Production lots and vendor sources for parts that comprise a design are subject

Production lots and vendor sources for parts that comprise a design are subject to change and variability in parts characteristics is likely to occur during the fielded life of a product. How does this affect design decisions that impact reliability?Discuss the relationship between manufacturing process control and stress margins. How does this affect qualification? What are the implications for product reliability?List five characteristic life-cycle loads for a computer keyboard. Describe how the product design could address these in order to ensure reliability.