A BRIEF HISTORY OF LEAN
Initial Lean thinking were evident in Arsenal in Venice in the 1450s, but Henry Ford was first to truly integrate an entire production process at Highland Park, MI, in 1913 where he synthesised interchangeable parts with standard work and moving conveyors and created flow production. Ford aligned manufacturing lines in process sequence using special-purpose machines and gauges to fabricate and assemble the components going into the vehicle within a few minutes, and deliver perfectly fitting components directly on line.
This was a first revolutionary break from the shop practices of general-purpose machines grouped by process, which made parts that found their way into finished products. The problem with Ford’s system was not the flow but it was his inability to provide variety. The Model T was not limited to black colour and also limited to one specification. All Model T chassis were essentially identical up through the end of production in 1926. Practically every machine in the Ford Motor Company worked on a single part number, and there were essentially no changeovers.
“Customers didn’t have choice”.
But the customers wanted variety and Ford lost his way. Other automakers responded to the need for many models, each with many options, but with production systems with much longer throughput times. Over time they populated their fabrication shops with larger and larger machines that ran faster and faster, apparently lowering costs per process step, but continually increasing throughput times. Even worse, the time lags between process steps and the complex part routings required ever more sophisticated information management systems culminating in MRP Systems
As Kiichiro Toyoda, Taiichi Ohno, and others at Toyota looked at this situation after World War II, and made a series of simple innovations might make it possible to provide continuity in process flow and a wide variety in product offerings. They revisited Ford’s original thinking, and invented the Toyota Production System. Toyota right-sized machines in line with actual volume needed, introducing mistake proofing to ensure quality, lining the machines in process sequence, and devised quick change over to process small volumes of many part numbers, and having each process step notify the previous step of its current needs for materials through its innovative Kanban system. All these made it possible to obtain low cost, high variety, high quality, and very rapid throughput times to respond to changing customer desires. Also, information management could be made much simpler and more accurate.
Continued success of TOYOTA over past two decades created an enormous demand for greater knowledge about lean thinking. There are literally hundreds of books and papers, not to mention thousands of media articles exploring the subject, and numerous other resources available to this growing audience.
The thought process of lean was thoroughly described in the book The Machine That Changed the World (1990) by James P. Womack, Daniel Roos, and Daniel T. Jones. In a subsequent volume, Lean Thinking (1996), James P. Womack and Daniel T. Jones distilled these lean principles even further.
As lean thinking continues to spread to every country in the world, leaders are also adapting the tools and principles beyond manufacturing, to logistics and distribution, services, retail, healthcare, construction, maintenance, and even government. Indeed, lean consciousness and methods are only beginning to take root among senior managers and leaders in all sectors today.