I was involved in a workshop recently where the second half of it was investigating a problem on a manufacturing production line. To make a long story short, the process of profiling a product generated unusable portions (ends) of the product which had to be cut off and thrown away. The scrap rate of 10% was adding up to be in the tens of thousands of dollars per year on this line alone in material, labor and disposition costs.
Using the A3, 7-step process, the team brainstormed potential causes for this problem of generating unusable portions of the product. These were direct causes and not root causes at this point. The team, based on experience and available data, was able to reduce the list to a few.
At this point, the team went to the actual production line (Gemba) and conducted a few experiments using the refined list of causes (factors). The team observed, took measurements as well as video clips which were evaluated later in the meeting room. It wasn’t long before the direct cause of the problem was determined and, by using the 5-why process, the root cause was reached. The team simply followed the funnel diagram below.
Based on the root cause (equipment alignment issue), the team brainstormed ideas for a solution. A temporary solution was implemented to reduces the defects significantly while a permanent solution was being planned.
The takeaway from this is the importance of conducting root cause analysis through experimentation right where the problem is occurring as opposed to doing so in a meeting or conference room. For management, it is important to allow time for experimentation on the production line and to let the team, including production associates, be creative in generating solutions.