00117 �763568ef45231a26817acde66e8e56

Input Variablcs

A =

exponential parameter (mean = \lA)

A =

number of standard deviations slip when out of control

PO, PI =

proportion of nonconforming items produced when in and

out of control

E =

time to sample and chart one item

TO =

expected search time when false alarm

T\ =

expected time to discover the assignable cause

T2 =

expected time to repair the process

Sl =

1 if production continues during searches; 0 otherwise

dl =

1 if production continues during repair; 0 otherwise

Co =

ąuality cost/hour while producing in control

Cl =

ąuality cost/hour while producing out of control (> Co)

Y =

cost per false alarm

W =

cost to locate and repair the assignable cause

a =

fixed cost per sample

b =

cost per unit sampled

Output and Calculated Yariables

C =

expected cost per hour

*

n,n =

sample size and its optimal value

h,h* =

time between samples (hours) and its optimal value

control limit and its optimal value

</,</* =

acceptance value for sampling by attributes and its optimal

value

5 =

expected number of samples taken while the process is in

control

=

e^_/Łfy( 1 - e^-^)

r =

expected time of occurrence of the assignable cause, within

a sampling interval

=

[1 - (1 + 1 - e^_>^)] or, equivalently, HA - hs