In the interest of avoiding unnecessary inventory storage and management, many assembly plants take advantage of Just in sequence (JIS) manufacturing. This process is highly specific and detailed, but assembly lines minimize wasteful buffers by utilizing this streamlining technique.
The Just in Time (JIT) Concept
In order to more efficiently manage inventory and deliver parts to assembly lines in only the quantities needed for the immediate need, just in time (JIT) was developed in Japan. It is a form of lean manufacturing and a logistics method for inventory control. Delivering products to customers at the specific time their assembly lines require them saves on inventory and other costs.
The ability to identify the exact manufacturing process in detail and order parts only as needed reduces component buffers. In the JIT way of thinking, component buffers represent unnecessary capital drains and loss of efficiency.
What Is Just in Sequence (JIS)?
Just in sequence manufacturing, or JIS, takes this Japanese concept to the next level. Implementing a JIT process is already highly efficient. But implementing a just in sequence process means the parts are delivered in the specific order they are required, leading to near perfect efficiency. While buffers can never be completely eliminated, JIS manufacturing comes close.
Using just in sequence – or sequencing – allows the production line to handle delivery and use of components in a matter of minutes. From product delivery to assembly typically only takes thirty minutes to two hours. If a product requires colored parts, for example, the components must be delivered in the order of colors needed. If a product requires left-side assembly before right-side assembly, only the left-side parts are delivered. Then the right-side parts are delivered when they are needed.
The three most common types of JIS processes include:
- Pick to sequence: the plant maintains on-site buffers from which components are picked in accordance with the sequence.
- Ship to sequence/receive to sequence: the operation orders and receives components from the supplier in accordance with the sequence.
- Make/assemble/build to sequence: the sequencing firm creates the components as they are needed for the customer’s required sequence.
Implementing a JIS Process
Implementing a just in sequence program requires careful planning and feedback. This is a highly technical and highly sensitive form of production logistics. Many manufacturing operations do not have the capability for detailed forecasting to allow for accurate sequencing. Just in sequence is possibly the most challenging example of the JIT concept. This is why it is vitally important for manufacturers to rely only on proven sequencing providers.
There are a number of processes additional to a just in time operation. A quality just in sequence plan will include several new practices:
- Production sequences must be shared with suppliers and sub-contractors.
- Feedback to customers should be organized according to output schedules to maximize efficiency.
- Quality inspection should be included in sequencing planning to ensure sequenced components match the assembly sequence.
It is important to note that this razor sharp efficiency comes at the cost of stability. The smaller the buffers are, the less margin for error there is. Implementing a JIS process in your production may greatly reduce costs. But this is only true if great attention to detail and care is taken by everyone involved. If the process is planned and executed carefully, the assembly line operating on a just in sequence method is a well-oiled machine with minimal to no waste.