Difference Between JIT and Lean

JIT vs Lean

Over the past couple of years, Just-in-Time (JIT) is a system and idea that has gradually seen wide acceptance within the business and manufacturing community. As the competition heats up between companies, and the pressures from Asian manufacturers’ continuous cultural improvements take their toll on manufacturers, many firms are forced to seek more innovative methods to reduce costs and cope with the competition.

However, increasingly, there has been a tendency to identify or associate JIT with Lean operations. Whereas there are similarities between the two, there are also fundamental differences between the two methodologies. That said, the two could also ‘play’ perfectly well together, and there are many advantages of using both methodologies concurrently.

Just-in-Time methodology requires that processes exhibit some level of stability and consistency. In this case, stability means the reduction of systemic errors, and the results achieved, must remain quite consistent. Obviously, this feat is not very easy to achieve at the start of a Lean initiative. The aim of JIT at this point, is to explicitly highlight all the problems in the process. Lean will focus on eliminating the problems pertaining to the process (system), in order to increase production.

The fundamental component of JIT, is the elimination of waste while adding value. There is a series of processes that a firm must monitor as targets for minimizing waste. Things like unreasonable waste times, exaggerated inventories, excess man power and unnecessary movement of material, plus any other activity that does not add value.

However, JIT alone was not effective at completely eliminating waste, as manufacturers realized that bringing items only when they are required, and only in the rightful quantities needed, is only one side of the story.
There was a need for JIT to become Lean. Lean has a whole range of specialized procedures of its own. Lean’s task is to define a project that will be beneficial at minimal costs. While JIT focuses more on inventory management, Lean’s focus is on manufacturing and operations management. The two methodologies share some tools, for instance, kanban and error proofing, and all aim at creating value for the end user, the customer. Generally, Lean tools are now often used to achieve JIT, such as the ‘flow’ based approach.

Summary:
JIT’s role is to explicitly highlight process problems, while Lean aims at eliminating the problems.
Lean can be used to achieve JIT, as the two employ almost the same set of tools, for example, kanban and error proofing.
Although both methodologies can be used to eliminate waste, JIT alone cannot achieve this, hence the transformation to Lean.

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