Category: Manufacturing Engineering Objective Questions

250+ TOP MCQs on Metrology-2 and Answers

tricky Manufacturing Engineering Questions & Answers on “Metrology-2”.

1. In an assembly of hole and shaft, smallest hole was having diameter of 49.98 mm and largest shaft was having diameter of 49.94 mm. Minimum clearance in mm will be
a) .08
b) .03
c) .001
d) .04
Answer: d
Clarification: Minimum clearance is the difference between size of smallest hole and size of biggest shaft. Maximum clearance is given by sum of size of biggest hole and smallest shaft.

2. In an assembly of hole and shaft, smallest shaft was having diameter of 49.98 mm and largest hole was having diameter of 50.14 mm. Maximum clearance in mm will be
a) 0.23
b) 0.26
c) 0.32
d) 0.12
Answer: b
Clarification: Maximum clearance is given by sum of size of biggest hole and smallest shaft. Minimum clearance is the difference between size of smallest hole and size of biggest shaft.

3. In an assembly of hole and shaft, largest shaft was having diameter of 50.18 mm and smallest hole was having diameter of 49.98 mm. Maximum interference in mm will be
a) 0.2
b) 0.3
c) 0.3
d) 0.1
Answer: a
Clarification: Maximum Interference is the difference between size of largest haft size and smallest hole size. Minimum interference is the difference between size of smallest shaft and size of biggest hole.

4. In an assembly of hole and shaft, minimum shaft diameter is 49.36 mm and maximum shaft diameter is 48.20 mm. It is an example of
a) Clearance fit
b) Interference fit
c) Transition fit
d) None of the mentioned
Answer: b
Clarification: When size of smallest shaft is more than size of biggest hole then it is
Interference fit. Maximum Interference is the difference between size of largest haft size and smallest hole size.

5. In an assembly of hole and shaft, smallest shaft was having diameter of 50.16 mm and largest hole was having diameter of 50.14 mm. Minimum interference in mm will be
a) 0.2
b) 0.3
c) 0.3
d) 0.1
Answer: a
Clarification: Minimum interference is the difference between size of smallest shaft and size of biggest hole. Maximum Interference is the difference between size of largest haft size and smallest hole size.

6. Maximum material limit of shaft is
a) Maximum diameter of hole
b) Maximum diameter of shaft
c) Smallest diameter of hole
d) Minimum diameter of shaft
Answer: b
Clarification: Maximum material limit of shaft is maximum diameter of shaft. Minimum material limit of shaft is minimum diameter of shaft.

7. Maximum material limit of hole is
a) Maximum diameter of hole
b) Maximum diameter of shaft
c) Smallest diameter of hole
d) Minimum diameter of shaft
Answer: c
Clarification: Maximum material limit of hole is smallest diameter of hole. Minimum material limit of hole is largest diameter of hole.

8. Minimum material limit of shaft is
a) Maximum diameter of hole
b) Maximum diameter of shaft
c) Smallest diameter of hole
d) Minimum diameter of shaft
Answer: d
Clarification: Minimum material limit of shaft is minimum diameter of shaft. Maximum material limit of shaft is maximum diameter of shaft.

9. Minimum material limit of hole is
a) Maximum diameter of hole
b) Maximum diameter of shaft
c) Smallest diameter of hole
d) Minimum diameter of shaft
Answer: c
Clarification: Minimum material limit of hole is largest diameter of hole. Maximum material limit of hole is smallest diameter of hole.

10. Allowance of hole and shaft assembly is equal to
a) Sum of maximum metal limit
b) Product of Maximum limit
c) Difference of maximum metal limit
d) None of the mentioned
Answer: c
Clarification: Allowance of hole and shaft assembly is equal to the difference of maximum metal limit.

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250+ TOP MCQs on Pattern and Allowances and Answers

Manufacturing Engineering Multiple Choice Questions on “Pattern and Allowances”.

1. The allowance provided to take care of the contraction of casting is known as?
a) Draft allowance
b) Shrinkage allowance
c) Machining allowance
d) Shake allowance
Answer: b
Clarification: Most metals contract or shrink volumetrically on cooling. The solid-state shrinkage refers to the reduction in volume caused metal loses temperature in solid state. To account for this, shrinkage allowance is provided on the patterns.

