Because issues with seats are mainly caused by the defective seats being sent by KFS, Friesen should focus his initial investigation on the process used when the seat assemblies are initially manufactured. Defective and/or incorrect seats being installed in the vehicles will only cause re-work and backlog in the Overflow Parking Area, so if there is a way to decrease the amount of re-work to be done, Friesen should try to identify it.
Drawing attention to incorrect or defective parts earlier in the process would allow the assembly teams the time to prepare for the appropriate next steps when the vehicle and seat assemblies come to them. Another area that Friesen could focus his investigation on would be andon pulls in the rear seat assemblies. The andon pulls in the rear seat assembly areas far outweigh the pulls in the front seat assembly areas. One potential cause of this is the hook breaking during the rear seat bolster installation. Friesen could consider the recommendations of Shirley Sargent with regards to the hook.
The root cause of the seat issue lies with the seat manufacturer KFS. The company was given only 10 days to begin production of the redesigned Camry’s seats and 10 weeks to go to full rate production. The short turn around and addition of seat variations caused quality to suffer.
The two major flows according to exhibit 8 & 10 are related to material flaws and missing parts, especially the rear seats. First and foremost a team from TMM needs to visit KFS and inspect the manufacturing and QC process as well as implement the jidoka principles to identify root cause and implement corrective actions. Lastly action should be taken to identify any potential causes of damage to the seats in receiving or assembly within TMM. Addressing each of the before mentioned areas of change will increase overall seat quality which will reduce cycle time and allow the company to follow the Toyota Production System.