g. To evaluate this group of plots (Figures 25-31), you must first consider the first six by
themselves. They show the gamma returning back towards a random variation on the target line. Now
concentrate on the seventh plot of that group, which is the last one on the control chart. It indicates
that the process is OUT OF CONTROL--unacceptable because it has plotted outside the control limits.
A plot that is out of control is called an ASSIGNABLE CAUSE. Any time you make a plot that is an
assignable cause, you must STOP THE PROCESS at once. The quality of the end product, with the
process out of control, would be inferior; so you MUST find why the process is out of control and
correct it (bring it back into control) before resuming production.
Figure 32
h. Figure 32 is the same basic chart as figure 31. The process control chart has been labeled to
indicate the various process performances in an overall view.
i. At this time you have a completed process control chart for a 31-day period. Take a moment
and review it; if there is anything on or about the chart you do not understand, go back to that portion
of the lesson topic.
EXERCISE
6.
What is the term applied to a plot or a group of plots that indicate
a.
the process is operating normally.
____ _
b.
a need to increase the replenishment.
____ _
c.
a need to decrease the replenishment.
____ _
d.
a need to stop the process.
____ _
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