统计过程控制之先进控制图培训(英文版)(ppt 30页)

统计过程控制之先进控制图培训(英文版)目录：
一、Variables Control Charts
1.X-MR Chart
2.Cusum Chart
3.EWMA Chart
4.Pre-Control Chart
二、Attributes Control Charts
1.Cumulative Count Chart

 

统计过程控制之先进控制图培训(英文版)内容提要：
In many processes, especially continuous processes, the mean drifts and consecutive samples tend to be correlated.

Consequently,
 The mean is not fixed, but jumps upward or downward or meanders around
 The inherent process variability t may not be independent
 “Tweaking” the process may decrease variability
 Not “tweaking” the process may increase variability

Despite its shortcomings, the Shewhart Chart continues to be the most commonly employed control chart by virtue of its ease in implementation and interpretation.

However, the Shewhart Chart only uses the information about the process contained in the last sampling.  Hence, it is not sensitive in detecting small shifts in process parameters.

Two control charts are known to be sensitive in detecting small shifts in parameters – the CUSUM Chart and the EWMA Chart.

..............................