Just in sequence

Just in sequence (JIS) is an inventory strategy that matches just in time (JIT) and complete fit in sequence with variation of assembly line production. Components and parts arrive at a production line right in time as scheduled before they get assembled. Feedback from the manufacturing line is used to coordinate transportation to and from the process area. When implemented successfully, JIS improves a company's return on assets (ROA), without loss in flexibility, quality or overall efficiency. JIS is mainly implemented with automobile manufacturing.

JIS is sometimes called in-line vehicle sequencing (ILVS).

Just in Sequence (JIS) is just one specialised strategy to achieve Just In Time (JIT). The process concept of JIT sees buffers at the production line as waste in capital bound. The aim is to eliminate buffers as much as possible at expense of stability when disturbances arise. Just In Sequence is one of the most extreme applications of the concept, where components arrive Just In Time and sequenced for consumption.

The sequencing allows companies to eliminate supply buffers as soon as the quantity in component part buffers necessary is reduced to a minimum. If not sequencing according to scheduled variety of production, all required components must be stocked in buffers. For flexible production lines, such as a modern automotive assembly line, the variety is an option to produce directly on customer orders. As soon as the next order arrives at the work center, the scheduler distributes the supply orders inline with the production sequence of the final production line.

However, with JIS the buffer quantities are displaced upward in material flow to the components suppliers. It is a misinterpretation of JIS to assume that all buffers will be eliminated. Hence just the cost for buffer inventory becomes re-allocated to the producers of the supplies. Sequencing eliminates buffers in the final assembly line by consolidating all similar components into distributed and sequenced buffers, which partly reside on the paths of transportation to final assembly. This strategy thus reduces the line-side inventory buffer. However, the effect is worse when the sequence does not get correctly scheduled upwards or when the transportation line gets congested.

Just In Sequence processes are typically implemented only after the company has achieved a high degree of competency on Just In Time processes. The first step for the organization is to implement JIT processes to synchronize all manufacturing and material departments inside the plant and to collaborate with suppliers, customers, and sub-contractors to reduce inventory buffers to within a few hours. This process typically uncovers deep manufacturing and logistic issues that are not easy to overcome (see JIT Implementation for more details). The manufacturing company can only benefit from sequencing items once these problems have been resolved successfully and components are delivered Just In Time.

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