1.What do you mean by production process classify it?

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Production process of a work piece involves transforming a raw material from its original state to a finished state by changing its shape or the properties of the material in a series of steps.
Classification I. Primary shaping processes (casting processes)
II. Deforming processes (forging, rolling, extrusion)
III. Machining processes (turning milling drilling)
IV. Surface finishing processes (Welding, soldering, brazing, screwing) V. Joining processes (Honing, Lapping, Grinding)
VI. Material properties modification processes (Hot working, Cold working, Heat treatment)

2.What are the steps involved in casting?

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I. Pattern making: Make the pattern of wood, metal or plastic.
II. Sand mixing and preparation: Select a particular sand, test it and prepare the necessary sand mixtures for mould and core making.
III. Core making: With the help of patterns prepare the mould and required cores.
IV. Melting: Melt the metal or alloy to be cast.
V. Pouring: Pour the molten metal or alloy into the mould and remove the casting from the mould after solidification of metal.
VI. Finishing: Clean and finish the casting.
VII. Testing: Test and inspect the casting and remove the defects, if any.
VIII. Heat treatment: Relieve the casting stresses by using various heat treatments. IX. Re-testing: Again inspect the casting and deliver it.
( NOTE Mould is a container having a cavity of the shape to be cast, whereas core is a body which is employed to produce a cavity in the casting and is generally made of sand.)

3.What are the common material used to make pattern?

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Wood, Metal, Plastic, Plaster, Wax

4.What are the types of allowance provided in pattern making?

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I. Shrinkage or contraction allowance
II. Draft or taper allowance
III. Machining allowance
IV. Distortion allowance
V. Rapping or shake allowance

5.What are the types of moulding sand?

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I.Natural sand: Natural sand can be used directly for making moulds as soon as it is received from its source.
It contains binding materials (5 to 20% clay) and needs only water (5 to 8%) to mix before making the mould.
II. Synthetic sand : Synthetic sand consists of natural sand with or without clay, moisture and binder like bentonite.
III. Special sands : The special sand includes green sand, loam sand, core sand, parting sand, facing sand and backing sand.

6.What are the characteristics of moulding san?

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I. Followability or plasticity It is the ability of the moulding sand to get compacted to a uniform density.
II. Green strength It is the strength of the sand in the green or moist condition.
III. Dry strength It is the strength of the moulding sand in the dry state.
IV. Permeability or porosity sand must be porous to allow the gases and steam generated within the moulds to be removed freely.This property of sand is known as permeability or porosity.
V. Refractoriness It is the ability of moulding sand to withstand high temperatures without fusion, cracking and buckling, hence facilitating a clean casting.
VI. Adhesiveness It is the property of moulding sand because of which it is capable of adhering to the surface of other materials.
VII. Cohesiveness It is the property of the sand due to which sand particles stick together.
VIII. Thermal stability To avoid breaking, buckling and flaking off of mould surtace at higher temperatures, sand possesses dimensional thermal stabilitv.
IX. Collapsibility It is the property due to which the sand mould automatically collapses after freezing of the casting, to allow the free contraction of the metal. (Read the description of each characteristics)

7.What is CO2 moulding?

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Carbon Dioxide Moulding Process:- In CO2 moulding process, moulding sand is mixed with sodium silicate . The mix is loosely rammed in the mould around the pattern. Carbon dioxide gas is sent into the mould . carbon dioxide is mixed with sodium silicate and hence silica gel is formed.

8. What are the components of gating system?

Ans:

Pouring cups and basins A pouring cup is a funnel shaped cup which forms the top portion of the sprue. pouring basin which acts as a reservoir from which it moves smoothly into the sprue. Spure Sprue is the channel through which the molten metal is brought into the parting plane where it enters the runner and gates. Runner In large casting, molten metal is generally carried from the sprue base to several gates around the cavity through a passage called as runner. Gates A gate is a channel which connects runner with the mould cavity, through which molten metal flows to fill the mould cavity. Riser A riser is a passage of sand made in the cope to permit the molten metal to rise above the highest point in the casting after the mould cavity is filled up (Examiner may also ask description of any one of above mentioned)