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Right choice is (a) True

To elaborate: Electron BEAM Melting (EBM) is a rapid manufacturing process in which when the high-speed electrons emitted from the electron beam gun, strikes the metal particles, the kinetic energy is INSTANTLY converted into the THERMAL energy. This makes a substantial increase in TEMPERATURE above the melting POINT of the material.

The correct ANSWER is (c) Centrifugal casting

The explanation is: Centrifugal casting technique is the best technique and widely used for casting the tubes and hollow PIPES which are symmetric in structure with a concentric hole. In this method, MOLTEN metal is accumulated at the inward SURFACE of the mould by the FAST rotation of mould and then the casting part is extracted from the mould after the complete solidification.

Correct choice is (a) True

To explain I WOULD say: In this technology, first the part is designed by the 3D CAD software, and then the file is transferred to the processing software where the geometry is sliced into thin layers. The material is melted by ELECTRON beam to fit the geometry defined by the COMPUTER MODEL. Then the metal parts are MADE by layers forming via electron beam melting process in a vacuum chamber.

Correct choice is (b) False

Best EXPLANATION: In the vacuum die casting METHOD, the removal of all the gases from the cavity makes the vacuum inside the mould cavity, so the FORCE and pressure are negligible in magnitude inside the mould cavity which could be opposite to the injecting pressure of the melt. So, the melt enters into the die with very high SPEED which ALSO decreases the filling time of melt.

Right answer is (b) False

To explain I would say: The electron BEAM technology is several times more efficient as compared to the laser technology. This technology RESULTS in less power consumption, less maintenance and low MANUFACTURING costs. In this technology, electron beam melting process combines with vacuum, which can provide high power and excellent material PROPERTIES.

Correct choice is (a) True

Explanation: In CO2 moulding technique, WATER is not mixed with the SAND mixture while preparing the mould. Sodium silicate is GENERALLY added in the place of water to act as a binder. So the moisture is completely eliminated from the mould. Due to moisture-less mould, the process can provide high accuracy in the production of CASTING parts.

The correct answer is (a) True

For explanation I would say: The operations of fabricating 3D part in the electron beam melting (EBM) are very SIMILAR to that of LASER beam melting (LBM). However, the major differences between the two systems are the DIFFERENT THICKNESS of powder layer and different building speed which is generally high in the LBM SYSTEM which gives rise to more rapid cooling in the fabrication of small size specimens.

Right answer is (a) True

For explanation: In the gravity die casting method, not EVERY metal can be casted easily because of using a metallic mould in the casting process. In this method, the sticking PROBLEM ARISES when metallic mould interacts with the casting metal. Due to this, MUCH of LUBRICANT is used, but still, this method is not suited for every metal.

The correct choice is (a) True

Best explanation: In electron beam MELTING technology, the VACUUM chamber is used which requires maintenance TIME to time and a shield is also used during the process which covers the x-rays produced by the electron beam in the process. These all expensive EQUIPMENT are used which makes this technology very costly.

Correct answer is (b) False

To explain: In permanent mould casting TECHNIQUE, metallic cores are not USED generally because the metallic cores cannot be COMPLEX with undercuts in the casting process. Also, the metallic core is to be withdrawn immediately after solidification; otherwise, its extraction becomes difficult due to its shrinkage in the mould. So, sand cores are mainly PREFERRED in this method for the casting process.

Right answer is (b) False

The explanation is: In the ELECTRON beam technology, when the whole process from CAD software to metal FORMATION is COMPLETED, then the net shape metal part can be cleaned and finished by any conventional methods. Finishing and cleaning are very necessary and important for a casting to be USED in APPLICATIONS.

Right OPTION is (a) True

Best explanation: In SLUSH casting technique, high melting temperature metals like BRASS and aluminium cannot be USED for casting because high temperature of molten metal can PRODUCE defects in the casting parts and mould. So, only low melting temperature metals can be used in the slush casting system.

Right option is (b) False

The explanation is: In ELECTRON beam melting TECHNOLOGY, the electrons are emitted from a filament which is generally heated to very high temperature. Then the electrons are accelerated to half the speed of light in the ELECTRIC field. The beam of electrons is mainly controlled by two magnetic fields in the vacuum chamber. No object can ACHIEVE the speed equal to the speed of light in the universe.

The correct option is (a) True

For explanation I would say: In continuous casting technique, the operations cannot be PERFORMED manually, so higher extent of automation is REQUIRED in this method to perform the operations easily. For example, cutters, metallic ROLLERS, water sprayers etc. are the automatic equipment which are required to be used for the production of casting COMPONENTS.

