QFD (Quality Function Expanding) originated in Japan in the 1960s and was proposed by Japanese quality management masters Yoji Akao and Shigeru Mizuno. At that time, Japanese industry changed from imitation production to innovation-based product development model. QFD, as a method or concept for the development of new products under comprehensive quality control, was widely used in the late 1970s in Japan's automobile and electrical appliance fields, helping Japan's product occupation. The world market is regarded as an important feature of Japanese-style quality management.

In 1985, QFD began to be used in the United States, and with the application of 6σ quality management technology in the United States, it became an important quality management technology. The first International Quality and Function Exhibition Seminar (ISQFD) was held in Tokyo in 1995, promoting QFD technology to the world and becoming a popular quality management technology and method. my country introduced this technology in 1994. The Quality Department of the State Administration for Quality Supervision invited Professor Yoji Akao to give lectures and train Chinese personnel. It has been applied in manufacturing and other fields and achieved good results.

Quality Function Deployment (QFD, Quality Function Deployment), also known as Quality Function Configuration. Japanese scholar Yoji Akao defines it as: converting the quality characteristics of users' demands into the design quality of the final product through systematic expansion, and extending to the quality of each functional component, part and process.

ASI (American Supplier Association) in the United States believes that QFD provides a corresponding technology to convert user needs into various stages of product development and production (including market analysis, system planning, product design, prototype evaluation, production process and sales services, etc.) The method of demand is a general term for all activities required to ensure the product quality required by users.

Ford Motor Company in the United States defines QFD as: converting user needs and expectations into a planning tool that the company is suitable for market needs.

Based on these definitions, the QFD method mainly contains the following meanings:

It is a product development and planning method driven by user needs.

It is a structured product planning and development method that helps to clearly understand user needs during product development.

It can systematically evaluate or compare the performance of products or services from the perspective of meeting user needs.

Use a systematic method to obtain and analyze user needs, and convert them into various technical specifications and information (product characteristics, process characteristics, quality control and processing processes, etc.) through structured (matrix diagram method), coordinate various work to ensure the final product Quality requirements.

The application practice of QFD method in many famous enterprises in Japan and the United States has proved that it plays a significant role in the development of new products and brings practical benefits. Quantitable benefits include shortening the development cycle of new products, reducing the number of design changes, reducing product development start-up funds, reducing policy claims, and increasing market sales.

In addition, there are a series of unquantifiable benefits:

During the product development process, help product developers to understand user needs more accurately, develop products that truly satisfy users, and significantly improve users' satisfaction with new products.

Taking into account factors such as user needs, competitors, technical characteristics and process costs can not only improve productivity, but also improve product quality, thereby enhancing the company's market competitiveness.

Promote the various departments participating in product development to reach consensus and establish information connections, transform top-down information flow into horizontal information flow, and establish a collaborative working model of multi-functional development teams, which will help to achieve higher development success rate and profitability A stronger new product.

The systematic and structured analysis problem-solving and planning decision-making methods provided by QFD can concisely and intuitively show developers the experience, knowledge and technology in product design, which facilitates the rational allocation and utilization of various resources within the enterprise and properly solve the product development process. conflicts or conflicts that may arise in.

The basic principle of QFD is to use the form of "House of Quality" to quantify the relationship between customer needs and engineering measures, and find out the engineering measures that contribute the most to meeting customer needs through data analysis, namely key measures. This guides designers to grasp the main contradictions, carry out stability optimization designs, and develop products that are satisfactory to customers. Quality houses are crucial to businesses, and product designers, sales staff and senior managers can get relevant information from them. It usually consists of the following 6 parts:

Customer needs and their weight: that is, the "What" of the quality house is the input information of the quality house. Most customer needs need to be obtained through questionnaires through market surveys on customers, converting customers' voices into real needs and then into product characteristics. The extraction of user demand information includes reasonably determining the survey object, determining reasonable research methods, and conducting comprehensive market research.

Technical requirements (final product characteristics): that is, the "How" of the quality house is a technical feature that must be achieved to meet user needs, and is also a means or measure to realize the needs. The establishment of technical characteristics must meet the targetedness (proposed for user needs), measurability (easy to measure and control), and globality (providing evaluation criteria for the selection of design plans, and do not involve specific design plans, and can meet at least one user needs. ) These 3 conditions.

Relationship matrix: reflects the degree of correlation between customer needs and technical needs, and reflects the mapping relationship from user needs to product technical characteristics. The development team needs to determine the extent to which each design requirement affects all customer requirements.

Technical Requirements Relevance Matrix: Located on the roof of a quality house, recording the degree of support, conflict and correlation between design requirements.

