Just in Sequence vs. Just in Time (JIT)

Manufacturers are constantly looking for more cost-effective and efficient ways to operate. When improving supply logistics, it is essential to consider and compare Just in Time (JIT) and Just in Sequence (JIS) delivery methods to see if they offer additional efficiencies.

Just in Sequence supply management and when it might make sense to implement this strategy depends on the industry and use case.

What is Just in Sequence delivery?

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

This form of delivery aims to simplify and speed up the production process by ensuring that assembly workers do not have to choose between different parts but can choose the next part in the supply queue.

Just in Sequence is also known as Sequential Parts Delivery (SPD) or, in the automotive industry, Online Vehicle Sequencing (ILVS).

Since the goal of Just in Sequence is to ensure that parts are delivered where they are needed for assembly and in the order that they are required, it eliminates the time, resources, and effort that warehouse personnel traditionally require to pick and move the parts from the warehouse to the line.

However, for Just in Sequence to work effectively, there needs to be thorough communication, planning, and coordination so that suppliers can prepare and ship components at the right time and in order.

The difference between Just in Sequence and Just in Time (JIT)

Just in Sequence has similar characteristics to JIT, another well-known logistics methodology, but the two methods respond to different manufacturing needs.

Both systems are designed to increase production efficiency and reduce waste by minimizing inventory amounts of components in the factory. In the case of JIT, this is achieved by having the parts or materials delivered when needed for assembly or as close as possible.

Just in Sequence takes the JIT methodology a step further by ensuring that 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 the various parts. They don’t have to decide about the next part to attach to the parent component. Instead, they know to pick up the next component in the sequence and assemble it.

By comparison, line operators working in a JIT environment have limited inventory from which they can choose parts, reducing the time they spend searching for the correct part but still having to decide which part to assemble next.

To work effectively, both methodologies require much more planning and communication than traditional factory operations, and Just in Sequence requires even more than Just in Time.

Advantages of Just in Sequence

As long as a manufacturing organization can establish a Just in Sequence process effectively, it can significantly improve production performance.

By having suppliers deliver components directly to the assembly line, when needed and in the correct sequence for assembly, the manufacturer can eliminate the complex process of coordinating the movement of parts on the production floor.

As a result, Just in Sequence can also significantly reduce the need and cost of storage and the need for human manipulation and decision-making during the assembly process.

Just in Sequence Challenges

The drawback of a Just in Sequence process is that any interruption or error can significantly impact production, quickly negating the system’s efficiency when running smoothly.

If parts are delivered to the line out of sequence, the entire production process is interrupted or stopped. And what can be worse, is if the problem is not detected in time, the wrong components may be assembled, which is an even bigger headache. If a sequence break is not detected immediately, all subsequent pieces will not match.

Sequence manufacturers rely heavily on their suppliers to ensure production runs smoothly. Effective communication between the manufacturer and the supplier is vital to ensure that parts appear when and how they are needed.

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

Sectors that benefit from Just in Sequence

Just in Sequence is best suited to provide efficiencies for manufacturers doing low volume, high mix production, i.e., where a wide variation of end products are coming off the line. One of the most common examples is the automobile industry, which produces vehicles with various specifications and colors.

To see a simple example of how Just in Sequence works in practice, let’s consider that a car manufacturer assembles doors into the bodies of new cars. As a sequence of differently colored vehicles moves down the line, it is evident that they must have doors of the same color. By instructing the door supplier to deliver a specific sequence of colored doors to the line at a particular time, the manufacturer not only has the necessary parts just in time for assembly but also just in the sequence so that the task of fixing them to the vehicles that pass through the line is as efficient as possible.

What are the benefits of Just in Sequence?

Among the benefits that manufacturers experience when employing Just in Sequence to their operations are.

Improved Production Efficiency: JIS helps optimize production processes by ensuring that the required parts arrive at the right time and in the correct order. This minimizes waiting time and reduces production line interruptions, leading to improved overall efficiency.

Reduced Inventory Levels: With JIS, manufacturers can minimize their inventory levels because parts are delivered in sequence, eliminating the need for excess stock. This results in cost savings by reducing storage requirements, minimizing obsolescence, and lowering carrying costs.

Enhanced Flexibility and Responsiveness: JIS enables manufacturers to quickly adapt to changes in customer demand or production requirements. By having parts delivered in sequence, it becomes easier to introduce product variations or modifications without the need for significant inventory adjustments.

Lower Lead Times: JIS reduces lead times by eliminating the need for parts to be stored and retrieved from inventory. This streamlined approach ensures that parts are readily available when they are needed, leading to shorter overall production lead times.

Improved Quality Control: By delivering parts in sequence, JIS minimizes the risk of mix-ups, incorrect installations, or production errors. This helps improve quality control as parts are verified and validated in a timely manner, reducing the likelihood of defects or rework.

Cost Savings: JIS can result in cost savings through various means. Reduced inventory levels, optimized production processes, and improved quality control contribute to lower operational costs. Additionally, the elimination of excess inventory helps free up capital that can be invested elsewhere.

Supply Chain Integration: JIS requires close collaboration and integration between manufacturers and their suppliers. This promotes stronger relationships, better communication, and improved coordination throughout the supply chain. It also facilitates information sharing, visibility, and alignment of production schedules, leading to smoother operations.

Waste Reduction: JIS helps reduce waste, such as excess inventory, overproduction, and unnecessary transportation. By delivering parts in sequence and aligning production with demand, manufacturers can minimize waste generation and improve sustainability

Conclusion

It’s important to note that implementing a Just in Sequence system may require significant coordination and collaboration with suppliers, as well as careful planning and synchronization of production processes. However, when effectively implemented, JIS can bring numerous benefits to manufacturing operations.