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

Patterns for Moulds - Design Considerations

A pattern is a model or the replica of the object to be casted.

Utility of a Pattern


1 Pattern prepares a mould cavity for the purpose of making a casting.
2 Pattern possesses core prints which produces seats in form of extra recess for core placement in the mould.
3 It establishes the parting line and parting surfaces in the mould.
4 Runner, gates and riser may form a part of the pattern.
5 Properly constructed patterns minimize overall cost of the casting.
https://www.metalcastingdesign.com/articles/2014/07/01/10-cost-considerations-your-castings

6 Pattern may help in establishing locating pins on the mould and therefore on the casting with a purpose to check the casting dimensions.
7 Properly made pattern having finished and smooth surface reduce casting defects.

Patterns are generally made in pattern making shop. Proper construction of pattern and its material may reduce overall cost of the castings.

Materials for Patterns

The common materials used for making patterns are wood, metal, plastic, plaster, wax or mercury. The some important pattern materials are discussed as under.

Advantages of wooden patterns
Wood is cheap, light in weight, easily available and  can be easily worked. It is easy to join and repair.

But it is susceptible to moisture,  tends to warp and  wears out quickly due to sand abrasion.


Metallic Patterns

Metallic  patterns are not much affected by moisture as wooden pattern. The wear and

tear of this pattern is very less. Metal can be shaped with good precision, surface finish and intricacy. The main disadvantages of metallic patterns are higher cost, higher weight and tendency of rusting.
It is preferred for production of castings in large quantities with same pattern. The metals commonly used for pattern making are cast iron, brass and bronzes and aluminum alloys.

Cast Iron
It is cheaper, stronger, tough, and durable and can produce a smooth surface finish. It
also possesses good resistance to sand abrasion. The drawbacks of cast iron patterns are that
they are hard, heavy, brittle and get rusted easily in presence of moisture.

But  it is heavy,  brittle and hence it can be easily broken and it  may rust.

Brasses and Bronzes
These are heavier and expensive than cast iron and hence are preferred for manufacturing
small castings. They possess good strength, machinability and resistance to corrosion and
wear. They can produce a better surface finish than cast iron. Very thin sections can be easily casted. Brass and bronze pattern is finding application in making match plate pattern

But it is costlier than cast iron and it is heavier than cast iron.

Aluminum Alloys
Aluminum alloy patterns are more popular and best among all the metallic patterns
because of their high lightness, good surface finish, low melting point and good strength.
They also possesses good resistance to corrosion and abrasion by sand and there by enhancing
longer life of pattern. These materials do not withstand against rough handling. These have
poor repair ability and are preferred for making large castings.

They can be damaged by sharp edges. . They are softer than brass and cast iron.  Their storing and transportation needs proper care.

White Metal (Alloy of Antimony, Copper and Lead)

Advantages
1. It is best material for lining and stripping plates.
2. It has low melting point around 260°C
3. It can be cast into narrow cavities.


Disadvantages
1. It is too soft.  Its storing and transportation needs proper care.  It wears away by sand or sharp edges.

Plastic
Plastics are getting more popularity now a days because the patterns made of these materials
are lighter, stronger, moisture and wear resistant, non sticky to molding sand, durable and
they are not affected by the moisture of the molding sand. Moreover they impart very smooth
surface finish on the pattern surface. These materials are somewhat fragile, less resistant to
sudden loading and their section may need metal reinforcement.

The plastics used for this purpose are thermosetting resins. Phenolic resin plastics are commonly used. These are originally in liquid form and get solidified when heated to a specified temperature. To prepare a plastic pattern, a mould in two halves is prepared in plaster of paris with the help of a
wooden pattern known as a master pattern. The phenolic resin is poured into the mould and
the mould is subjected to heat. The resin solidifies giving the plastic pattern. Recently a new
material has stepped into the field of plastic which is known as foam plastic. Foam plastic is
now being produced in several forms and the most common is the expandable polystyrene
plastic category. It is made from benzene and ethyl benzene.


 Plaster
This material belongs to gypsum family The main advantages of plaster are that it has high compressive strength and is of high expansion setting type which compensate for the shrinkage allowance of the casting metal. Plaster of paris pattern can be prepared either by directly pouring the slurry of plaster and water in moulds prepared earlier from a master pattern or by sweeping it into desired shape or form by the sweep and strickle method. It is also preferred for production of small size intricate castings and making core boxes.

Wax
Patterns made from wax are excellent for investment casting process. The materials used
are blends of several types of waxes, and other additives which act as polymerizing agents,
stabilizers, etc. The commonly used waxes are paraffin wax, shellac wax, bees-wax, cerasin
wax, and micro-crystalline wax. The properties desired in a good wax pattern include low
ash content up to 0.05 per cent, resistant to the primary coat material used for investment,
high tensile strength and hardness, and substantial weld strength. The general practice of
making wax pattern is to inject liquid or semi-liquid wax into a split die. Solid injection is
also used to avoid shrinkage and for better strength. Waxes use helps in imparting a high
degree of surface finish and dimensional accuracy castings. Wax patterns are prepared by
pouring heated wax into split moulds or a pair of dies. The dies after having been cooled
down are parted off. Now the wax pattern is taken out and used for molding. Such
patterns need not to be drawn out solid from the mould. After the mould is ready, the wax
is poured out by heating the mould and keeping it upside down. Such patterns are
generally used in the process of investment casting where accuracy is linked with intricacy
of the cast object.


SELECTION OF PATTERN MATERIAL

The following factors must be taken into consideration while selecting pattern materials.

