Definition of Lean Production

Lean production began as a manufacturing technique to enhance efficiency and profitability. Its primary focus is speed of output by waste elimination. Waste is anything that does not add value to the end product. Many industries aside from manufacturing are now adopting lean principles.

History

Henry Ford was one of the first to understand workflow and to employ automation for mass production. Although production flow was good, his techniques did not allow for variety. "You can have any color Model T as long as it's black," he famously said. About 25 years later, Kiichiro Toyoda and others at Toyota revised much of Ford's thinking and developed the Toyota Production System, which focused on matching machines to the workflow, quick setups and machine change-overs for various products and waste elimination.

Value-Added

The focus of lean manufacturing is value. Any step or process that adds value to the end product is kept. Anything that does not add value is waste and is eliminated. Assessing value-added functions is the first step in lean production. Once those you know those, you can begin eliminating waste. Lean manufacturing identifies seven different types of waste.

Motion and Transportation

The first type of waste in lean production is unnecessary motion. Wasted motion might be that of humans or machines. If a worker takes 10 steps when five will suffice, the additional five are deemed waste and eliminated in a lean company. Similarly, transportation also has the potential to be wasteful. Moving the product along the line is necessary and adds value. Moving components to wait for the next step in the process is waste.

Inventory and Overproduction

Inventory of either component parts or end products is also considered waste by lean organizations. The ideal state is to have parts arriving at the very moment they are needed. This is often referred to as JIT, or just in time.
Overproduction is linked to both inventory and transportation waste. If you create too many parts before they are needed, those parts will have to be moved into storage and held as inventory.

Waiting

Lean companies are adept at reducing waiting time or time in a queue. This type of waste goes hand in hand with overproduction, as well. Parts that are waiting to have something done with them are not adding value to the end product. Sometimes workers have wasted time waiting for parts to arrive, as well.

Processing Waste

Processing waste is similar to motion waste. Over-processing is doing more work to add value than needed resulting from poor design. Using a six-inch bolt when a five-inch one will do is a good example.

Defects

The last type of waste defined in lean manufacturing is defects. A successful lean company will have processes in place throughout the workflow to eliminate defects. A final quality-control check doesn't exist in a lean company, as the quality has been controlled through the entire process. The last look is wasted effort.