Fundamentals of JIT
(1) Flow layout- The physical layout of production facilities is arranged so that the process flow is streamlined, l.e., the ratio of value-added time for each component should be high, there should be minimum queue and non-value-added time. Use of dedicated lines, U-shaped or parallel lines, use of small machines is preferred. Flexibility of equipment is required to adjust quickly to changing market demand.
(2) Smooth manufacturing rate- The manufacturing rate should be smooth during the monthly cycle. To achieve this, capacity scheduling is resorted to so that they can respond to changes in demand.
(3) Mixed model scheduling- The objective of JIT is to make the production rate as consistent with demand as possible. One way of doing this is to increase the flexibility of production lines to allow concurrent assembly of different models on the same line.
(4) Small lots and minimum set-up time- The objective of reducing set-up time is to reduce the batch size to the minimum possible. This reduces the manufacturing cycle time and inventory. The use of SMED technique (Single Minute Exchange of Die) is recommended.
(5) Buffer Stock Removal- The emphasis is on frequent elimination of buffer stock to uncover production problems set by high inventory levels.
(6) Kanban Card- It is a pull system of managing material movement consisting of “Kanban Cards” based on information system. It helps to trigger the movements of material from one operation to the next (next) operation. Only by alternating the frequency of circulating Kanbans, the production system can be made to accommodate fluctuations in demand within limits. The number of cards in the system determines the total inventory. Therefore, the objective is to minimize the number of Kanbans.
(7) Quality- Achievement of high quality level is a prerequisite of successful JIT. Zero defect, statistical process control, process data collection and worker centered quality are the commonly used quality programs.
(8) Product and process simplification- This is achieved through.
Convention of product category.
Simplification of construction methods
component items simplification through standardization,
(9) Standard container-JIT emphasizes small standardized containers. It simplifies the movement of material and the use of MH tool.
(10) Preventional maintenance- JIT needs to remove uncertainty and causes of waste, breakdown is a major cause of uncertainty. Rigid preventive maintenance attempts to remove uncertainty.
(11) Flexible workforce- This is important requirement of JIT. Flexible workforce is developed through cross functional training. It is necessary to match the production rate and demand rate as closely as possible.
(12) Organizations in modules or cells – Many JIT factories are held in small autonomous modules or cells, each cell is fully responsible for its own production and supply of imminent modules. The cells are designed in a way that the flow of materials between the cells is at least.
(13) Continuous Improvement – JIT is not one, lime attempt. It’s the philosophy of continuous improvement. It wants everyone’s participation in constant improvement.