Six Sigma and Beyond: Statistical Process Control, Volume IV

V

Value engineering, 34

Variable charts

control chart, 457

description of, 125 “126

long run use of, 268

moving range chart, 145 “147

overview of, 213

R chart

advantages and disadvantages of, 133

construction of, 133 “145

control limits, 134 “135

moving range chart vs., 145 “146

process control, 136 “137

sampling frequency and size , 133 “134

vertical scale, 136

short-run

description of, 277

nominal MA and MR chart, 287 “288

nominal X and MR chart, 284 “285

nominal Xbar and R, 278 “279

short-run MA and MR chart, 289

short-run X and MR chart, 286 “287

short-run Xbar and R, 281 “282

short-run Xbar and s chart, 282 “283

standardized Xbar and s chart, 283 “284

target MA and MR chart, 288

target X and MR chart, 285 “286

target Xbar and R, 280 “281

specification limits, 275 “276

Xbar and s chart, 148, 150

Xbar chart

advantages and disadvantages of, 133

construction of, 133 “145

control limits, 134 “135

description of, 65 “66

process control, 136 “137, 141

sampling frequency and size, 133 “134

vertical scale, 136

X chart vs., 145 “146

Variable data

control charts for, 420

description of, 117, 155, 276

SQC session, 395 “397

Variable errors, 330

Variable sampling plan, 197 “198

Variation

abnormal nature of, 11

assessment of, 11

common

control charts for detecting cause of,106 “107

definition of, 100 “102

description of, 214 “215

trending processes, 308

control charts for detecting causes of

common, 106 “107

description of, 104

mathematical theorems used, 113 “114

measurement system, 317, 319

natural, 99

overview of, 4, 7 “11, 99 “100

reduction of, 9

repeatability , 323 “324, 338

reproducibility , 323 “325, 338 “339

sources of, 320

special

description of, 102 “103

in measurement system, 320

signals that indicate

cycle of points, 219

description of, 215, 224 “225

points beyond control limits, 215 “217

run of seven points, 217

runs test for, 221 “222

trend of seven points, 217 “219

unusual variation, 219 “221

trending processes, 308 “309

understanding of, 13

unusual, 219 “221