17. Quality Development

Quality Development is an advanced method of transforming customer requirements for technical characteristics of the product. This method was developed by a Japanese Yoshi Akaoand first used in Mitsubishi in 1971. The starting point in the design of quality by means of QFD method is uncompromising fulfillment of customer demand, so that he or she is satisfied, not just a client or a technologist.

It’s particular power derives from the fact that is a planning tool for use upstream, off-line, to ensure that customers needs are first understood in the customer’s own terms: then deployment into design requirements and subsequently through the manufacturing chain of critical part characteristics and key process requirement, and finally deployed to operational specifications.

Robert Hales stated in IIE Solutions the key benefits of QFD is the understanding about the direction they are headed. This common view is gained through the identification and resolution of conflicts arising from the cross-functional team’s different perspective. Equally important is the team’s supplier focus.

The team is developing a product or service that will thrill customers to the extent that they will part with their money. Usually, they are just charged with developing a product that meets the specifications. Instead of being reactive, they are now proactive. The distinction has proven to be one of the keys to the success of QFD. If product development team focused too early on solutions, they might miss creative opportunities.

The primary tool of the QFD is a diagram, which is composed of defined fields. Below chart presents scheme of House of Quality. Their number depends on the purpose and use of the method. The result of individual actions which are determined by the functionality of various stages in QFD is placed on these fields.

In the literature we can usually find a diagram of the determined nine following fields:

  1. customer requirements toward the product,
  2. importance toward the customer’s requirements,
  3. technical parameters of the product,
  4. the relationship between customer requirements and technical parameters,
  5. importance of the technical parameters,
  6. the relationship between customer requirements and technical parameters,
  7. comparison of own product with competitive products,
  8. target technical parameters,
  9. indicator of technical complexity.


Scheme of the House of Quality

The functionality and the implementation of the stages in QFD method are as follows:

  • Determine the customer’s requirements by defining the characteristics of the product.
  • Features of product are put that were pointed by potential customers. Typically, they are expressed by the language of the client, therefore the right interpretation by the designer plays an important role.
  • Determining the importance toward customer requirements.
  • This field is used to give the attributes to a hierarchy which have been presented earlier. The progressive scale needs to be used which reflects the relish of customers. The result of this step is to assign the validity coefficients to individual feature.
  • Determination of the product technical parameters.
  • This step consists in the set technical feature to a product mentioned in earlier customer requirements. Technical features should be measurable and realistic (achievable) and associated with the requirements’ function.
  • Determination of the relationship between customer requirements and technical parameters.
  • At this stage, dependence and its power between the customer’s “wish” and technical parameters are examined.
  • Typically, there are three levels of dependencies the interaction. The progressive (1-3-9) scale is frequently met in the literature.
  • Assessment of the technical parameters importance.
  • The next step determines the important technical parameters of the designed product.
  • Using mathematical operations the significance of technical parameter is calculated . It is the factor’s quotient of the requirements importance and the coefficient of correlation between the requirement and the technical parameter.
  • Recognition the relationship between technical parameters.
  • Technical specifications may exclude each other, positively or negatively affect each other so it is important to consider the mutual impacts of the parameters. The positive influence is marked by plus (+), the negative is determined by (-), while the neutral by space.
  • Susan Hart in her book “New Product Development” pays particular attention to the synergy that arises due to the positive mutual reaction of technical parameters and its appropriate use. This situation often occurs when the positive relationship outweighs which also points to the future development of the product. In case when the situation is reversed, there are lots of minuses and product development may be limited.
  • Comparison of the own product with the competing ones.
  • The result of this QFD part is to be an assessment of the product competitiveness of in comparison to the others. It not only shows the data about own product but also the possible directions of the product development. A strong part of the product is often sought in order to be able to distinguish it in marketing.
  • Determination of technical parameters’ target values.
  • After analyzing and comparing the coefficients, the optimized numerical values ought to be fixed ​​(with appropriate units of measurement) that will be the technical specifications of the product which meets customer requirements included in the first field in the diagram.
  • Determination of the complexity’s technical indicators.
  • Certain technical parameters may be not only the difficulty in designing but also in fulfillment of the product. Determination of the complexity’s technical indicators is to distinguish them and indicate possible problems with their implementation. They are frequently evaluated on a scale of 1-5 where a high value indicates a higher level of established guidelines’ complexity.

The QFD method is designed to assist in the design of the product so that at the very beginning of the process it is signified a high degree of fulfillment ideal product and reduce maximally a number of corrections.