Quality Function Deployment

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Quality Function Deployment
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What is QFD?

• QFD is a customer-driven planning process to
  guide the design, manufacturing, and marketing of
  goods.
• Through QFD, every design, manufacturing, and
  control decision is made to meet the expressed
  needs of customers. It uses a type of matrix
  diagram to present data and information.
• Under QFD, all operations of a company are driven
  by the voice of the customer, rather than by
  edicts of top management or the opinions or
  desires of design engineers.

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Why was QFD developed?

• The Japanese developed an approach called quality
  function deployment (QFD) to meet customers'
  requirements throughout the design process and
  also in the design of production systems.

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Why is product design so difficult in a company
organized in a traditional hierarchy?

• Communication is difficult because departments
  are separate.
• Customers and engineers speak different
  languages.
• A customer might express a desire to own a car
  that is easy to start. The translation of this
  requirement into technical language might be "car
  will start within 10 seconds of continuous
  cranking."
• Or, a requirement that 'soap leaves my skin
  feeling soft' demands translation into pH or
  hardness specifications for the bar of soap.
• The actual intended message can be lost in the
  translation and subsequent interpretation by
  design or production personnel.

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How does a QFD reduce costs versus traditional
product design approaches?

• Reduce time required to translate customer
  requirements into product specifications  
• QFD reduces the time for new product development.
  
• Improved communication and teamwork between all
  constituencies in the production process

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How does a QFD reduce costs versus traditional
product design approaches?
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How does a QFD reduce costs versus traditional
product design approaches?
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Why is QFD a tool for developing a competitive
advantage?

• Use of QFD determines the causes of customer
  dissatisfaction, making it a useful tool for
  competitive analysis of product quality by top
  management.

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The Quality Function Deployment Process

• Building the House of Quality consists of six
  basic steps
• Identify customer requirements.
• Identify technical requirements.
• Relate the customer requirements to the technical
  requirements.
• Conduct and evaluation of competing products.
• Evaluate technical requirements and develop
  targets.
• Determine which technical requirements to deploy
  in the remainder of the production process.

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Step 1 Identify customer requirements
The voice of the customer is the primary input to
the QFD process. What is the most critical and
most difficult task of QFD? The most critical and
most difficult step of the process is to capture
the essence of the customer's comments. The
customer's own words are vitally important in
reventing misinterpretation by designers and
engineers.   Listening to customers can open the
door to creative opportunities.  
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Step 1 Identify customer requirements

• Not all customers are end-users, however. For a
  manufacturer, customers might include government
  regulators, wholesalers, and retailers.
• CAs can include the demands of regulators ("safe
  in a side collision"), the needs of retailers
  ("easy to display"), the requirements of vendors
  ("satisfy assembly and service organizations"),
  and so forth.
• In terms of QFD, customer wants are referred to
  as Customer Attributes (CA's)
• CAs are often grouped into bundles of attributes
  that represent an overall customer concern, like
  "open-close" or "isolation.

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Step 1 Identify customer requirements

• CAs are generally reproduced in the customers'
  own words.
• Why?
• Experienced users of the house of quality try to
  preserve customers' phrases and even cliches -
  knowing that they will be translated
  simultaneously by product planners, design
  engineers, manufacturing engineers, and
  salespeople.
• What does a customer really mean by "quiet" or
  "easy"?
• Designers' words and inferences may correspond
  even less to customers' actual views and can
  therefore mislead teams into tackling problems
  customers consider unimportant.

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Step 1 Identify customer requirements
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Step 2 List the product requirements necessary
to meet the customer requirements

• Product requirements are design characteristics
  that describe the customer requirements as
  expressed in the language of the designer and
  engineer.
• How can we change the product?
• The marketing domain tells us what to do, the
  engineering domain tells us how to do it.
• Now we need to describe the product in the
  language of the engineer.
• Along the top of the house of quality, the design
  team lists those engineering characteristics
  (ECs) that are likely to affect one or more of
  the customer attributes (see Exhibit VI).

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Standard Data in Worksheets
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Why must the product requirements be measurable?