1. Number of castings to be produced. Metal pattern are preferred when castings are required large in number.
2. Type of mould material used.
3. Kind of molding process.
4. Method of molding (hand or machine).
5. Degree of dimensional accuracy and surface finish required.
6. Minimum thickness required.
7. Shape, complexity and size of casting.
8. Cost of pattern and chances of repeat orders of the pattern

TYPES OF PATTERNS

____________

____________



The types of the pattern and the description of each are given as under.



1. One piece or solid pattern
2. Two piece or split pattern
3. Cope and drag pattern
4. Three-piece or multi- piece pattern
5. Loose piece pattern
6. Match plate pattern
7. Follow board pattern
8. Gated pattern
9. Sweep pattern
10. Skeleton pattern
11. Segmental or part pattern



PATTERN ALLOWANCES

Pattern may be made from wood or metal and its color may not be same as that of the casting. The material of the pattern is not necessarily same as that of the casting. Pattern carries an additional allowance to compensate for metal shrinkage. It carries additional allowance for machining. It carries the necessary draft to enable its easy removal from the sand mass. It carries distortions allowance also. Due to distortion allowance, the shape of casting is opposite to pattern. Pattern may carry additional projections, called core prints to produce seats or extra recess in mold for setting or adjustment or location for cores in mold cavity. It may be in pieces (more than one piece) whereas casting is in one piece. Sharp changes are not provided on the patterns. These are provided on the casting with the help of machining. Surface finish may not be same as that of casting.

CORE AND CORE BOX

Cores are compact mass of core sand that when placed in mould cavity at required location with proper alignment does not allow the molten metal to occupy space for solidification in that portion and hence help to produce hollowness in the casting. The core  has to withstand the severe action of hot metal which completely surrounds it. Cores are classified according to shape and position in the mold. There are various types of cores  are horizontal core), vertical core, balanced core, drop core  and hanging core.

Functions of cores


1. Core is used to produce hollowness in castings in form of internal cavities.
3. It may be deployed to improve mold surface.
4. It may provide external under cut features in casting.
5. It may be used to strengthen the mold.
6. It may be used to form gating system of large size mold
7. It may be inserted to achieve deep recesses in the casting




 CORE PRINTS

When a hole blind or through is needed in the casting, a core is placed in the mould cavity to produce the same. The core has to be properly located or positioned in the mould cavity on pre-formed recesses or impressions in the sand. To form these recesses or impressions for generating seat for placement of core, extra projections are added on the pattern surface at proper places. These extra projections on the pattern (used for producing recesses in the mould for placement of cores at that location) are known as core prints. Core prints may be of horizontal, vertical, balanced, wing and core types. Horizontal core print produces seats for horizontal core in the mould. Vertical core print produces seats to support a vertical core in the mould. Balanced core print produces a single seat on one side of the mould and the core remains partly in this formed seat and partly in the mould cavity, the two portions balancing each other. The hanging portion of the core may be supported on chaplets. Wing core print is used to form a seat for a wing core. Cover core print forms seat to support a cover core.

DESIGN CONSIDERATIONS IN PATTERN AND CORE MAKING

http://www.themetalcasting.com/casting-designing-framework.html



1. All Abrupt changes in section of the pattern should be avoided as far as possible.
2. Parting line should be selected carefully, so as to allow as small portion of the
pattern as far as possible in the cope area.
3. The thickness and section of the pattern should be kept as uniform as possible.
4. Sharp corners and edges should be supported by suitable fillets or otherwise rounded
of. It will facilitate easy withdrawal of pattern, smooth flow of molten metal and
ensure a sound casting. Wherever there is a sharp corner, a fillet should be provided, and the corners may be rounded up for easy withdrawal of patterns as well as easy flow of molten metal
in the mould.
5. Surfaces of the casting which are specifically required to be perfectly sound and
clean should be so designed that they will be molded in the drag because the
possible defects due to loose sand and inclusions will occur in the cope.
6. As far as possible, full cores should be used instead of cemented half cores for
reducing cost and for accuracy.  This will reduce cost and ensure greater dimensional accuracy.
7. For mass production, the use of several patterns in a mould with common riser is
to be preferred.
8. The pattern should have very good surface finish as it directly affects the corresponding
finish of the casting. As for as possible, the pattern should have a good surface finish because the surface finish of the casting depends totally on the surface finish of the pattern and the kind of facing of the mold cavity.
9. Shape and size of the casting and that of the core should be carefully considered to
decide the size and location of the core prints.
10. Proper material should always be selected for the pattern after carefully analyzing
the factors responsible for their selection.
11. The use of offset parting, instead of cores as for as possible should be encouraged
to the great extent.
12. For large scale production of small castings, the use of gated or match- plate
patterns should be preferred wherever the existing facilities permit.
14. If gates, runners and risers are required to be attached with the pattern, they should
be properly located and their sudden variation in dimensions should be avoided.
15. Proper allowances should be provided, wherever necessary.




PATTERN LAYOUT

A layout of the different parts of the pattern has to be made first. The next stage is to shape them. The layout preparation consists of measuring, marking, and setting out the dimensions on a layout board including needed allowances. The first step in laying out is to study the working drawing carefully and select a suitable board of wood that can accommodate at least two views of the same on full size scale. The next step is to decide a working face of the board and plane an adjacent edge smooth and square with the said face. Select a proper contraction scale for measuring and marking dimensions according to the material of the casting. Further the layout is prepared properly and neatly using different measuring and making tools specifying the locations of core prints and machined surfaces. Finally on completion of the layout, check carefully the dimension and other requirements by incorporating all necessary pattern allowances before starting construction of the pattern.