2. Which one of the following statement is not true regarding Contraction?
a) Contraction of liquid takes place from the pouring temperature to the freezing temperature
b) Contraction is associated with the change of phase from liquid to solid
c) Contraction of solid is from the freezing temperature to the room temperature
d) Contraction is not associated with the change of phase from liquid to solid
Answer: d
Clarification: As most metals contact during solidification, this contraction can happen at two stages. The liquid stage refers to the reduction in volume when the metal changes from liquid state to solid state at the solidus temperature. To account for this shrinkage; riser; which feed the liquid metal to the casting, are provided in the mold. To compensate the solid state shrinkage, shrinkage allowance is provided on the patterns.

3. While calculating the linear dimension of a material, shrinkage allowance is always?
a) Added
b) Subtracted
c) Multiplied
d) Divided
Answer: a
Clarification: While calculating the linear dimension of a material shrinkage allowance is always added. The allowance provided to take care of the contraction of a casting is known as shrinkage allowance. During solidification of casting, volume decreases and hence contraction occurs.

4. Which one of the following is a negative allowance?
a) Draft allowance
b) Shrinkage allowance
c) Shake allowance
d) Machining allowance
Answer: c
Clarification: All metals shrink when cooling except perhaps bismuth. This is because of the inter-atomic vibrations which are amplified by an increase in temeprature. The shrinkage allowance is always to be added to the linear dimensions. Even in case of internal dimensions.

5. Which one of the following is not used to make patterns?
a) Wood
b) Plastics
c) Metals
d) Ceramics
Answer: d
Clarification: There are different types of pattern materials: 1. wood pattern (teak wood, Mohagaoni, etc.), 2. metal pattern (aluminium, white metal, titanium), 3. Plastic pattern (epoxy resin, PVC, nylon, cellulose, polystyrene, etc.), 4. wax patterns (handicrafts).

6. Which one of the following will not give good dimensional accuracy in the presence of moisture?
a) Wood
b) Plastics
c) Metals
d) Ceramics
Answer: a
Clarification: Wood absorbs moisture as a result of which the dimension changes. To compensate such losses some allowance should be given.

7. The choice of pattern material depends upon:
i. On size of casting
ii. Number of casting to be made from pattern
iii. Dimensional accuracy
Which of the following is correct?
a) (i) and (ii)
b) (i) only
c) (i), (ii) and (iii)
d) (ii) and (iii)
Answer: c
Clarification: All the statements are correct about pattern materials. The choice of pattern material depends upon on size of casting, number of casting to be made from the pattern, dimensional accuracy.

8. In order to reduce the chances of damage due to withdrawing of a pattern from the mould is done by giving ________
a) Draft allowance
b) Shrinkage allowance
c) Distortion allowance
d) Shake allowance
Answer: a
Clarification: While removing the pattern from the mould, the parallel surface to the direction at which pattern being withdrawn has a chance of getting damaged. The draws allowance will allow this easy removal of pattern from the old and does not affect the actual dimension of casting.

9. To have good surface finish and accuracy which of the allowance is given?
a) Draft allowance
b) Shrinkage allowance
c) Shake allowance
d) Machining allowance
Answer: d
Clarification: The necessity of machining allowance is as follows: 1. for removing surface roughness, slag, dirt and other imperfections form the casting, 2. For obtaining exact dimensions on the casting, 3. To achieve desired surface finish on the casting.

10. For good dimensional tolerances and smooth surface which of the following is used as pattern material?
a) Wood
b) Plastics
c) Metals
d) Ceramics
Answer: c
Clarification: The primary benefits of using ceramic patterns are as follows: 1. It is a reusable pattern, 2. close dimensional accuracy, 3. excellent surface finish. There are two types of ceramic mold casting known as the “unicast process” and the “shaw process”.

250+ TOP MCQs on Deep Drawing and Answers

Manufacturing Engineering Multiple Choice Questions on “Deep Drawing”.

1. In which of the following process the work piece is pulled through a die resulting in reduction of area?
a) Forging
b) Drawing
c) Forming
d) Extrusion
Answer: b
Clarification: Large quantities of wires, rods, tubes and other sections are produced by drawing process which is basically a cold working process. In this process, the material is pulled through a die in order to reduce it to the desired shape and size. In a typical wire drawing operation, one end of the wire is reduced and passed through the opening of the die, gripped and pulled to reduce its diameter.

2. In drawing which angle allows the introduction of lubricant into the working zone?
a) Entrance angle
b) Die angle
c) Semi-die angle
d) Relief angle
Answer: a
Clarification: The entrance angle provides the entry zone to allow the introduction of lubricant into the working zone and to protect the work material against scoring by die edges. The angle is usually about 40°.

