For root cause analysis resulting from quality failures, an alternative approach to a simple tracking list is to use an 8D report. An 8D report is not a quality tool but a method for addressing and investigating quality failures. The 8D report will not identify the cause of a failure, but it will provide a structure that requires immediate actions and preventive actions to be carried out. It also provides an easy-to-understand report on the investigation that can be saved as a form of lessons learned after the issue is closed. The predecessor to the 8D report was MIL- STD-1520C: Corrective Action and Disposition System for Nonconforming Material, which was created by the US Department of Defense in the 1940s for dealing with quality problems in products supplied to the Department of Defense (1986). The concept of the 8D report was further developed by Ford Motor Company in the 1970s and quickly spread through the automotive industry and then outside the automotive industry.
The D in 8D stands for “disciplines”; these disciplines are the steps in an 8D report (Figure 6.2). The name of the actions at each step may vary from one company’s 8D report to another company’s 8D report; however, the actions to take at each step should not vary between companies. The actual 8D form could be in the form of a text document, a spreadsheet, a slide- based presentation, or a document generated by a company’s computer system. The eight steps are as follows (Rambaud, 2011):
D1: Use a team approach.
D2: Describe the problem.
D3: Implement and verify the temporary fix.
D4: Use root cause analysis.
D5: Develop permanent solutions.
D6: Implement and validate a permanent solution.
D7: Prevent reoccurrence.
D8: Close the problem and recognize contributions.
The first step is forming a team. The team must be interdisciplinary and have representatives from all departments that are affected by the issue. There should be a designated team leader who ensures that all assigned activities are carried out and the 8D report is regularly updated.
The second step is describing the problem. This is not the right place to list the root cause of the failure; that should be identified later and only after an investigation.
The next step (3) is the immediate containment action. A brief explanation should be given if it is determined not relevant. If containment is required, the person responsible and the implementation date should be given.
A root cause analysis, requiring the use of quality tools should be performed and described in detail in step 4. This step may require an additional sheet of paper for details or the attachment of documents, such as laboratory or measurement reports. An interpretation and summary of the reports should be available in the 8D report. Many companies simply list “worker error” when the problem was caused by an employee’s mistake; this is a poor choice in root cause analysis. It is better to describe how and why the person made the mistake. The root cause of the failure to detect the problem should also be described.
The planned corrective actions are detailed in step 5. Here, the planned actions as well as the method or methods used to verify that they will actually work should be described. A common proposed action for human error is “employee training.” Perhaps training is necessary; however, this does little to ensure the failure cannot happen again. It is better to implement changes that will prevent the possibility of a failure. For example, if somebody forgets to install a component, it may be necessary to design an automatic check device to ensure that the assembly cannot leave the workstation if the component is missing. Corrective actions should also consider ways in which a reoccurrence of the failure can be detected prior to it reaching the next process or the customer.
Step 6 is the implementation of corrective actions that have been evaluated and found effective. Although these actions have been evaluated in the previous step, they should still be monitored to ensure that they are effective after implementation.
An additional step (7) is taken to ensure the failure cannot occur again. This is often done by updating documents such as the FMEA and control plan as well as standards and procedures. This step is not only to ensure the failure will not reoccur on the same part that previously failed but also to ensure that other parts or processes cannot experience the same failure.
The final step is congratulating the team to ensure the team understands that its contributions were appreciated. The 8D team is disbanded at this point, and a new team is formed if a new failure occurs. The new team may consist of the same team members or others if different departments are affected by the failure. The 8D report is closed at this point and submitted to the customer or department that initiated the complaint. The closed-out 8D report should then be filed in a location where it can be accessed if it is needed as a lesson learned.