PATTERN CONSTRUCTION

From the layout, try to visualize the shape of the pattern and determine the number of separate pieces to be made and the process to be employed for making them. Then the main part of pattern body is first constructed using pattern making tools. The direction of wood grains is kept along the length of pattern as far as possible to ensure due strength and accuracy. Further cut and shape the other different parts of pattern providing adequate draft on them. The prepared parts are then checked by placing them over the prepared layout. Further the different parts of the pattern are assembled with the main body in proper position by gluing or by means of dowels as the case may be. Next the relative locations of all the assembled parts on the pattern are adjusted carefully. Then, the completed pattern is checked for accuracy. Next all the rough surfaces of pattern are finished and imparted with a thin coating of shellac varnish. The wax or leather fillets are then fitted wherever necessary. Wooden fillets should also be fitted before sanding and finishing. The pattern surface once again prepared for good surface and give final coat of shellac. Finally different parts or surfaces of pattern are colored with specific colors mixed in shellac or by painting as per coloring specifications.

https://www.indiamart.com/proddetail/cast-iron-casting-pattern-with-core-box-15991422588.html

Manufacturing Processes - Book Information and Important Points

INTRODUCTION TO BASIC MANUFACTURING PROCESSES AND
WORKSHOP TECHNOLOGY 

Rajender Singh
Professor, Deptt. of Mechanical Engineering
CRSCE, Murthal, Haryana
Publishing for one world, NEW AGE INTERNATIONAL (P) LIMITED, PUBLISHERS, 2006

Table of Contents

1 . Introduction
2. Plant and Shop Layout
3. Industrial Safety
4. Ferrous Materials
5. Non-Ferrous Materials
6. Melting Furnaces
7. Properties and Testing of Metals
8. Heat Treatment
9. Carpentry
10. Pattern and Core Making
11.Foundry Tools and Equipments
12.Mold and Core Making
13. Casting
14. Forging
15. Hot Working of Metals
16.Cold Working
17.Welding
18.Sheet Metal Work
19. Fitting
20. Metal Cutting
21. Lathe Machine
22. Drilling Machine
23. Shaper, Planer and Slotter
24. Milling
25. Powder Metallurgy
26. Inspection and Quality Control

Manufacturing  Processes - Important Points

1 . Introduction

Manufacturing is derived from the Latin word manufactus, means made by hand. In modern
context it involves making products from raw material by using various processes, by making
use of hand tools, machinery or even computers.


Advance manufacturing engineering involves the following concepts —

1. Process planning.
2. Process sheets.
3. Route sheets.
4. Tooling.
5. Cutting tools, machine tools (traditional, numerical control (NC), and computerized numerical control (CNC).
6. Jigs and Fixtures.
7. Dies and Moulds.
8. Manufacturing Information Generation.
9. CNC part programs.
10. Robot programmers.
11. Flexible Manufacturing Systems (FMS), Group Technology (GT) and Computer
integrated manufacturing (CIM).

 Generally there are three basic types of production systems:

1. Job production
2. Batch production
3. Mass production
A fourth is now added. Lean Production


PROCESS PLANNING

Process planning consists of selection of means of production (machine-tools, cutting tools, presses, jigs, fixtures, measuring tools etc.), establishing the efficient sequence of operation, determination of changes in form, dimension or finish of the machine tools in addition to the specification of the actions of the operator. It includes the calculation of the machining time, as well as the required skill of the operator. It also establishes an efficient sequence of manufacturing steps for minimizing material handling which ensures that the work will be done at the minimum cost and at maximum productivity. 

The basic process of process planning is  generally explained in connection with  with the machining only. But  the process is valid and required for  other processes such as casting, forging, sheet metal forming, assembling and heat treatment etc.

Important primary shaping processes are:

(1) Casting, (2) Powder metallurgy, (3) Plastic technology, (4) Gas cutting, (5) Bending and
(6) Forging.

Secondary or machining processes are —

(1) Turning, (2) Threading, (3) Knurling, (4) Milling, (5) Drilling, (6) Boring, (7) Planning,
(8) Shaping, (9) Slotting, (10) Sawing, (11) Broaching, (12) Hobbing, (13) Grinding, (14) Gear
cutting, (15) Thread cutting and (16) Unconventional machining processes namely machining
with Numerical Control (NC) machines tools or Computer Numerical Control (CNC) machines
tools using ECM, LBM, AJM, USM setups etc.

The process of putting the parts together to form the product, which performs the desired function, is called assembly An assemblage of parts may require some parts to be joined together using various joining processes.

The joining processes are carried out by fusing, pressing, rubbing, riveting, screwing
or any other means of assembling.

Some of the important and common joining processes are:

(1) Welding (plastic or fusion), (2) Brazing, (3) Soldering, (4) Riveting, (5) Screwing,
(6) Press fitting, (7) Sintering, (8) Adhesive bonding, (9) Shrink fitting, (10) Explosive welding,
(11) Diffusion welding, (12) Keys and cotters joints, (13) Coupling and (14) Nut and bolt joints.

Some of the commonly used surface finishing processes are:

(1) Honing, (2) Lapping, (3) Super finishing, (4) Belt grinding, (5) Polishing, (6) Tumbling,
(7) Organic finishes, (8) Sanding, (9) deburring, (10) Electroplating, (11) Buffing, (12) Metal
spraying, (13) Painting, (14) Inorganic coating, (15) Anodizing, (16) Sheradising, (17) Parkerizing,
(18) Galvanizing, (19) Plastic coating, (20) Metallic coating, (21) Anodizing and (22) Sand blasting.

Heat treatments affect the physical  properties and also make a marked change in the internal structure of the metal. Similarly the metal forming processes effect on the physical properties of work pieces Similarly shot peening process, imparts fatigue resistance to work pieces. A few such commonly used processes that change physical properties are given below: 

(1) Annealing, (2) Normalising, (3) Hardening, (4) Case hardening, (5) Flame hardening,
(6) Tempering, (7) Shot peeing, (8) Grain refining and (9) Age hardening.