3. Degree of drawing is measured in terms of?
a) Reduction in stress
b) Reduction in force
c) Reduction in area
d) Reduction in strain
Answer: c
Clarification: The degree of drawing is measured in terms of “reduction of area” which is defined as the ratio of the difference cross-sectional area before and after drawing to the initial cross-sectional area.

4. The maximum reduction in cross sectional area per pass is?
a) 45%
b) 63%
c) 55%
d) 67%
Answer: b
Clarification: For perfectly plastic material, the ideal maximum reduction per pass is 63%. For a strain hardening material, the ideal maximum reduction per pass depends on the strain hardening coefficient. For example, for n = 0.19, then the maximum reduction per pass is 69.5%.

5. Which of the following die is used in drawing flat strips?
a) Square shaped
b) Rectangular shaped
c) Circular shaped
d) Wedge shaped
Answer: d
Clarification: Wedge shaped die is used in drawing flat strips.

6. As the reduction increases, drawing force must be?
a) Decreases
b) Increases
c) Does not change
d) First increases and then decreases
Answer: b
Clarification: With the increase in reduction the drawing force increases.

7. Which of the following angle influence the drawing force and the quality of drawn products?
a) Entrance angle
b) Die angle
c) Relief angle
d) Flake angle
Answer: b
Clarification: Die angle influence the drawing force and the quality of drawn products. Die angle should be kept appropriate for better surface finish.

8. Degree of drawing is given by the expression?
a) (di-df)
b) (Ai-Af)
c) (Ai-Af)/Ai
d) 1-((df-di))
Answer: c
Clarification: Degree of drawing is given by the expression(Ai-Af)/Ai. Where d is the diameter of tube.

9. If the initial diameter is 50mm2 and the final diameter after drawing is 40mm2, then the degree of drawing is?
a) .64
b) .20
c) .80
d) .36
Answer: d
Clarification: Degree of drawing is given by [1- (df/di)2]. Where d is the diameter of tube.

10. If the degree of drawing is 0.5 and the initial area is 100mm2 then the final area in mm2 is equal to?
a) 50
b) 60
c) 40
d) 30
Answer: a
Clarification: Degree of drawing= (Ai-Af)/Ai. Where d is the diameter of tube, A is area.

250+ TOP MCQs on Shaping and Answers

Manufacturing Processes Multiple Choice Questions on “Shaping”.

1. What is a shaping process?
a) A type of casting process
b) A type of grinding process
c) A metal removal process in which reciprocating workpiece is fed against a stationary tool
d) A process in which metal is removed by a reciprocating tool fed against a stationary workpiece
Answer: d
Clarification: It is a process in which cutting motion provided by linear-forward motion of the reciprocating tool and the intermittent feed motion provided by the slow transverse motion of the workpiece resulting in a flat surface by gradual removal of excess material layer by layer.

2. Which of the following is the advantage of shaping process?
a) Large objects can be machined easily
b) Thin or fragile workpiece can also be machined
c) Lower machining time
d) Higher tool life
Answer: b
Clarification: In shaping process very less cutting forces are generated. Therefore thin or fragile jobs can be conveniently machined. Large objects cannot be machined by shaping, for that purpose planning process is used.

3. What is the purpose of the RAM in shaping machine?
a) To hold the tool
b) To hold the tool head
c) To hold the saddle
d) To hold workpiece
Answer: b
Clarification: Ram supports tool head on its front. It reciprocates on accurately horizontal machined guide ways on top of the column.

4. What is the use of clapper block in the shaper?
a) To hold the tool post
b) To hold the feed handle
c) To house the down feed screw
d) To operate the angular graduation scale
Answer: a
Clarification: Tool post is mounted upon the clapper block to prevent the interface between the tools and workpiece on the return stroke.

5. Clapper block is connected to the clapper box by means of hinge pin.
a) True
b) False
Answer: a
Clarification: The clapper box house the clapper block which is connected to it by means of hinge pin. It prevents the tool cutting edge from dragging and wear. The work surface is also prevented from any damage due to dragging.

6. How many types of shapers are there?
a) 5
b) 8
c) 10
d) 11
Answer: c
Clarification: Shapers are classified as follows:
(a) As per the type of motion.
• Crank type
• Geared type
• Hydraulic type
(b) As per the position and travel of ram.
• Horizontal type
• Vertical type
• Travelling head type
(c) As per the design of the table
• Standard shaper
• Universal shaper
(d) As per the cutting stroke
• Push type
• Draw type.

