LEAN MANUFACTURING

Lean Manufacturing



Lean Manufacturing

Introduction

Although the terms “lean production” and “lean manufacturing” have only been in circulation since the publication of The Machine That Changed the World in 1990, the concepts and practices have a much longer history. Indeed, the core idea of lining production steps in process sequence can be traced back to Colt's armory in Hartford, Connecticut, in 1855. What Henry Ford later called “flow production” reached its peak at his plant in Highland Park in 1915, where every machine making parts and every step toward assembling them were lined up in single-piece flow, so that it took a matter of hours from raw casting to the finished product.

This system could not offer customers enough choice. So when Ford built his next plant at River Rouge in 1931, it was organized quite differently. Large machines able to make large batches of different parts were grouped together in separate departments, maximizing efficiency by ensuring there was always work waiting to be done. Batches of products wandered from department to department and throughput times stretched from several hours to several months. Long lead times entailed making to forecast and selling from several months' stock of finished cars in dealer lots. Thus the world of mass “production” was born and became the dominant model as long as producers could sell everything they made.

Discovering Lean Production

Whom were independent contractors, created each part. Each craftsman used his own gauging system during part manufacture. Problems developed when part A did not fit with part B. To achieve part interchangeability, Ford required the same gauging system to be used for every part throughout the manufacturing process. Through this interchangeability and simplicity, Ford was able to gain a competitive advantage. By 1913, Ford had introduced the first moving assembly line. Rather than creating a complete car before beginning another, the worker remained in one spot and the parts and tools would come to the worker. Ford mastered what is known as the mass production system. In the 1920's, General Motors began the mass production of automobiles with five major companies owned by GM. While mass production was perfected in the United States, it was also successful in Europe. By the 1970's, Europeans were developing mass-produced cars that were much different than the American cars. They were offering compact, economy cars, such as the VW Beetle, and sporty cars such as the MG. In addition, the European automobile makers were developing new product features such as front wheel drive, disc brakes, fuel injection, engines with appealing power-to-weight ratios, and five-speed transmissions. Meanwhile in 1950, Japanese engineer Eiji Toyoda visited Ford's Detroit plant to study the mass production system in an effort to gather valuable information to be used in the manufacturer of Japanese automobiles.

After much study, Toyoda went to Japan, and with the help of production authority, Taiicgi Ohno, concluded that mass production would not work in Japan. Japan's domestic market was small, but demand was for a wide range of ...