Evaluation matrix: Competition analysis: From the customer's perspective, evaluate the products of our company and other competitors in the market in meeting customer needs. The purpose is to determine the competitive advantages and disadvantages of our company's products, find breakthrough improvement directions and areas, and set strategic goals for new products or services.

Technical evaluation: conduct competitive assessment of technical needs, determine the importance and target value of technical needs, etc. Including determining the weight of design requirements based on the importance and relationship matrix of customer requirements; conducting technical capabilities assessment of the company and its main competitors from the company's perspective; comprehensively integrating the weight of correlation matrix, technical competitive analysis and design requirements to determine the goals of design requirements value.

The commonly used method of QFD is the 4-stage decomposition method, which decomposes user needs into 4 stages: product planning, component configuration, process planning and production planning. Through four matrices, the process and quality control parameters of the product are obtained. When applying the QFD method, you need to first establish a quality house at each stage, then change the requirements, and finally form clear production requirements and complete the entire process of product development quality function development.

Product planning matrix: convert customer needs into product technical characteristics, and based on customer competitive evaluation (evaluation of similar products on the market from the customer's perspective) and technical competitive evaluation (evaluation of similar products on the market from the technical perspective) results, Determine the target values ​​of each technical requirements of the product.

Product/part configuration matrix: Use the product technical characteristics defined in the product planning stage as input, determine the best product design plan, conduct product structural design, and then convert the product technical characteristics into key component characteristics. For complex products, it can be completed in several sub-stages.

Process planning matrix: On the basis of determining the process plan, the key process operations and process parameters that must be guaranteed to ensure the realization of important product technical characteristics and component characteristics through the "quality house" of process planning.

Production planning matrix: convert key process operations and process parameters into specific and feasible production and quality control methods and means, including control parameters, control points, sample capacity and inspection methods.

Affinity Diagrams: Make customer needs with deep structural characteristics "surface".

Relations Diagrams: Used to discover priority needs, the root causes of product quality process problems, and silence customers' needs.

Hierarchy Trees: used to find defects and omissions in affinity and tree maps.

Various Matrixes: used to represent the relationship, priority and responsibility between indicators.

Process Decision Program Diagrams: Used to analyze potential factors that may cause the failure of new products or services.

Analytic Hierarchy Process: prioritizes a series of customer needs and selects design and production solutions that meet these needs.

Blueprinting: Analyze and describe the entire process of providing products or services.

House of Quality: The core tool of QFD, used to quantify the relationship between customer needs and engineering measures.

QFD is currently widely used in product design and development, product production, quality improvement, planning, management and other aspects, and the potential application areas are constantly expanding.

Product design and development: Unlike traditional quality control methods, QFD takes quality as a consideration at the beginning of product design, and transforms the post-control of product quality into precautions. It has been used in the design and development of pruning scissors, high-voltage resistant electronic components, social systems, sports products and other products.

Product production: QFD originated from the quality control practice of Kobe Shipyard in Japan, and now plays a role in the manufacturing process of semiconductors, electronic products, automobiles and other products.

Quality improvement: As one of the tools of total quality management, the application of QFD in product quality management includes process improvement, process management and quality function development, process control, quality assurance in the use stage, etc. Total quality management emphasizes the management of the entire process from customer quality requirements to customer satisfaction, and QFD helps achieve this goal.

Plan: QFD is an active "customer-driven planning process", which can discover and solve problems at the beginning of product development to avoid losses caused by quality problems in the subsequent stages. Its concept can be applied to ordinary product plans and process plans, and can also be used in comprehensive plans, strategic plans and other types of plans, such as civil engineering, corporate resource plans, manufacturing strategic plans, investment plans, etc.

Management: QFD determines product design parameters and specifications by analyzing customer needs and considering competitors. It is a customer-driven and market-oriented management process. Specifically applied to knowledge management, supplier selection, cost control, time control, project management, benchmark management and other aspects.

Taking the design and development of mountain bike frames as an example, building a quality house requires the following seven steps:

List customer requirements: Customers’ needs or expectations for products or services can be defined in hierarchical terms. For example, customers' requirements for mountain bike frames, the first level is economy, aesthetics, and performance; the second level is further developed, and the economy requires appropriate prices, and aesthetics requires coordinated appearance, polished appearance, corrosion-proof, and performance. In terms of aspects, it requires lightness, fastness, durability, etc.

List technical or measure requirements: that is, engineering characteristics or technical requirements, which can also be defined in hierarchical levels. The technical requirements of mountain bike frames, the first level is material selection and manufacturing process; the second level is material selection and steel, aluminum, and titanium, and the manufacturing processes include welding, pressure casting, sand casting, forging and powder. metallurgy.

