Quality function deployment (qfd)
Step 7—Develop Prioritized Technical Descriptors
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- Degree of Difficulty
- Target Value
- Absolute Weight and Percent
- Relative Weight and Percent
Step 7—Develop Prioritized Technical DescriptorsThe prioritized technical descriptors make up a block of rows corresponding to each technical descriptor in the house of quality below the technical competitive assessment, as shown in Figure 11–13. These prioritized technical descriptors contain degree of technical difficulty, target value, and absolute and relative weights. The QFD team identifies technical descriptors that are most needed to fulfill customer requirements and need improvement. These measures provide specific objectives that guide the subsequent design and provide a means of objectively assessing progress and minimizing subjective opinions. Degree of DifficultyMany users of the house of quality add the degree of technical difficulty for implementing each technical descriptor, which is expressed in the first row of the prioritized technical descriptors. The degree of technical difficulty, when used, helps to evaluate the ability to implement certain quality improvements. EXAMPLE PROBLEM Continue the development process of designing a handlebar stem for a mountain bike (see previous Examples) by determining the degree of difficulty for each technical descriptor. The degree of difficulty is determined by rating each technical descriptor from 1 (least difficult) to 10 (very difficult). For instance, the degree of difficulty for die casting is 7, whereas, the degree of difficulty for sand casting is 3 because it is a much easier manufacturing process. The degree of difficulty for designing a handlebar stem for a mountain bike is shown in Figure 11-13. Target ValueA target value for each technical descriptor is also included below the degree of technical difficulty. This is an objective measure which defines values that must be obtained to achieve the technical descriptor. How much it takes to meet or exceed the customer’s expectations is answered by evaluating all the information entered into the house of quality and selecting target values. 
Figure 11–13 Adding prioritized technical descriptors to the house of quality EXAMPLE PROBLEM Continue the development process of designing a handlebar stem for a mountain bike (see previous Examples) by determining the target value for each technical descriptor. The target value for each technical descriptor is determined in the same way that the target value was determined for each customer requirement (see appropriate Example). The target value for designing a handlebar stem for a mountain bike is shown in Figure 11-13. Absolute Weight and PercentThe last two rows of the prioritized technical descriptors are the absolute weight and relative weight. A popular and easy method for determining the weights is to assign numerical values to symbols in the relationship matrix symbols, as shown previously in Figure 11–8. The absolute weight for the jth technical descriptor is then given by  = 
where aj = row vector of absolute weights for the technical descriptors (j = 1,..., m) Rij = weights assigned to the relationship matrix (i = 1 ,..., n, j = 1,..., m) ci = column vector of importance to customer for the customer requirements (i = 1,..., n) m = number of technical descriptors n = number of customer requirements EXAMPLE PROBLEM Continue the development process of designing a handlebar stem for a mountain bike (see previous Examples) by determining the absolute weight for each technical descriptor. The absolute weight for each technical descriptor is determined by taking the dot product of the column in the relationship matrix and the column for importance to customer. For instance, for aluminum the absolute weight is 98 + 15 + 95 + 92 + 97 + 35 + 33 = 227. The absolute weight for designing a handlebar stem for a mountain bike is shown in Figure 11-13. The greater values of absolute weight indicate that the handlebar stem should be an aluminum die casting. Relative Weight and PercentIn a similar manner, the relative weight for the jth technical descriptor is then given by replacing the degree of importance for the customer requirements with the absolute weight for customer requirements. It is  = 
where bj = row vector of relative weights for the technical descriptors (j = 1,..., m) di = column vector of absolute weights for the customer require- ments (i = 1,..., n) Higher absolute and relative ratings identify areas where engineering efforts need to be concentrated. The primary difference between these weights is that the relative weight also includes information on customer scale-up factor and sales point. These weights show the impact of the technical characteristics on the customer requirements. They can be organized into a Pareto diagram to show which technical characteristics are important in meeting customer requirements. Along with the degree of technical difficulty, decisions can be made concerning where to allocate resources for quality improvement. Each QFD team can customize the house of quality to suit their particular needs. For example, columns for the number of service complaints may be added. EXAMPLE PROBLEM Continue the development process of designing a handlebar stem for a mountain bike (see previous Examples) by determining the relative weight for each technical descriptor. The relative weight for each technical descriptor is determined by taking the dot product of the column in the relationship matrix and the column for absolute weight in the prioritized customer requirements. For instance, for die casting the relative weight is 316 + 98 + 95 + 32 + 018 + 35 + 93 = 213. The relative weight for designing a handlebar stem for a mountain bike is shown in Figure 11-13. The greater values of relative weight also indicate that the handlebar stem should be an aluminum die casting. Download 0.94 Mb. Share with your friends:
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