Waterfall

Waterfall

Overview

The Waterfall model, also known as the Generic Product Development Process for market-pull products, is a sequential approach with six distinct phases. Each phase must be completed before the next begins. This documentation-driven approach is commonly used for products with well-understood requirements such as sporting goods, furniture, and tools.

ELI5

Waterfall is like baking a cake by following a recipe EXACTELY:

Step 1: Read the whole recipe first Step 2: Buy all ingredients Step 3: Mix everything Step 4: Bake it Step 5: Eat it

The Problem: You can’t go back!

If you forgot sugar in Step 2, and you’re already at Step 4 (baking)… TOO LATE! You can’t add sugar now!

Good for: Recipes you’ve made before (you know exactly what you need)

Bad for: Making a NEW kind of cake (what if the recipe is wrong?)

Core Concept

The Generic Product Development Process (also called Waterfall) is used for market-pull products and consists of six sequential phases.

Phase 0: Planning - Technology assessment and market objectives are defined. This phase sets the foundation for the entire project.

Phase 1: Concept Development - Customer needs are identified and concepts are evaluated. Multiple concepts may be generated and compared.

Phase 2: System-level Design - Product architecture is defined and subsystems are identified. The overall structure of the product takes shape.

Phase 3: Design Detail - Geometry, materials, and tolerances are specified. Every component is fully defined.

Phase 4: Testing and Refinement - Preproduction prototypes are built and tested. Problems are identified and fixed.

Phase 5: Production Ramp-up - Workers are trained and any remaining flaws are resolved. Full-scale production begins.

This approach is commonly used for sporting goods, furniture, and tools - products where requirements are well understood and changes are costly once production begins.

Components / Framework

Phase	Name	Key Activities	Source
Phase 0	Planning	Technology assessment, market objectives	Chapter3.pptx, Slide 9
Phase 1	Concept Development	Identify needs, evaluate concepts	Chapter3.pptx, Slide 9-15
Phase 2	System-level Design	Product architecture, subsystems	Chapter3.pptx, Slide 9-15
Phase 3	Design Detail	Geometry, materials, tolerances	Chapter3.pptx, Slide 9-15
Phase 4	Testing and Refinement	Preproduction prototypes	Chapter3.pptx, Slide 9-15
Phase 5	Production Ramp-up	Train workers, resolve flaws	Chapter3.pptx, Slide 9-15

Example

From Slides: The Generic Product Development Process is illustrated with six sequential phases, starting from planning (Phase 0) through production ramp-up (Phase 5). Each phase produces deliverables that feed into the next phase.

Real-World Example - Furniture Design: A furniture company designing a new chair follows the Waterfall approach:

• Phase 0: Assess market for office furniture trends
• Phase 1: Develop concepts (ergonomic, modern, traditional)
• Phase 2: Define overall chair architecture (seat, back, legs, armrests)
• Phase 3: Specify exact dimensions, wood types, joint details
• Phase 4: Build prototypes, test for comfort and durability
• Phase 5: Train assembly workers, begin full production

Real-World Example - Sporting Goods: A golf club manufacturer uses Waterfall:

• Requirements are well understood (distance, accuracy, feel)
• Design is fully specified before tooling is created
• Changes after Phase 3 are very expensive (new molds)

Implications

• Best suited for products with stable, well-understood requirements
• Provides clear milestones and documentation at each phase
• Changes become increasingly expensive as the project progresses
• Not suitable for products with high uncertainty or rapidly changing requirements
• Commonly used in industries where safety and reliability are critical
• Provides clear handoffs between functions

Related Concepts

• Concurrent Engineering: Replaces sequential Waterfall with simultaneous development
• Agile: Iterative alternative to Waterfall for uncertain requirements
• QFD: Can be used within Phase 1 (Concept Development) to capture customer needs

Quick Summary

• Generic Product Development Process (market-pull products)
• Six sequential phases:
  1. Phase 0: Planning (technology assessment, market objectives)
  2. Phase 1: Concept development (identify needs, evaluate concepts)
  3. Phase 2: System-level design (product architecture, subsystems)
  4. Phase 3: Design detail (geometry, materials, tolerances)
  5. Phase 4: Testing and refinement (preproduction prototypes)
  6. Phase 5: Production ramp-up (train workers, resolve flaws)
• Used for: sporting goods, furniture, tools
• Sequential: each phase must complete before next begins

Exam Tips:

• Waterfall = SEQUENTIAL phases (one finishes, next begins)
• If requirements are uncertain or likely to change, Waterfall is NOT appropriate
• Changes are expensive once you’re past Phase 3 (Design Detail)

Sources

• Chapter3.pptx [Slide 9-15]
• MGH_book.pdf