The Basic Elements of JIT
JIT or just in time is a concept that each one of us practices unknowingly throughout our waking hours. One gets up in the morning just in time to complete the various actions that constitute the beginning of the day. Whether it is making that cup of coffee, going down to the gym, or even watering your garden, most of us have fixed schedules with tasks that need to be completed before moving on to the next item or beginning our day.
The elements of JIT, when applied to manufacturing, ensure that parts or raw materials arrive on the factory floor only at the point of required use or when they are actually needed. Not only does this help with inventory control and costs, but also with inventory storage concerns. Ideally, JIT also ensures that the finished product is only achieved when it is required by the end user or customer. If such JIT methods are properly implemented, the vast savings in inventory can translate to lower costs and benefit the customer as well as the manufacturer.
Wallace. J. Hopp, a Herrick Professor of Manufacturing at the University of Michigan and an expert on JIT, has defined JIT as "an approach to achieving excellence in a manufacturing company based on continuing elimination of waste and consistent improvement in productivity."
JIT was originally conceived as a means to eliminate waste. Items were allowed to move into a production system only when they were needed. The elements of JIT include establishing processes that ensure items moved into the production system are at acceptable levels with no defective parts.
Waste Reduction and JIT
Most manufacturing processes involve concentration on repeated processes involving the same item. This can sometimes lead to overproduction, which is considered as waste. The elements of JIT also classify time wasted by any worker or machine that must wait for needed items to continue the process, and this time would be deemed unnecessary. Transportation of raw materials or finished goods are also considered wasteful processes and are drastically reduced in JIT. Processing time in any manufacturing process has to be severely controlled. This can be done by layout or technology changes or the introduction of more efficient machines. Excessive inventory has always been considered a waste of time and money blocked, especially when some inventory items which are found to be defective are not sorted appropriately and discarded or returned in the JIT process.
JIT requires the constant elimination of waste and consistent improvement of productivity through training, new machineries or other industrial engineering processes. This can be done by constant evaluation of all processes and steps involved with a definite goal of making improvements which help the manufacturing process. Complete involvement of all concerned persons and team members in a particular process is a must in the JIT process.