Tracking Down a Perplexing Problem
Hey blog readers - I got permission to share just one of the many stories from The Toyota Engagement Equation. This story is about going to see, and finding the point of occurrence. It is a relentless attempt to find one scratch by a trainer and a supervisor! Enjoy! More to come soon! The book will only be at a discounted rate about 5-6 more weeks. Click the link above to pre-order!
One day a team member at TMMK noticed an intermittent scratch occurring on one of the interior parts. The team member pulled the andon to alert the team leader, since it had occurred more than once. The team leader looked at the process carefully and confirmed that the scratch hadn’t been created by equipment, another part, or a person. A deeper observation of the standard work and discussions with the team member failed to uncover any potential causes that could be re-created. The vendor who provided the part was then asked to do a process confirmation to ensure that the defect wasn’t occurring within its processes. The supervisor at the vendor did the same level of checks. (At TMMK, we worked with our vendors so that they followed the same approach to these situations as we did.) After the vendor was unable to find any indication of the defect in its processes, the only logical conclusion was that the defect was occurring in the transportation of the parts from the vendor to TMMK. These particular parts were being shipped in truckloads (each truck was considered a kanban) of approximately 80 sets, that is, the number of sets needed for 80 cars.
To find out where in the transportation process the defects occurred, the team decided to have somebody “ride” with the parts. They designed a safe way for the supervisor to sit in the back of the truck during the entire trip and equipped that person with a radio to pass on observations as they occurred. The first ride yielded no clues as to where the problem was occurring. The parts went in without a scratch, and came off the truck without any. The same occurred the next day, and after several days of this, it was becoming more and more a mystery as to why this was happening. Then, a few days later, the defect appeared again. Each side did their confirmations as before, and were honestly becoming a little frustrated. How could they ever get to the root cause of this intermittent problem?
They decided that they would take another ride with the parts to just be sure there wasn’t something they had missed on the previous observations. Grasp the Situation.
As the supervisor boarded the truck along with the parts, he strapped in for the ride with eyes wide open. On this particular journey, something happened that hadn’t happened the other ride-alongs. About halfway between the two facilities, there was a jolt as if the truck had hit a large bump in the road. Most trucks aren’t equipped with the kind of shock absorption you get in a passenger car, so it gave a little “jump” to all the parts in the truck. The parts were suddenly lifted by about four to five inches, and then came crashing down. The supervisor radioed the driver and asked, “Did you hit something? We had a good bounce back here!” The driver said, “No, I didn’t see anything.” But then he added, “Usually I have to stop at the light here because this is a very busy intersection, but this time I made the light.
There’s an indentation in the road just past the light, but we only get a bounce from it when we make the light and are driving at our normal speed.” After a few questions, the supervisor determined that the driver made the light 10 to 15 percent of the time, and the bounce had occurred when the truck was traveling at the speed limit of 35 mph. So the point of occurrence was identified as the back of the truck at the point where it crossed that particular indentation in the road, but only when the truck made the light and was traveling at 35 mph.
This led to more precise observations. There were parts of the truck van that were more affected than others, and it turned out that the defects were coming from parts at the rear end of the truck that were at the bottom of their particular stack. It also turned out that some were covered with plastic foam better than others. So as you can see, the point of occurrence can be very elusive, and it can take a lot of observation, grasping the situation, and open discussion to uncover it.
Of course countermeasures were put in place to address the issue as short term and longer term since the indentations of the road path of the opposite traffic couldn't be fixed easily nor within their control. This is a great example of the depth of going to see, otherwise they would have continued to fight symptoms!
Until next time
Tracey and Ernie Richardson