BUS606: Operations and Supply Chain Management

We have applied for new operational availability model into Toyota in U.S.A. (Toyota USA) with a 4 step system as shown in Fig. 5.

Figure 5. Model to link impact of multiple Steps

Inherited Impact of Step 2=$\frac{\text { ST2 }}{\text { ST2+WT2+ET2 }} \times \frac{S T 3}{S T 3+W T 3+E T 3} \times S T 4$

Where $ST2$ is Short time to Step 2 from previous steps.

$WT2$ is work delay at Step 2

$ET2$ is equipment downtime at Step 2

$ST2$ is Short time to Step 3 from Step 2

Introduced Impact of Station 2=$\frac{W T 2+E T 2}{S T 2+W T 2+E T 2} \times \frac{W T 3+E T 3}{S T 3+W T 3+E T 3} \times S T 4$

Inherited Impact of Step 1= $\frac{S T 1}{S T 1+W T 1+E T 1} \times \frac{S T 2}{S T 2+W T 2+E T 2} \times \frac{S T 3}{S T 3+W T 3+E T 3} \times S T 4$

$E T 1$ is equipment downtime at Step 1

$S T 1$ is Short time to Step 2 from Step 1

Introduced Impact of Station $1=\frac{W T 1+E T 1}{S T 1+W T 1+E T 1} \times \frac{S T 2}{S T 2+W T 2+E T 2} \times \frac{S T 3}{S T 3+W T 3+E T 3} \times S T 4$

$E S=\frac{\frac{\frac{E T 1}{S T 1+W T 1+E T 1} \times S T 2+E T 2}{S T 2+W T 2+E T 2} \times S T 3+E T 3}{S T 3+W T 3+E T 3} \times S T 4+E T 4$

$E s$ is the overall equipment impact to the system shown in Fig.5.

$E O A=\frac{\text { Production Time-Es }}{\text { Production Time }} \times 100 \%$

$E O A$ is the Equipment $\mathrm{OA}$ of the overall system shown in Fig.5.

$W O A=\frac{\text { Production Time-Ws }}{\text { Production Time }} \times 100 \%$

$WOA$ is the Work Delay $OA$ of the overall system shown in Fig.5.