness on castings can also be maintained.

The principal base metals most commonly employed in the casting are zinc, aluminum, and copper, magnesium, lead and tin. Depending upon the melting point temperature of alloys and their suitability for the die casting, they are classified as high melting point (above 540°C) and low melting point (below 500°C) alloys. Under low category involves zinc, tin and lead base alloys. Under high temperature category aluminum and copper base alloys are involved.

Applications

1. Carburetor bodies
2. Hydraulic brake cylinders
3. Refrigeration castings
4. Washing machine
5. Connecting rods and automotive pistons
6. Oil pump bodies
7. Gears and gear covers
8. Aircraft and missile castings, and
9. Typewriter segments


Chapter Contents - Groover

10 FUNDAMENTALS OF METAL CASTING

Chapter Contents

10.1 Overview of Casting Technology
10.1.1 Casting Processes
10.1.2 Sand-Casting Molds

10.2 Heating and Pouring
10.2.1 Heating the Metal
10.2.2 Pouring the Molten Metal
10.2.3 Engineering Analysis of Pouring
10.2.4 Fluidity

10.3 Solidification and Cooling
10.3.1 Solidification of Metals
10.3.2 Solidification Time
10.3.3 Shrinkage
10.3.4 Directional Solidification
10.3.5 Riser Design

The starting work material is either a liquid or is in a highly plastic condition, and  parts are  created through solidification of the material. Casting and molding processes dominate this category of shaping operations.

Casting is a process in which molten metal flows by gravity or other force into a mold where it solidifies in the shape of the mold cavity. Casting also means the part that is made by the casting  process.

11. METAL CASTING PROCESSES

Chapter Contents

11.1 Sand Casting
11.1.1 Patterns and Cores
11.1.2 Molds and Mold Making
11.1.3 The Casting Operation


11.2 Other Expendable-Mold Casting Processes
11.2.1 Shell Molding
11.2.2 Vacuum Molding
11.2.3 Expanded Polystyrene Process
11.2.4 Investment Casting
11.2.5 Plaster-Mold and Ceramic-Mold Casting


11.3 Permanent-Mold Casting Processes
11.3.1 The Basic Permanent-Mold Process
11.3.2 Variations of Permanent-Mold Casting
11.3.3 Die Casting
11.3.4 Squeeze Casting and Semisolid Metal Casting
11.3.5 Centrifugal Casting

11.4 Foundry Practice
11.4.1 Furnaces
11.4.2 Pouring, Cleaning, and Heat Treatment

11.5 Casting Quality

11.6 Metals for Casting

11.7 Product Design Consideration

Foundry

Principles of Foundry Technology

P. L. Jain

Tata McGraw-Hill Education, 2003 - Founding - 401 pages

https://books.google.co.in/books?id=NOotk64Grx0C

Updated on 2 September 2019, 12 August 2018