When any serious problems arise in your production areas, then we have been told here, what you should do to solve those problems. The aim should never be only to find and eliminate the problems, one should go to the root of those problems and find out their main reasons. And the solution to eliminate all those harmful causes forever is called “Root Cause Analysis”. And the plan to eliminate those problems from the root is called “Root Cause Action Plan”.
What does this process do?
This process modifies the organization’s quality system, policies, procedures, and work instructions to eliminate the root causes of quality problems.
RCA not just helps to identify the causes of quality problems, but also helps to develop effective solutions to prevent these problems from recurring in the future.
It focuses on the root causes of problems associated with resources, instead of the symptoms of the problems. Hence, the management can focus on the right path to target actual causes.
The root cause analysis helps management to identify trends & patterns in quality issues. Which may support the improvements in the processes.
Who will implement this process?
Responsibility for corrective action rests with the department manager who is responsible for the relevant element. The Quality Manager is responsible for ensuring that the Quality Management System is managed effectively.
The quality manager conducts an analysis for corrective action using one of the following:
- Customer complaint
- Customer Returns (Out of House Repair Report)
- Management review minutes
- Nonconforming Content Report
- Audit report
What is the process for corrections?
- The first responsible/preventive work request should be issued to the responsible department manager.
- Department manager evaluates and investigates the extent of the problem, records the results upon correction/preventive work request.
- The department manager, along with the troubleshooting team, determines the root cause of the non conformance.
- The department manager along with the troubleshooting team, to implement the corrective action correctly, the troubleshooting team discusses and decides on the corrective action to be taken.
- A copy of the corrective action is placed in an “open” corrective action file in Quality Assurance and monitored once a month until closed.
What actions should be taken when corrective action has been implemented?
When the corrective action is effective, the Quality Manager keeps the file open for at least 3 years and closes it after 3 years. And corrective action is reviewed on those topics at the time of management review.
The Quality Manager updates any related documentation in accordance with the Quality System process.
If not effective, the Quality Manager will issue a revised Correction Action to the Department Manager.
Role of Root cause analysis in Quality Analysis & Six Sigma
Here we are going to include the role of RCA in the quality analysis and six sigma. The quality analysis & Six sigma both are much important for product quality. Hence, we will try to describe – How the RCA helpful for implementing the Quality analysis & Six sigma for improvement in the Quality system.
Here as below we are describing the role of RCA in the QA & 6 Sigma:
| QUALITY ANALYSIS | SIX SIGMA | |
|---|---|---|
| Role | For QA, it is identifying the cause(s) of a quality related issues & problems. | In the Six sigma, it is identified and eliminate defects in manufacturing processes, products, or services. |
| Purpose | To improve product or service quality and reduce quality problems. | To improve process efficiency and effectiveness, increase customer satisfaction, and reduce costs associated with rework, scrap, and customer complaints. |
| Benefits | Helps identify the root cause(s) of quality problems, enabling organizations to develop and implement effective solutions to prevent these problems from recurring. | Helps reduce variability and defects in business processes, products, or services, resulting in increased customer satisfaction, improved efficiency, and reduced costs. |
| Steps | Define the problem, collect data, identify possible causes, analyze the data, determine the root cause(s), develop, and implement solutions, monitor, and evaluate. | Define the problem, measure the process, analyze the data, improve the process, control the process. |
| Tools Used | Brainstorming, data collection and analysis, statistical process control (SPC), Pareto charts, and Fishbone diagrams. | Statistical process control (SPC), Six Sigma DMAIC methodology, control charts, and other statistical tools. |
Example
To understand the basics of the Root cause analysis – how works for quality system, here as below given simple example that may clear all the doubts:
Issue: The manufacturing unit identifies a high rate of defects during the quality inspection process at various levels of production lines.
To eliminate these issues, the management team conducts the RCA process. Steps are as below:
Describe issue.
The quality team should very first define the issues which were identified during the inspection process. Herein, we are considering the “High rate of defects” as an issue which is general in manufacturing units.
Collection of information.
At the second stage, the quality team will be collecting the data from the production lines. Usually, these may be processing variables, machine settings, operator actions, as well as inspection data, at time when issue identified.
Analyzing information.
There are so many techniques and methods that can be use for analysis of data. But the goal is to identify any patterns or trends that may be contributing to the high rate of defects.
Identify possible causes.
The outcome from the analysis is use to identify possible causes of the issues. Herein this example, we will be going to consider the following issues as examples for defect that identify.
- Incorrect machine settings
- Poor quality raw materials
- Operator error
- Insufficient training
- Environmental factors, such as temperature or humidity.
Determine the root cause(s).
For this example, herein the team using a structural approach, such as “5 Whys“, fishbone diagram to determine the root causes. As well, creates the set of questions that helps to identify the real causes:
- Why are we experiencing a high rate of defects? Because the machines are producing parts that do not meet specifications.
- Why are the machines producing parts that do not meet specifications? Because the machines are not calibrate correctly.
- Why are the machines not calibrated correctly?. Because the calibration procedure is not being following consistently.
As results of these set of questions, the team determining the root cause of the high rate of defect is that the machines are not properly calibrate. And the calibration procedure is not being followed consistently.
Develop and implement solutions.
At this stage, quality team will be implementing proper solutions for high rate of defects in production lines.
- Very first require prepare & documenting a standard calibration procedure.
- Provide training to operators on the calibration procedure and ensure that it is being follows consistently.
- Implement a schedule for regular calibration checks, to ensure that the machines are calibrate correctly.
In this example, we described the entire process of the root cause analysis. How the root cause analysis starts and what actions & steps require to eliminate causes of defects. However, for each defect, action plans, analysis tools, and implementation of solutions can be different as per problem. But the structure of the steps may be similar.