Just in Time (JIT) Implementation of lean manufacturing tools in garment manufacturing process

Traditionally operated garment industries are facing problems like low productivity,longer production lead time, high rework and rejection, poor line balancing, low flexibility of style changeover etc.These problems were addressed in this study by the implementation of lean tools like cellular manufacturing, single piece flow, work standardization, just in time production etc.

1 Just in Time

Just in time is an integrated set of activities designed to achieve high volume production using the minimal inventories of raw materials, work in process and finished goods. Just in time is also based on the logic that nothing will be produced until it is needed (Shivanand, 2006, p. 45).

Just-in-time manufacturing is a Japanese management philosophy applied in manufacturing. It involves having the right items with the right quality and quantity in the right place at the right time. The ability to manage inventory (which often accounts for as much as 80 percent of product cost) to coincide with market demand or changing product specifications can substantially boost profits and

improve a manufacturer’s competitive position by reducing inventories and waste. In general, Just in Time (JIT)

helps to optimize company resources like capital, equipment, and labor. The goal of JIT is the total elimination of waste in the manufacturing process. Although JIT system is applied mostly to manufacturing environment, the concepts are not limited to this area of business only. The philosophy of JIT is a continuous improvement that puts emphasis on prevention rather than correction, and demands a companywide focus on quality. The requirement of JIT is that equipment, resources and labor are made available only in the amount required and at the time required to do the work. It is based on producing only the necessary units in the necessary quantities at the necessary time by bringing production rates exactly in line with market demand. In short, JIT means making what the market wants, when it wants, by using a minimum of facilities, equipment, materials, and human resources  (Roy, 2005, p. 170).

JIT principles are based on the following:

    · It is commonly used to describe the stockless production manufacturing approach, where only the right parts are completed at the right time.

    · It is not a destination but a journey.

    · Reducing inventory, improving quality and controlling cost.

    · A “Pull System” where the parts are produced only when they are required

1.1Pull and Push System

In push system, when work is finished at a workstation, the output is pushed to the next station; or, in the case of the final operation, it is pushed on to the final inventory. In this system, work is pushed on as it is completed, with no regard for whether the next station is ready for the work or not. In this way, the WIP is unbalanced in all operations throughout the shop floor (Roy, 2005, p. 174).

TABLE 1: Difference between push and pull manufacturing system.

The push system is also known as the Materials Requirements Planning (MRP) system. This system is based on the planning department setting up a long-term production schedule, which is then dissected to give a detailed schedule for making or buying parts. This detailed schedule then pushes the production people to make a part and push it forward to the next station. The major weakness of this system is that it relies on guessing the future customer demand to develop the schedule that production is based on and guessing the time it takes to produce each part. Overestimation and underestimation may lead to excess inventory or part shortages, respectively (Shivanand,2006, p. 50).

Whereas in pull system; each work station pulls the output from the preceding station as it is needed. Output from the final operation is pulled by customer demand or the master schedule. Thus in pull system work is moved in response to demand from the next stage in the process. The Kanban system is used to monitor the effective pull process. Table 1 helps to differentiate Pull and Push system.

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