Just in time

what is just in time

Rapid technological advances in manufacturing companies result in reduced direct labor usage, but on the other hand require relatively large investment expenditures to use modern equipment. Due to limited funds, there are still many companies that use traditional procedures to deal with technological progress itself. But people in advanced countries like Japan, especially the manufacturing community began to develop a system called Just in Time, where the system is backed from waste of labor, space and industrial time, which occurred due to the inventory management so that the cost of production becomes higher. The superiority of a company compared with its competitors is determined by the factors of time, quality, cost, and human resources. Time is one of the leading determinants of competitiveness. If a company wants to excel from a time factor then the company must be able to serve customer demand on time, eliminating or reducing time for non-value-added activities, and streamlining time for value-added activities. One of the way for companies to have an advantage in terms of time factor is to develop and apply Just in Time concepts.

Jericho Atmaja Bhaktinegara

Just in time

Just In Time (JIT) is an integration of a series of design activities to achieve high volume production using minimum inventories for raw materials, work in process, and finished products. The basic concept of a JIT production system is to produce the required product, at the timeframe conceivable by the customer, in accordance with customer requirements, and at every stage of the process in the production system is the most efficient way through elimination waste and continuous improvement.

The concept of Just In Time (JIT) is a modern fabrication management system developed by the big companies in Japan, since the early 1970s, JIT was first developed and refined at the Toyota Manufacturing plant by Taiichi Ohno, therefore Taiichi Ohno is often called As the founding father of JIT, the Principled JIT concept only produces the types of goods that are required (what) the amount required (How much) and when needed (When) by consumers.

Just In Time (JIT) is an overall philosophy in management operations where all resources, including raw materials and inventories, personnel, and facilities are used as needed. The goal is to lift productivity and reduce waste.

Fujio Cho of Toyota defines waste as: Everything that is excess, beyond the minimum requirement of equipment, materials, components, places, and working time is absolutely necessary for the value-added process of a product. In simple way, the notion of waste is everything does not add value to product produced.

There are 7 (seven) types of waste due to:
  • Defects
  • Transportation
  • Over Production
  • Waiting time
  • Production Process
  • Unnecessary Inventory
  • Unnecessary Motion

Basic principle of just in time

To apply the JIT method then there are eight principles that should be the basis of consideration in determining the production system strategy, namely :

Producing in accordance with the order of the planned production schedule

The manufacturing system will be operated to produce the waiting product after it has been obtained order in a certain amount of entry. The main objective is to produce finished goods on time and to the extent of the amount just to be consumed, for that the production process will produce as much as needed and immediately sent to customers who need to avoid the occurrence of stock and to reduce the cost of storage.

Production is done in lot size

Production in lot size is used to avoid complex planning and lead times as it does in the production of large quantities. The flexibility of production activities will be feasible, as it makes it easy to make adjustments in production plans especially to face of changing market demand.

Respect to others

With the Just in Time method in the production system, each worker will be given full opportunity and authority to organize and decide whether a flow of operations can be continued or to be stopped because of problems in a particular work station.

Seek to eliminate contigencies

Inventory which is expected to anticipate fluctuating demand and all unforeseen conditions, it will turn into waste when not immediately usehttps://www.blogger.com/blogger.g?blogID=7545331924505090277#allpostsd. Similarly, recruitment of large amounts of labor in an uncontrollable manner as commonly encountered in project activities will lead to waste if not utilized in time. Therefore, in the planning and scheduling of production must be made and controlled carefully. Any form that gives the impression of uncertainty should be eliminated and should be included in the consideration and formulation of the forecasting model.

Eliminate waste

Wastes must be eliminated in every area of operation. All use of input sources (materials, energy, machine work hours or labor, etc.) should not exceed the minimum required to achieve production targets.


In the Just In Time (JIT) system, workflows are controlled by the following operations, where each work station draws output from the previous workstation as needed. Based on this fact, JIT is often referred to as the Pull System. In the JIT system, only the final assembly line receives the production schedule, while all other workstations and suppliers receive production orders from subsequent operations. In other words, the previous work station receives the production order from the next work station, then delivers the product according to the quantity needed at the right time with the exact specification. In such cases, the second work station is often referred to as the work station of the user. If the user's workstation discontinues production for a given time, automatically the supplying work station will stop delivering the product, as it does not accept production orders.

In a broad sense, JIT is a timely philosophy that focuses on the activities required by other internal segments within an organization. JIT has four main aspects as follows:
  1. All non-value-added activities of the product or service must be eliminated. Non value-added activities increase unnecessary costs.
  2. There is a commitment to always improve the higher quality. So that there’s zero defective product, and does not require the time and cost to rework the defective product.
  3. Always strived for continuous improvement in improving the efficiency of activities.
  4. Emphasizes the simplification of activities and enhances the understanding of value-added activities.

mechanism of just in time

Benefits of just in time:

