Ch.07 Design for Quality and Product Excellence pt1

Introduction to Quality by Design (QbD)

• Definition of QbD: Building quality into products and processes.
• Benefits: Reduces costs and improves quality.
• Flaws in Design: Many failures arise from inadequate designs.
• Role of Design: Supports customer needs, enhances quality, and promotes innovation.

Product Development Phases

• Structured into six phases:
  1. Idea Generation: Brainstorming and generating new product ideas.
  2. Preliminary Concept Development: Selecting the best ideas and developing them into feasible concepts.
  3. Product/Process Development: Finalizing the product design and necessary processes for production.
  4. Full-Scale Production: Initiating mass production in alignment with market demand.
  5. Market Introduction: Launching the product into the market.
  6. Market Evaluation: Assessing product performance and customer feedback.

Concurrent Engineering

• Definition: A collaborative process where all functions (design, manufacturing, marketing) are involved throughout product development.
• Advantages: Shorter development time, reduced costs, and better products upon introduction.
• Disadvantages of Serial Development: Longer time frame, higher costs before engineers’ input, and potentially suboptimal market fit.

Design for Six Sigma (DFSS)

• Purpose: To ensure product quality and customer satisfaction.
• Four Principal Activities:
  1. Concept Development: Ideating potential product features.
  2. Detailed Design: Creating precise design specifications.
  3. Design Optimization: Refining the design for performance and manufacturability.
  4. Design Verification: Testing the design to ensure it meets required specifications.
• DMADV Process: Define, Measure, Analyze, Design, and Verify.

Concept Development, Innovation, and Creativity

• Concept Development: Merging scientific, engineering, and business principles to innovate.
• Types of Innovation:
  • Entirely new products.
  • Products new to the market.
  • Significant enhancements of existing products.
  • Minor improvements on current offerings.
• Creativity: Involves novel thinking and seeing problems differently.
• TRIZ: Theory of Inventive Problem Solving, involving 200 exercises to enhance creativity.

Detailed Design

• Definition: Converts conceptual designs into actionable technical specifications.
• Axiomatic Design Principles:
  • Independence Axiom: Ensure functional requirements are independent of one another.
  • Information Axiom: Keep design complexity low for optimal functionality.
• Benefits: Shorter design times and superior outcomes.

Quality Function Deployment (QFD)

• Definition: A process integrating customer voice into product design and marketing.
• Benefits: Enhances communication, decreases costs and development time.
• House of Quality: A tool for customer requirement planning and product performance assessment.

Steps for Building a House of Quality

1. Identify Customer Requirements: Gather data on what customer needs are.
2. List Technical Requirements: Define specifications needed to meet those needs.
3. Relate Customer to Technical Requirements: Establish connections between the two sets of requirements.
4. Evaluate Competing Products: Assess other market offerings.
5. Develop Targets: Set performance metrics for each technical requirement.
6. Deploy Technical Requirements: Implement these specifications into production.

Tolerance Design

• Definition: Establishing acceptable variations in product specifications.
• Importance of Narrow Tolerances: Reduces reject rates and improves quality, whereas wide tolerances lead to higher costs due to scrap.

Taguchi Loss Function

• Concept: Advocates for minimizing variations from target specifications, monetizing the cost impact of deviations.
• Equation: L(x) = k (x - T)^2 ; E[L] = k (σ^2 + D^2)
• Types of Loss Functions: Nominal-Is-Best, Smaller-is-Better, and Larger-is-Better.

Practical Examples of Taguchi Loss Function Application

• RoadRunner Fertilizer: Analyzed costs of repackaging outside of specifications leading to formulation of a loss function.
• Sony TVs Case Study: Demonstrated cost differences in expected losses between production in different locations based on variation levels.
• Musical Instrument Example: Discussed how to set tolerances for CT speed to ensure quality and minimize costs.

Summary

• Broad Insights: QbD, DFSS, and rigorous design principles lead to enhanced product performance and market success. Applied frameworks like QFD and Taguchi's concepts help in aligning product design with customer expectations and maintaining cost-efficient practices.