Analysis of the correlation relationship between customer requirements and technical requirements: Use specific symbols to define the correlation, such as "=9" means a strong relationship, "O=3" means a medium relationship, "△=1" means a weak relationship, and blank means no relationship.

Analysis of correlation between various technical requirements: specific symbol definition is also used, "=9" means strong positive correlation, "O=3" means positive correlation, "×=-3" means negative correlation, and "=-9" It indicates a strong negative correlation, and blank indicates no correlation.

Competitive evaluation and analysis: mainly includes customers' evaluation of product competitiveness and product technical competitiveness. The scoring benchmarks are 1-5 points, 1 point means the worst, and 5 points means the best.

Carry out the order of customer requirements: Consider the following factors:

Carry out technical requirements sorting order: consider the following factors:

After completing these seven steps, a complete quality house will be built to achieve the conversion of demand in product design and development. By analyzing the structure of the quality house and the various numerical relationships, it can be seen that product design and development that meets the most concerned requirements of customers and has technical and technological feasibility must comprehensively consider the absolute value/relative value (the larger the value, the more priority it is) and the degree of technical difficulty ( The lower the higher the correlation), and the HOWS (positive or strong positive correlation can be considered). In the mountain bike frame design case, a comprehensive analysis shows that in terms of material selection, aluminum material is the first choice because of its low technical difficulty; in terms of manufacturing process, sand casting technology is low and positively related to aluminum material, which is a feasible choice. However, due to possible deviations in data collection, R&D personnel can only use these output information as an important reference for design and development input information, rather than an absolute basis.

QFD converts customer or market requirements into design requirements, component characteristics, process requirements, and production requirements, and is a multi-level deductive analysis method. According to literature reports, the use of QFD method can bring many positive effects:

The product development cycle can be shortened by one third, the cost can be reduced by one half, the quality can be greatly improved, and the output can be increased exponentially.

Prompt product developers to consider manufacturing issues during the product design stage, achieve cross-parallel parallelism of product design and process design, reduce engineering design changes by 40%-60%, and shorten product development cycle by 30%-60%.

QFD emphasizes effective planning in the early concept design stage of the product, which can reduce product development and trial production costs by 20%-40%.

The entire product development process is driven by customer needs, which can greatly improve customer satisfaction with the product.

By implementing QFD, it can enhance the awareness of all employees to meet customer needs, which is of great significance to the development of the enterprise.

Customer-driven product development method: Customer needs run through the entire process of product development and are the goal of product development. QFD technology can help companies develop products that customers truly satisfy. The company ensures that the product meets customer expectations by studying and analyzing customer needs and converting them into final product characteristics and configuring them into various processes and production plans of the manufacturing process. The distinctive feature of QFD is that it continuously listens to customer opinions and needs and reflects these needs in its products.

Methods for coordinating work of various functional departments: In the process of achieving customer needs, QFD assists various functional departments in product development to formulate relevant technical requirements and measures. It has achieved the transformation from the traditional passive and reactive "design-test-adjustment" product development model to the active and preventive modern product development model, focusing on planning and problem prevention rather than just solving problems.

Quality assurance method in the product design stage: The outstanding advantage of QFD is that it can effectively plan and prevent problems in the early design stage of the product, and avoid unnecessary rework and repetitive work in the later stage of product development. Applying the QFD method in the stages of product planning, part configuration, process planning and quality control planning can make the information in the manufacturing field originate from user information. This means that when the product is manufactured, if the operating instructions are followed, the product produced should be able to meet user needs, which is more practical than the traditional concept of only meeting design requirements.

Methods to help products occupy the market: QFD obtains customer needs through market research, uses matrix diagram method to break down demands into various process and functional departments of product development, and coordinates the work of each department to ensure the quality of the final product so that the product can truly meet customer needs. Developing a QFD matrix helps enterprises understand customer needs, determine the technical needs of the part configuration stage when resources are limited, and improve customer satisfaction. When choosing a priority configuration project, we need to comprehensively consider factors such as the importance of technical requirements, user competitive evaluation, technical competitiveness evaluation, technical implementation difficulty and cost, and technical requirements correlation matrix, so that the product can be at the fastest speed, lowest cost and best quality. Capture the market in volume.

QFD is a new product development and quality assurance technology formed to meet user needs, improve product quality, and win market competition. It has been successfully applied in product development and service industries. It can accurately transfer customer and market demand to technical needs and measures at all stages of product development. In an environment of fierce market competition, enterprises need to constantly understand customer needs and reflect them in their products to produce products that satisfy customers. As the demand trend of user-made products increases, the definition of quality has changed from "meeting design needs" to "meeting customer needs", and the role of QFD in corporate development is becoming increasingly important.