Just in Sequence vs. Just in Time: Optimizing Your Inventory Management

Manufacturers are constantly searching for more efficient, cost-effective ways of operating. When it comes to improving their inventory management and procurement logistics, it’s worth assessing and comparing the Just in Time (JIT) and Just in Sequence (JIS) delivery methods, to see if they offer added efficiencies.

In this post, we’ll review Just in Sequence inventory management and when it might make sense to implement this strategy depending on the industry and use case.

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Just in Sequence is a manufacturing process where the parts or components to be assembled are delivered by the supplier directly to the line at the time they are required and in the sequence they are needed.

This form of delivery aims to simplify and speed up the production process by ensuring assembly workers don’t have to choose from different parts, but are able to just pick the next part in the supply queue.

JIS is also known as Sequential Parts Delivery (SPD) or, in the automotive sector, In-Line Vehicle Sequencing (ILVS).

Because the aim of JIS is to ensure parts are delivered to where they are required for assembly, and in the order they are needed, it eliminates the time, resources, and effort traditionally required by warehouse staff to pick and move parts from storage to the line.

For JIS to work effectively, however, detailed communication, planning, and coordination are required so suppliers are able to prepare and ship components at the right time and in the correct order.

JIS has similar characteristics to JIT, another well-known logistics methodology, but the two methods cater to different manufacturing needs.

Both systems are designed to increase production efficiencies and reduce waste by minimizing component inventory quantities at the factory. With JIT, this is achieved by arranging for parts or materials to be delivered at, or as close as possible to, the time they are needed for assembly.

JIS takes the JIT methodology a step further by ensuring parts are delivered at the scheduled time and in the exact order needed for assembly.

Unlike JIT, with JIS, line operators follow a simple sequence to assemble various parts. They don’t have to make decisions about what part they next need to attach to the main component, they know they just have to take the next component in the sequence and assemble it.

In comparison, line operators working in a JIT environment have a limited inventory to pick parts from—reducing the time they spend searching for the right one—but they are still required to make decisions about which part needs to be assembled next.

To operate effectively, both methodologies require significantly more planning and communications than traditional factory operations—JIS even more so than JIT.

Provided a manufacturing organization can set up a JIS process effectively, it can deliver significant improvements to production performance.

By having suppliers deliver components directly to the assembly line—at the time they are needed and in the correct sequence for assembly—a manufacturer can eliminate the complex process of coordinating the movement of parts around the factory floor.

As a result, JIS can also greatly reduce the need for (and the cost of) warehousing, as well as the requirement for handling and human decision-making during the assembly process.

The downside of a JIS process is that any disruption or errors can have a major impact on production, quickly negating the efficiencies the system delivers when it is running smoothly.

If parts are delivered to the line out of sequence, the entire production process is disrupted or stalled. Even worse, if the problem is not noticed in time, it’s possible the wrong components may be assembled, creating an even bigger headache. If a break in sequence isn’t spotted immediately, every subsequent part will be mismatched.

JIS manufacturers are heavily dependent on their suppliers when it comes to ensuring production flows smoothly. Effective communication between manufacturer and supplier is vital to ensure parts turn up when and as they are needed.

The complex requirements of a JIS operation mean that having a flexible and reliable software solution capable of interfacing with suppliers is vital to manage the production process.

JIS is best suited for delivering efficiencies to manufacturers doing low-volume, high-mix production—i.e., where there is a wide variation of final products coming off the line. One of the most common examples is the automotive industry, where vehicles are manufactured to a range of specifications and colors.

For a simple example of how JIS works in practice, consider an automaker assembling doors onto the body of new cars. As a sequence of different colored vehicles travels down the line, they obviously need to be fitted with matching-colored doors. By instructing the door supplier to deliver a specified sequence of colored doors to the line at a specified time, the manufacturer not only has the required parts available “just in time” for assembly but also “just in sequence” so the task of attaching them to the vehicles passing along the line is made as efficient as possible.

Ultimately, when it comes to ensuring production flows smoothly with minimal errors and disruptions, manufacturers must make an investment in digital systems that connect back-end systems and suppliers with the shop floor workers carrying out the work.

Tulip integrates seamlessly with most major ERPs and inventory management tools to error-proof production processes and ensure operators are assembling the correct component given the work order they’re working on.

If you’re interested in learning how Tulip can help you error-proof your production processes and keep production flowing smoothly, reach out to a member of our team today!