The Quality of Lean

For good reason Toyota is used as the premier example of manufacturing excellence.  But 2005 has has been a difficult time for the company.  Some of the major issues:

• The popular Prius is being investigated for a stall problem
• Over 100,000 cars recalled in Asia for a transmission problem
• 750,000 SUV's and trucks recalled in the U.S. for a suspension problem

What happened?  In many cases, especially lesser ones not cited here, the problem is due to a design flaw.  Lean manufacturing cannot correct fundamental design issues.  However in the case of the suspension issue the problem is directly tied to a manufacturing-induced defect.  Three quarters of a million vehicles, plus a few hundred thousand more outside of the U.S. and Canada. 

I have no doubt that Toyota is still the best large manufacturer in the world, but one core component of their success has been an extremely tightly knit and closely controlled supply chain.  As Toyota builds new plants around the world, that type of supply chain can become very stretched.  Although some of their plants, such as in Georgetown, Kentucky, attempt to have most second tier suppliers nearby, many parts are still sourced from their primary component manufacturers in Japan.  The lengthy supply chains lead to the evils of inventory... including the hiding of potential problems.

The July 14th issue of The Wall Street Journal offered another possibility: a shortage of lean manufacturing gurus.  Lean has become so popular that companies (especially General Motors) have been snatching up lean experts, especially those with true TPS experience.  Toyota itself is having difficulty finding and training appropriate people for their new plants, and in many cases are having to rely on the Lean experts at their component suppliers.  This has even led to Toyota outsourcing Lean management for some plants, and their admitted expectation that they'll soon have to outsource full plant management to non-Toyota personnel.  The impact on true TPS within those Toyota plants, and especially the culture of TPS, is unknown.

Lean manufacturing does create quality... manufacturing quality.  Shortened cycle times bring problems to the surface faster.  However lean manufacturing cannot inherently fix fundamental design issues... that requires a rigorous and disciplined approach to design itself.