An assembly line to be balanced has six tasks in precedence.The task times are shown in the following table.Based on demand forecasts,the output rate has to be 160 units per day.The line operates 8 hours a day.Compute the balance efficiency E. $$\begin{array} { | l | l | l | }
\hline \text { Tasks } & \text { Immediate Predecessor } & \begin{array} { l }
\text { Task Time in } \
\text { Minutes }
\end{array} \
\hline \mathrm { A } & \text { NONE } & 3 \
\hline \mathrm { B } & \mathrm { A } & 1 \
\hline \mathrm { C } & \mathrm { A } & 2 \
\hline \mathrm { D } & \mathrm { B } , \mathrm { C } & 3 \
\hline \mathrm { E } & \mathrm { C } & 3 \
\hline \mathrm { F } & \mathrm { D } , \mathrm { E } & 2 \
\hline
\end{array}$$

Question

An assembly line to be balanced has six tasks in precedence.The task times are shown in the following table.Based on demand forecasts,the output rate has to be 160 units per day.The line operates 8 hours a day.Compute the balance efficiency E. $$\begin{array} { | l | l | l | } 
\hline \text { Tasks } & \text { Immediate Predecessor } & \begin{array} { l } 
\text { Task Time in } \
\text { Minutes }
\end{array} \
\hline \mathrm { A } & \text { NONE } & 3 \
\hline \mathrm { B } & \mathrm { A } & 1 \
\hline \mathrm { C } & \mathrm { A } & 2 \
\hline \mathrm { D } & \mathrm { B } , \mathrm { C } & 3 \
\hline \mathrm { E } & \mathrm { C } & 3 \
\hline \mathrm { F } & \mathrm { D } , \mathrm { E } & 2 \
\hline
\end{array}$$

Quizplus · Accepted Answer

First, we need to calculate the cycle time.

Total Task Time = 3 + 2 + 1 + 3 + 3 + 2 = 14 minutes

Operating Time = 8 hours = 480 minutes

Number of workstations (N) = Demand / (Cycle Time) = 160 / (480/14) = 4.67

Since we cannot have fractional workstations, we need to round it up to 5.

Using the largest candidate rule, we can start with Task F since it has the largest task time (2 minutes).

Task F = 2 minutes

Task D = 3 minutes

Task E = 3 minutes

Task C = 2 minutes

Task A = 3 minutes

Task B = 1 minute

Total Task Time for the first five tasks = 2 + 3 + 3 + 2 + 3 = 13 minutes

Idle Time = Cycle Time - Total Task Time = 14 - 13 = 1 minute

Efficiency = (Total Task Time) / (Number of Workstations x Operating Time) = 13 / (5 x 480) = 0.0542

Balance Efficiency = 1 - (Idle Time / Operating Time) x Efficiency = 1 - (1/480) x 0.0542 = 0.9271 = 92.71%

Therefore, the closest choice to the balance efficiency is A) 93%.

An Assembly Line to Be Balanced Has Six Tasks in Precedence.The