• They must be measurable, since the output is
  controlled and compared to objective targets.
• Technical requirements are the "hows" by which
  the company will respond to the 'whats'-customer
  requirements.
• Engineering characteristics should describe the
  product in measurable terms and should directly
  affect customer perceptions.
• The weight of the door will be felt by the
  customer and is therefore a relevant EC.
• By contrast, the thickness of the sheet metal is
  a part characteristic that the customer is
  unlikely to perceive directly. It affects
  customers only by influencing the weight of the
  door and other engineering characteristics, like
  "resistance to deformation in a crash"

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Step 3 - Develop a relationship matrix between
the customer requirements and the technical
requirements

• Customer requirements are listed down the left
  column technical requirements are written across
  the top.
• In the matrix itself, symbols indicate the degree
  of relationship in a manner similar to that used
  in the roof of the House of Quality.

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Step 3 - Develop a relationship matrix between
the customer requirements and the technical
requirements
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Step 3 - Develop a relationship matrix between
the customer requirements and the technical
requirements

• What is the purpose of the relationships matrix?
• The purpose of the relationship matrix is to show
  whether the final technical requirements
  adequately address customer requirements.
• The strength of a given relationship in the
  matrix is based on 3 criteria. What are these
  criteria?
• This assessment is usually based on
• Expert experience
• Customer responses
• Controlled experiments.

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Step 4 Add market evaluation and key selling
points

• This step identifies importance ratings for each
  customer requirement and evaluates existing
  products for each of them.
• Customer importance ratings represent the areas
  of greatest interest and highest expectations as
  expressed by the customer.

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Step 4 Add market evaluation and key selling
points

• What information does the competitive evaluation
  provide?
• Competitive evaluation highlights the absolute
  strengths and weaknesses in competing products.
• By using this step, designers can discover
  opportunities for improvement.
• It also links QFD to a company's strategic vision
  and indicates priorities for the design process.

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Step 4 Add market evaluation and key selling
points

• Are all preferences equally important?
• Imagine a good door, one that is easy to close
  and has power windows that operate quickly.
• There is a problem, however. Rapid operation
  calls for a bigger motor, which makes the door
  heavier and, possibly, harder to close.
• Sometimes a creative solution can be found that
  satisfies all needs. Usually, however, designers
  have to trade off one benefit against another.  

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Step 4 Add market evaluation and key selling
points

• How do we bring the customer's voice into
  tradeoff decisions?
• To bring the customer's voice to such
  deliberations, house of quality measures the
  relative importance to the customer of all CAs.
• How do we determine the weightings?
• Weightings are based on team members' direct
  experience with customers or on surveys.
• Weightings are displayed in the house next to
  each CA - usually in terms of percentages, a
  complete list totaling 100 (see Exhibit IV)

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Step 4 Add market evaluation and key selling
points
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Step 4 Add market evaluation and key selling
points

• Will delivering perceived needs yield a
  competitive advantage?
• Companies that want to match or exceed their
  competition must first know where they stand
  relative to it.
• So on the right side of the house, opposite the
  CAs, we list customer evaluations of competitive
  cars matched to "our own" (see Exhibit VI.

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Machine Speeds and Feeds - Constant Feed Rates
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Step 5 Evaluate technical requirements of
competitive products and develop targets
Once the team has identified the voice of the
customer and linked it to engineering
characteristics, it adds objective measures at
the bottom of the house beneath the ECs to which
they pertain (see Exhibit VIII).
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Step 5 Evaluate technical requirements of
competitive products and develop targets
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Step 5 Evaluate technical requirements of
competitive products and develop targets

• When objective measures are known, the team can
  eventually move to establish target values -
  ideal new measures for each EC in a redesigned
  product.
• If the team did its homework when it first
  identified the ECs, tests to measure benchmark
  values should be easy to complete. Engineers
  determine the relevant units of
  measurement-foot-pounds, decibels, etc.
• Incidentally, if customer evaluations of CAs do
  not correspond to objective measures of related
  ECs -if, for example, the door requiring the
  least energy to open is perceived as "hardest to
  open"-then perhaps the measures are faulty or the
  car is suffering from an image problem that is
  skewing consumer perceptions.

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Step 5 Evaluate technical requirements of
competitive products and develop targets

• How are technical requirements of competitive
  products evaluated?
• This step is usually accomplished through
  in-house testing and then translated into
  measurable terms.
• In-house evaluations are compared with the
  competitive evaluation of customer requirements
  to determine inconsistencies between customer
  requirements and technical requirements.
• On the basis of customer importance ratings and
  existing product strengths and weaknesses,
  targets for each technical requirement are set.

