To balance the line with a 60 second cycle time, what is the theoretical minimum number of work stations required? A 7 hour day is worked.

Calculating the Theoretical Minimum Number of Workstations

To determine the theoretical minimum number of workstations required, we need to first calculate the total available work time in a day and then divide it by the cycle time. The cycle time represents the maximum time allowed at each workstation to complete its assigned tasks.

Step 1: Calculate Total Available Work Time

A 7-hour workday translates to:

• 7 hours * 60 minutes/hour = 420 minutes

Step 2: Divide Total Work Time by Cycle Time

The cycle time is given as 60 seconds, which is equivalent to 1 minute.

• 420 minutes / 1 minute/workstation = 420 workstations

Therefore, the theoretical minimum number of workstations required to balance the line with a 60-second cycle time, given a 7-hour workday, is 420.

Important Considerations and Assumptions

This calculation provides a *theoretical* minimum. In reality, several factors can influence the actual number of workstations needed:

• Task Times: This calculation assumes that the total work content (sum of all task times) is equal to the available work time. If the total task time exceeds 420 minutes, more workstations will be required.
• Precedence Constraints: Tasks often have dependencies, meaning some tasks must be completed before others can begin. These constraints can limit the effectiveness of line balancing and necessitate more workstations.
• Idle Time: Workers may experience unavoidable idle time due to factors like machine breakdowns, material shortages, or personal needs. This reduces the effective work time and may require additional workstations.
• Workstation Capacity: Each workstation has a limited capacity. If tasks assigned to a workstation exceed its capacity, it will become a bottleneck.

Line Balancing Techniques

Several techniques are used to achieve effective line balancing:

• Largest Task Rule: Assign the longest task to the first workstation, then the next longest to the second, and so on.
• Smallest Task Rule: Assign the shortest task to the first workstation, then the next shortest to the second, and so on.
• Kingman’s Algorithm: A more sophisticated algorithm that considers both task times and precedence constraints.
• Heuristic Approaches: Using trial and error and practical experience to find a balanced line.

Example of Line Balancing in Automotive Industry

In the automotive industry, assembly lines are meticulously balanced to ensure efficient vehicle production. Each workstation is responsible for a specific set of tasks, such as installing doors, engines, or interiors. Engineers use line balancing techniques to minimize the overall assembly time and maximize throughput. For example, Toyota Production System (TPS) heavily relies on line balancing and continuous improvement (Kaizen) to optimize its assembly lines.