Genichi Taguchi

    Born: Jan 1, 1924

    Died: June 2, 2012

    Genichi Taguchi is best known For:

  • Taguchi Methods
  • Taguchi Loss Function
  • Design of Experiments
  • Robust Design
  • Quality Engineering
  • About

    The executive director of the American Supplier Institute, the director of the Japan Industrial Technolgy Institute, and an honorary professor at Nanjing Institue of Technology in China. Genichi Taguchi is well known for developing a methodology to improve quality and reduce costs, which, in the United States, is referred to as the Taguchi Methods. he also developed the quality loss function.


    Mid 50's: Genichi Taguchi was Indian Statistical Institutes visiting professor, where he met Walter Shewhart.

    1960: Genichi Taguchi was awarded the Deming Application prize

    1986: Willard F Rockwell Medal by the International Technologies Insitute

    Taguchi's methodology

    Taguchi's methodology is geared towards pushing the concepts of quality and reliability back into the design stage, i.e. prior to manufacturing.

    His method provides an efficient technique for designing product tests prior to beginning manufacturing.

    Taguchi methodology is fundamentally a prototyping technique that enables engineers/ designers to produce a robust design that can survive repetitive manufacturing to deliver the functionality required by the customer.

    Taguchi considered the design to be more critical than Quality Control in manufacturing processes.

    Taguchi Loss Function

    In the traditional goalpost mentality a product is considered good or bad, depending or whether or not it is within the specification range (between the lower and upper spec limits i.e. the goalposts).

    With this approach, the specification range is more important than the nominal (target) value. But, is the product as good as it can be, or should be, just because it is within specifications? Taguchi says no to this.

    Taguchi specified three situations:

    1. Larger the better (for example, process yield);
    2. Smaller the better (for example, emissions, rejection rate); and
    3. On-target, minimum-variation (for example, a mating part dimensions in an assembly).

    Robust Design - Taguchi's Three Stages of Product Development:

     The philosophy of off-line quality control, designing products and processes so that they are insensitive ("robust") to parameters outside the design engineer's control.

    System design stage

    The non-statistical stage for engineering, marketing and customer knowledge.

    Parameter stage

    How should the product perform against defined parameters? The robust solution of cost-effective manufacturing irrespective of the operating parameters.

    Tolerance design stage

    Tolerance around the desired settings. Finding the balance between manufacturing cost and loss.

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