Lean manufacturing
is as much a philosophy as it is a process. The basic tenet of the system is to eliminate waste, be it waste of motion, waste of time or waste of personnel. Behind the concept lies an ideal of value, with value defined by what the customer is paying for, and any action that does not contribute to that value is waste.
History
The roots of lean manufacturing can be found in the likes of Eli Whitney with his concept of interchangeable parts and Henry Ford, known for his assembly line production. While there have been many contributors to the development of lean manufacturing as a business strategy, it was Toyota Motor Co. that melded the ideas of Whitney, Ford and others and created the Toyota Production System, sometimes called the Just In Time system. Toyota's system is the cornerstone of contemporary lean manufacturing.
Function
Lean manufacturing is a process by which the production of any product is streamlined. Lean manufacturing is designed not to eliminate personnel or create more pressure on workers to produce, but rather it is a process by which personnel can reach higher production goals through specified motion and procedure. For example, computer technicians building computers would each have a power cord, keyboard and mouse at his station, thereby eliminating the motion--and time--to pull equipment for each system he builds.
Effects
This elimination of wasted motion adds up to time saved. Employees' time is not diverted away from the task that adds value to the product for the customer. Taking this a step further, employees are task-oriented and do not divide their time with tasks outside of their undertaking. An example of this would be that highly paid technicians would not be used as cleanup crew. The pay devoted to technicians then is entirely devoted to value.
Features
One of the features of lean manufacturing is 5S. 5S stands for Sort, Set in Order, Shine, Standardize and Sustain. Sort calls for all unnecessary items to be removed from the workstation. Set in Order means to have all tools and needed items arranged for quick access. Shine is the practice of keeping the workstation clean. Standardize means that the three previous aspects remain constant and sustain is maintaining the practices outlined in the collective.
Benefits
The primary benefit of lean manufacturing lies in elimination of the seven wastes. The first waste is overproduction. The "Just in Time" theory holds that every item be produced only when it is needed, thereby eliminating excess product. The second waste is waiting. This goal is to move product along where one process feeds directly into the next without the product waiting for the next step in the production process. The third waste is transporting. Just as processes need to feed directly into one another, distance between processes must be minimized.
The fourth waste is inappropriate processing. This deals with the equipment used and placement of that equipment. Equipment should be designed to perform well without costing a great deal and should be placed to create work cells or work areas.
Unnecessary inventory is the fifth waste, and is the result of overproduction. Excess inventory interrupts the flow between processes and workstations, and adds cost. The sixth waste is excess motion on the part of employees. If an employee's job is ergonomically challenged it should be re-evaluated and new methods should be adapted.
The seventh waste is defects. Defects in product cost time and money. Employees become well trained to detect defects through the concepts of task orientation and the 5S aspect of lean manufacturing.
