1. The document discusses various manufacturing processes including primary shaping processes like casting, rolling, forging, extrusion, and drawing as well as secondary shaping (machining) processes.
2. It provides details on specific primary shaping processes like metal casting methods, rolling being divided into breaking down and finish rolling, forging types, and the extrusion and drawing processes.
3. Secondary shaping processes involve machining components produced in primary processes to improve accuracy, with machining operations including turning, drilling, milling, grinding, boring, and others.
4. Primary Shaping Processes
Metal obtained by extraction of ores is refined and cast to form big blocks, called ingots. These
ingots are reduced to smaller size and shape by one or more of the primary shaping processes. A
list of the important primary shaping processes is given below.
1. Metal casting 6. Powder metallurgy
2. Rolling 7. Oxy-gas cutting
3. Forging 8. Press work
4. Extrusion 9. Sheet metal work
5. Metal drawing 10. Metal spinning
5. Metal Casting
1. Pattern making
2. Core making
3. Moulding
4. Melting and pouring
5. Fettling and cleaning
6. Testing and inspection
6. Metal Casting
The metal casting methods other than the conventional sand-casting process are
grouped as special casting processes. They include the following:
1. Shell mould casting
2. Investment mould casting
3. Permanent mould casting
4. Die casting
5. Slush casting
6. Plaster mould casting
7. Centrifugal casting
8. Continuous casting
7. Rolling
๏Rolling is a process of shaping metals and alloys into semi-finished products by passing them between two
rolls rotating in opposite directions
๏ The rolling processes can be broadly divided into two sections as mentioned below:
1. Breaking down processes: to produce semi-finished products called blooms,
slabs, and billets from the heavy initial metal block called ingot.
2. Finish rolling processes: to produce rails, beams, plates, sheets, structural
sections, rods, etc., from the blooms, slabs and billets.
8. Forging
๏Forging is basically a hot-working process of metal, performed by means of hammer blows or the pressure
applied by a press.
๏ Depending on the method of production, forging processes are classified into the following types:
1. Hand forging
2. Power hammer forging
3. Drop forging or closed die forging
4. Press forging
9. Extrusion
๏Extrusion is the process of forcing metal enclosed in a container and forming the shape by passing out
through the opening of a die.
10. Metal Drawing
๏ Metal drawing is a process in which wire, bar stock or tube is drawn in tension through the hole of a
drawing die. The hole has a conical shape built in such a way that the inlet side is slightly larger and the
outlet side is slightly smaller than the object drawn.
11. Press Work
Press work is a term applied to a large variety of operations in connection with the metallic and nonmetallic
articles. The operations are done generally in cold state.
12. Press Work
Shearing operations
(a) Blanking: This is the process of cutting a closed outside contour of a shape.
(b) Piercing: This is the process of cutting holes of any shape or size inside the
contour.
(c) Perforating: This is the process of cutting a number of small holes inside the
contour.
(d) Notching: This is the cutting of relatively small indentation on the edge of
a part.
13. Press Work
Shearing operations
(e) Trimming: This is a process of cutting of the excess metal from a piece.
(f) Shaving: This is a secondary cutting operation in which the surface of a
previously cut edge is finished for bringing close dimensional accuracy.
(g) Slitting: This is a process of making incomplete cut in a sheet so that a
projected portion is obtained.
(h) Lancing: This is the process of cutting along a line in the workpiece,
without producing a detached portion.
14. Press Work
Forming operations
(a) Bending: This is a process of forming bends in one plain only.
(b) Forming: This is a process of bending into complicated shapes in more than
one plane.
(c) Curling: This is a process of shaping an edge to circular cross section along
the edge of a sheet or at the end of a shell or tube.
(d) Wiring: This is a curling process in which a wire is inserted within the
curled edge.
15. Press Work
Forming operations
(e) Embossing: This is a forming process in which projections like letters,
designs etc. are made on a thin metal sheet.
(f) Coining: This is a forming process by which the surface is deformed into
fine detail by compression.
(g) Drawing: This is a forming process by which a flat blank is converted into
a cup or a cylindrical form with one end closed.
16.
17. Secondary Shaping Processes
The components or parts produced by primary shaping processes may not have the
required accuracy in shape, dimension and surface finish due to the limitations of the
process used. A secondary shaping process called machining is applied on these
components for obtaining the desired finish. Machining is defined as metal-cutting
process in which metal is removed from a surface in the form of chips using a tool.