Correct answer is (b) False

Best explanation: The electron beam melting (EBM) process can produce hollow metal PARTS with internal FEATURES, which are not easily produced by any other method. The EBM technology can provide the required mechanical strength and MANY properties with much LESS mass of the metal parts. This reduces the cost involved in the RAW materials and the weight of the component.

The correct answer is (d) Negligible impurities

Explanation: Electron beam melting is a vital technology in industries. This method has many ADVANTAGES LIKE high strength properties of metal, high energy LEVEL and the most important is the negligible impurities in the metal parts, because this process uses a vacuum chamber that eliminates the all kind of impurities like oxides, NITRIDES etc.

Correct ANSWER is (b) False

Easiest explanation: In die casting technique, the casting PROCESS starts when the parts of the die are apart. It generally CONSISTS of two parts in which one part is called as stationary half or COVER die that fixed to the die casting machine. Another part is called a moving part or ejector die that can slide for extracting out the casted product.

Correct CHOICE is (d) Labour intensive

Best explanation: In sand casting process, the sand is rammed by using the rammer and then the cope and drag box are used as a moulding box to prepare the mould. In this process, much of time is spent and it requires too much labour work. So this METHOD is NORMALLY used for small scale production for producing small size CASTINGS.

Right choice is (c) Electron BEAM gun

Best explanation: In electron beam melting process, the electron beam is generated by a device called electron beam gun which is generally located at the TOP of a VACUUM chamber. The Electron Beam Gun is fixed and the beam is deflected to arrive at the DESIRED area, which can melt the metal to form the desired shape of metal parts.

Correct option is (a) Limited size of casting parts

Easiest EXPLANATION: In SHELL moulding process, a dump box is used in which a heated metallic pattern is inserted with the sufficient amount of coating SAND, then the dump box is ROTATED by which the pattern has adhered to the coating sand and then the pattern is extracted out by melting. In this process, due to limited size of the dump box, only limited size of casting parts can be produced.

Right answer is (a) True

Easy explanation: The squeeze casting TECHNIQUE almost has negligible GAS entrapment which results in less shrinkage CAVITIES and good QUALITY of surface with fine details on the casting parts. Aluminum and copper alloys are widely MANUFACTURED by this technique. It also produces the fine grain size to enhance the properties of the castings.

Correct answer is (b) False

Easy EXPLANATION: In investment casting METHOD, COMPLEX shapes castings are easily manufactured WITHOUT any significant defects in the castings. In this method, the pattern is withdrawn by melting it, that’s why it can produce any complex shape casting with deep features. And the thin sections with complexities can also be PRODUCED by this method.

The correct OPTION is (c) Complex shapes

To elaborate: In investment casting method, wax is used as pattern material on which slurry is COATED and then wax is taken out by MELTING it. This process of casting is widely used for PRODUCING complex shapes of castings. It has many other advantages like good dimensional accuracy and rapid production RATE of the casting components.

Correct answer is (b) False

The best I can EXPLAIN: In the squeeze casting METHOD, the main purpose is to produce CASTINGS of COMPACT size with better strength. In this method, product quality is greatly improved by solidifying the casting under heavy pressure to prevent the dissolving of gases in the solution until the solidification of the casting is completed.

The correct CHOICE is (a) True

Best explanation: The metal does not get wasted by the SLUSH casting method. EVEN this method saves the molten metal by collecting it, which can be REUSED for the other casting process. This method makes the casting light in weight by saving the molten metal; hence this method is very economical for the production of castings.

Correct answer is (b) Maximum casting yield

The explanation: In centrifugal casting technique, there is no need for the gates and runners to be used in the process, which can save a lot of MOLTEN metal. This MAKES the increase in casting yield which can reach to the maximum that means negligible metal loss. And no cores are required during the process which makes this method very economical for the large SCALE production of CASTINGS.

Correct ANSWER is (C) Very COMPLEX shapes of casting can be produced

To explain I WOULD say: In permanent mould casting method, a metallic mould is used which can be used again and again, and it has good THERMAL conductivity too. But this method is not appropriate for producing very complex shapes of castings. For complex shapes casting, the investment casting method is mainly preferred which can produce high extent of complexities in the casting components.

Correct option is (b) False

To EXPLAIN: Sand casting is a PROCESS which is WIDELY used for the PRODUCTION of simple casting products and it is very economical method of casting as compared to other methods of CASTINGS because the mould making process is very cheap process, so low cost is involved in the operations and it can be used for casting almost all the alloys.

Correct answer is (d) Uneconomical for SMALL scale PRODUCTION

The best explanation: Low-pressure die casting technique is not economical for small-scale production because the MACHINES used in the PROCESSES are very expensive, the parts LIKE riser tube and the device used for compressing the gas makes this method very expensive. So this method is only economical when it is used for large scale productions.