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Step 5 Evaluate technical requirements of
competitive products and develop targets

• How does one engineering change affect other
  characteristics?
• An engineer's change of the gear ratio on a car
  window may make the window motor smaller but the
  window go up more slowly. And if the engineer
  enlarges or strengthens the mechanism, the door
  probably will be heavier, harder to open, or may
  be less prone to remain open on a slope
•  
• What does the roof of the House of Quality show?
• The roof of the House of Quality shows the
  interrelationships between any pair of technical
  requirements.

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Step 5 Evaluate technical requirements of
competitive products and develop targets
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Step 5 Evaluate technical requirements of
competitive products and develop targets

• What questions do the relationships identified in
  the roof of the house answer?
• These relationships indicate answers to questions
  such as "How does one change of product
  characteristics affect others?' and assessment of
  trade-offs between characteristics.
• To improve the window motor, you may have to
  improve the hinges, weather stripping, and a
  range of other ECs.
• Sometimes one targeted feature impairs so many
  others that the team decides to leave it alone.

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Step 5 Evaluate technical requirements of
competitive products and develop targets

• The roof matrix also facilitates necessary
  engineering trade-offs.
• The foot-pounds of energy needed to close the
  door, for example, are shown in negative relation
  to "door seal resistance" and "road noise
  reduction!'
• In many ways, the roof contains the most critical
  information for engineers because they use it to
  balance the trade-offs when addressing customer
  benefits.
•  

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Step 5 Evaluate technical requirements of
competitive products and develop targets

• Engineers may add a row that indicates the degree
  of technical difficulty, showing in their own
  terms how hard or easy it is to make a change.
• Some users of the house impute relative weights
  to the engineering characteristics. They'll
  establish that the energy needed to close the
  door is roughly twice as important to consider
  as, say, "check force on 10' slope' " By
  comparing weighted characteristics to actual
  component costs, creative design teams set
  priorities for improving components. Such
  information is important when cost cutting is a
  goal.

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Step 6 Select technical requirements to be
deployed in the remainder of the process

• The technical requirements that have a strong
  relationship to customer needs, have poor
  competitive performance, or are strong selling
  points are identified during this step.
• These characteristics have the highest priority
  and need to be 'deployed' throughout the
  remainder of the design and production process to
  maintain a responsiveness to the voice of the
  customer.
• Those characteristics not identified as critical
  do not need such rigorous attention.

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Step 6 Select technical requirements to be
deployed in the remainder of the process
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Using the House of Quality
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Using the House of Quality
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The Houses Beyond

• The House of Quality provides marketing with an
  important tool to understand customer needs and
  gives top management strategic direction.
• However, it is only the first step in the QFD
  process. The voice of the customer must be
  carried throughout the production process.
• Three other "houses of quality" are used to
  deploy the voice to the customer to component
  parts characteristics, process planning, and
  production planning.

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The Houses Beyond
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The Houses Beyond House 2

• The second house is similar to the first house
  but applies to subsystems and components. The
  technical requirements from the first house are
  related to detailed requirements of subsystems
  and components.
• At this stage, target values representing the
  best values for fit, function, and appearance are
  determined.
• Most of the QFD activities represented by the
  first two houses of quality are performed by
  product development and engineering functions.
•  

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The Houses Beyond House 3

• At the next stage, the planning activities
  involve supervisors and production line
  operators.
• In the next house, the process plan relates the
  component characteristics to key process
  operations, the transition from planning to
  execution.
• If a product component parameter is critical and
  is created or affected during the process, it
  becomes a control point.
• A control point indicates what needs to be
  monitored and inspected. It forms the basis for a
  quality control plan delivering those critical
  characteristics that are crucial to achieving
  customer satisfaction.

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The Houses Beyond House 4

• Finally, the last house relates the control
  points to specific requirements for quality
  control.
• The vast majority of applications of QFD in the
  United States concentrate on the first and, to a
  lesser extent, the second houses of quality.
• The third and fourth houses of quality utilize
  the knowledge of about 80 percent of a company's
  employees-supervisors and operators. If their
  knowledge goes unused, this potential is wasted.