Chapter 6: Process Capability Analysis
Abstract: Process capability analysis (PCA) is a statistical method to determine if a process consistently meets customer specifications by comparing its natural variation to required limits ( Specification Limits ) . It uses indices like Cp (potential capability) and Cpk (actual capability) to quantify this, assessing if the process is centered and its spread is narrow enough, often using data from control charts (like X-bar & R charts) and visualized with histograms, to guide quality improvement in manufacturing and other fields . Key Concepts Specification Limits (USL/LSL): Customer-defined upper (USL) and lower (LSL) limits for product characteristics. Control Limits: Limits derived from process data (via SPC charts) showing natural variation, distinct from customer specs. Process Variation: The inherent spread or variability of the process output (often measured by standard deviation, sigma). Cp (Process C...