In addition, some allied manufacturing activities are also required to produce the finished
product such as measurement.

PRODUCT SIMPLIFICATION AND STANDARDISATION

Industrial engineering focuses on these tasks as staff support to all engineering departments.

The technique of simplification and standardization of product is closely inter-related that
leads to higher efficiency in production, better quality and reduced production cost.

Simplification is a process of determining limited number of grades, types and sizes of a components or products or parts in order to achieve better quality control, minimize waste, simplify production and, thus, reduce cost of production. By eliminating unnecessary varieties, sizes and designs, simplification leads to manufacture identical components or products for interchangeability and maintenance purposes of assembly of parts. 

Standardization is the important step towards interchangeable manufacture, increased output and higher economy. The technique of standardization comprises of determining optimal manufacturing processes, identifying the best possible engineering material, and allied techniques for the manufacture of a product and adhering to them very strictly so long as the better standards for all these are not identified. Thus definite standards are set up for a specified product with respect to its quality, required equipment, machinery, labor, material, process of manufacture and the cost of production. The identified standard with time for a specified product should never be taken as final for ever because improvement is always possible. It must accommodate the outcome of all the new researches in the manufacturing areas in order to keep pace with increasing global competition. Improvements over the existing standards in all respects should always be welcomed. The different standards prevailing in different industries may be of the types of managerial, design, manufacturing and technical needs. Managerial standards are applicable to administrative functions within industry. These include the company policy, accounting procedures, personnel policies, performance evaluation, control of expenditures, safety aspects, security procedures and regulations, etc. where as design, manufacturing and technical standards are needed for manufacturing concepts of the industry. These include design and manufacturing techniques, practices, materials and parts, supplies, methods of testing, drafting method, abbreviations and symbols, specifications and nomenclature, etc.  

Mechanization means something is done or operated by machinery and not by hand.

The word ‘automation’ is derived from the Greek word automatos meaning self-acting. Automation can also be defined as the process of following a predetermined sequence of operations with little or no human intervention, using specialized equipment and devices that perform and control the manufacturing process.

The essential elements of automation comprise of mechanization, sensing, feedback,
and control devices. The reasons why one should go for automation are:

1. Increased productivity
2. Reduced cost of labor and dependence on labor shortages
3. Improved quality
4. Reduced in-process inventory
5. Reduced manufacturing time
6. Reduced dependence on operator skills
7. Increased safety or reduced risk of humans.

Automation can be classified into three categories, viz.

1. Fixed automation
2. Programmable automation
3. Flexible automation.

The computer aided manufacturing implies manufacturing itself, aided or controlled by
computers. In a wider sense, it denotes all the activities in the manufacturing environment
like use of computers in inventory control, project management, material requirement planning,
data acquisition, testing and quality control.

The integration of CAD and CAM systems is called Computer Integrated Manufacturing
(CIM) system.


MANUFACTURING SYSTEM: It is a chain of interrelated activities of production process and other support services activities of an manufacturing environment such as order processing, product design, design and manufacturing of tools, die, mould, jigs, fixtures and gauges, selection of material,
planning, managing and maintaining control of the processes, production, and reliable quality
of processed product in a systematic and sequential manner with proper coordination,
cooperation and integration of the whole manufacturing system that will lead to economical
production and effective marketing of proposed product in the minimum possible time.

PRODUCT DEVELOPMENT

A product development has to go through the following concepts of product engineering which
are given as under.

Product functions

1. Product specifications
2. Conceptual design
3. Ergonomics and aesthetics
4. Standards
5. Detailed design
6. Prototype development
7. Testing
8. Simulation
9. Design for manufacture
10. Design for assembly
11. Drafting.




Manufacturing activities  controlled by computers.

1. Computer Aided Design (CAD)
2. Computer Aided Engineering (CAE)
3. Computer Aided Design And Drafting (CADD)
4. Computer Aided Process Planning (CAPP)
5. Computer Aided Tool Design (CATD)
6. Computer Aided Manufacturing (CAM)
7. Computer Aided Numerical Control (NC) Part Programming
8. Computer Aided Scheduling
9. Computer Aided Material Requirement Planning, etc.
10. Flexible Manufacturing System (FMS)
11. Group Technology (GT)
12. Computer aided Testing (CAT).





2. Plant and Shop Layout



3. Industrial Safety

4. Ferrous Materials

Sometimes, it is possible to use more than one  material and manufacturing processes. The best possible material and process must be utilized in manufacture of product. It is therefore important to know what materials are available in the universe with its usual cost, their properties and their amenability to fabrication methods.

A product designer, tool designer and design engineer should always be familiar with various kinds of  engineering materials, their properties and applications to meet the functional requirements of the  product. Industrial engineers whose job is to reduce cost of products and processes by using alternative materials, design rules and production and service processes also need to have the same familiarity.

Ferrous metals are those which have the iron as their main constituent, such as pig iron, cast iron, wrought iron and steels.

The ferrous metals commonly used in engineering practice are cast iron, wrought iron, steel and
alloy steels. The basic principal raw material for all ferrous metals is pig iron which is obtained by smelting iron ore, coke and limestone, in the blast furnace.

Main Types of Ferrous Materials used in Engineering Products

1. Pig iron
2. Cast iron  (A) White cast iron  (B) Gray cast iron  (C) Malleable cast iron (D) Ductile cast iron
(E) Meehanite cast iron (F) Alloy cast iron
3. Wrought iron
4. Steel
(A) Plain carbon steels 1. Dead Carbon steels  2. Low Carbon steels  3. Medium Carbon steels  4. High Carbon steels
(B) Alloy steels  1. High speed steel  2. Stainless steel

The carbon content in cast iron varies from 1.7% to 6.67%. Cast iron has low cost, good casting characteristics, high compressive strength, high wear resistance and excellent machinability. The compressive strength of cast iron is much greater than the tensile strength. Hence the cast iron is used for components that are subjected more to compressive loads.

