Introduction: Quality Function Deployment (QFD)- is a quality tool conceived in Japan in the late 1960’s and introduced to America and the world in 1980’s that help translate the voice of customer (VOC) into a product that satisfy their needs/requirements under the umbrella of Total Quality Management (TQM). It’s a systematic and organized approach of rendering customer’s needs into engineering specifications. It makes sure that the needs are considered into the design efforts by interlinking customers – design Engineers –manufacturing team and the competitors resulting in a better product. It’s currently being used in manufacturing, healthcare and service organizations.
How to use it: QFD is deployed using series of matrices, referred to as House of Quality (HOQ). The four phases of the process are:
Product Planning: Gather customer requirement to be converted into product technical requirement.
Product Design: Translate technical requirement into key part characteristics or system.
Process planning: Identify operations to achieve key part characteristics.
43434028733750Production Planning: Control operations by establishing process control plans, maintenance plans and training plans.
1379220104140Figure SEQ Figure * ARABIC 1: Phases of QFD
0Figure SEQ Figure * ARABIC 1: Phases of QFD
1615440726440HOUSE OF QUALITY: It’s a diagram resembling a house and used for defining the relationship between the customer desires/requirements and the firm’s products and capabilities.
1615440248920Figure SEQ Figure * ARABIC 2: House of Quality
Figure SEQ Figure * ARABIC 2: House of Quality
Walls (Customer’s Requirements)
Prioritized customer Requirements.
Voice of Customer (VOC)
Ceiling (Technical Descriptors)
Consistency of the product
Relation (Between customer requirements and technical descriptors)
Roof of the House
Interrelation (Between technical descriptors)
Trade off similar
Identify conflicting descriptors
Prioritized technical descriptors
35966402007870Figure SEQ Figure * ARABIC 3: Customer’s Requirements
Figure SEQ Figure * ARABIC 3: Customer’s Requirements
3596640000Degree of technical difficulty
Step 1: List customer requirements (What’s).
Customer Needs or Expectations.
36048952135505Figure SEQ Figure * ARABIC 4:Listing Technical Descriptors
Figure SEQ Figure * ARABIC 4:Listing Technical Descriptors
Step 2: List technical Descriptors (How’s)
Counterpart characteristics: – An expression of the voice of the customer in technical language
Primary characteristics/ Descriptors.
35960052052320Figure SEQ Figure * ARABIC 5: L shaped structured diagram
Figure SEQ Figure * ARABIC 5: L shaped structured diagram
35960054445000Secondary characteristics/ Descriptors.
Tertiary characteristics/ Descriptors.
Step 3: Develop a relationship matrix between What’s and How’s.
Structure an L shaped Diagram inside the house using shape to represent the shape of that relation.
Degree of influence between each technical descriptor and each customer requirement.
33528056515 Strong Relationship = 9
33528042545 Medium Relationship = 3
280416000033528059055 Weak relationship = 1
Blank For no relationship
Additional Descriptors are required in case a row is left empty.
2802255133985000If a column is empty it means that a (particular) technical descriptor does not affect any of the customer requirement and can be removed from the house of quality.
Step 4: Develop an interrelationship matrix between roof of the house.
Called the correlation matrix.
2797810133159500Identify the interrelationship between each of the technical descriptors (support or conflict?). Positive and negative correlation identify the trade-off’s where necessary.
Step 5: Competitive Assessments: Competitive analysis is done to identify key areas to concentrate on the next design.
27279602647950Figure SEQ Figure * ARABIC 6: Technical competitive assessment
Figure SEQ Figure * ARABIC 6: Technical competitive assessment
2727960000Competitive products compare with organization current products
27241503213100Figure SEQ Figure * ARABIC 7: Prioritized technical descriptors
Figure SEQ Figure * ARABIC 7: Prioritized technical descriptors
272415056515000Step 6: Develop prioritized customer’s requirements by ranking each customer requirements.
Importance to customer
Step 7: Develop Prioritized technical Descriptors
Degree of difficulty: Rating from 1(least difficult) to 10(most difficult).
2316480320675Target value: Rating from 1(worst) to 5(best).
Figure SEQ Figure * ARABIC 8: Sample QFD matrix
MAJOR BENEFITS OF USING QFD:
Major reductions in development, cost and time, A significant reduction in start up problems and shorter design cycles.
Improved internal communication within teams.
Satisfied and delighted customer.
The quality and productivity of the service becomes more precise.
The house of quality clarifies the customer requirements to the team that results in a product with a competitive advantage.
