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• Upset Forging: Upset forging involves increasing the cross-sectional area of a part by compressing its length. This is often used to create short
and thicker parts like bolts and fasteners.
• Roll Forging: Roll forging uses a pair of cylindrical rolls to shape the material between them. It is commonly used for producing long parts with
consistent cross-sections, such as shafts and axles.
• Swaging: Swaging is a forging process that reduces the diameter of a part by placing it within a die and applying radial compressive forces. It
is often used to create tapered shapes or to refine dimensions.
• Press Forging: Press forging uses hydraulic or mechanical presses to apply force to the material. It is suitable for producing components with
intricate details and precise dimensions.
Forging is widely used in industries such as automotive, aerospace, construction, and manufacturing. It is used to produce a variety of components,
including crankshafts, connecting rods, gears, bolts, flanges, and more. The choice of forging method depends on factors such as the material being
forged, the desired component shape, and the intended application of the final product.
Extrusion Extrusion is a manufacturing process in which a material is pushed or drawn through a die to create a specific cross-sectional shape. It is a highly
versatile process used to produce continuous lengths of objects with a consistent profile. Extrusion is widely employed with various materials,
including metals, plastics, ceramics, and even food products.
The basic principle of extrusion involves applying pressure to force the material through a specially designed die, which determines the final shape
of the extruded product. The material can be in a solid or semi-solid state, and the process can be performed at various temperatures depending
on the material's properties.
Here are some common types of extrusion processes:
• Hot Extrusion: In hot extrusion, the material is heated above its recrystallization temperature to reduce its resistance to deformation. This is
commonly used for metals like aluminium and copper. Hot extrusion is employed to create products like rods, bars, and structural shapes.
• Cold Extrusion: Cold extrusion occurs at or near room temperature. It is used with materials that are not easily deformable when heated, such
as some metals and plastics. Cold extrusion is often used to produce small parts like screws, fasteners, and metal cans. (Source of image:
• Direct Extrusion: In direct extrusion, the material is pushed through the die in the same direction as the ram (the device applying force). It is https://www.metallurgyfordummies.com/
a common method for producing simple shapes and profiles. extrusion.html)
• Indirect Extrusion: Indirect extrusion involves pushing the material through the die in the opposite direction of the ram. It can offer better
control over the extrusion process and is suitable for more complex shapes.
• Hydrostatic Extrusion: In hydrostatic extrusion, the material is placed in a sealed container filled with a fluid, which transmits the pressure to
the material. This method is used to achieve high deformation rates and better surface finish.
• Impact Extrusion: Impact extrusion combines extrusion and forging. A punch is used to deform the material through the die, often used for
creating small and intricate parts.
The extrusion process offers several advantages:
• High production rates for continuous lengths of products.
• Precise control over the final shape and dimensions.
• Reduced material waste compared to traditional machining methods.
• Can be used with a variety of materials, including metals, plastics, and ceramics.
However, extrusion also has limitations:
• Limited to producing linear or continuous shapes.
• More suitable for simple and consistent cross-sectional profiles.
• Complex shapes may require multiple extrusion steps or secondary operations.

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