Lean Manufacturing essentially aims to compress time. Typically, if you quarter your lead time, you will double productivity and take 20% off your costs.
Lean principles come from the Japanese manufacturing industry. The term was first coined by John Krafcik in a Fall 1988 article.
What most Companies know ad use of the entire Lean manufacturing philosophy is the set of "tools" that assist in the identification and steady elimination of waste (muda). As waste is eliminated, quality improves and production time and cost are reduced. The best known of such "tools" are:
Toyota reckons that the Lean main method is not the tools, but the reduction of three types of waste:
In order to expose problems systematically and to use the tools where the ideal cannot be achieved.
These principles are part of the Toyota Production System socio-technical system known as TPS.
The main objectives of the TPS are to design out overburden (MURI) and inconsistency (MURA), and to eliminate waste (MUDA). The most significant effects on process value delivery are achieved by designing a process capable of delivering the required results smoothly; by designing out "MURA" (inconsistency). It is also crucial to ensure that the process is as flexible as necessary without stress or "MURI" (overburden) since this generates "MUDA" (waste). Finally the tactical improvements of waste reduction or the elimination of MUDA are very valuable. There are eight kinds of MUDA that are addressed in the TPS:
The elimination of waste has come to dominate the thinking of many when they look at the effects of the TPS because it is the most familiar of the three to implement. In the TPS many initiatives are triggered by inconsistency or overburden reduction which drives out waste without specific focus on its reduction.
The TPS has two pillar concepts: Just-in-time (JIT) or "flow", and "autonomation" (smart automation). Adherents of the Toyota approach would say that the smooth flowing delivery of value achieves all the other improvements as side-effects. If production flows perfectly then there is no inventory; if customer valued features are the only ones produced, then product design is simplified and effort is only expended on features the customer values. The other of the two TPS pillars is the very human aspect of autonomation, whereby automation is achieved with a human touch. The "human touch" here meaning to automate, so that the machines/systems are designed to aid humans in focusing on what the humans do best. This aims, for example, to give the machines enough intelligence to recognize when they are working abnormally and flag this for human attention. Thus, in this case, humans would not have to monitor normal production and only have to focus on abnormal, or fault, conditions.
Read more on TPS and Lean Manufacturing at:
Taiichi Ohno is considered to be the father of the Toyota Production System, which became Lean Manufacturing in the U.S. He devised the seven wastes (or muda in Japanese) as part of this system.
Read more on Taiichi Ohno on wikipedia: http://en.wikipedia.org/wiki/Taiichi_Ohno
Transport: Transporting product between processes is a cost incursion which adds no value to the product. Excessive material handling may cause damage to the goods. Movement must be minimized by moving equipment and processes closer together.
Inventory: Too little inventory will lose sales; too much inventory can hide problems. Excess inventory increases lead times, uses up productive floor space and inhibits communication. By achieving a seamless flow between work centers, customer service will be improved, and inventories with related costs slashed. It is necessary to aim for "Just in Time" (JIT) manufacturing in order to expose problems to be eliminated and reduce costs.
Motion: This waste is related to ergonomics and is seen in all instances of bending, stretching, walking, lifting, and reaching. These are also health and safety issues. It is necessary to remove unnecessary motion of the operations and improve the ergonomics of the workplace.
Waiting: 99% of a product’s life time is spent waiting to be processed and most of its lead time is tied up in waiting for the next operation; Minimize waiting time and maximize "value adding" time. You can achieve a smoother flow and waiting time reduction by linking processes together so that one feeds directly into the next.
Overproduction: this waste occurs when an item is manufactured before it is actually required. Overproduction is highly costly to a manufacturing plant because it prohibits the smooth flow of materials and actually degrades quality and productivity. This creates excessive lead times, results in high storage costs, and makes it difficult to detect defects. Always aim to make exactly what the customer orders, just in time, to the correct quality standard.
Over (or inappropriate) Processing: many organizations use expensive high precision equipment where simpler tools would be sufficient. It is necessary to aim at reducing the waste of inappropriate processing by Investing in smaller, more flexible equipment where possible, creating manufacturing cells and combining steps.
Defects: Quality defects have a direct impact to the bottom line causing rework and tremendous cost to organizations. Related costs include quarantining inventory, re-inspecting, rescheduling, and capacity loss. Through employee involvement and Continuous Process Improvement (CPI), you can reduce defects.
Underutilization of Employees has been added as an eighth waste to Ohno’s original seven wastes as stated in the latest edition of the Lean Manufacturing classic Lean Thinking. Organizations use to employ their staff for their nimble fingers and strong muscles, but forget they have a free brain. It is only by capitalizing on employees' creativity that organizations can eliminate the other seven wastes and continuously improve their performance.
Many changes over recent years have driven organizations to become world class organizations or Lean Enterprises. The first step in achieving such goal is to identify and eliminate the seven wastes. As Toyota and other world-class organizations have realized, customers will pay for value added work, but never for waste.