Sunday, November 9, 2014

TPS House - Use of House Metaphor in the Description of Toyota Production System

The TPS House is a metaphor used within the Toyota Motors.. 

TPS contains a large number of unique and interconnected elements. Fujio Cho, a student of 
Taiichi Ohno and chairman of Toyota Motor Corporation developed the TPS House to 
aid in communicating the large number of elements and their interconnectedness. 

The “TPS House” diagram is used by Toyota in order to illustrate the structure of the manufacturing system. The house metaphor communicates the structural nature of the system and its fitness for use. A house is strong and useful only if all elements are simultaneously strong, e.g., the roof, the pillars and the foundation. One weak link weakens the entire house. The metaphor is widely used in Toyota and many other organizations as well as methods use it. 

The overall goals of the TPS are shown on the roof and it includes:  best quality; lowest cost, shortest lead time; best safety and high morale. These goals are followed up in every production unit  and performance feedback is supposed to be given to employees in both management and non-management positions. These goals form the ultimate desirable output for the “TPS-house”. 

The center of figure is all about the people in the system and their activity. The first goal of the “TPS house”  people is widely understood as waste reduction and it is done through people who are trained to see waste and solve problems at the root cause through a constant focus on the question why. In 
order to detect and eliminate waste the following eight categories of waste are used: overproduction; waiting; unnecessary transport; over-processing or incorrect processing; excess inventory; unnecessary movement, defects and unused employee creativity. This is the heart of the TPS and for the most part this means reducing the amount of resources used without reducing customer value. Waste reduction is pursued with a level of commitment that may be unmatched. The Toyota employees  observe, reflect and refine their activities continuously.  

The concept of pillar is used on the TPS house metaphor. The first main pillar of the “TPS house” is jidoka, which is use of automatic machines.They stop is there is alikelihood of defect production. The second main pillar is called Just-in-time. It basically makes sure the right part in the right quantity is in a certain spot at the right time. 

The “TPS house” diagram has foundation.  It  consists of: the Toyota Way philosophy; visual management; stable and standardized processes and leveled production (heijunka). 

Each part of the “TPS house” is by itself critical, and  they also reinforce and support each other. The metaphor of “house” is intended to show that the elements are part of a larger whole. The TPS House is a very compact presentation of the Toyota Production System.

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