Thank you for your response.
I want to clarify: we do our best to prevent failures during production process, but we're obligated to perform the final inspection of our products in order to prevent shipping of nonconforming items. There are methods and tehniques for performing visusal inspection, specially, if there are some items in production batch. For example, first step is checking compliance of first item in batch to drawing. There are additional steps which give high confidence that customer will not receive nonconforming parts after final inspection. Can somebody give tips for this?