Lovely Professional University 2010 B.Tech Computer Science and Engineering Assignment -2 Quality Engineering and Management Systems - Question Paper
Part A
Q.1
Control charts for X' and R are maintained on certain dimensions of a manufactured part, measured
in mm. The subgroup size is 4. The values of are calculated for every subgroup. After 20 subgroups SX
and SR . calculate the values of three sigma limits for the X' and R charts and estimate the values of on
the assumption that the process is in statistical control.
Q.2
Control charts for X', R and sigma are to be maintained on drawings from a bowl of chips the
distribution of which is approximately normal. The subgroup size is 5, X'' is 60 and Sigma is 18
presume that three sigma control limits are to be based on three sigma limit . calculate the value of the
upper control chart limit, the control line and the lower control limit for the X', R and sigma
charts respectively.
Q.3
An item is made in lots of 200 every. The lots are provided 100% inspection. The record sheet for the
first 25 lots inspected showed that a total of 75 items were defective.
a) Determine the trial control limits for np chart showing numbers of defectives in every lot.
b) presume that al points fall within the control limits. What is your estimate of the process
avg. fraction defective p’?
c) If this p’ remains unchanged, what is the probability that the 26th lot will contain exactly seven
defectives? That it will contain seven or more defectives?
Part B
Q.4 describe QFD and house of quality.
Q.5 describe ISO and its importance.
Q.6 A control chart for defects per unit u uses probability limits corresponding to probabilities
of 0.975 and 0.025. The central line on the control is at u’ = 2.0. the limits vary with the value
of n. Determine the accurate position of these upper and lower control limits when n = 5.
Course Code: MEC 309
Course Name: Quality Engineering & Management Systems
Assignment No. 2
DOA: 28-Feb-2010 DOS: 12- Mar-2010, 12 noon (For Section OE 165)
13- Mar -2010, 12 noon (For Section OE 166)
Note: Bonus marks may be given, if submission would be before time and vice versa.
Part A
Q.1 Control charts for X and R are maintained on certain dimensions of a manufactured part, measured in mm. The subgroup size is 4. The values of X and R are computed for each subgroup. After 20 subgroups %X = 4 1 2 . 8 3 R = 3 . 3 9. Compute the values of
3 sigma limits for the X and R charts and estimate the values of a' on the assumption that the process is in statistical control.
Q.2 Control charts for X and R, a are to be maintained on drawings from a bowl of chips the distribution of which is approximately normal. The subgroup size is 5, X' is 6 0 and a' is 1 8 . Assume that 3 sigma control limits are to be based on X' and a'. Compute the value of the upper control chart limit, the control line and the lower control limit for the X charts respectively.
Q.3 An item is made in lots of 200 each. The lots are given 100% inspection. The record sheet for the first 25 lots inspected showed that a total of 75 items were defective.
a) Determine the trial control limits for np chart showing numbers of defectives in each lot.
b) Assume that al points fall within the control limits. What is your estimate of the process average fraction defective p?
c) If this p remains unchanged, what is the probability that the 26th lot will contain exactly 7 defectives? That it will contain 7 or more defectives?
Part B
Q.4 Define QFD and house of quality.
Q.5 Define ISO and its importance.
Q.6 A control chart for defects per unit u uses probability limits corresponding to probabilities of 0.975 and 0.025. The central line on the control is at u = 2.0. the limits vary with the value of n. Determine the correct position of these upper and lower control limits when n = 5.
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