Process control and stability are critical aspects to regulated medical device and aerospace processes. It is important to ensure that a process has input and output variable limits which are defined and fully tested during process design, Equipment Qualification (IQ), Operational Qualification (OQ) and Process Qualification (PQ) validation testing. Setting up a proper DOE (Design of experiments) to test these limits is also important as it result of the DOE will give statistical confidence intervals of the limits.
Being that operators and employees perform various process operations different no matter how instructed in work instructions, the variation of operators must also be captured during process qualification (PQ) validation. An automated system typically eliminates many of the operator variability in the manufacturing process and this process “input” elimination also allows for tighter process output controls.
For example, in our automated passivation system, the elimination of relying on an operator to move the parts basket from stage to stage ensures that the parts remain in the appropriate (wash, rinse, acid passivation, etc) solutions for the process defined times and in accordance with the proper ASTM A967, AMS2700, etc specification. If a parts basket is immersed in the acid passivation solution too short or long duration, the passivation can likely fail and be outside specification limits.