  1. The warehouse set-up time can be reduced. Setting up time is significantly reduced in warehouses that will allow companies to increase their bottom line to see more time efficiently and focused spend in other areas.
  2. The flow of goods from warehouse to production will increase. Some workers will focus on the work area to work quickly. Having employees focused on specific areas of the system will allow them to process items faster than they should be vulnerable to exhaustion from doing too many jobs at once and simplifying the tasks at hand.
  3. Workers who master a variety of skills are used more efficiently. This will allow the company to use workers in situations where they are needed if there is a shortage of workers and a high demand for a particular product.
  4. Product scheduling and working hours will be more consistent. Better consistency of scheduling and consistency of possible employee hours. This can save companies money by not having to pay workers for unfinished jobs or be able to ask them to focus on other jobs around the warehouse that is not necessarily done on a normal day.
  5. Increased emphasis on supplier relationships. No company wants to break in their inventory system that will create a supply shortage while not having supplies sitting on the shelves. Inventory continues around the clock keeping productive workers and businesses focused on turnover. Having management focused on meeting deadlines will make employees work hard to meet company goals to see benefits in terms of job satisfaction, promotion or even higher pay.
  6. Inventory Turnover. Speed up of turnover occurs involving company resources: cash, there will be an increase in net income. The shorter the time interval between the acceptance of raw materials and the incorporation of them in the manufacturing process, the greater the profitability. The inventory philosophy played on designing a perfect inventory system blends the basics of minimizing costs and maximizing profits. These fundamentals are men, materials and machines often called 3ms of manufacturing or inventory operations, if well balanced outcomes in JIT philosophy can be applied.

Despite the many advantages that can be obtained, Just In Time Production System is still has some weaknesses :
  1. Just In Time Production System has no fault tolerance or "Zero Tolerance for mistakes" so it will be very difficult to repair / rework the production materials or finished products that are defective. This is because the level of inventory of materials production and finished products are very minimum.
  2. A very high dependence on Suppliers in both quality and delivery accuracy that is generally outside the scope of the manufacturing company concerned. Delayed shipments by one supplier will result in a hampering of all planned production schedules.
  3. Transaction Fees will be relatively high due to high transaction frequency.
  4. The corresponding Manufacturing Company will be difficult to meet the sudden high demand because of constraints amount of finished goods

Comparasion between just in time System and traditional one

  • The pull and push system
  • Just in Time using Pull system in production process. Pull system is a system of determining activities based on consumer demand, both internal and external consumers. For example, in a manufacturing company consumer demand through sales activity determines the activity of production, and production activity determines the activity of purchasing. Push system is a system of determining activities based on the encouragement of previous activities. Purchase of materials through purchasing activities encourages production activities, and production activities drive sales activity. Push system commonly used in traditional system
  • Significance of inventory
  • Because JIT uses a pull system it can reduce inventory to be in small amount even zero. In traditional systems, on the other hand, because of the use of a push system, the quantity inventory is significant as a result of the amount of material purchased exceeding the production requirements, the number of products produced exceeds the demand of the consumers and the need for a buffer stock. Buffer stock is required if the consumer demand exceeds the amount of production and the amount of material used for production exceeds the amount of material purchased
  • TQC and AQL
  • TQC (Total Quality Control) in Just in Time is a quality control approach that covers all efforts on an ongoing and endless basis to improve the quality to achieve zero or damage-free products. Defective products should be avoided as they may lead to discontinuation of production and consumer dissatisfaction. AQL (Accepted Quality Level) in traditional systems is a quality control approach that allows or reserves damage but should not exceed pre-determined levels of damage.
  • Engagement and involvement
  • In the traditional system, employee involvement and empowerment is relatively low because the employees function to carry out orders from upper management. Whereas in JIT system management must be able to empower its employees by involving them or member for opportunity to them to participate in organizational management. In JIT's view, increased empowerment and employee engagement can improve overall productivity and cost efficiency. Employees may make decisions about how the plant operates.
  • Cellular and departmental structure
  • The cellular structure in Just in Time is the grouping of machines, usually into a semi-circular structure or the letter "U" so that one particular cell can be used to process one group or one specific product in sequence. Each manufacturing cell is basically a mini factory inside the factory. The use of this cellular structure can eliminate activities, time, and costs that are not worth adding. While the department structure in the traditional system is the structure of product processing through several production departments in accordance with its stages and requires several service departments that supply services to the production department. As a result, the structure of the department raises activities and time and costs are not valued in large numbers.
  • Double-skilled and specialized employees
  • JIT systems using pull systems, idle time of the employee should be used to practice other skill so that experts in other part of production and in certain service areas such as preventive maintenance, reparation, setup, quality inspection. While in the system of traditional system employees are specialized based on the workplace department such as production department or service department. Employees in the service department specialize in materials handling activities, electricity, repairs, and maintenance, employees in the production department are specialized in mixing, smelting, molding, assembling, and refining activities.


Just in Time is a production system to reduce costs, efficient workmanship and obtain the quality desired by the company. This system is designed to minimize waste due to overproduction, excess inventory, waiting. JIT has the basic principles of Producing in accordance with the order of Production Schedule, Production is done in lot size, reduced waste, continuous product flow improvements, improved product quality, Respect to everyone, reduced all forms of uncertainty.

Just in Time (JIT) has the key to what is (what kind of order), how much (how much goods are ordered), and when (when the goods are ordered) so that production will only be done in accordance with the above three concepts aims to increase productivity and reduce waste



Popular posts

Sistem informasi global dan penerapannya oleh perusahaan multinasional

Apa itu budaya global?

Sistem pendukung keputusan kelompok (GDSS)