The 8D team oriented problem solving method is a great bolt-on to that control chart that is telling you that you have a problem. An 8D is a structured method that reinforces team work, encourages a bias for action, and delivers robust and permanent solutions across functions.
Here are the eight disciplines in an 8D:
(1) Form a team. Select a small group of people with the product/process knowledge to understand the problem as well as the authority to implement solutions.
(2) Describe the problem. In quantifiable terms, specify the problem: who, what, when, where, why, how, and how many (5W2H).
(3) Implement and verify interim actions. Put containment actions (typically 100% inspection) in place to protect the customer until the root causes have been identified and eliminated.
(4) Define and verify root causes. Identify and prioritize all potential causes for the problem. A fishbone diagram is an excellent tool for this. Use the “5-Why” method to identify, isolate and verify potential root causes. Develop corrective action(s) for each root cause.
(5) Verify corrective actions. Run trials to confirm that corrective actions have indeed eliminated the problem. If the containment net finds no defects, then then corrective actions are successful.
(6) Implement permanent corrective actions. Choose the best corrective actions and implement on-going controls to ensure that they remain in place. The control chart that started the 8D is a great tool for on-going process monitoring.
(7) Prevent recurrence. Where else could this problem occur? Put procedures in place to prevent the problem from coming back on the next product, the next program, next factory, etc.
(8) Congratulate your team. Thank everyone for their great work!
As the 8D as evolved over the last 30+ years, the concept of “escape points” has been added to the fourth discipline. This is a really clever idea that drives improvements in control plans, process controls, error proofing, etc.