The Pacific Fruit Company in Problem 3-13 has designed its packaging process for boxes to hold a net weight (nominal value) of 255 g of raisins with tolerances of  ± 15 g. Using the process mean and control limits developed in Problem 3-13, compute the process capability ratio and index, and comment on the capability of the process to meet the company€™s box weight specifications.

Problem 3-13

A machine at the Pacific Fruit Company fills boxes with raisins. The labelled weight of the boxes is 255 g. The company wants to construct an R-chart to monitor the filling process and make sure the box weights are in control. The quality-control department for the company samples five boxes every two hours for three consecutive working days. The sample observations are as follows:

Construct an R-chart from these data with 3σ control limits, plot the sample range values, and comment on process control.

Box Weights (g) Samples 256.85 258.83 254.30 250.89 239.84 241.54 244.09 257.70 261.10 253.73 12 265.07 253.73 260.82 256.00 238.70 3 3. Samples Box Weights (g) 259.97 261.10 256.56 255.43 270.17 261.10 251.46 246.92 256.56 265.07 247.77 236.72 240.97 256.85 252.03 255.15 261.10 256.56 261.67 248.91 259.40 260.82 261.67 259.40 256.85 282.93 252.31 249.76 256.56 258.83 10 256.00 257.98 262.52 268.19 240.12 11 270.17 255.71 258.26 251.74 252.88 12 253.73 257.98 255.15 256.85 253.73 6)