JIT Just-in-Time manufacturing
`Just-in-time' is a management philosophy and not a technique.
It originally referred to the production of goods to meet customer demand exactly, in time, quality and quantity, whether the `customer' is the final purchaser of the product or another process further along the production line.
It has now come to mean producing with minimum waste. "Waste" is taken in its most general sense and includes time and resources as well as materials. Elements of JIT include:
- Continuous improvement.
- Attacking fundamental problems - anything that does not add value to the product.
- Devising systems to identify problems.
- Striving for simplicity - simpler systems may be easier to understand, easier to manage and less likely to go wrong.
- A product oriented layout - produces less time spent moving of materials and parts.
- Quality control at source - each worker is responsible for the quality of their own output.
- Poka-yoke - `foolproof' tools, methods, jigs etc. prevent mistakes
- Preventative maintenance, Total productive maintenance - ensuring machinery and equipment functions perfectly when it is required, and continually improving it.
- Eliminating waste. There are seven types of waste:
- waste from overproduction.
- waste of waiting time.
- transportation waste.
- processing waste.
- inventory waste.
- waste of motion.
- waste from product defects.
- Good housekeeping - workplace cleanliness and organisation.
- Set-up time reduction - increases flexibility and allows smaller batches. Ideal batch size is 1item. Multi-process handling - a multi-skilled workforce has greater productivity, flexibility and job satisfaction.
- Levelled / mixed production - to smooth the flow of products through the factory.
- Kanbans - simple tools to `pull' products and components through the process.
- Jidoka (Autonomation) - providing machines with the autonomous capability to use judgement, so workers can do more useful things than standing watching them work.
- Andon (trouble lights) - to signal problems to initiate corrective action.
JIT - Background and History
JIT is a Japanese management philosophy which has been applied in practice since the early 1970s in many Japanese manufacturing organisations. It was first developed and perfected within the Toyota manufacturing plants by Taiichi Ohno as a means of meeting consumer demands with minimum delays . Taiichi Ohno is frequently referred to as the father of JIT.
Toyota was able to meet the increasing challenges for survival through an approach that focused on people, plants and systems. Toyota realised that JIT would only be successful if every individual within the organisation was involved and committed to it, if the plant and processes were arranged for maximum output and efficiency, and if quality and production programs were scheduled to meet demands exactly.
JIT manufacturing has the capacity, when properly adapted to the organisation, to strengthen the organisation's competitiveness in the marketplace substantially by reducing wastes and improving product quality and efficiency of production.
There are strong cultural aspects associated with the emergence of JIT in Japan. The Japanese work ethic involves the following concepts.
- Workers are highly motivated to seek constant improvement upon that which already exists. Although high standards are currently being met, there exist even higher standards to achieve.
- Companies focus on group effort which involves the combining of talents and sharing knowledge, problem-solving skills, ideas and the achievement of a common goal.
- Work itself takes precedence over leisure. It is not unusual for a Japanese employee to work 14-hour days.
- Employees tend to remain with one company throughout the course of their career span. This allows the opportunity for them to hone their skills and abilities at a constant rate while offering numerous benefits to the company.
These benefits manifest themselves in employee loyalty, low turnover costs and fulfilment of company goals.
- Kiyoshi Suzaki, 1987, The New Manufacturing Challenge: techniques for continuous improvement, the Free Press, London.
- Yasuhiro Monden, 1993, Toyota Production System: an integrated approach to Just-In Time. Second edition, Industrial Engineering and Management Press, Institute of Industrial Engineers, Norcross, Georgia.
- Cheng TCE and Podolsky S, 1993, Just-in-Time Manufacturing - an introduction, Chapman and Hall, London.