Just In Time Concept
Just-in –Time manufacturing is a new philosophy of manufacturing management that provides a set of tools and techniques to compete in the increasingly fierce market and enables organizations to provide better value in their offerings by constantly improving their operations and eliminating waste from the system. The core logic of the JIT is one of elimination of waste in a manufacturing system using a deliberate method. The crux of the JIT philosophy is to go one step further, unlike traditional way, and deliberately create some disturbances in the system in order to uncover the problem. Once the problems are exposed, the organization will work towards solving the ...view middle of the document...
The same signal is sent back to each preceding workstation so a smooth flow of parts and materials is maintained with no appreciable inventory buildup at any point. Thus all workstations respond to the pull exerted by the final assembly stage, which in turn respond to customer orders. As one worker explained, "Under just in time system you don't produce anything, anywhere, for anybody unless they ask for it somewhere downstream. Inventories are evil that we are taught to avoid".
The pull approach described above can be contrasted to the push approach used in conventional manufacturing system. In conventional system, when a workstation completes its work, the partially completed goods are pushed forward to the next work station regardless of whether that workstation is ready to receive them. The result is an unintentional stockpiling of partially completed goods that may not be completed for days or even weeks. This ties up funds and also results in operating inefficiencies. For one thing, it becomes very difficult to keep track of where everything is when so much is scattered all over the factory floor.
Traditionally manufacturers have forecasted demand for their products into the future and then have attempted to smooth out production to meet that forecasted demand. At the same time, they have also attempted to keep everyone as busy as possible producing output so as to maximize efficiency. Unfortunately, this approach has a number of major drawbacks including large inventories, long production times, high defect rates, production obsolescence, inability to meet delivery schedules, and (ironically) high costs. Another characteristics of conventional manufacturing system is emphasize on "keeping every one busy" as an end on itself. This inevitably leads to excess inventories particularly work inventories. In Just in time manufacturing, the traditional emphasize of keeping everyone busy is abandoned in favor of producing only what customers actually want. Even if that means some workers are idle.
More specifically JIT seeks to achieve the following goals.
1. Estimation of non-value added activities.
2. Zero inventories.
3. Batch size of one.
4. A 100% on time delivery service.
The following are the key features of JIT production:
1. The production line is run on a demand pull basis, so that activity of each work station is authorised by the demand of downstream work stations. Thus, parts move through production system based on end unit demand, focusing on maintaining a constant flow of parts rather than batches of WIP.