Steps of Line Balancing in the Apparel Industry
Line balancing is a tools used for production lines to capacitate the flow line of production. A flow line can be divided into elemental tasks. Each of these tasks will require a specified time to complete. It also has a sequential relationship with other tasks in the flow line. In order to ensure that the line is run efficiently, efforts have to be made to balance the line. In this article, we explain the Steps of Line Balancing in the Apparel Industry.
Flow line balancing:
In the line balancing sequential work must be done. This is called the flow line of balancing in the apparel industry. It is the assignment of sequential work activities into workstations in order to gain a high utilization of labor and equipment, and therefore, minimize idle time. Compatible work activities are combined into approximately equal time groupings that do not violate the order (or precedence) in which they must be done. The line is balanced when the operation time per worker per unit is the same. Practically, a line cannot be perfectly balanced, so idle time will occur. The speed of a flow line is limited by its slowest operation (the bottleneck). The bottleneck is the barrier to increasing production capacity. To remove this bottleneck operation time should be minimized by the help of line balancing.
Applications of line balancing:
Line balancing is applied in continuous manufacturing industries such as automotive, electronics, or assembly operations. A technique applied to assembly lines to achieve JIT. The lines are associated with “product layout”, where components of products are refined or assembled as they pass through work centers, and finally, become a completed product. A designated number of work elements are performed at each work center. The times to perform work elements are derived from work measurement studies. The period allowed to complete operations at each station is determined by the cycle time (or tact time). For fruitful results in production line balancing plays a vital role.
Objectives of Line Balancing:
Line balancing has some objectives in the garments industry. Basically, its motto is to increase the production of the garments industry. I have given some objectives below-
- To minimize the total amount of unassigned or idle times at the workstation.
- To eliminate bottlenecks, ensuring a smoother flow of production.
- To determine the optimal number of workstations and operations in each station.
- To maintain the morale of workers since the work content of the different workers will not be of great difference.
- To maximize manpower utilization by minimizing the idle times of the operators.
- To minimize intermediate stock or work-in-progress (zero inventory or just-in-time concept).
- To improve the quality and productivity of the assembled products.
- To reduce waste of production and delay.
Steps of Line Balancing:
To get fruitful results and also do line balancing in the apparel industry is the easiest and perfect way some steps should be followed which are given below-
- Construct the precedence diagram if not given.
- Determine the cycle time required.
- Determine the theoretical minimum number of workstations required. This is done by adding up all the task times and dividing the total by the cycle time.
- Select either the Kilbridge & Wester method or the Rank Positional Weights Method to allocate task elements to each workstation.
- Each workstation should not exceed the cycle time determined earlier. Use a table, setting out the workstations from left to right.
- Use the Longest Operation Time (LOT) rule; select the task with the longest operation time next. Consider adding to the station any task whose time fits within the remaining time for that station.
- Ensure that the sequencing is in order, even for the task elements in each station. Precedence relationships may interfere with assigning two tasks to the same workstation.
- Ensure that the restrictions or constraints for the flow line are adhered to.
- Analysis of the balanced flow line to improve efficiency and to reduce idle times. An efficient balance will minimize the amount of idle time.
- Calculate the idle times, and hence the balancing loss (balancing delay) or line efficiency.
Factors Affecting Line Balancing & Problems Encountered:
Some factors that created the problems during line balancing. These factors should be removed during line balancing. These factors are given below-
- There are constraints in operations in terms of the size of machines, location, space, jigs and fixtures, building structure, etc.
- The workers in the line have great variations in level of skill and aptitudes for certain jobs. Thus, it is difficult to synchronize the time.
- Some work content cannot be broken down further into elements.
- Long machining times can become bottlenecks.
- The design of parts, shape, and size of materials may pose constraints (e.g., bulky materials).
- Special processes, such as electroplating, curing, and baking by batch, have fixed sequences.
- Long set-up times.
- Small production volumes do not justify the use of line balancing.