For many, LEAN is the set of “tools” that assist in the identification and steady elimination of waste (muda). As waste is eliminated quality improves while production time and cost are reduced. Examples of such “tools” are Value Stream Mapping, Five S, Kanban (pull systems), and poka-yoke (error-proofing).
There is a second approach to LEAN Manufacturing, which is promoted by Toyota, in which the focus is upon improving the “flow” or smoothness of work, thereby steadily eliminating mura (“unevenness”) through the system and not upon ‘waste reduction’ per se. Techniques to improve flow include production leveling, “pull” production (by means of kanban) and the Heijunka box. This is a fundamentally different approach to most improvement methodologies which may partially account for its lack of popularity.
The avoidance and then progressive removal of waste has a long history and as such is not the history of Lean but is its motivator. In fact many of the concepts now seen as key to lean have been discovered and rediscovered over the years by others in their search to reduce waste. Lean has developed as an approach and style that has been demonstrated to be effective.
Most of the basic goals of lean manufacturing are common sense and documented examples can be seen as early as Benjamin Franklin. Poor Richard’s Almanac says of wasted time, “He that idly loses 5s. worth of time, loses 5s., and might as prudently throw 5s. into the river.” He added that avoiding unnecessary costs could be more profitable than increasing sales: “A penny saved is two pence clear.
The original seven muda are:
- Transportation (moving products that is not actually required to perform the processing)
- Inventory (all components, work-in-progress and finished product not being processed)
- Motion (people or equipment moving or walking more than is required to perform the processing)
- Waiting (waiting for the next production step)
- Overproduction (production ahead of demand)
- Over Processing (due to poor tool or product design creating activity)
- Defects (the effort involved in inspecting for and fixing defects)
ePraxis seeks to use LEAN management processes in our analysis and recommendations where deemed appropriate.