6.2. A high-voltage power supply should have a nominal
output voltage of 350 V. A sample of four units is selected each
day and tested for process-control pur- poses. The data shown in
Table 6E.2 give the difference between the observed reading on each
unit and the nominal voltage times ten; that
is, xi = (observed voltage on unit i -
350)10
(a) Set up x and R charts on this process.
Is the process in statistical control?
(b) If specifications are at 350 V ± 5 V, what can
you say about process capability?
(c) Is there evidence to support the claim that volt-age is
normally distributed?
Please check page 272 ( Ex. 6.2.).
Solve the
question comprehensively and show the steps, please use
excel to perform the calculation.
- 6 2 A High Voltage Power Supply Should Have A Nominal Output Voltage Of 350 V A Sample Of Four Units Is Selected Each 1 (220.77 KiB) Viewed 224 times
272 Chapter 6 Control Charts for Variables Phase II control chart usage Probability limits for control charts Process capability Process capability ratio (PCR) Cp R control chart Rational subgroups s control chart ² control chart Exercises W The Student Resource Manual presents compre- hensive annotated
solutions to the odd-numbered exercises included in the Answers to Selected Exercises section in the back of this book. 6.1. The data shown in Table 6E.1 are x and R values for 24 samples of size n = 5 taken from a process produc- ing bearings. The measurements are made on the inside diameter of the bearing, with only the last three dec- imals recorded (i.e., 34.5 should be 0.50345). (a) Set up x and R charts on this process. Does the process seem to be in statistical control? If necessary, revise the trial con- trol limits. (b) If specifications on this diameter are 0.5030 ± 0.0010, find the percentage of nonconforming bearings produced by this process. Assume that diameter is normally distributed. 6.2. A high-voltage power supply should have a nominal output voltage of 350 V. A sample of four units is selected each day and tested for process-control pur- poses. The data shown in Table 6E.2 give the differ- ■ TABLE 6E.1 Bearing Diameter Data Sample Number Sample Number R x R 1 35.4 8 13 14 2 34.5 3 4 4 34.0 34.2 3 31.6 6 15 37.1 5 4 34.9 7 5 16 17 18 33.5 4 6 31.7 3 7 31.5 4 35.0 5 34.1 6 32.6 4 33.8 3 34.8 7 33.6 8 19 34.0 8 8 35.1 4 9 20 21 22 23 33.7 2 32.8 1 33.5 3 3 9 24 34.2 2 10 11 31.9 12 38.6 Shewhart control charts Specification limits Three-sigma control limits Tier chart or tolerance diagram Trial control limits Variable sample size on control charts Variables control charts x control chart ence between the observed reading on each unit and the nominal voltage times ten; that is, x = (observed voltage on unit i-350)10 (a) Set up x and R charts on this process. Is the process in statistical control? (b) If specifications are at 350 V±5 V, what can you say about process capability? (c) Is there evidence to support the claim that volt- age is normally distributed? 6.3. The data shown in Table 6E.3 are the deviations from nominal diameter for holes drilled in a carbon-fiber composite material used in aerospace manufacturing. ■ TABLE 6E.2 Voltage Data for Exercise 6.2. Sample Number X1 x2 X3 1 6 9 10 2 10 4 6 3 7 8 4 8 9 5 9 10 6 12 11 7 16 10 5 7 8 9 10 11 12 13 14 15 16 17 18 19 20 7 9 15 8 6 16 BTHSan ∞0 m 7 11 15 9 15 8 13 16 12 13 9 13 7 10 8 7 6 14 10 6 7 10 8 10 8 10 14 9 13 10 10 11 12 10 9 11 X4 15 11 5 13 13 10 9 4 12 13 16 11 15 12 16 14 10 11 12 15