Applications ; The grey iron castings are mainly used for machine tool bodies, automotive cylinder
blocks, pipes and pipe fittings and agricultural implements. The other applications involved are:
(i) Machine tool structures such as bed, frames, column etc. (ii) Household appliances etc.
(iii) Gas or water pipes for under ground purposes. (iv) Man holes covers. (v) Piston rings.
(vi) Rolling mill and general machinery parts. (vii) Cylinder blocks and heads for I.C. engines.
(viii) Frames of electric motor. (ix) Ingot mould  (x) General machinery parts. (xi) Sanitary wares.
(xii) Tunnel segment.

Wrought iron is the assumed approximately as purest iron which possesses at least 99.5%. It is said as a mechanical mixture of very pure iron and a silicate slag. The wrought iron can be easily shaped by hammering, pressing, forging, etc. It is never cast and it can be easily bent when cold. It is tough and it has high ductility and plasticity with which it can be forged and welded easily. Its ultimate strength can be increased considerably by cold working followed by a period of aging. It possesses a high resistance towards corrosion. It can accommodate sudden and excessive shocks loads without permanent injury.

It is used for making chains, crane hooks, railway couplings, and water and steam pipes.

Steel is an alloy of iron and carbon with carbon content maximum up to 1.7%.

Types of Steels

1 . Dead carbon steel — up to 0.15% carbon

Steel wire, sheets, rivets, screws, pipe, nail and chain are made from this steel. This steel is used for making camshafts, sheets and strips for fan blades, welded tubing, forgings, chains, stamping, rivets, nails, pipes, automobile body etc.

2.Low carbon or mild steel — 0.15% to 0.45% carbon

It is tough, malleable, ductile and more elastic than wrought iron. It can be easily forged and welded. It can absorb shocks. It rusts easily. It is used for making angle, channels, case hardening steel, rods, tubes, valves, gears, crankshafts, connecting rods, railway axles, fish plates, small forgings, free cutting steel shaft and forged components etc.


3.Medium carbon steel — 0.45% to 0.8% carbon

It can be easily hardened and it possesses good balance of strength and ductility. It is generally used for making railway coach axles, bolts, connecting rods, key stock, wires and rods, shift and break levers, spring clips, gear shafts, small and medium forgings, railway coach axles, crank pins on heavy machines, spline shafts, crankshafts, forging dies, set screws, die blocks, self tapping screws, clutch discs, valve springs, plate punches, thrust washers etc.

4.High carbon steel— 0.8% to 1.5% carbon
Because of their high hardness,these are suitable for wear resistant parts. Hence they were used and are still used in the manufacture of cutting tools. But they operated at low cutting speeds in the case of machine tools. These steels are easy to forge and simple to harden.

High carbon steels containing 0.7 to 0.8% carbon possesses hardness of 450-500 BHN. It has application for making cold chisels, drill bits, wrenches, wheels for railway service, jaws for vises,
structural wires, shear blades, automatic clutch discs, hacksaws etc.

HC Steel containing 0.8 to 0.9% C possesses hardness of 500 to 600 BHN. This steel is used for making rock drills, punches, dies, railway rails clutch discs, circular saws, leaf springs, machine chisels, music wires.

HC Steel containing 0.90 to 1.00% carbon is also known as high carbon tool steel and it possesses hardness of 550-600 BHN. Such steel is used for making punches, dies, springs keys and shear blades.

Steel containing 1.0 to 1.1 % C is used for making railway springs, mandrels, taps, balls, pins, tools, thread metal dies.
Steel containing 1.1 to 1.2% C is used for making taps, twist drills, thread dies, knives.
Steel containing 1.2 to 1.3% carbon is used for making files, reamers Files, dies for wire drawing, broaches, saws for cutting steel, tools for turning chilled iron.

Alloy Steels

The chief alloying elements used in steel are nickel, chromium, molybdenum, cobalt, vanadium, manganese, silicon and tungsten.

An alloy containing 25% nickel possesses maximum toughness and offers the greatest resistance to rusting, corrosion and burning at high temperature. It has proved beneficial in the manufacture of
boiler tubes, valves for use with superheated steam, valves for I.C. engines and sparking plugs for petrol engines. A nickel steel alloy containing 36% of nickel is known as invar. It has nearly zero coefficient of expansion. Therefore, it is in great demand for making measuring instruments for everyday use.

Chromium improves corrosion resistance (about 12 to 18% addition). It increases tensile strength, hardness, wear resistance and heat resistance. It provides stainless property in steel. It is used in steels as an alloying element to combine hardness with high strength and high elastic limit.  Alloy steel containing 23-30% chromium with less than 0.35% C are are particularly suitable for working at high temperatures and are thus stable at high temperatures.  The furnace parts and annealing boxes are generally made by this steel.



Spring steels are used for the making springs. Various types of these steel and their uses are:

(i) Carbon-manganese spring steels. These steels are quenched and tempered up to 350 BHN. They are widely used for laminated springs for railway and general purposes.

(ii) Hyper-eutectoid spring steels. These steels are oil quenched and tempered at low temperature. This type of steel is used for volute and helical springs.

(iii) Silicon-manganese spring steels. These steels are hardened and tempered. This type of steel is used for the manufacturing of railway and road springs generally.

