lean manufacturing

Archive for the ‘Kaizen’ Category

Five Whys
The practice of asking why repeatedly whenever a problem is encountered in order to get beyond the obvious symptoms to discover the root cause. For instance, Taiichi Ohno gives this example about a machine that stopped working (Ohno 1988, p. 17):
1. Why did the machine stop? There was an overload and the fuse blew.
2. Why was there an overload? The bearing was not sufficiently lubricated.
3. Why was it not lubricated? The lubrication pump was not pumping sufficiently.
4. Why was it not pumping sufficiently? The shaft of the pump was worn and rattling.
5. Why was the shaft worn out? There was no strainer attached and metal scraps got in. Without repeatedly asking why, managers would simply replace the fuse or pump and the failure would recur. The specific number five is not the point. Rather it is to keep asking until the root cause is reached and eliminated.
See: Kaizen; Plan, Do, Check, Act (PDCA).

Five Ss
Five related terms, beginning with an S sound, describing workplace practices conducive to visual control and lean production. The five terms in Japanese are:
1. Seiri: Separate needed from unneeded items—tools, parts, materials, paperwork—and discard the unneeded.
2. Seiton: Neatly arrange what is left—a place for everything and everything in its place.
3. Seiso: Clean and wash.
4. Seiketsu: Cleanliness resulting from regular performance of the first three Ss.
5. Shitsuke: Discipline, to perform the first four Ss. The Five Ss often are translated into English as Sort, Straighten, Shine, Standardize, and Sustain. Some lean practitioners add a sixth S for Safety: Establish and practice safety procedures in the workshop and office. However, Toyota traditionally refers to just Four Ss:
1. Sifting (Seiri): Go through everything in the work area, separating and eliminating what isn’t needed.
2. Sorting (Seiton): Arrange items that are needed in a neat and easy-to-use manner.
3. Sweeping Clean (Seiso): Clean up the work area, equipment, and tools.
4. Spic and Span (Seiketsu): The overall cleanliness and order that result from disciplined practice of the first three Ss. The last S—shitsuke (sustain)—is dropped because it becomes redundant under Toyota’s system of daily, weekly, and monthly audits to check standardized work. Whether four, five, or six Ss are used, the key point to remember is that the effort is systematic and organic to lean production, not a “bolt-on” stand-alone program.
See: Standardized Work.

On this site lean manufacturing, also known as Toyota Production system, will be discussed in more detail.  Lean focuses on the processes that add value and onto avoiding waste.  The overall process is outlined on a value stream map for better visibility.  Just in time (JIT) is a similar approach.