Quality Function Deployment (QFD) is a focused methodology, process, and set of tools used by organizations to understand and meet the needs and expectations of their customers. Also known as matrix product planning, decision matrices, House of Quality matrix, or customer-driven engineering, it focuses on carefully listening to the voice of the customer and effectively responding to their requirements. QFD is used to translate Voice of the Customer (or VOC) into measurable design targets and drive them from the assembly level down through the sub-assembly, component, and production process levels.
Originating in Japan in the late 1960s, QFD was first developed in Japan by Yoji Akao while working for Mitsubishi’s shipyard. It was later adopted by other companies including Toyota and its supply chain. Yoji Akao wanted to help transform the voice of the customer into engineering characteristics for a product. His idea was to turn qualitative user demands into quantitative parameters, deploying the functions forming quality and the methods for achieving design quality into subsystems, component parts, and ultimately to specific elements of the manufacturing process.
In the early 1980s, QFD was introduced in the United States mainly by the big three automotive companies and a few electronics manufacturers. Acceptance and growth of the use of QFD in the US was initially slow but has since gained popularity and is currently being used in manufacturing, healthcare and service organizations. The goal of QFD is to measure customer satisfaction with a product or service, using a structured approach that utilizes the management and planning tools to quickly and effectively identify and prioritize customers' expectations.
At the core of QFD is the House of Quality, an initial matrix that helps prioritize the most important attributes and qualities of a product or service. These attributes consist of customer wants and needs, as determined through an analysis of customer perception versus reality. Once these attributes are prioritized, QFD deploys them to the relevant organizational functions for action, effectively aligning customer-driven qualities with the responsible functions of the organization.
The House of Quality is a design tool that classifies and correlates customer desires, importance levels, engineering characteristics, and system requirements. It provides a matrix with customer desires on one dimension and correlated nonfunctional requirements on the other. By assigning weights to stakeholder characteristics and system parameters, the House of Quality facilitates the identification of key correlations and priorities for system requirements. This tool enables the assessment of different system compositions and allows for the refinement of stakeholder needs based on correlations.
The application of QFD can be in various fields, including product design, manufacturing, production, engineering, research and development (R&D), information technology (IT), support, testing, regulatory compliance, and more. It is employed across different industries, such as hardware, software, services, quality improvement, quality management, military, and consumer products.
In addition to traditional QFD, there are derived techniques and tools that enhance the process. Fuzzy QFD applies fuzzy logic to incorporate uncertainty and multiple-criteria decision analysis methods. Modular function deployment uses QFD to establish customer requirements and emphasize modularity in design.
Implementing QFD provides several benefits to organizations. It ensures that the emphasis remains on the wants and needs of the customer, allowing for the translation of the Voice of the Customer into technical design specifications. QFD enables VOC competitor analysis, facilitating direct comparisons with competitors and aiding in design decisions. By focusing on customer requirements, QFD reduces development time and costs associated with non-value-added features. It also provides a structured method for documentation, recording decisions, and lessons learned during the product development process, serving as a valuable knowledge base for future projects.
The QFD methodology follows a four-phase process throughout the product development cycle. It involves collecting VOC, translating customer requirements into product specifications, identifying critical parts and assemblies, designing manufacturing and assembly processes, and implementing process quality control measures:
This phase begins with the collection of VOC and translating the customer wants and needs into product specifications. It can also involve a competitive analysis to evaluate how effectively the competitor’s product fulfills customer wants and needs. The initial design concept is based on the particular product performance requirements and specifications.
During this phase, the critical parts and assemblies are identified. The critical product characteristics are cascaded down and translated to critical or key part and assembly characteristics or specifications. The functional requirements or specifications are then defined for each functional level.
In this phase, the manufacturing and assembly processes are designed based on product and component specifications. The process flow is developed and the critical process characteristics are identified.
Prior to production launch, the QFD process identifies critical part and process characteristics. Process parameters are determined and appropriate process controls are developed and implemented. In addition, any inspection and test specifications are developed. Full production begins upon completion of process capability studies during the pilot build.
Quality Function Deployment (QFD) is a powerful methodology for understanding and meeting customer needs. By utilizing structured tools and techniques, organizations can align their products and services with customer expectations, leading to improved customer satisfaction and successful business outcomes.