Only products that are 100 percent defect-free continue on through the production line. In this way, each step uncovers and then corrects the defects that are found, before any more can be produced.The upstream processes only produce what has been withdrawn. This includes only producing items in the sequence in which the kanban are received, and only producing the number indicated on the kanban.The necessary parts in a given step always accompanies the kanban to ensure visual control. At each step, only as many parts are withdrawn as the kanban instructs, helping ensure that only what is ordered is made. Kanban works from upstream to downstream in the production process (i.e., starting with the customer order).In implementing a kanban system, organizations typically focus on four important 'rules'. Kanban are a critical part of a JIT system. Different types of kanban include: supplier kanban (indicate orders given to outside parts suppliers when parts are needed for assembly lines) in-factory kanban (used between processes in a factory) and production kanban (indicate operating instructions for processes within a line). In this way, kanban serves to ultimately eliminate overproduction, a key form of manufacturing waste. Kanban are used to control work-in-progress (WIP), production, and inventory flow. The kanban contain information on the exact product or component specifications that are needed for the subsequent process step. More specifically, a kanban 1 is a card, labeled container, computer order, or other device used to signal that more products or parts are needed from the previous process step. Contrary to more traditional 'push' methods of mass production which are based on an estimated number of expected sales, kanban's 'pull' system creates greater flexibility on the production floor, such that the organization only produces what is ordered. Kanban. Often referred to as the 'nervous system' of lean production, kanban is a key technique that determines a processes production quantities, and in doing so, facilitates JIT production and ordering systems. Production Sequencing. This involves calculating the pattern for making each product type in the required amount for any given day, by calculating the takt time for the daily quantity of each type. It is the rate at which each product must be completed to meet customer needs, expressed in amount of time per part. Takt time is critical to the daily scheduling required in leveled production described above. This technique allows organizations to produce products with a variety of customer specifications each day (using a daily schedule), in a smooth sequence that minimizes inventory and delay. Load leveling. This technique involves determining appropriate quantities and types of products needed in a given day to meet customer orders. Key elements of JIT, and techniques for achieving JIT, are discussed below. The end result is typically a significant reduction in waste associated with unnecessary inventory, WIP, and overproduction. The company signals its suppliers, using computers or delivery of empty, reusable containers, to supply more of a particular component when they are needed. Many companies implementing lean production systems are also requiring suppliers to deliver components using JIT.

In some cases, a limited number of reusable containers are used as kanban, assuring that only what is needed gets produced. JIT frequently relies on the use of physical inventory control cues (or kanban) to signal the need to move raw materials or produce new components from the previous process. Varying the mix of products produced on a single line, sometimes referred to as 'shish-kebab production', provides an effective means for producing the desired production mix in a smooth manner. JIT techniques work to level production, spreading production evenly over time to foster a smooth flow between processes. Under conventional mass production approaches, large quantities of identical products are produced, and then stored until ordered by a customer. JIT enables a company to produce the products its customers want, when they want them, in the amount they want. JIT leverages the cellular manufacturing layout to reduce significantly inventory and work-in-process (WIP). Just-in-time production, or JIT, and cellular manufacturing are closely related, as a cellular production layout is typically a prerequisite for achieving just-in-time production. Implications for Environmental Performance.

Just in time inventory