BALANCEO DE LÍNEAS (PESO POSICIONAL) | EJERCICIO RESUELTO

Summary

In this video, the process of solving a line balancing exercise for the assembly of a copier is explained. The video demonstrates how to create a precedence diagram, calculate cycle time, determine the number of workstations, and assign tasks to each workstation. The video also covers calculating efficiency using a formula to assess the effectiveness of the balance, highlighting the importance of minimizing workstations to maximize production efficiency. With clear steps and calculations, the method ensures that the assembly line is optimized for producing 40 units per day in an 8-hour shift.

Takeaways

• 😀 The video demonstrates how to balance a production line for assembling a copier, using a precedence diagram and task times to ensure efficient work distribution.
• 😀 A precedence diagram is created by listing tasks and their respective times, along with predecessor relationships that dictate task sequencing.
• 😀 The first task (A) has no predecessor and serves as the starting point for the diagram. Subsequent tasks depend on the completion of previous ones.
• 😀 Tasks with the same predecessor are represented by two arrows leading to subsequent tasks. Task E and Task D, for example, share Task B as a predecessor.
• 😀 The cycle time is calculated by dividing the available production time (480 minutes) by the required number of units (40 per day), which equals 12 minutes per unit.
• 😀 The minimum number of workstations is calculated by dividing the total task time (66 minutes) by the cycle time (12 minutes), which results in 5.5, rounded up to 6 workstations.
• 😀 The video introduces the concept of positional weight, where tasks are assigned a weight based on their successors and the time taken for each task.
• 😀 Tasks are assigned to workstations based on their positional weight, starting with the task that has the highest weight and continuing sequentially.
• 😀 The first workstation is assigned Task A, with a total time of 10 minutes, leaving 2 minutes available, but no further task fits in that remaining time.
• 😀 The task allocation continues with each workstation, ensuring tasks are assigned based on the precedence diagram, and the accumulated time does not exceed the available cycle time.
• 😀 Efficiency is evaluated by comparing the sum of task times to the product of the number of stations and cycle time. The final efficiency for 6 workstations is 91.7%, while it would drop to 78.6% if 7 workstations were used instead.

Q & A

What is the first step in creating a precedence diagram for an assembly process?

The first step is to develop a precedence diagram based on the tasks involved in the assembly process. You need to list the tasks, their execution times, and the predecessors for each task.

How do you determine the sequence of tasks in a precedence diagram?

The sequence of tasks is determined by the predecessors listed for each task. Tasks must be carried out in the order specified by the precedence relationships, indicated by arrows in the diagram.

What role does the cycle time play in balancing the assembly line?

Cycle time determines the maximum allowable time for each unit to be assembled in each station. It helps in calculating the number of workstations required and ensures that the assembly process is efficient and meets production goals.

How is the cycle time calculated for this particular assembly process?

The cycle time is calculated by dividing the total available production time (480 minutes per day) by the required units per day (40 units). This gives a cycle time of 12 minutes per unit.

Why is the minimum number of workstations calculated as 6 instead of 5?

The minimum number of workstations is calculated by summing the times of all tasks and dividing it by the cycle time. Since the result (5.5) is a fraction, it is rounded up to the next whole number, which is 6 workstations.

What is the 'position weighting heuristic' used for in the assembly process?

The position weighting heuristic is used to assign tasks to workstations based on the relative importance of each task in terms of its succession and execution time. This helps optimize the distribution of tasks across stations.

How do you assign tasks to workstations in this example?

Tasks are assigned to workstations based on their position in the precedence diagram and their position weight. Tasks are grouped into workstations until the cycle time is exhausted, ensuring that no workstation exceeds the available time.

Why is the total idle time calculated for each workstation?

Total idle time is calculated to assess the efficiency of the line balancing. Idle time represents the unutilized time within a workstation and can indicate how well tasks are distributed across workstations.

What is the efficiency of the line balancing when 6 workstations are used?

The efficiency is calculated by dividing the total task time (66 minutes) by the product of the number of workstations (6) and the cycle time (12 minutes), then multiplying by 100%. The efficiency in this case is 91.7%.

How does the number of workstations affect the efficiency of the assembly line?

The number of workstations significantly affects efficiency. With fewer workstations, the tasks are more evenly distributed, reducing idle time and improving efficiency. If 7 workstations had been used instead of 6, the efficiency would have decreased to 78.6%.