Manufacturing Technology 1 solved MCQs

explanation:-a pattern is basically a duplicate of the object that we intend to cast. patterns can be made up of wood, plastics or metals. a pattern is generally made up of two or three pieces, whereas it is casting which is in one piece.

explanation:-patterns are duplicates of the objects we desire to cast. these patterns can be made up of plastics, metals or wood. a pattern is slightly larger in size as compared to casting because a pattern carries various allowances and the core prints.

explanation:-draft allowance is also known by the name of tapering allowance, as the diameter of the cast goes on increasing in a trapezoidal shape from the bottom. a pattern has a draft allowance of an order of 1 and 3 degrees for external and internal surfaces respectively.

explanation:-none.

explanation:-machining allowance does not depend on solidifying contraction as it is one of the form of shrinkage allowance. but,

explanation:-in distortion allowance, the amount goes on to vary from 2mm to 20mm. this allowance depends on the shape of the casting that is being used. it also depends on the size of the cast and the material that is being employed for the casting.

explanation:-ferrous metals have dimensions on casting which have a larger size to provide stock than the dimensions of the casting of the non-ferrous metals.

explanation:-in rapping or shake allowance, the pattern is taken out of the mould and it is rapped or shaken, so as to free it from the adjoining sand. due to this, there may be a little increase in the size of the mould cavity.

explanation:-the pattern is being taken out of the mould without the mould cavity getting damaged. the pattern is having a tapered shape, that is, it has a tapering allowance.

explanation:-the coal is a material which is not used in the formation of the molding sand as the particle size of the coal is high and there are chances that it will react with the possible gases that are produced during the pouring of the metal and result in casting defects.

explanation:-the molding sand is made up of several particles. the properties such as porosity, texture are all considered while

explanation:-in a foundry, the molding sand

explanation:-molding sand is added with chemicals to enhance properties such as permeability, compressive strength etc., however, the chemical reactions happening is not viable for the formation of the casting as it might cause explosion or severe fatal effects in the casting.

explanation:-the adhesiveness is a property of molding sand to get the stick or adhere to foreign material such as sticking of molding sand with an inner wall of the molding box. hence, as the sand sticks to the box and the excess sand is removed.

explanation:-the cohesiveness is a property of molding sand by virtue which the sand grain particles interact and attract each other

explanation:-after the molten metal in the mould gets solidified, the sand mould must be collapsible so that free contraction of the metal occurs and this would naturally avoid the tearing or cracking of the contracting metal. in absence of collapsibility property, the contraction of the metal is hindered by the mold and thus results in tears and cracks in

explanation:-the adhesive property refers to the sticking of the sand particles to each other so that they can take up the desired shape.

explanation:-flowability or plasticity is the ability of the sand to get compacted and behave like a fluid. it will flow uniformly to

explanation:-cupola is a heavy furnace and has the capability to melt down heavy metals like cast iron. hence, the cupola furnace is mostly used to melt cast iron for casting purposes.

explanation:-a sand bed needs to be prepared because it provides a necessary refractory bottom for molten metal and coke.

explanation:-slag hole is a tapping hole in a

explanation:-the air enters the cupola through the tuyers. but the air blowers in the wind box controls the requisite pressure and quantity of air coming inside.

explanation:-limestone (caco3) is used as flux in cupola furnace in a proportion of about 2-4% of the metal charge.

explanation:-iron is the metal having a melting point of about 1537oc and latent heat of fusion of 65.0 cal/g. it has a mean specific heat of 0.141 cal/g-oc and heat required for melting 1 kg of iron is 1168 kj.

explanation:-the hearth is that bowl shaped bottom of the furnace. it is made up of a high refractory material (bricked and granular).