In manufacturing world, Quality Assurance (QA) and Quality Control (QC) are important processes for maintaining product quality. You can think that it is very closely related, but QA and QC both plays different role and functions to achieve product quality. It is helpful for every quality engineer to understand their meaning and difference, also helps in building a good quality management system.
What is Quality Assurance (QA)?
Quality Assurance is focused on system approach to prevent defects from happening. It is a proactive, process-oriented and documentation approach.
QA involves setting up the process documentation and quality standard, which ensures that product should meet customer specified requirements from production.
What is Quality Control (QC)?
On the other side Quality control is focused on identifying defects in finished products. It is a reactive, product oriented and inspection based approach.
Basically QC involves inspection and testing of parts followed by taking corrective actions if parts found not ok. The QC acts on produced parts, and take care that produced parts meet all required quality specification and customer requirements.
Key Differences between QA & QC: Quality Assurance vs. Quality Control
| Aspect | Quality Assurance (QA) | Quality Control (QC) |
|---|---|---|
| Definition | Focuses on system and production processes to prevent defects. | Focuses on final product to identify and correcting defects. |
| Nature | Proactive : aims to prevent defects before happening. | Reactive : aims to find and fix defects after production. |
| Approach | Process-oriented : ensures proper processes followed to achieve quality. | Product-oriented : inspect and ensures the final product meet quality standards. |
| Primary Focus on | On Process Improvement | On Product Verification and Validation |
| Goal is | To make quality parts from process standardization and ensure products meet requirements from start. | To identify defects in products before they deliver to customer. |
| Activities Involved | Setting standards, creating procedures, conducting audits, training, and preventive actions. | Inspections, testing, sampling, defect correction, and final product evaluation. |
| Timing | QA works before and during production. | QC works after production step. |
| Responsibility | Typically a supervisors and managerial responsibility, involving process planning and standardization. | Often a inspector, operator or technical responsibility, having hands-on knowledge of inspection and testing. |
| Examples | Documenting quality procedures, work instructions, conducting audits, and provide employee training. | Doing product inspections, testing samples, and defect analysis. |
| Tools and Techniques | Process checklists, Audit checklists, standard operating procedures (SOPs), quality management software. | Inspection methods and techniques, sampling, statistical process control (SPC), and defect tracking. |
| Documentation Focus | Process documentation : Focus on documenting work instruction, control plan, procedures and quality management standards. | Product documentation : focus on filling inspection and testing results into reports/records. |
| Outcome / Result | QA ensures that the process is capable of consistently manufactured quality products. | QC ensures that only quality products are delivered to customer. |
Best Tools for Quality Assurance (QA) & Quality Control (QC) in Manufacturing
| QA | QC |
|---|---|
| Failure Mode and Effects Analysis (FMEA) Control Plans ISO / IATF Quality Management System (QMS) Layered Process Audits (LPA) Measurement System Analysis (MSA) Quality Function Deployment (QFD) Process Mapping Control Charts Ishikawa (Fishbone) Diagram Check Sheets 5S Kaizen Poka-Yoke (Mistake-Proofing) | Statistical Process Control (SPC) Inspection Checklists Acceptance Sampling Root Cause Analysis (RCA) Ishikawa (Fishbone) Diagram Pareto Analysis Scatter Diagrams Histograms Check Sheets |
How QA and QC Work Together in Manufacturing
Both QA and QC support each other and critical in quality management system.
You know now that QA helps manufacturing processes to provide procedures, methods and trainings to produce high quality products.
And QC helps manufacturing company to check the products that either they meet quality specifications or not. If not then QC will take action to correct them.
Now in other words QA creates standardization and documentation on how process should work and how you can inspect the products, everything including inspection methods and all. And QC is the one who follows these all procedures and methods to inspects the products and find out that if there is any defects in it or not.
Conclusion
Understanding Quality Assurance and Quality Control helps quality engineer to implement a best approach to quality management. QA prevents defects by creating system into process, and QC focus on finding issues/defects in product. Together, both QA and QC creates good quality culture and best practices for better quality management.