Everything is preserved in writing and can be effectively considered for a trade off in future.
Ensures consistency between planning and production process.
DRAWBACKS IMPLEMENTING QFD
For a product with a lot of relational matrix, combined matrix gets complex and large.
It takes a lot of precision to make a right QFD for a product that is not physical in nature but rather a software.
It’s difficult to categories the demands of the customer into the house of quality chart due to ambiguity in VOC.
It takes time to develop a complete QFD chart thus it might get late and stop the rest of the development process.
QFD is not applicable for all the applications.
INDUSTRIES THAT MAKE BEST USE OF QFD: Benefits and Drawbacks
QFD originated in japan and its potential was realized in Japanese manufacturing industries and is often attributed to TOYOTA AUTO BODY INC. There use of QFD contributed to successfully solving their problem of rusting cars in the mid -1970s. In 1996 Hauser and Clausing compared start-up and preproduction costs in 1977 (before QFD), to those costs in 1984, when QFD was well under the way. HoQ meetings early on reduced the costs by more than 60%. As a result, the Japanese automaker with QFD made fewer changes than U.S automaker without QFD.
QFD in Japan: – The first ever study (1987) was done on mainly large manufacturing industries in japan. The highest ranked benefit was ‘easier setting up of design quality’ and ‘initial quality troubles reduced’.
QFD in USA: – Overall 35 manufacturing companies were surveyed (1992) of which only 25% were successful but all the projects gave some surprising benefits that were ‘more rational decisions in the product development process’, ‘improved information flow and ‘capture knowledge’. But the difficulties were attributed to the non-cross-functional environment in the team. Looking at this from another prospective: cross-functional teamwork is likely to improve.
QFD in Sweden: – Overall 31 Swedish manufacturing companies were investigated (1997), companies that were most successful in utilizing the benefit of the QFD stopped using it further after development of the House of Quality and did not carry further phase progression. Problems reported were as follow in rank order: ‘lack of management support’, ‘group member commitment’, ‘lack of resources and ‘lack of QFD experience’. Benefits that were reported in rank order were: – ‘Better communication’, ‘Knowledge was preserved’, ‘Unity in the group’ and ‘Better decision’.
“QFD is a method to transform qualitative user demands into quantitative parameters, to deploy the functions forming quality, and to deploy methods for achieving the design quality into subsystems and component parts, and ultimately to specific elements of the manufacturing process.”
Yes, I completely agree with this statement as QFD has its basis in being a quality tool that helps translate the Voice of the Customer (VOC) into product that truly satisfy their needs. The statement can be showcased with the help of describing the implementation process as below.
Level 1 QFD effort is to analyze and investigate the customer needs. VOC data is reduced into a set of critical customer needs using techniques such as higher to lower priority and documented in customer needs data table known as house of quality. The matrix is data concentrated and allows the team to visualize a large amount of information in one place.
Level 2 QFD matrix is a used during the Design Development Phase. The team can discover which of the assemblies, systems, sub-systems and components have the most impact on meeting the product design requirements and identify key design characteristics. The information used is a direct input to the Design Failure Mode and Effects Analysis (DFMEA) process. Level 2 QFDs may be developed at the following levels:
Level 3 QFD is used during the Process Development Phase where it is examined of the processes or process steps that have any correlation to meeting the component or part specifications. This information allows production and quality team to focus on critical to quality process.
Level 4 QFD is not utilized as often but lists all the critical processes or process characteristics in the “What’s” column on the left and then determine the “How’s” for assuring quality parts are produced and list them across the top of the matrix. This information is used for creating input to control plans.
In short, there is a rigorous consideration of a variety of factors in developing requirements and specifications. The matrix highlights which of the processes have the most impact on meeting the part specifications. The intent is to identify a more optimal, and perhaps even a break-through solution rather than continuing with the traditional concept used for past products. Using concept selection matrix requirements as a basis for decision criteria QFD places an emphasis on innovation and achieve design quality in subsystems and component parts. QFD, when performed with full understanding of the process and with adequate effort to collect and analyze the required data addresses the limitations that are common in product development hence improving specific elements in manufacturing process.
HOUSE OF QUALITY: VACUMN CLEANER
Customer requirements are divided according to properties into low weight, easy handling/cleaning, quite operation etc. Following steps to fulfill all the customers requirements and again adding each engineering parameter’ score and record in the far right “importance” column. The highest engineering parameter is found to improve “Dirt time Removal” and “power”. These two will be used to improve customer requirements “Strong Suction power”, “size of vacuum cleaner” and “filter bag volume”