7. In draw type shaper, the metal is removed when the ram moves towards the machine.
a) True
b) False
Answer: a
Clarification: In this type of the shaper, metal is removed when the ram and thus tool moves towards the column of the machine, i.e. draw the workpiece towards the machine. The ram is generally supported by an overhead arm which ensures rigidity and eliminates deflection of the tool.

8. In travelling head type shaper, ram can move only in vertical direction.
a) True
b) False
Answer: b
Clarification: In travelling head shaper, the ram carrying the tool can move crosswise while it reciprocates to give the required feed. Heavy jobs which are difficult to handle are held static on the basement of the machine while the ram reciprocates and supplies the feeding movement.

9. Which of the following is true about push type shapers?
a) The workpiece moves away from the column machining
b) The ram moves away from the machine column while cutting the metal
c) The ram moves towards the machine column while cutting the metal
d) The ram moves away and the workpiece moves towards the machine column
Answer: b
Clarification: It is the most general type of shaper used in common practice. In this type, the metal is removed when the ram moves away from the column, i.e. it pushes the workpiece. As in shaping process workpiece remains stationary.

10. What will be the cutting time for machining the workpiece of 1000 mm when the bull wheel is rotating at 150 rpm with the feed of 2 mm per stroke?
a) 90 sec
b) 120 sec
c) 200 sec
d) 500 sec
Answer: c
Clarification: Cutting time is calculated by formula,
CT = W/ (Ns*Fc) where, W is of the work piece
Ns is the bull wheel rpm
Fc is the feed rate

Therefore,
CT = 1000/ (150*2)
= 3.34 min = 200 sec.

250+ TOP MCQs on Electrochemical Etching – 6 and Answers

Manufacturing Processes test on “Electrochemical Etching – 6”.

1. Which of the following is true about chemical dissolution of hydrogen-terminated silicon in HF based solutions.
a) Si atoms are replaced by F atoms
b) H atoms are replaced by F atoms
c) F− ions are replaced by Si atoms
d) H atoms are replaced by F− ions
Answer: d
Clarification: As far as the chemical dissolution of hydrogen-terminated silicon is concerned, this process requires the replacement of superficial H atoms by fluoride ions (F−), which are incorporated from the etching electrolyte solution.

2. To create a neutralized Si–F bound, an electronic hole (h+) is generated.
a) True
b) False
Answer: a
Clarification: Under open circuit conditions, the silicon surface remains passivated. Therefore, an electronic hole (h+) must be generated to create a neutralized Si–F bound. The Si–F bound can be created under certain anodic bias by the polarisation effect induced by the F atom over the Si atom.

3. Si + 4HF2— + h+ -> SiF62- + 2HF + _____ + e—. Complete the reaction for dissolution of hydrogen-terminated Si in HF based solution.
a) F2
b) SiF4
c) H2
d) Si-H
Answer: c
Clarification: A new F− atom bounds the Si atom at a different position and a gas hydrogen molecule (H2) is generated. The progressive repetition of this process weakens the Si–Si bounds by the strong electronegativity of F atoms through nucleophilic attack. In this way, Si atoms are etched away by reaction with HF and pores are generated.

4. In the fabrication of pSi structures, wet chemical etching with alkaline etchants is used.
a) True
b) False
Answer: a
Clarification: An important aspect in the fabrication of pSi structures is the use of wet chemical etching with alkaline etchants, which are mainly used for chemical polishing or anisotropic etching of silicon. These pre- and post-treatments make it possible to design and engineer a broad range of pSi structures.

5. Which of the following alkaline etchant is most widely used to etch silicon?
a) Tetramethyl ammonium hydroxide
b) Aluminium hydroxide
c) Calcium hydroxide
d) Formaldehyde
Answer: a
Clarification: The most widespread alkaline etchants used to etch silicon are potassium hydroxide (KOH) and tetramethyl ammonium hydroxide (TMAH), although other inorganic and organic compounds such as lithium hydroxide (LiOH), sodium hydroxide (NaOH), rubidium hydroxide (RbOH), caesium hydroxide (CsOH), ammonium hydroxide (NH4OH), cholin and ethylenediamine have been used as well.

6. Etching rate of silicon is independent of the crystal planes.
a) True
b) False
Answer: b
Clarification: The etching rate of silicon in these etchants is highly dependent on the crystal planes, the doping level of the silicon crystal and the etchant concentration and its temperature.

7. Porous materials are classified according to_____
a) total area
b) difference between initial and final mass
c) pore size
d) manufacturing method
Answer: c
Clarification: Following the International Union of Pure and Applied Chemistry (IUPAC) nomenclature used to classify porous materials as a function of their pore size (dp).

