• DFSS is a systematic methodology to design new products or processes so that quality is built into every phase of product design. It is also used for improving existing products through redesign.
• The roots of DFSS are in systems engineering. It combines systems engineering methodology with statistical methods to achieve 'built-in quality' objectives.
• DFSS optimizes the critical to quality (CTQ) characteristics to achieve the best system performance. (CTQs are the selected few measurable quality characteristics that are key to a specific product, process, or service that must be controlled to meet or exceed customer expectation).
• DFSS uses Robust Design, Design of Experiment (DOE), Design for Manufacturability, Simulation and several other tools to optimize product design.
• DFSS balances the cost and quality.
• DFSS reduces the development cycle time in the long run.
• In DFSS, both engineering methods and statistics are used to optimize the design requirements.
• Like Six Sigma, the DFSS also uses a collection of tools. These tools must be understood in context to the engineering design for achieving DFSS objectives.

Design for Six Sigma Methodology

• The DFSS methodology has been identified by a five-step process: DMADV that stands for Define, Measure, Analyze, Design, and Verify. These are explained briefly.
• Define: determine the project need, identify the project goals and objectives, determine customers' needs and requirements, and include the voice of customers (VOC)
• Measure: determine the characteristics critical to quality, prioritize customer needs and requirements, and assess customers' needs and CTQ metrics
• Analyze: evaluate the process options to meet customers need and CTQs
• Design: design product and process to meet the customer requirements, include customer requirements in the development process
• Verify: check the design to ensure that the customers' requirements are met

The DFSS is also identified by IDOV process that stands for Identify, Design, Optimize, and Validate.

• Identify: Identify customer requirements, and address the voice of customer (VOC) issues. Prioritize customer requirements, use house of quality to identify and define CTQs.
• Design: Identify product design parameters and characteristics; build a database about the product and related process, and 'design in' key customer requirements.
• Optimize: Optimize the design to achieve a balance of quality, cost, and time to market. Create 'robust' design that will minimize the impact of variation in the production process.
• Validate: Demonstrate using data that the product and process is capable, the process capability meets appropriate sigma level, satisfies the CTQs, and meets the customer's requirements (VOC) and expectations.

Design for Six Sigma Tool

Tools available to aid in the product design and development process

• Quality Function Deployment and House of Quality
• Concurrent Engineering
• CAD/CAM
• Robust Design
• Detailed Design and Analysis (Tolerance Design, Design for Manufacturability, Standardization and Simplification)
• Failure Mode and Effects Analysis (FMEA)
• Reliability Testing

QFD (Quality Function Deployment): An Important Tool for DFSS

Quality Function Deployment (QFD) is an approach used to meet the customers' requirements in the product design and development.

It helps to integrate the voice of customers and critical quality characteristics in the design of the products so that the products meet or exceed customer expectations.

QFD helps eliminate the traditional and wasteful design/redesign efforts by identifying and incorporating customer requirements at the earliest stage of design. Other benefits of QFD include:

• Closer interaction between marketing, design, manufacturing, purchasing, and suppliers
• Reduced product development time,
• Faster market entry, and
• Customer focus.

An example of QFD follows:

QFD (Quality Function Deployment) Process

Minitab Course Material Learning Modules & Tools Lean Six Sigma & DFSS