Lean Production
Lean production is the name given to a group of highly efficient manufacturing techniques developed (mainly by large Japanese companies) in the 1980s and early 1990s. Lean production was seen as the third step in an historical progression, which took industry from the age of the craftsman through the methods of mass production and into an era that combined the best of both. It has been described as “the most fundamental change to occur since mass production was brought to full development by Henry Ford early in the 20th century”.
The methods of lean production are said to combine the flexibility and quality of craft production with the low costs of mass production. In lean-production systems a manufacturer’s employees are organised in teams. Within each team a worker is expected to be able to do all the tasks required of the team.
These tasks are less narrowly specialised than those demanded of the worker in a mass-production system, and this variety enables the worker to escape from the soul-destroying repetition of the pure assembly line. With lean production, components are delivered to each team’s work station just-in-time, and everyworker is encouraged to stop production when a fault is discovered. This is a critical distinction from the classic assembly-line process. Stopping an assembly line is expensive and to be avoided at all costs. Often it is only the line foreman who is allowed to stop it.
Faulty products are put to one side to be dealtwith later, and a large stock of spares is kept on hand so that faulty components can be replaced immediately without causing hold-ups. The problem with such a system is that workers on the assembly line learn nothing, so the faults often persist.Workers are not encouraged to look back and find the source of the fault, and then to be involved in its correction. When a lean-production system is first introduced, stoppages generally increase while problems are ironed out.
Gradually, however, there are fewer stoppages and fewer problems. In the end, a mature lean-pro- duction line stops much less frequently than a mature mass-production assembly line. Lean production gains in another way too. In typical assembly-line operations, design is farmed out to specialist outsiders or to a separate team of insiders. Gaining feedback from both the production-line workers and the component suppliers is a long and awkward process. With lean production, designers work hand-in-hand with production workers and suppliers. There is a continuous two-way interchange. Snags can be ironed out immediately and machine tools adapted on the hoof. With the assembly-line model, the communication is linear.