8. In how many categories porous silicon can be divided?
a) 2
b) 3
c) 4
d) 5
Answer: b
Clarification: pSi structures can be divided into three categories: (i) microporous silicon (μpSi) with dp < 2 nm, mesoporous silicon (mpSi) with 2 nm < dp < 50 nm and macroporous silicon (MpSi) with dp > 50 nm.

9. According to morphological details, pSi can be divided as sponge-like pSi and pSi featuring cylindrical pores.
a) True
b) False
Answer: a
Clarification: pSi can present a variety of morphological details, these can be divided into two main categories: (i) sponge-like pSi, which features densely and randomly distributed branched pores and (ii) pSi featuring cylindrical pores, which can have rough or smooth walls. While μpSi and mpSi structures feature sponge-like morphology, MpSi structures have cylindrical pores.

10. MpSi structures have a random distribution of pores.
a) True
b) False
Answer: a
Clarification: As far as the spatial distribution of pores, MpSi structures present a random distribution. However, these structures can be produced featuring a perfectly ordered spatial distribution of pores. To this end, the surface of the silicon wafer must be patterned by lithographic techniques before the electrochemical etching process is carried out.

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250+ TOP MCQs on Abrasive Jet Micromachining – 2 and Answers

Manufacturing Processes Multiple Choice Questions on “Abrasive Jet Micromachining – 2”.

1. Abrasive particles are suspended in the carrier gas.
a) True
b) False
Answer: a
Clarification: Abrasive particles should be fine enough to remain suspended in the carrier gas. It should have excellent flow characteristics so that narrow and fine areas are reachable to them.

2. SiC is used as abrasive for harder materials.
a) True
b) False
Answer: a
Clarification: Following are the materials used as abrasive in AJMM:
1) Al2O3: For cleaning, cutting and de-burring
2) SiC: Similar applications as Al2O3 but for harder work materials
3) Glass beads: Matte finish
4) Sodium Bicarbonate: Cleaning, cutting and de-burring of soft material.

3. Which of the following is commonly used as a carrier gas in AJMM?
a) O2
b) He2
c) N2
d) H2
Answer: c
Clarification: In AJMM, commonly used gases are CO2, nitrogen, and air. Air is mostly preferred due to universal availability, practically at no cost, and its non-toxic nature.

4. The Carrier gas should spread more after discharge.
a) True
b) False
Answer: b
Clarification: Following are the required properties for the carrier gas:
1) It should be non-toxic
2) It should be cheap
3) It should be easily available.
4) It must not flare excessively when discharged from the nozzle.

5. There should be supersonic air flow velocity in the nozzle.
a) True
b) False
Answer: a
Clarification: The following requirements have to be fulfilled on nozzle design:
1) Pressure-less constant feeding system
2) Supersonic air flow velocity in the nozzle
3) Homogeneous dispersion of abrasive particles over the of the nozzle
4) Long life time of the nozzle (It has to withstand the erosive action of abrasive particles).

6. A decrease in stand-off-distance (SOD) _____
a) increases machining time
b) increases energy consumption
c) improves surface finish
d) improves accuracy
Answer: d
Clarification: A decrease in stand-off-distance (SOD):
1) improves accuracy,
2) decreases kerf and
3) reduces taper in the machined groove.

7. Material removal rate (MRR) in AJMM _____
a) increases with SOD
b) can only decrease
c) first increases upto certain value and then decreases
d) first decreases upto certain value and then increases
Answer: c
Clarification: MRR increases only upto a certain value of abrasive flow rate beyond which it starts decreasing. After a certain value of abrasive flow rate, abrasive flow velocity decreases to the extent that it results in reduction in MRR.

8. MRR increases with abrasive flow rate increase.
a) True
b) False
Answer: a
Clarification: As abrasive flow rate increases, then the number of abrasive particles cutting the material also increases there by increasing Material removal rate (MRR).

9. In the case of ductile materials, material is removed by plastic deformation.
a) True
b) False
Answer: a
Clarification: When ductile materials are machined by AJMM, the material is removed by plastic deformation and cutting wear, or plastic strain and deformation wear.

10. In case of ductile materials, plastic deformation starts when yield strength is exceeded.
a) True
b) False
Answer: a
Clarification: In case of ductile materials, during an impact of the jet, plastic deformation takes place in the vicinity of the impact when the yield strength of the material is locally exceeded. And yield strength increases due to hardening of the material.