Mechanical Process Viva Question and Answer:-2019 {Part-2}

Question Number: 1. what is MOLDING, BENDING, BROACHING, CALENDARING, CROWNING process?

Answer:

MOLDING – Practice of making molds in which to pour molten metal to form castings

BENDING – In bending there is a thinning of the material, accompanied by a spreading of the metal on the inside of the bend and a narrowing at the outside.

BROACHING – Consecutive shearing of a hole or contour by a series of stepped cutting edges similar to a saw used in low acting presses for accurate sizing of holes or contours, such as gear teeth, and key ways.

CALENDARING – A process that involves rolling of the product into sheets to achieve the desired surface finishes and thickness.

CROWNING – Shaping of the rim of a belt pulley so that the diameter at the center of the face is greater than at the edges so as to keep the belt on the crown of the pulley.

Question Number: 2. what is CENTRIFUGING, CENTRIFUGAL CASTINGS, CLADDING DIFFUSION process?

Answer:

CENTRIFUGING – Casting of molten metals by using centrifugal force instead of gravity. The mold is rotated about a center where molten metal is poured and allowed to follow spruces outward and get into the mold cavity.

CENTRIFUGAL CASTINGS – Castings of cylindrical design are made by the introduction of molten metal into revolving permanent molds, known as centrifugal casting machines, where the centrifugal force is employed to bring pressure in filling of the mold.

CLADDING – The joining of one metal (usually sheet or plate) to another by using heat and pressure or by an explosive force. With this method, a thin sheet of more expensive metal or one less likely to corrode may be applied to a less expensive metal or one more likely to corrode.

DIFFUSION – The process of atoms or other particles intermingling within a solution. In solids, it is a slow movement of atoms from areas of high concentration towards areas of low concentration. The process may be

(a) Migration of interstitial atoms such as carbon,

(b) Movement of vacancies or

Question Number: 3. what is EMBOSSING, EXTRUSION, FORGING, DROP FORGING process?

Answer:

EMBOSSING – Operation of raising a design or form above the surface of a component by means of high pressure affected by pressing or squeezing action.

EXTRUSION – Process in which metal (often heated) is caused to flow through a restricted orifice by using an extremely high force, so creating an extremely elongated strip of uniform, but comparatively small cross-section.

FORGING – A method of metal working in which the metal is hammered into the desired shape, or is forced into a mold by pressure or hammering, usually after being heated to a more plastic state. Hot forging requires less force to form a shape than that of cold forging, which is usually done at room temperature.

DROP FORGING – Drop forging is the operation in which a metal part is formed by repeated hammer blows on a bar or billet placed between a pair of dies containing the impression of the finished shape desired.

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