Process control sample size selection

To illustrate the use of designed experiments in this process, a case study is presented involving a packaging sealer (3). Designed experiments in conjunction with other tools are used to create a control plan that is then validated. The DOE results are also used to identify worst-case conditions for worst-case testing, and to help select sample sizes for worst-case and final PQ testing. 

Many statistical tools have been developed to control critical process parameters. The most commonly used is the control chart, which is an effective way to monitor and control processes and can be defined for both vtuiables and attributes data. The selection of variables data will typically make basic statistical tools more efficient (i.e., lower sample size requirements to achieve necessary confidence levels). 

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