53114-mt----quality Engineering & Manufacturing

NR

Code No: 53114/MT M.Tech. – I Semester Supplementary Examinations, September, 2008 QUALITY ENGINEERING & MANUFACTURING (Advanced Manufacturing Systems) Time: 3hours

Max. Marks:60 Answer any FIVE questions All questions carry equal marks ---

1.a) b) 2.a)

b)

3.

Explain briefly the methodology for the evaluation of total quality system. What is quality engineering and what are the responsibilities of this section? Discuss the concepts of i) Loss function ii) Parameter design iii) S/N ratio in the Taguchi method. How are they related to the concept of `robust’ design? Explain the importance of experimental design in quality control and improvement. What are the relative advantages and disadvantages of factorial experiments? Explain why it does not make sense to test for the main effects in a factorial experiment if the interaction effects are significant? There are four tips available for hardness testing on four specimens. Each tip is tested once each specimen, resulting in a randomized complete block design. The data obtained are given below: Types of the TIP

Specimen 1 2 3 4 1 9.3 9.4 9.6 10 2 9.4 9.3 9.8 9.9 3 9.2 9.4 9.5 9.7 4 9.7 9.6 10 10.2 Write the coded data for hardness testing experiments. Assuming the order in which the tips were tested on a particular specimen was determined randomly, find out whether the types of tip has any effect on the hardness reading (Assume f 0.5(3,9) = 3.86, α = 0.5 ). Contd…2

Code No: 53114/MT

4.a) b) 5.a) b)

6.a)

b)

7.a) b) 8.

::2::

What are the various uses of orthogonal array based matrix experiments? Define degrees of freedom and variance ratio. How error variance is estimated? What is the difference between natural tolerance limits and specification limits? Explain narrow limit gauging. Three components A, B and C are to be assembled. Their lengths are A=1.000 ± 0.001, B=0.5000 ± 0.0005 and C=2.000 ± 0.002. Calculate the assembly tolerance by arithmetic and statistical methods. A cricket manager believes that eight factors, namely A, B, C, D, E, F, G and H each at two levels, affect the runs scored by batsmen. Also he believes that interaction A × B, A × C, B × C, D × E and D × F are also important. Which orthogonal array will you use to estimate the eight factor effects/ main effects and these five interaction effects? Give reasons for your choice. Also specify the column assignments for the orthogonal array chosen by you. Discuss Taguchi’s concept of signal-to-noice. Briefly explain the three types of S/N ratios, enunciated by Taguchi. How are they used in the robust design methodology [Taguchi method]? Explain what is meant by Bench Marking. What steps are to be followed for introducing it? What are it gains? What are the applications and benefits of robust design? Write short notes on any three of the following: a) Detection and Prevention b) Interpretation of engineering tolerances c) Role of S/N ratios in reliability improvement d) ISO 9000 Quality improvement e) Six sigma. ^*^*^