Just in Time is a production management concept that aims to reduce the amount of inventory. The necessary components and materials come at the right quantity at the right place and at the right time.
The Just in Time use increases production efficiency by reducing losses. The losses are any actions that add cost, but do not increase the value of the product - unnecessary movement of materials, excess inventory, etc.
Primary, JIT is applied to regularly repeatable processes. These are production processes. Products or components are produced as a serial (or massive). The effective use of JIT is possible when synchronizing process flows and material flows in production.
The core elements of Just in Time were developed in the 50s of the 20th century at the Toyota Corporation factories. These became known as the Toyota production system. Just in Time was formed as a production management system in the early 70s. It was extended at many Japanese factories and in the 80s it appeared in American and European productions.
It is important to provide the necessary and high-quality products to the customer with a lower price in the shortest possible. This is important advantage for any organization if it attempts to competitive in the market.
Just in Time makes it possible to get this by setting and achieving a number of goals:
The Just in Time production management system is based on several key elements:
1. Stable production program. It is necessary to create a uniform load of all production and assembly operations in order to work the Just in Time system. The change in the program should occur only due to changes in demand.
2. Reducing the installation operations time. The goal is to achieve the installation of parts for processing "in one touch". This can be achieved by optimizing planning, changing production operations or the shape of the processed parts.
3. Reduction of lot sizes (both in production and in procurement). It is necessary to achieve closer cooperation with suppliers in order to work this element of the "Just in time" system. More frequent deliveries will be required, so suppliers must ensure reliable and accurate deliveries.
4. Reducing the waiting time (during production and delivery). Reducing the waiting time can be achieved by placing equipment short to each other, using group processing technologies, reducing the length of the processing queue, increasing coordination and consistency between sequential processes. Reducing the waiting time for deliveries can be obtained due to a short location of suppliers.
5. Execution of the preventive maintenance. Preventive maintenance of the equipment should be carried out during of outage periods or non-working hours.
6. The use of "universal" human resources. The Just-in-time system involves training workers to manage various types of equipment and machinery. This allows workers to carry out maintenance and quality control operations while at their workplace. JIT requires the creation of competent teams at production that are fully responsible for the results of their work.
7. Application of the "Zero Defects" program. All actions leading to defects or reject must be eliminated in order to work Just in Time system, since there are no reserves for their elimination in this system. The implementation of the program makes it possible to achieve personal responsibility of employees for the quality of the work they perform. Every employee should have the right to stop production if there is a possible breach of the quality of work.
8. The use of small production lot when moving. The JIT provides a signal system in order to implement this element (for example, Kanban cards). This ensures the transfer small quantities of item between workstations (production equipment). There should be a transfer of one item per unit of time in the best case.
Just in Time is a system that is successfully used in many manufacturing enterprises. JIT has certain advantages and disadvantages like any production system.
The main advantages of the "Just in time" system include:
1. Reduction of monetary funds required for inventory management. A smaller volume of stocks allows you to reduce the amount of financial resources "frozen" in stocks.
2. The ability to use the storage facilities for other needs. The Just-in-time system reduces the capacity of raw materials inventory, production stocks, and finished product stocks. Significant areas may be released as a result. They can be used for other purposes.
3. Reduction of the volume of unsold goods with a reduction in demand. The aim of the Just-in-Time system is to produce the quantity of products that the customer needs. If the demand for products sharply decreases, then the amount of unsold goods will be minimal in the JIT system.
4. Reduction of the production lot. This allows you to react on changing market needs faster. Small production lot make possible to introduce based on customer needs changes faster.
5. Reducing the defects quantity. This leads to a reduction of reject and the cost of its correction. The detected in production defects quantity should tend to zero f or the effective operation of the "Just in time" system. In order to achieve zero defects a lot of efforts are being made to improve the quality of work.
The most serious and obvious disadvantages of the Just in Time system are:
1. Reducing the possibility of reject correcting that has arisen and can be missed for the next operation. It is quite difficult to remake or correct an admitted reject in the production process because the JIT system does not provide for stocks and reserves, both material and temporary (or they are minimized). It is required to stop all production in order to correct the defect.
2. Strong production dependence from the quality of suppliers' work. Suppliers, as a rule, are outside the company's control field, so any problems in the supply chain can to stop production.
3. Minor opportunities to meet the suddenly increased demand. It is required additional time to meet the increased demand since the JIT system does not provide for stocks of finished products.
The JIT system implementation requires major and long-term efforts from the organization.
The key success factors in the implementation are:
It is necessary to apply various methods, tools and techniques of quality in order to work the JIT system. It will be necessary to change the consciousness of employees and corporate culture. This is the most important thing.
ISO 9001:2015 Explanations. Interpretation of requirements. Implementation guide.