Just In Time

Just In Time (JIT) manufacturing is one of the principles of lean manufacturing that can help you to improve your business.

The principle of Just In Time is producing what the customer wants when they want it, it is one of the main ideas behind lean manufacturing, if not the most import principle.

Why do I say that it is the most important principle? Because if you look at the definitions for lean manufacturing it is defining value in the eyes of the customer and making that value flow at the pull of the customer without having it delayed or caught up in inventory. Then striving for continual improvement in everything that you do.

Just In Time is about creating flow at the pull of the customer, it is about preventing the creation of work in progress and stock. It is through the implementation of JIT that waste is prevented, lean is not about waste elimination and reduction, through implementing JIT you PREVENT waste.

If you consider the implications of implementing Just In Time you will Prevent waste through the reduction of work in progress and stock due to trying to achieve single piece flow, close coupling of processes and pulling production through the process when ordered by the customer. Not producing large batches of material before the customer makes an order that require complex planning systems to coordinate them through the different processes, material handling equipment and people, space and containers for storage and so on.

Just In Time reduces costs through reduction in capital tied up in materials, reduction in people, reduction in space and many other savings. But many people look at this and say it can’t be done! You have to produce large batches, you have to forecast customer demand and so forth, but this is wrong, they are just hiding from the problems that force us to do this!

The reasons for large batches and forecasting demand is because we have problems within our production that we have failed to tackle. We have setups that are too long so we try to optimize the usage of the machines by extending the run times so that they are “economical”. We have reliability and quality problems with our equipment, our suppliers and our own processes, so we run large batches in advance of when the customer wants them just in case anything else goes wrong. We run large batches prior to the customer needing it just to cushion us from the effects of these problems, but in doing so we create more problems.

Just in Time manufacturing forces you to tackle these problems and remove these wastes from the your systems, designing a process with the principles of JIT in the first place will prevent the creation of waste in your systems.

Typically the first step in any implementation of Just in Time is the reduction of setup times so that you can be able to run smaller batches of materials, this is usually achieved through implementing a tool called single minute exchange of die (SMED). Once you can run smaller batches you can then work on the other principles, bringing processes closer together to enable (single piece) flow, then implementing kanban systems to allow production to be pulled through your processes.

The following links give some good descriptions of just in time and some case studies;

Just In Time Manufacturing

Just In Time

Just In Time Case Study

JIT Case Study

Just In Time Manufacturing Case Study