BUS606: Operations and Supply Chain Management

5.1. Case Study with New Operational Availability Model for Toyota USA

The new operational availability model was confirmed in the paint shop of Toyota Motor Manufacturing Texas (TMMTX) for Toyota USA, as shown in Fig.6. The target of this study is to improve the shop operational performance and reduce the overtime. There are over 20 steps in this system and we need to fully understand the throughput issue at each step for improvement. The final step was set as study target to judge the shop performance and throughput issues (step in red circle in Fig.6).

Figure 6. Case study automotive shop layout in TMMTX

Figure 7 shows the evaluation result with new operational availability model. The short time impact from previous steps is clearly quantified in Fig.7 (a). The 5 steps before the last step are the contributors of the short time. This information helps the management to prioritize the efforts for problem solving and improvement. The impact level from different downtime is clearly identified in Fig.7 (b). The information helps the management to prioritize resource who is responsible for the majority impact to focus on productivity. In this case, the production group is responsible for the work delay and they will lead the improvement activity.

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Figure 7. Final step throughput evaluation result with new operational availability model

5.2. Effectiveness of New Operational Availability Model

Figure 8 (a) shows the throughput improvement with problem solving activities at steps with most impact and correct working group. In 6-months period, the shop OA improves 1.7%. This is because the production group who is responsible for the work delay made 1.5% improvement as shown in Fig.8 (b).

Another benefit of this OA model is that with clarified equipment OA and work delay OA, the target level can be set individually. The target level for each category can refer to plants with similar set up in Japan or abroad. The target setting will be more feasible and effective. It also helps to control the cost by invest into correct improvement area to achieve the best overall OA target.

Figure 8. Final step operational availability improvement result