By adopting this philosophy, manufacturers have been able to achieve great improvements in quality and efficiency and enjoy higher returns on investment.
History of JIT
JIT was developed and perfected in the 1970s in the Toyota manufacturing plants. Taiichi Ohno of Toyota, often referred to as the father of JIT, used the technique to eliminate risk to his business by building vehicles to order. The great motivation of Japanese workers to rebuild their nation's economy after the devastation of World War II, along with their terrific work ethic, made JIT a success and eventually led to its export to the West.
Main Features of JIT
The following are the key features of JIT, which revolves around the total involvement of people, plants, and systems in the manufacturing process:
- Continuous improvement
- Attacking fundamental problems
- Devising systems to identify problems
- Striving for simplicity
- A product-oriented layout
- Quality control at source
- Poka-yoke (foolproof tools, methods, etc., prevent mistakes)
- Preventative maintenance
- Total production
- Eliminating waste
- from overproduction
- of waiting time
- of transportation
- of processing
- of inventory
- of motion
- from product defects
- Good housekeeping
- Setup-time reduction
- Multi-process handling
- Leveled/mixed production
- Kanbans (simple tools to pull products and components through the process)
- Jidoka (providing machines with the autonomous capability to use judgment)
- Andon (trouble lights to signal problems to initiate corrective action)
Targets of JIT
The targets of JIT can vary depending on the type of company, the product, the process, and the customers. Nonetheless, most companies adopt JIT to achieve continuous competitiveness, customer focus, balanced quality-cost relationships, zero-defect production, the development of relationships with suppliers, and a commitment to continuous improvement.
Limitations of JIT
Despite the fact that it has brought phenomenal improvement to the manufacturing process, JIT has some limitations. The primary limitation of the philosophy is its dependence on historical demands. Variations in demand can severely affect the process. Secondly, industries used to storing huge inventories for backup during rough times don't find the JIT system attractive. The shorter cycle time of JIT also adds to the stress of the workers. Moreover, JIT is not useful to low-volume manufacturers.
All in all, JIT is a no ordinary technique that marginally increases quality or quantity; it has proven itself as a philosophy for achieving excellence in manufacturing.