Quality Control Articles & Insights

A Quality Management System (QMS) is the organizational framework — policies, procedures, responsibilities, and documentation — that governs how quality is managed across the organization. Quality control (QC) is the operational activity of inspecting and testing products to verify they meet specifications. QC is one component of a QMS. Other components include quality planning, quality assurance (process design to prevent defects), and continuous improvement. ISO 9001 certification audits the QMS, not just QC activities.

SPC uses control charts to monitor process parameters in real time. When a measurement falls outside control limits or shows non-random patterns (trends, runs, shifts), operators are alerted to investigate and correct the process before it produces defects. The key insight is that process variation follows predictable statistical patterns when the process is stable. Deviations from these patterns signal that something has changed — a tool wearing, a material batch varying, or an environmental condition shifting — and early intervention prevents the defect cascade that follows.