introductio to casting lecture 1 history of casting

Brief introduction to syllabus
• Foundry
• Welding
• Metal working

Foundry Technology and its History
• Ötzi, also called the Iceman, is the natural mummy of a man
who lived between 3400 and 3100 BCE. The mummy was
found in September 1991 in the Ötztal Alps, hence the
nickname "Ötzi", near Similaun mountain and Hauslabjoch on
the border between Austria and Italy.

Development in foundry
• Stone age
• Copper age (7700-3300 BC)
• Bronze age (3300-1200 BC)
• Iron age(1200 BC onwards)
steel is discovered in 500 BC in India and
China.
• Modern industrial age (18th
century onwards)

Study links
• https://www.reliance-foundry.com/blog/foun
dry-and-foundries/
• https://marketing.metaltek.com/smart-blog/h
istory-of-metal-casting
• https://www.hitchiner.com/history-of-the-pro
cess/#:~:text=Shortly%20after%20the%20dark
%20ages%20in%20Europe%2C%20the,1100%
29%20whose%20SchedulaDiversarumArtiumis
%20the%20earliest%20known%20foundry%2
0text.

Basic classification of manufacturing
processes
1. Casting
2. Metal forming
3. Machining
In this course we will cover above two types in
detail.
[ Sand Casting ] - Learn More about Sand Casting Process.mp4
Extrusion Processes.mp4
Cutting Tool Geometry (3D Animation).mp4

Casting
• Casting is one of the oldest materials shaping methods known. Casting means
pouring molten metal into a mold with a cavity of the shape to be made, and
allowing it to solidify. When solidified, the desired metal object is taken out from
the mold either by breaking the mold or taking the mold apart. The solidified
object is called the casting. By this process, intricate parts can be given strength
and rigidity frequently not obtainable by any other manufacturing process. The
mold, into which the metal is poured, is made of some heat resisting material.
Sand is most often used as it resists the high temperature of the molten metal.
Permanent molds of metal can also be used to cast products.

Casting
Casting is a process in which molten metal is allowed to solidify
in a predefined mould cavity. After the solidification by breaking
the mould the component is taken out. This is known as
CASTING.

Classification of Casting Processes

Sand moulding and Casting
Casting process involving the use of sand as a moulding medium is known as
sand moulding.
The steps in sand moulding are :
Sand preparation→Pattern making→Core making→Moulding→Closing
The equipments needed in a sand moulding process are:
• Pattern
• Mould box
• Moulding sand
• Crucible- used for melting metal.

Advantages
The metal casting process is extensively used in manufacturing because of its many advantages.
Molten material can flow into very small sections so that intricate shapes can be made by this process. As a
result, many other operations, such as machining, forging, and welding, can be minimized or eliminated.
It is possible to cast practically any material that is ferrous or non-ferrous.
As the metal can be placed exactly where it is required, large saving in weight can be achieved.
The necessary tools required for casting molds are very simple and inexpensive. As a result, for production
of a small lot, it is the ideal process.
There are certain parts made from metals and alloys that can only be processed this way.
Size and weight of the product is not a limitation for the casting process.
Limitations
Dimensional accuracy and surface finish of the castings made by sand casting processes are a limitation to
this technique. Many new casting processes have been developed which can take into consideration the
aspects of dimensional accuracy and surface finish.
Some of these processes are die casting process, investment casting process, vacuum-sealed molding
process, and shell molding process.
The metal casting process is a labor intensive process

The Pattern and their functions
(ii)
Pattern is a replica of a object to be made with
some modifications, The modifications are
(i) Allowances
Core Print
 A pattern prepares a mould cavity for the
purpose of making a casting.
 A pattern may contain projections known as core prints if
the casting requires a core and need to be made hollow.
 Runner, gates and risers may form a part of the pattern.
Core in Sand Casting (3D Animation).mp4

A pattern may help in establishing locating points on the
mould and therefore on the casting with a purpose to
check the casting dimensions,
Patterns establish the parting line and parting surfaces
in the mould.
A pattern may help position a core before the moulding
sand is rammed.
Properly made patterns having finished and smooth
surfaces reduce casting defects.
Properly constructed patterns minimize overall cost of
the castings.

Pattern Materials
1. Wood - common material because it is easy to work, but it
warps.
2. Metal - more expensive to make, but lasts much longer
3. Plastic - compromise between wood and metal.
Selection of pattern Materials depends upon.
(i) The number of castings to be produced. Metal Pattern are
preferred when the production is large.
(ii) Method of moulding i.e., Hand or machine moulding.
(iii) Shape, complexity and size of the casting.
(iv) Type of moulding materials i.e., Sand etc.
(v) The chances of repeat orders.

Difference between Pattern and Casting
The main difference between a pattern and the casting
is as regards their dimensions. A pattern is slightly
larger in size as compared to the casting, because a
pattern:
(i) Carries Shrinkage allowance, it may be of the order
of 1 to 2 mm/100mm.
(ii) Is given a Machining allowance, to clean and finish
the required surfaces.
(iii) Carries a Draft allowance of the order of 1 and 3
degree for external and internal surfaces respectively.
(iv) Carries core prints.

In addition;
(i)A pattern may not have all holes and slots which a
casting will have. Such holes and slots unnecessarily
complicate a pattern and therefore can be drilled in
the casting after it has been made.
(ii)A pattern may be in two or three pieces whereas a
casting is in one piece.
(iii)A pattern and the casting also differ as regards the
material. Out of which they made.

Types of pattern
1) Single piece pattern
2) Two piece pattern
3) Gated pattern
4) Multi piece pattern
5) Match plate pattern
6) Skeleton pattern
7) Sweep pattern
8) Lose piece pattern
9) Follow board pattern
10) Cope and drag pattern
11) Segmental pattern and
12) Shell pattern

Types of Pattern in Sand Casting (3D Animation).mp4
Types of pattern animation

introductio to casting lecture 1 history of casting

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