Tungsten increases hardness, wear resistance, shocks resistance and magnetic reluctance. It increases ability to retain hardness and toughness at high temperature. It prohibits grain growth and increases wear resistance, shock resistance, toughness, and the depth of hardening of quenched steel. The principal uses of tungsten steels are for cutting tools, dies, valves, taps and permanent magnets.

Vanadium. It improves tensile strength, elastic limit, ductility, fatigue resistance, shock resistance and response to heat treatment.  These steels are frequently used for parts such as springs, shafts, gears, pins and many drop forged parts.

Applications of free cutting steel

These steels are used for manufacturing axles, bolts, screws, nuts, special duty shafts, connecting rods, small and medium forgings, cold upset wires and rods, solid turbine rotors, rotor and gear shaft, armature, key stock, forks and anchor bolts screw stock, spring clips, tubing, pipes, light weight rails, concrete reinforcing etc. This property is due to higher sulphur and phosphorus. Sulphur exists in the form of manganese sulphide (MnS) which forms inclusions in steel.

The principal alloying elements in structural steels are chromium, nickel and manganese. These steels have various applications as structural members of bridges, buildings, rail road, cars etc. They are also used for manufacturing components subjected to static and dynamic loads. These components include valves, pins, studs, gears, clutches, bushes, shafts etc.

Stainless steel contains chromium together with nickel as alloy and rest is iron. It has been defined as that steel which when correctly heat treated and finished, resists oxidation and corrosive attack from most corrosive media.

It is used for making heat exchangers, conveyors chains, furnaces, spokes, brewery, dairy and chemical industrial components, cutlery parts, surgical and dental instruments, household appliances such as kitchen utensils, sinks and saucepans. These are also used in making components in power stations, especially in nuclear power stations, steam pipes, boiler tubes, radiator and super heater tubes.

High Speed Steels (HSS) have been given this name due to the fact that these steels may be operated as cutting tools at much higher speeds that are possible with plain high carbon tool steel. High speed steels cutting tools operate at cutting speed 2 to 3 times higher than for High carbon steels.    High speed steel (18:4:1) contains 18% tungsten, 4% chromium and 1 % vanadium, 0.8 carbon and remaining iron.

5. Non-Ferrous Materials

Aluminium - Applications

It is mainly used in aircraft and automobile parts where saving of weight is an advantage.The high resistance to corrosion and its non-toxicity make it a useful metal for cooking utensils under ordinary conditions.  It is a cheap and very important non ferrous metal used for making cooking utensils.

Aluminium metal of high purity has got high reflecting power in the form of sheets and is, therefore, widely used for reflectors, mirrors and telescopes. It is used in making furniture, doors and window components, rail road, trolley cars, automobile bodies and pistons, electrical cables, rivets, kitchen utensils and collapsible tubes for pastes.Aluminium foil is used as silver paper for food packing etc. In a finely divided flake form, aluminium is employed as a pigment in paint.

Various aluminium alloys are:
1. Duralumin,
2. Y-alloy,
3. Magnalium and
4. Hindalium

Copper - Applications

Copper is mainly used in making electric cables and wires for electric machinery, motor winding, electric conducting appliances, and electroplating etc. It can be easily forged, casted, rolled and drawn into wires. Copper in the form of tubes is used widely in heat transfer work. It is used for household utensils. It is also used in production of boilers, condensers, roofing etc. It is used for making useful alloys with tin, zinc, nickel and aluminium.

Brasses

Red brass - Applications: Red brass is mainly utilized for making, heat exchanger tubes, condenser, radiator cores, plumbing pipes, sockets, hardware, etc.

Yellow brass - Applications: Yellow brass or muntz metal is suitable for hot working by rolling, extrusion and stamping. It is utilized for making small various components of machine and electrical equipment such as bolts, rods, tubes, valves and fuses. This metal is utilized for making for pump parts, valves,taps, condenser tubes, sheet form for ship sheathing (because of excellent corrosion resistance).

Cartridge Brass -  Applications: It is utilized for making for making tubes, automotive radiator cores, hardware fasteners, rivets, springs, plumber accessories and in tube manufacture.

Admiralty brass is highly resistant to corrosion.  It is highly resistant to impingement attack of sea water. It can be cold worked.

Applications: Admiralty brass is utilized for making condenser tubes in marine and other installations.

It is used for making plates used for ship building. It is utilized also for making bolts, nuts, washers, condenser plant and ship fittings parts, etc.

Naval brass is similar to muntz metal. 1% zinc in muntz is replaced by 1% tin. Corrosion resistance to sea water is significantly improved. Applications: Navel brass is commonly utilized for making marine hardware casting, piston rods,
propeller shafts, welding rods etc.

Manganese brass possesses sufficient toughness and good corrosion resistance. It is very active in reducing the oxides of other metals. Applications: Manganese brass is utilized for making hydraulic rams, valves and cylinders, tubes, pump rods, propellers, bolts, nuts etc.

Iron brass or delta metal is hard, strong, tough, and having good corrosion resistance. It can be casted easily. Applications: If corrosion is to be resisted in mild steel, then some amount of iron brass or delta metal is added in mild steel.

Gilding brass is a very cheap metal for making jewellery, decorative and ornamental products. Applications: Because of better appearance this metal is commonly used for jewellery, decorative and ornamental work.

Free cutting brass is highly machinable and it does not allow bending. Applications: Free cutting brass is used for making cast, forged or stamped blanks to be used for
further machining such as high speed turning and screwing.

Lead brass is also known as cloak brass. Applications:Lead brass or cloak brass is used in making small gears and pinions for clock work.

Bronzes

Bronze is a common alloy of copper and tin.
Properties: Bronze has higher strength, better corrosion resistance than brasses. It is comparatively
hard and resists surface wear and can be shaped or rolled into wire, rods and sheets very
easily. It has antifriction or bearing properties. Bronze is costlier than brass.

