‘Corrective Action and Preventive Action’ this tool is popularly known as CAPA or 8D method in industries. The main purpose of using this tool is to investigate the problem, implement corrective or preventive action, and measure the effectiveness of corrective action to avoid recurrence of the problem. It’s a systematic approach to solve the problem. CAPA tool is not a problem-solving tool it acts as an improvement tool also. CAPA is also known as 8D Problem solving method.
Is the CAPA (Corrective Action & Preventive Action) process mandatory as per ISO 9001, TS16949, and other standards?
The answer is YES.
Benefits of the Corrective Action & Preventive Action (CAPA) process.
- Systematic way of solving a complex problem.
- CAPA process helps to avoid the recurrence of the problem.
- Prevention action of the CAPA process provides the opportunity to implement ‘preventive measures’ like mistake-proofing in the manufacturing process or in mistake-proofing in the design itself.
- CAPA tool is very effective to solve complex problems like product recall in the market.
- Systematic root cause analysis in the CAPA process helps to detect flaws/gaps in the design or manufacturing process.
- CAPA process involved cross-functional team involvement and the CAPA process also helps to maintain proper documentation and record to solve a problem.
- CAPA tool does not just cover the implementation of corrective action, it does cover the verification and validation of corrective action and effectiveness check of corrective actions.
- Corrective and preventive action of the CAPA phase can be implemented horizontally for other products and processes.
- CAPA tool also helps in soft or hard saving.
- CAPA also helps to implement statistical process control to control non-conformity.
- It’s a standard practice to determine CAPA outcome or status in the management review meeting. This process ensures a track on ongoing and aging CAPA.
Let’s understand the phases of CAPA.
Phase#1 Problem Statement:
The CAPA tool is applicable to internal and external problems. Internal problems like internal audits and external problems like customer complaints. It’s very important to define the clear problem statement. Use the following simple template to define the problem statement in a SMART way.
|1. What went wrong?|
|2. Where the problem/defect observed?|
|3. When the problem recorded/observed?|
|4. Which manufacturing/business process affected?|
|5. Who reported the problem/defect? (Customer / internal stakeholder)|
|6. How severe the problem/defect?|
Phase 2 Team Formation:
It’s a very important step to form the right team to work in the CAPA process. It’s better to involve a cross-functional team in CAPA. Following cross-functional team members can be selected.
- Process Owner
- Quality Assurance / Control Personnel
- Continual Improvement / Lean management team
- CAPA owner
- CAPA approval team (management team)
- Non-conformity (NC) Identifier
Depending on the type of problem team member selection can be changed. For example, if an external auditor reported non-conformity in the audit report, you can skip adding NC identifiers in the CAPA system.
Phase 3 Impact Assessment & Corrective / Containment Action:
Once the CAPA team is formed following task must be initiated.
Impact assessment is necessary to categorize problem severity in three different types.
- Incidental Risk: Problem identified the first time and there is a past history of the problem. Not direct impact on product or process. Eg. Internal audit findings related to the gap in supplier quality auditor qualification.
- High Risk: Direct or indirect impact on product or process.
- Critical Risk: Impact on brand value, customer dissatisfaction. Non-conformity raised by a statutory/regulatory body. Product recalls, financial loss.
Impact assessment and problem severity method differs from industry to industry. It’s not limited to define only 3 impact assessment categories, an organization can decide more severity or impact assessment categories.
It’s an action initiated to stop spreading or further generation of problem / non-conformity. Effective communication is also important during containment action. For example, if defects observed in supplied material during the manufacturing, the supplier must be communicated immediately to avoid further production of components at the supplier end with similar defects. Containment action is not just limited to email communication. Following additional containment action types can be considered in the CAPA.
- Production stoppage
- Shipment hold
- Segregation of defective parts and good parts from a lot or batch.
- Rejection of defective lots.
- Identification of defective parts/lot with ‘non-conformity’ tag. Re-inspection of raw materials in store.
- Repair and rework of defective products.
- Block defective lot/batch in ERP System so after repair/rework.
- Timely information on defect /non-conformance to concerned stakeholders, suppliers, customers.
In some critical cases, containment action can be initiated before CAPA Team formation.
Action to eliminate detected non-conformity is known as a correction. After completion of impact study and containment action, correction action must be initiated. Following correction actions can be considered in CAPA,
- Identification & Traceability
- Replacing defective parts / components
- Re-testing after rework and Quality acceptance.
