This is a management technique which developed from the emergence of Quality Assurance. Lean manufacturing/production has become an extremely important tool for business to employing because of its many virtues. Its overall purpose is to reduce and control manufacturing/production costs in pursuit of increased efficiency and through greater market share increase profitability.
Any significant sized business now faces world wide competition hence the drive to improve flexibility, sharpen production responses and improve output whilst reducing costs.
The logic behind lean manufacturing/production is to build a philosophy within the business unit which seeks to eliminate waste at all levels whilst engendering an attitude of mind which will question every action and procedure in the pursuit of reduced cost and lower process investment.
Another view of lean manufacture/production is for the business to strife to produce an ever higher level of throughput whilst reducing inventory at every point of the process. Within this approach is the practice of reducing - even eliminating stores, stocks, inventories, at every point they occur. These to be replaced by just sufficient material at each work point to enable production to proceed unhindered. It is this concept which gave rise to the Japanese term - kanban.
So a powerful concept in the context of efficient manufacture.
Manufacturing/production output once established inevitably leads to the need for constant repetition of the process involved to generate profit over the long term. Apart from any one process seldom being perfect is the inevitable set backs which occur on the introduction of new raw materials or design changes however small these changes may be individually. So the need to foster the spirit of a drive for constant improvement of the process is never ending - hence continuous improvement.
Once a product line has been established and is operational most effective improvements are the result of small, often incidental, changes and amendments. But it is the very nature of small changes and their constant maintenance thereafter which leads to significant overall change when aggregated. Continuous improvement provides the pressure to enable these small incremental change to be identified to be introduced and to thrive so minimising the need for massive leaps often into the unknown.
The introduction of the thinking behind lean manufacturing/production was just that; to change the attitude of management and their relationship and treatment of production workers. Originally the stark separation of responsibility was between management who managed, organised and thought, and the people involved in physical production. It was realised that the small incremental change could and would occur at the point of production given the opportunity. Accordingly shop floor personnel are encouraged to propose any change which would aid the flow and make production simpler and more effective. Clearly again, this constant awareness of the working process is continuous and to be as successful as possible needs to be continuous.
Originally the thought was that the quest for improved quality would almost certainly increase costs. It took many years and much grief before realisation of the opposite contention was realised. As increased effort was put into reducing production costs it emerged that improved efficiency resulting in improved quality and so customer satisfaction; in fact reduced production costs overall.
A breakthrough in this way of thinking occurred with the development of the six sigma concept. Six sigma refers to a statistical assessment of the number of failures which can be expected to arise in the course of meeting a customers specification. Refinement of this concept particularly at Motorola in the 1980's arrived at the production target of only 3.4 defects per million. This target was given the label of six sigma.
The technique is widely used across the world in all significant manufacturing business.
In life in general the name 'black belt' has many uses. Here we are addressing its use in the implementation in the main of six sigma which itself effectively brought about the professionalisation of quality management.
Originally six sigma operated on the shop floor with statisticians somewhat divorced therefrom in a quality department. This relationship was counter productive and demanded integration.
People are now charged to act as 'black belts' to apply six sigma methodology to specific projects in defined production areas. They are enabled and encouraged to devote one hundred percent of their working time to this quest. In this process the physical operation and its statistical assessment is brought down to the production floor.
Trainees to six sigma are named 'green belts' and aspire to re-clarification.
In large production units some co-ordination was still required which gave birth to 'master black belts' to lead and motivate green and black belts.
Other Quality Production Tools
Detailed above are a small sample of the quality management tools which have been developed since the 1920's. There are many other tools and many refinements to apply both to general and specific manufacturing and production situations. The list is expanded in acronyms.