Concept of Bottleneck Operation in Garment Industry

What is bottleneck?
Bottleneck is a constraint in a system or operation where the departments, facilities, machines or resources work at their full capacity and therefore, cannot handle any additional demand placed on it. We can also denote bottleneck as, the lowest output point in production line is called bottleneck. It is also called critical resource as it limits the throughput of associated resources. Throughput simply means the rate of output or the amount of material processed within a given time.

A bottleneck has a terrible effect on the productivity and efficiency. The stages following the bottleneck must function below their capacity because they do not receive enough input to operate at full capacity. The stages before the bottleneck need to slow down the garment production because the subsequent stages cannot handle the capacity. As a result, the overall efficiency of the system is significantly reduced.
Figure-1: Bottleneck operation
The capacity of the bottleneck operation is less than the combined capacities of the operations that provide input, so the units queue up waiting to be processed. This is illustrated in the fiqure-1 where 4 machines, each having a capacity of 10 units per hour, cannot provide a total yield of 40 units per hour as the bottleneck operation restricts the capacity to 30 units per hour.

A non-bottleneck operation indicates that resources or capacity is greater than the demand placed upon it. If bottleneck capacity is kept equal to demand and demand drops, costs will go up resulting in a loss of money. Usually total plant capacity equals the bottleneck capacity. Bottlenecks should be optimized by eliminating time wasted through idle bottleneck time, processing defective parts or producing parts which do not contribute to throughput.

In operations management, the bottleneck theory is an explanation of what happens when a certain part of the production system performs at a lower rate than the rest of the system. Understanding the bottleneck theory is important as it allows an individual to optimize the efficiency of the business.

Explanation of bottleneck operation:
Bottlenecks are processes which cannot keep pace with their preceding suppliers, thus creating idle time and inefficiency. A bottleneck occurs in sequential manufacturing when a backup happens in one step of the sequence. For example, if there are three machines on an assembly line and the first and last machines can produce 100 units per hour, but the second machine can produce only 50 units per hour, it will cause a bottleneck to occur. This is because the second machine cannot produce enough units to keep pace with the other machines.

Again consider the following case of scrubbing-rinsing-drying operation in figure-1. The bottleneck in this process is caused by rinsing section as it takes 2 minutes more than the other operations and consequently generates idle time. It can easily be eliminated by building a new rinsing station but, the decision must be based on financial considerations. Therefore, it becomes the responsibility of the operation managers to evaluate alternative solutions so that the tasks are assigned in another way to achieve better throughput.
Figure-2: Effect of bottleneck on operation throughput
Identification of bottleneck:
A bottleneck in the garment manufacturing process can be difficult to identify in a complex system. The bottleneck can be found by looking at each sequence of the process individually and measuring the production level at each step. If a particular sequence has a low production level then it is the source of the bottleneck. It should be noted that there can be multiple bottlenecks within a complex system.

How to reduce bottleneck in apparel industry:
A bottleneck can be solved by increasing the process capacity or adjusting the production level in the sequence where the bottleneck is happening. This might be achieved by:
  • Installing more efficient equipment
  • Increasing labors and shifts
  • Arranging pre-production meeting in time
  • Allocation the task as per standard produced value equally
  • Maintain sequence of task accordingly
  • Reducing excess task from overloaded operator / find capacity where else
  • Reducing ineffective time / task by production study
  • Minimizing non-value adding activities like transport, rework, waiting, testing and inspecting.
  • Redesigning the product for better manufacturability
  • Layout making before input in line
  • Customizing activities so as to increase flexibility
  • Select right operator for right task
  • Keeping the supply available in time
  • Should not forward the reject products
  • Supply should be forwarded after checking
  • Should not be forwarded inconsistency process
  • Should not be forwarded quality fault product
  • Reducing lead time
  • Reducing costs
  • By improving method.
  • By improving workers performance.
  • By reducing sewing burst
However, it should be kept in mind that productivity improvements to any non-bottleneck operation will not affect the productivity of the system. Improvements in the bottleneck operation will lead to increased productivity. 
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