Just in time (business)

Just- in -time production (in short: just in time, JIT ) or require synchronous production refers to a principle of organization, in which only the material is produced and delivered in the quantities and at the time, as it actually needed to fulfill customer orders will. This goal is achieved through different production and delivery methods. The principle of JIT production requires a coordinated production and material flow along a supply chain ( Supply Chain engl. ). This can only be achieved through close cooperation between a supplier and a customer. As a result, the overall process leaner, the lead times and capital commitment is reduced and the storage redundancy and therefore be cost-effective for all parties involved.

JIT delivery

The JIT delivery is a logistical retrieval and delivery method in which the material is supplied by the subcontractor only when you need directly in the production of the purchaser. In some cases, the part is also specifically made ​​for the supply, in particular for high-priced parts. This method has been particularly established in the automotive industry, where mainly large and varied parts and assemblies are delivered directly to the assembly line. For this purpose, the required material is ordered according to the needs of the final assembly. The supplier is contractually obligated to deliver the ordered material within a defined lead time. The material is unloaded directly at the installation site or in the immediate vicinity, so that it can be installed as directly as possible. If the material is not installed immediately, or can be installed temporarily small buffers and certain waiting period is possible, but there is no stock for this material in the classical sense. If the material is precisely ordered and delivered in the sequence of vehicles in the final assembly, one also speaks of a just- in-sequence delivery, which is also referred to as pearl necklace.

Since there is no more stock, cause a delay in delivery, wrong delivery, quality defects or committee immediately to a shortage of supply and the interruption of production at the customer. Therefore, the entire production and supply process and the information chain must be planned exactly, are reliably implemented and executed correctly. The JIT production is therefore particularly sensitive and vulnerable to exogenous factors such as earthquakes, storms, floods or strikes, accidents etc.

History of JIT

The JIT concept has its origins in the Japanese automobile manufacturer Toyota. The first, developed at the end of the thirties this idea was Kiichiro Toyoda, the first president of Toyota Motor Corporation ( TMC). At Toyota JIT is not just a delivery method, but a comprehensive principle, which is next to the Jidoka principle is the second cornerstone of the Toyota Production System (TPS). To the JIT principle also includes and leveling of production programs, the pull principle, the flow production and the cycle time.

Unlike in the U.S., the Japanese market just was not big enough to economies of scale (English economies of scale ) to be economic. Kiichiro Toyoda concluded that in Japan only through the elimination of waste ( muda Jap ) an economic and competitive automobile production can be achieved. He wanted to produce the pure mass production of Henry Ford more than the market or customer require and overcome the associated stockpiling and storage, as both represented wastes his opinion.

According to Taiichi Ohno innovate this direction for Toyota after 1945 was of vital importance, as Kiichiro Toyoda demanded that his company would find within three years of America connection ( Taiichi Ohno, 1988 Hopp, 1999). Obviously did not meet Toyota this claim, but the resulting impetus would not weaken over the next 50 years. JIT was in 1973 ( the time of the oil shocks in Japan) for the first time by the continued success of Toyota's striking.

Within the scope of JIT is divided into:

Requirements for use

Other considerations

Area of ​​application

JIT is used for example in the automotive industry when

• Have the shoring components so many variants that not all can be accommodated directly to the assembly line.

Example: The Smart has about 150 harness variants. All need to be retained for production. However, it may not be available on all variants band, because the space for accommodation is not enough there. Therefore, the order of the required wiring harnesses (see sequencing ( production ) ) is output via a printer station and the harness variants are inserted in order into a vehicle Sequenzierwagen, which is then brought to the assembly line. This internal JIS supply is also called SILS (Sequence inlining system).

• The shoring components are pre-assembled from an outside supplier as ordered in the required order and delivered ( etc. cockpit, front, door trim, wheels ) than larger varied modules. In this case, the supplier is notified of the individual variant via EDI 180 minutes before the sheeting, then assembled by the supplier, several modules are combined into a truck lot size and then delivered to the manufacturer.

The JIT concept means that several suppliers settle in the immediate vicinity of the manufacturer in industrial parks or logistic distribution. The suppliers are thus directly involved in the assembly process. The final assembly time of a car decreases by the JIT concept from the original 20 to about 8 (Smart 4) hours. Composition of materials for the corresponding modules must hold the supplier, so that the manufacturer can reduce its storage capacity. As production may come to a halt at the customer when the parts arrive late, refer companies with JIT manufacturing the same parts often from multiple suppliers. High penalties are also not uncommon in such construction concepts.

In the case of not localnear JIT delivery increases the truck volume, as the loading volume of large assemblies is significantly larger than that of the individual parts. In short delivery frequency more smaller trucks are needed, which also increases the truck traffic. In localnear JIT deliveries, for example, logistics or industrial parks outside the factory gates of the car manufacturers, the truck arising almost falls away when the JIT volumes are transported directly into the assembly hall by the supplier or logistics service providers.

Kanban

A subsystem of the JIT concept is the Kanban principle: where one strives in series production low inventories in the various workshops at. Short lead times and guaranteed deadlines are more overarching goals. For this purpose, in the production of self-regulating loops is divided (according to the principle of store ). With the help of so-called kanban (Japanese for: Shield / card) of each consumer solves a contract with a mostly predefined amount and a specific order date. The producer or supplier brings then the required date in the required installation quality to the customer. This is a so-called pick-up or pull principle. Today, the cards are becoming more common by PC monitors replaced (E -Kanban ). The necessary data transactions are very often carried out by EDI or Web EDI

Holistic approach

To implement a JIT production, the holistic view of the customer order fulfillment is in a supply chain (see also Supply Chain Management).

Thus, the production efficiency can be measured, in addition to cost and productivity, the throughput and the replenishment lead time must be considered. When JIT therefore need to be optimized production flows and not the individual functions. This makes it possible to minimize the total order cycle time, ie, to produce demand accurately, thus minimizing inventory (cost ).