Study On Process Control Chart And Process Capability Of Water For Injection

The traditional control chart is based upon the assumption that the observation data which came from the process is independent mutually. In the consecutive process of chemical and pharmaceutical industry, the requirement of quality is very strict, the process data is collected automatically with the improvement of equipment and instrument automatization and intelligentize, some process data exist obvious autocorrelated due to the sampling period is reduced , these autocorrelated data can not comply with the suppose that every data is independent which based on the traditional statistic theory. Thus fact proved that the traditional control chart was not suitable for autocorrelated data control and brought a mass of error alarm during the process control, thus badly influence the impact of control chart, resulted in losing to effectively control process and improve the quality. Autocorrelation has caused concern from internal and external academe and gained valuable achievement, for example, Sun Jing's article of State in Control for Autocorrelated Process, also Sampling Interval in Autocorrelated Process and Control Effect, Nien Fan Zhang's article of A Statistical Control Chart for Stationary Process Data as well as Estimating Process Capability Indexes for Autocorrelated Data etc.. in these articles, they discuss the autocorrelated process control method and process capability index calculation, but some of the statistic analysis in these articles rely on the assumption which the time series model has been known, and also some of the data is emulational. In fact, the time series model generally is unknown; it needs to modeling through collecting the actual data from the production locale. Based on the foregoing theory and its insufficiency, on account of the feature of pharmaceutical industry, by collecting and observation a series of quality indexes characteristic in the process of pharma production, confirmed the process data "WFI conductance " as the investigated object to deploy the research about the autocorrelated data control chart and process capability, with the tool of SPSS software to analysis the autocorrelation at different sampling time by means of Time Zone Analytical Method, and show that when sampling time is less than 14 minutes, the autocorrelation is existed, and the characteristic of autocorrelation is enhanced gradually along with the sampling time shorted, testify the models are AR(1) at different sampling time based on Pandit-Wu Method, and conclude that the method of residual control chart can be used to judge the autocorrelated process avoiding some cost loss by comparison with the traditional control chart which will bring an error alarm. Under the system is controlled stably without autocorrelation influence, the best sampling time is more than 14 minutes so as to simplify the control method, put forward the opinion of using traditional control chart for the process control again in case of troublesome brought by the method of residual control chart. By calculating and analyzing the process capability index, indicate that the process capability is superabundant and evaluate its economic depending on the Quality Loss Function, put forward the opinion of lowing the process capability process via ways of widen the process tolerate range and simplify the working procedure etc.