Phosphor Bronze
Properties: Tensile strength, ductility, elasticity, soundness of castings, good wearing quality and resistance to fatigue of phosphor bronze increases with increase of phosphorus in bronze. This material possesses good corrosion resistance especially for sea water, so that it is much used for propeller blades. Phosphor bronze of proper composition can be easily casted, forged, drawn, and cold rolled.
Applications: Phosphorus bronze is used making for bolts, electric contact springs, bearings, bushes,
gears, ship sheathing, valve parts, propeller blades, worm wheels, gears, nuts for machine lead screws, pump parts, linings and for many other purposes. It is also suitable for making springs and corrosion resistance mine cables.

Silicon bronze has good general corrosion resistance of copper combined with higher strength. It can be cast, rolled, stamped, forged and pressed either hot or cold and it can be welded by all the usual methods.
Applications:Silicon bronze is widely used for making boilers, tanks, stoves or where high strength and good corrosion resistance is required. It is used also for making screws, tubing’s, pumps etc.


Beryllium bronze possesses higher tensile strength than other bronzes. It possesses excellent corrosion resistance. It is having high yield point and high fatigue limit. It is having good hot and cold resistance. This can be heat treated by precipitation hardening. It possesses excellent formability in soft condition, and high fatigue and creep resistance in hardened condition. However it involves high cost.



Applications: Beryllium bronze is particularly suitable material for making springs, tubes, diaphragms and electrical contacts, heavy duty electrical switches, cams and bushings. This is used for springs, heavy duty electrical switches, cams and bushings. Having non-sparking characteristics,
it is used for making chisels and hammers using for such conditions where spark might cause
explosion. It has a film forming and a soft lubricating property, which makes it more suitable
as a bearing metal. Since the wear resistance of beryllium copper is five times that of
phosphorous bronze, therefore it is used as a bearing metal in place of phosphor bronze.


Manganese bronze is highly resistant to corrosion. It is stronger and harder than phosphor bronze. Applications: Manganese bronze is mainly used for bushes, plungers, feed pumps, rods etc. Worm
gears are frequently made from this bronze.

The aluminium bronze with 8% aluminium possesses very good cold working properties. When iron is added to this metal, its mechanical properties are greatly improved by refining the grain size and improving the ductility. This material possesses good resistance to corrosion and it is somewhat difficult to cast due to oxidation problem.
Applications:Aluminium bronze is generally used for making fluid connection fittings, gears, propellers, air pumps, bushings, tubes, slide and valves etc. Cams and rollers are commonly produced
using this alloy.

Bell metal is very strong. It possesses resistance to corrosion water and atmosphere. It is used to make bells.


Constantan has high specific resistance and it is unaffected by temperature variation. Applications: Constantan is used for accurate resistors like thermo-couples, Wheet-stone bridge, Low temperature heaters and Resistances

NICKEL AND ITS ALLOYS
LEAD
ZINC
TIN
BEARING OR ANTIFRICTION ALLOYS
CUTTING TOOL MATERIAL

6. Melting Furnaces



7. Properties and Testing of Metals



8. Heat Treatment



9. Carpentry



10. Pattern and Core Making



11.Foundry Tools and Equipment



12.Mold and Core Making


13. Casting


14. Forging



15. Hot Working of Metals



16.Cold Working



17.Welding



18.Sheet Metal Work



19. Fitting



20. Metal Cutting



21. Lathe Machine



22. Drilling Machine



23. Shaper, Planer and Slotter



24. Milling



25. Powder Metallurgy



26. Inspection and Quality Control 

Chicago White Metal Casting, Inc. - Casting Information

http://www.cwmdiecast.com/

Online library on die casting
http://www.cwmdiecast.com/design-center.html
You have to sign up for a free subscription

Pressure Die Casting Automotive Components

Low pressure die casting

Low pressure die casting is a well-known casting process, especially for aluminium wheels
in passenger cars. The process is also used in the production of big V-engine blocks in
hypereutectic aluminium alloys and in the casting of air-cooled cylinder heads for motor
cycles.

The casting unit of a low-pressure machine consists of a pressure-tight holding furnace, the
pressure control unit, the hydraulic die manipulators and usually one die for the casting.

http://www.alueurope.eu/wp-content/uploads/2012/01/AAM-Manufacturing-1-Casting-methods.pdf

High pressure die castings 

Filling speed and intensification pressure differentiates high-pressure die casting 

from most other casting processes. 

 After liquid metal is transferred to the shot sleeve (s. fig. below), the plunger slowly 

closes to shut-off the filling port. 

The plunger is then moved towards the die at a controlled but high speed in order to 

fill the die cavity. 

 With the potential for highly automated operation, the high-pressure die casting 

(HPDC) process is capable of extremely high levels of productivity. 

 HPDC machines are size rated by the closing force (s. figs.) 

The pressure cycle in a modern HPDC machine is closely controlled in all stages. 

 Filling times are typically on the order of 10-25 milliseconds. 

 Once the die is filled, pressures, which may exceed 70 MPa, are maintained on the 

casting, using an accumulator, until solidification is complete (third stage, at right) 

 With the potential for highly automated operation, the high-pressure die 

casting process is capable of extremely high levels of productivity. 

 Multiple hydraulic circuits are used depending on the plunger speed needed at each 

stage as shown below. 

To be die cast, engine blocks must designed with an open deck 

 

The common size range and close tolerances have been used to good effect in defining the 

hydraulic network in large transmission cases shown above. The Belt Tensioners (below) are 

typical of small die cast parts: 

Physical design considerations: 

 Only straight steel core pulls can be used to define internal passages. 

 Core pulls increase tooling costs. 

 Sand coring is generally not possible. 

