Just-in-time (JIT) is a revolutionary production system developed by Taiichi Ohno, a Toyota vice-president. He examined and challenged a known manufacturing principle, and developed a disciplined system that placed Toyota a quantum step ahead of their rivals in the Western countries. This system, now known as, “the Toyota Production System,” has set the standard for world-class manufacturing. The concept may be adopted within IT.
The ultimate goal of JIT production is to supply each process with exactly the required items, in exactly the required quantity, at exactly the required time. There are two conditions necessary to reach this situation: large amounts of production flexibility, and very short lead times.
The basic difference between the old method of supply and the new system is that the concept of a one-process department is eliminated. The same work tasks are no longer all performed in the same work area.
These highly specialized departments are replaced with mixed lines of processing capabilities laid out in the sequence required to make the part or groups of parts. Parts having similar size, shape, material, and processing sequence are allocated to those lines by a system known as “group technology.” Parts are processed over these lines one at a time in very small batches.
The key to JIT production is the ability of the production area to quickly switch from job to job within a few moments. The manufacturing technique for doing this is known as SMED (Single-Minute Exchange of Dies). This technique of quickly changing work capabilities can significantly reduce the cost of doing work.