Question Paper: Metrology & Quality Engineering : Question Paper May 2015 - Mechanical Engineering (Semester 6) | Mumbai University (MU)
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## Metrology & Quality Engineering - May 2015

### Mechanical Engineering (Semester 6)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.

1 (a) State and explain any one most primitive length standards used in measurements. State reasons why these standards were replaced by optical / length standards. (5 marks)

1 (b) What are objectives of quality control. (5 marks)

1 (c) Enlist and explain characteristics of a good comparator. (5 marks)

1 (d) Draw and explain various surface roughness symbols. (5 marks)

2 (a) Explain following terms with suitable diagram:
i) Basic size
ii) Fundamental deviation
iv) Maximum and minimum metal conditions
v) Allowance.
(10 marks)

2 (b) Derive necessary expression to calculate the best wire diameter. With the help of suitable diagram explain three wire method used in screw thread measurements. (10 marks)

3 (a) Explain construction and working of laser interferometer. (10 marks)

3 (b) How will you maintain compromise compromise between quality and cost. (10 marks)

4 (a) Explain following concepts with suitable diagrams.
i) Importance of surface conditions
ii) Rougness and waviness
iii) Ra value.
(10 marks)

4 (b) Explain use of X & R charts in quality control. (10 marks)

5 (a) Explain construction and working of Parkinson's Tester. (10 marks)

5 (b) A certain product is given 100% inspection as it is manufactured and the resultant data are summarised by the hour in following table 16 hrs of data is recorded, calculate the central line and variable control limits of P chart using 3-sigma control limits and indicate the value that are out of control.

 Hour Inspected Number of units outside specification Instead of number of units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 48 36 50 47 48 54 50 42 32 40 47 47 46 46 48 39 5 5 0 5 0 3 0 1 5 2 2 4 1 0 3 0
(10 marks)

### Write short notes on:

6 (a) Tool maker's microscope. (5 marks)

6 (b) 3D co-ordinate measuring machine. (5 marks)

6 (c) OC curves. (5 marks)

6 (d) Double sampling plans. (5 marks)