 Inserts can frequently be cast into the part. Hollow tubes, threaded inserts to fill out 

bosses, engine bore liners, and wear resistant inserts are common. 

 Feeding of shrinkage is via the gates alone; parts should be designed with as uniform 

a thickness as possible. 

 

Metallurgical design considerations: 

 Part ductility is limited by process considerations to <3% on average. 

 Die castings should not be used for load bearing safety critical parts. 

 Die castings are not heat treatable. 

 Die casting are generally produced using secondary (recycled) alloys; this reduces 

cost. 

 Fatigue properties of die castings are good so long as the very smooth as-cast 

surface is not machined away. 

http://www.alueurope.eu/wp-content/uploads/2012/01/AAM-Manufacturing-1-Casting-methods.pdf

Gravity Die Casting - Automotive Components

Gravity die casting is one of the standard processes for the manufacture of high-integrity
automotive castings. It represents proven and absolute precision technology for the
production of large batch quantities. This process is used in carousel casting units or in
shuttle technique particularly for the manufacture of engine castings.

Optimum heat dissipation from the solidifying casting through the die leads to short
solidification times. This results in castings which have good mechanical properties,
especially after an additional heat treatment.


In addition to producing ever more complicated cylinder heads for petrol and diesel engines,
gravity die casting is also used for the manufacture of diesel engine blocks with cast-in grey
iron liners

4 Valve Cylinder Head
3 Cylinder Diesel engine block

http://www.alueurope.eu/wp-content/uploads/2012/01/AAM-Manufacturing-1-Casting-methods.pdf

Centrifugal Casting - Automotive Components

Cylinder liners and sleeves  are made by centrifugal casting process.

Full Process:
http://www.anandenterprise.com/process.html

http://www.winnerautoindia.com/cylinder_liners.htm


Typical parts made by this process are pipes, boilers, pressure vessels (see autofrettage), flywheels, cylinder liners and other parts that are axi-symmetric. It is notably used to cast cylinder liners and sleeve valves for piston engines, parts which could not be reliably manufactured otherwise.
http://en.wikipedia.org/wiki/Centrifugal_casting_(industrial)



________________

________________

Read the description gives on the manufacturing process of cylinder liners on youtube page
https://www.youtube.com/watch?v=DjWJcCCupaY

http://www.winnerautoindia.com/cylinder_liners.htm

Sand Casting - Automotive Components

The classic sand casting process, which aluminium foundries are making use of today, relies on gravity to fill the die in order to manufacture an array of components for the drivetrain and chassis of cars and commercial vehicles. These include gearbox cross members, trapezoidal links, the engine bracket, anti-roll bars, wheel carriers, consoles and the auxiliary frame, as well as intake manifolds and oil sumps.
However, the potential of aluminium for lightweight construction cannot be fully exploited because the process determines the components’ wall thickness, which cannot normally be less than five millimetres.

For components with a large surface area, e.g. oil sumps, three millimetres wall thickness is entirely sufficient, but conventional sand casting cannot be used.


A new process low-pressure sand casting  is now available to give smaller wall thickness.  Sand casting is thus benefitting from new options for the economic manufacture of highly resilient aluminium components.

Low-pressure sand casting combines classic aluminium sand casting with low-pressure chill casting. In Germany it was developed by companies including Honsel AG in Meschede and KSM Castings GmbH in Hildesheim. In Switzerland, GF Automotive in Schaffhausen is a respected supplier with production facilities are located in Garching, close to the Bavarian city of Munich. Using the auxiliary frame and wheel carriers as an example, the company has demonstrated the process’s advantages and that it now offers an alternative to pressure and chill casting.
Because the molten metal rises up from below, there is almost no swirling as the die is filled. This results in better filling of the die and very good mechanical properties, both of which are sought by the car industry for chassis safety components.

http://www.aluminiumindustry.org/en/sand-casting-car-manufacturing.html


Sand Castings vs. Die Castings:  Choice Criteria

Sand castings are used when parts are hollow; there’s no practical
alternative.  An example is automotive (intake exhaust) cylinder heads.  Internal water
passages  preclude the use of die castings for these applications.

Engine blocks  are also traditionally sand cast because they, too, have internal passages, although many modern automotive engines use blocks cast with “hybrid” processes, which may include permanent mold, sand, and multiple injections of metal.

Sand castings are more costly, but can produce shapes that are not possible with die castings.

Lightweight, thin wall castings,  such as those found on simple BBQ enclosures are almost always die castings; a grill lid that costs $10 to die cast costs $100 to produce as a sand casting, even though die castings require more machining. Die castings generally have smoother surfaces, however.

Tooling is less expensive in case of sand casting as the pattern is made with wood or plastic.  One advantage of sand castings over die castings is that, given the short life cycle of many of today’s products, the substantial upfront investment in hard tooling for die castings is avoided.  Sand castings do not commit the customer to costly tooling for a part life with a brief life. Changes are also quite costly for a die casting.


Die casting is economical only for very high-volume production.

http://www.accuformmfg.com/die-castings-vs-sand-castings.htm


http://www.castingquality.com/metal-casting-parts/cast-iron-parts/cast-iron-automobile.html

Squeeze Casting Process

It is a combination of casting and forging

Squeeze Casting Process: Part One
http://www.keytometals.com/page.aspx?ID=CheckArticle&site=ktn&NM=172


SQueeze Casting - Furture - A Report 2011
http://issinstitute.org.au/wp-content/media/2011/05/ISS-FEL-REPORT-A-IYER-low-res.pdf


Aluminium in Automotive - Casting Processes Manual
http://www.alueurope.eu/wp-content/uploads/2012/01/AAM-Manufacturing-1-Casting-methods.pdf