Resistors for electronic circuits are manufactured on a high-speed automated mac
ID: 405698 • Letter: R
Question
Resistors for electronic circuits are manufactured on a high-speed automated machine. The machine is set up to produce a large run of resistors of 1,000 ohms each. Use Exhibit 13.7.
To set up the machine and to create a control chart to be used throughout the run, 15 samples were taken with four resistors in each sample. The complete list of samples and their measured values are as follows: Use three-sigma control limits.
Calculate the mean and range for the above samples. (Round "Mean" to 2 decimal places and "Range" to the nearest whole number.)
Determine the UCL and LCL for R-chart. (Leave no cells blank - be certain to enter "0" wherever required. Round your answers to 3 decimal places.)
Resistors for electronic circuits are manufactured on a high-speed automated machine. The machine is set up to produce a large run of resistors of 1,000 ohms each. Use Exhibit 13.7.
To set up the machine and to create a control chart to be used throughout the run, 15 samples were taken with four resistors in each sample. The complete list of samples and their measured values are as follows: Use three-sigma control limits.
Explanation / Answer
a)
Mean is Sum of observations / Number of observations and Range is Highest - Lowest
So, the mean and range are shown in below table
b)
Mean of mean = Sum of observations / Number of observations
= 14,982.75 / 15 = 998.85
Mean of Range = 571 / 15 = 38.07
c)
UCL and LCL of X chart
UCL = Mean + 3 x Square root of mean
= 998.85 + 3 x 31.60
= 1,093.65
LCL = Mean - 3 x Square root of mean
= 998.85 - 3 x 31.60
= 904.05
d)
UCL and LCL of R chart
UCL = Mean + 3 x Square root of mean
= 38.07 + 3 x 6.17
= 56.58
LCL = Mean - 3 x Square root of mean
= 38.07 - 3 x 6.17
= 19.56
e)
In the case of X chart, all the values are within UCL, so the process is under control but in the case of R chart, the value of sample No 8 is above UCL which means the process is not under control.
Sample no. Reading 1 Reading 2 Reading 3 Reading 4 Mean Range 1 1,027 994 977 994 998.00 50 2 975 1,013 999 1,017 1,001.00 42 3 988 1,016 974 997 993.75 42 4 998 1,024 1,006 1,010 1,009.50 26 5 990 1,012 990 1,000 998.00 22 6 1,016 998 1,001 1,030 1,011.25 32 7 1,000 983 979 971 983.25 29 8 973 982 975 1,030 990.00 57 9 992 1,028 991 998 1,002.25 37 10 997 1,026 972 1,021 1,004.00 54 11 990 1,021 1,028 992 1,007.75 38 12 1,021 998 996 970 996.25 51 13 1,027 993 996 996 1,003.00 34 14 1,022 981 1,014 983 1,000 41 15 977 993 986 983 984.75 16Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.