ENGR1025 - Lecture 20

ENGINEERING DESIGN

  • Course Code: ENGR1025U
  • Lecture: 20
  • Topics Covered: Design for Manufacturing & Design for Environment

PRODUCT DEVELOPMENT PROCESS

  • Stages:

    • Planning
    • Concept Development
    • System-Level Design
    • Detail Design
    • Testing and Refinement
    • Production Ramp-Up

  • Focus: How to integrate manufacturing considerations throughout the development process.

CASE STUDY: DESIGN OF GENERAL MOTORS 3.8-LITER V6 ENGINE

  • Production: GM manufactures approximately 3500 3.8 Liter V6 engines daily.

  • Goals: Reduce costs while enhancing quality.

  • Team objective: Improve the air intake manifold, a costly subassembly.

  • Design Change:

    • Original Material: Cast Aluminum
    • Redesigned Material: Molded Thermoplastic Composite

DESIGN FOR OBJECTIVE FUNCTIONS (DFx)

  • DFM: Design for Manufacturing
  • DFA: Design for Assembly
  • DFQ: Design for Quality
  • Other objective functions can also be considered as DFx.

DESIGN FOR MANUFACTURING (DFM)

  • Definition:
    • DFM is a design approach that focuses on manufacturing issues early in the product development stage.
  • Key Insight: Quality and cost objectives cannot be met in isolation from design and manufacturing considerations.

DEFINITION OF DFM

  • Emphasizes the importance of manufacturing throughout design.
  • Successful implementation leads to lower production costs without compromising on quality.

THREE METHODS TO IMPLEMENT DFM

  1. Organization: Form cross-functional teams.
  2. Design Rules: Create firm-specific guidelines.
  3. CAD Tools: Utilize specialized software like Boothroyd-Dewhurst and SolidWorks for modeling and design optimization.

FIVE STEPS OF DFM

  1. Estimate manufacturing costs.
  2. Reduce costs of components.
  3. Reduce assembly costs.
  4. Decrease supporting production costs.
  5. Assess DFM decisions' impact on other factors.

UNDERSTANDING MANUFACTURING COSTS

  • Components of Manufacturing Cost:
    • Assembly Cost
    • Overhead Cost
    • Labor Costs
    • Equipment and Tooling Costs
    • Material Costs (Both Standard and Custom)

TOTAL MANUFACTURING COST

  • Exhibit Reference: Comparative cost analysis for injection molding vs. machining.
  • Injection Molding: Lower cost per unit with scale.
    • Mold Cost: $10,000
    • Fixture Cost: $1,000
    • Cost per unit: $1 (Material + Processing for large runs).

DESIGN FOR ASSEMBLY (DFA)

  • Key Principles:

    • Minimize parts count.
    • Encourage modular designs and stacked assemblies.
    • Eliminate unnecessary adjustments and cables.
    • Incorporate self-fastening and self-locating parts.

  • Benefits of DFA:

    • Reduced labor costs.
    • Lower indirect costs.

METHOD FOR PART INTEGRATION

  • Questions to determine necessity and integration of parts:

    • Does the part require independent movement?
    • Should it be made of different materials?
    • Is it necessary for assembly, access, or repair?

  • If a part fails to meet these criteria, it can potentially be combined with another part.

PART II: DESIGN FOR ENVIRONMENT

  • Goals of DFE: Minimize human health and environmental impacts throughout the product lifecycle.

DESIGN FOR ENVIRONMENT GUIDELINES

  • Focus Areas:
    • Processing and Manufacturing: Use environmentally safe materials and processes.
    • Packaging: Use recyclable or reduced packaging materials.
    • Disposal or Reuse: Design for end-of-life to minimize negative environmental impacts.
    • Energy Efficiency: Design to reduce energy consumption.

THE PRODUCT REALIZATION PROCESS

  • Stages: IDEA RECYCLING -> SALES & USE -> MANUFACTURE -> DEVELOPMENT -> CONCEPT -> PRELIMINARY DESIGN -> MATURE DESIGN.

PRP GATE QUESTIONS

  • Gate 1: Is the product meeting a need? Are there environmental/sustainability concerns?
  • Gate 2: Is it manufacturable? Profitable investment? Building on past experience?
  • Gate 3: Is the product well-defined? DFE approaches applied? Preliminary lifecycle assessment?
  • Gate 4: Does design meet expectations? Cost estimates accurate?
  • Gate 5: Does the product perform as designed? Manufacturing process effective? Environmental burdens acceptable?

LIFE CYCLE ASSESSMENT (LCA)

  • Purpose: Forecast impacts of different production alternatives to choose the most sustainable methods.
  • Criteria for Comparison: Energy use, toxicity, emissions, resource depletion, etc.
  • Examples of Analysis: Coffee container alternatives and their environmental impacts (mass to landfill, biodegradability, energy consumption).

STATS ON HOT DRINK CONTAINERS

  • Comparative Analysis:
    • Energy Consumed in Manufacturing:
    • Environmental Impact: Different containers analyzed based on recycling potential, energy consumed in washing, and heat recovery.

DISCLAIMER

  • Materials sourced from "Product Design and Development" by Karl T. Ulrich and Steven D. Eppinger.