Example of Correction:
Production supervisor in car assembly plant handed over a list of affected VIN (Vehicle Identification Number) to the operator and instructed the operator to replace the faulty ABS (Anti lock brake system) unit in the affected car.
Example of Containment:
The quality manager blocked faulty VIN cars in the ERP system, so these cars cannot be dispatched to the dealer. In this example, quality manager initiated containment action to avoid further spread of problem / non-conformity.
The identification & traceability system is very important to trace back defective products.. If identification & traceability is missing, it’s highly impossible to track affected lot/batch, in this case, the organization end-up with 100% inspection and chances of accepting defective products will be very high.
Phase 4 Root Cause Analysis (Investigation):
In this phase, root cause analysis is conducted to determine the root cause of the non-conformance. Various tools can be used for root cause analysis.
- Pareto Analysis
- 5 Why Analysis
- Fishbone/Ishikawa Diagram
- Control Plan
- Scatter diagram
- Check sheet
- DOE (Design of Experiments)
- Process flow diagram study
- Process Audit
Root cause analysis is an important phase of the CAPA tool. If root cause analysis is failed, it will affect the corrective action process and CAPA will not be helpful to stop the recurrence of defect/problem. For solving a complex problem, the CAPA team can divide affected manufacturing process systems in different components and use multiple problem-solving tools. This action will help team members to execute root cause analysis effectively.
Phase 5 Corrective Action:
Once we determine the root cause of the problem, the next step is to implement corrective action. The success of corrective/preventive action depends on perfection in root cause analysis. Corrective actions help to eliminate the root cause of the problem. Based on the type of root cause, various corrective actions can be implemented.
- Engineering Change Management – Process re-design, Product re-design (design change)
- Material change
- Supplier change
- Machine/tool replacement with a new tool
- Change in the manufacturing process
- Improvement in product and process quality control
- Change in operator training
- Implementation of Statistical Process Control.
- Improve procedure, work-instructions
The corrective action phase is not just limited to the implementation of corrective action. In the corrective action phase, an organization can work on the implementation of preventive action. If similar processes are used for multiple product lines, corrective action can be initiated for other product lines as a horizontal deployment of corrective action. This process serves as preventive action.
In CAPA, following preventive action can be initiated.
- Design mistake proofing
- Process Mistake Proofing – Level 1, 2 & 3.
- Statistical Process Control
- DFSS – Design for Six Sigma
- Automation (eg. Robotic welding)
- Automation in material handling, storage, and preservation.
- Artificial intelligence
- Design FMEA
- Process FMEA
- System FMEA
Preventive action prevents the occurrence of a non-conformity. In the long run, preventive action serves as a cost-saving tool.
Phase 6 Implement Corrective Action / Preventive Action:
Once corrective action determined next phase is implementation of corrective/preventive action. In the corrective action phase, it’s very important to verify and validate the proposed corrective/preventive action. If proposed corrective actions are not appropriate, the CAPA team should re-evaluate corrective actions.
Corrective and preventive action must be documented as per the following details,
- Details of corrective/preventive action
- Responsible person name
- Tools/equipment details
- If investment to be made, approval for purchase order and other financial formalities.
- Time/schedule of corrective/preventive action
- Verification & Validation of corrective action
CAPA team should track the successful implementation of corrective/preventive. All actions should be time-bound.
Phase 7 Effectiveness Check:
After the implementation of corrective/preventive action, an effectiveness check must be initiated in order to verify whether implemented corrective/preventive actions are preventing the occurrence of non-conformity? The success of CAPA is measured in the effectiveness phase. If the effectiveness check is not satisfactory, the CAPA team re-start the process from phase-4 root cause analysis.
Following effectiveness criteria can be considered,
- Reduction in internal rejection (reduction in PPM or meeting PPM target)
- No / reduced customer complaints.
- Improved customer satisfaction
- Improved efficiency & lower lead time
- Improved supplier and customer relationship
- Improved supplier performance
- Reduction in warranty cost
Phase 8 Team Recognition & Closure:
This is the final phase of CAPA. CAPA closure evidence shall be recorded for future reference. It’s also important to maintain CAPA evidence as it’s considered as audit evidence.
Last but least, without teamwork & effort, the CAPA tool will not achieve its purpose. Team recognition boosts the morale of the team member.
Please do watch a small video tutorial about Quality control (7QC) tools & FMEA.
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