Engineering Design Process Notes

Engineering Design Process Notes

  • The speaker emphasizes that engineering design is a formal, repeatable process used to turn ideas into reality and to create devices, structures, or systems that meet a need without causing harm. It is a cycle of continuous improvement and involves an iterative, nonlinear path rather than a simple straight line.
  • Key perspective: engineers aim for safety, reliability, success, and value (including financial rewards and accolades) while fulfilling user needs.
  • There is a recognition that there are many variations of the engineering design process (different numbers of steps, different depths), but eight steps are presented as a structured framework students can follow.
  • Real-world anchors given:
    • Internal ideas can originate within a company (example: 3M posters born from brainstorming while working on another project).
    • External needs come from outside the company (example: airports or military needs where technology is contracted from outside the core business).
  • The process is data- and research-driven, with emphasis on defining needs, constraints, and specifications before designing solutions.
  • A recurring theme is balancing time, cost, and performance, and recognizing that market demand can change the economics of a concept (value, cost, and price can diverge as demand grows).
  • The facilitator stresses collaboration and teamwork, and at one point assigns a group activity to explore the steps in more depth.

Key concepts and definitions

  • Engineering design process: a formal, repeatable sequence of steps used to transform an idea into a realizable device, structure, or system that satisfies a need. It is iterative, nonlinear, and aimed at continuous improvement toward a measurable goal.
  • Eight steps in the presented process (in order):
    1. Customer need or opportunity
    2. Definition of the problem or opportunity and listing of specifications/constraints
    3. Data and information collection
    4. Development of alternative designs
    5. Evaluation of designs and selection of the best design
    6. Implementation of the best design
    7. Testing and evaluation of the design
    8. Redesign and retest if necessary
  • Internal vs external needs:
    • Internal: ideas generated within the organization (e.g., 3M poster idea stemming from brainstorming during other work)
    • External: needs identified outside the company (e.g., military or security needs requiring external technology)
  • Specifications categories:
    • Performance specifications: weight, size, speed, safety, reliability, etc.
    • Economic specifications: cost, value, marketability, profitability
    • Scheduling specifications: production/delivery dates, seasonal demand, timeline
  • Important caveat about Step 4 (development of alternatives): procrastination can undermine success; always generate multiple designs, not just one.
  • Important caveat about Step 7 (testing): often the most neglected step, but crucial for validating that the design functions, is safe, and meets requirements before proceeding to final retesting or redesign.
  • Practical implication: even with a great idea, if it cannot be implemented within time constraints, a second-best design that meets the need more quickly may be preferable.

Step 1 — Customer need or opportunity

  • Sourced from two origins: internal and external.
    • Internal needs arise from ideas identified within the company while working on other projects (example: 3M brainstorming leading to posters that were posted around the workspace).
    • External needs arise from outside the company (example: US airports and border security requiring new technology; the core business is security, but the technology is contracted from outside or provided by another supplier).
  • Purpose: identify what the customer or stakeholder needs or what opportunity exists to improve a product, process, or system.

Step 2 — Problem definition and specifications/constraints

  • The problem or opportunity is defined clearly, with written specifications or constraints.
  • Specifications can be supplied by the client or gleaned from the concept, and may be refined later after further research (leading to Step 3 and possibly returning to Step 2).
  • Subcategories of specifications:
    • Performance specifications: focus on what the product must do (weight, size, speed, safety, reliability).
    • Economic specifications: cost, value, marketability; important for future redevelopments and scaling to mass production.
    • Scheduling specifications: production timelines, delivery dates, seasonal demand, and the overall project timeline.
  • Example discussion: a concept for a writing pen that doubles as a mini computer (integrating technology akin to a cell phone, while still allowing manual writing).
    • For cost considerations, imagine the initial cost to produce is $C_1 = 1000$ (currency units).
    • Later market expansion and demand can drive price/value higher, while costs may scale. An illustrative scenario shows costs increasing modestly (e.g., a 10% cost rise leading to $C2 = 1.1 imes C1 = 1100$) and price rising to $P_2 = 2000$.
    • The change in value due to demand can lead to higher profitability, illustrated by a higher selling price while costs rise only modestly.
  • Economic intuition: as demand grows, the price can rise (value increases) but cost may not increase proportionally, raising profitability. This is contextualized with an example where initial profit is modest (around 5%), and later profit becomes healthier as price increases and the cost increase is limited.

Step 3 — Data and information collection

  • Purpose: perform extensive data gathering to inform design decisions and to identify constraints that may need to be added to Step 2.
  • Research focus areas can include:
    • Dimensions and physical scales
    • Location and needs for communication or programming
    • Materials and structural considerations
  • Output of Step 3 can require revisiting Step 2 if new constraints are discovered during research.
  • This step grounds the design in evidence and helps determine the feasibility of proposed solutions.

Step 4 — Development of alternative designs

  • Key message: generate multiple designs (plural) after data collection; do not settle for a single design due to time pressure or perception of lack of time (procrastination).
  • Process: use creative problem solving and brainstorming to generate as many potential solutions as possible.
  • Methods mentioned:
    • Creative problem solving: a major method for generating multiple approaches.
    • Brainstorming: a technique to generate multiple ideas.
  • Purpose: create a broad set of viable options to enable meaningful evaluation in Step 5.

Step 5 — Evaluation and selection of the best design

  • If there is only one design, there is nothing to evaluate or compare; therefore, multiple designs are essential.
  • Evaluation approaches mentioned:
    • Common sense analysis: intuitive judgment based on experience and physical plausibility (e.g., which design body would most likely yield the fastest jet given two options).
    • Economic analysis: determine whether an alternative design fits within budget and provides expected value; consider cost vs. benefit and return on investment.
    • Compatibility analysis: assess which design is easiest to produce within the time schedule and the project constraints; check manufacturability and alignment with project timelines.
  • Important caution about time and practicality:
    • In classroom or project contexts, students may become infatuated with the best-looking or most ambitious idea and neglect simpler, faster alternatives.
    • If a project has a tight deadline (e.g., three weeks) but the best idea would take longer (e.g., ten weeks), consider selecting a second-best design that meets the essential needs and completes on time.
  • The goal is to narrow the set of alternatives to the most viable design(s) that best meet customer needs within constraints.

Step 6 — Implementation of the best design

  • Put the chosen design into production or execution plans.
  • This step requires moving from planning to action, with documentation and resources aligned to make the design a reality.
  • The emphasis is on ensuring the best design meets the overall objective and can be implemented effectively within the given constraints.

Step 7 — Testing and evaluation of the design

  • Often cited as the most important step by the speaker because it validates whether the design actually functions as intended.
  • Testing goals include:
    • Assessing physical appearance, quality of materials, and safety
    • Evaluating functionality, sturdiness, and operational performance
  • Common pitfalls:
    • Skipping testing due to time constraints or overconfidence in the chosen design
    • Demonstration day failures where the device does not operate as expected, leading to embarrassment or team reputational harm
  • The outcome of testing informs Step 8 (redesign) if changes are needed to meet requirements or fix issues revealed during tests.

Step 8 — Redesign and retest if necessary

  • If testing reveals deficiencies, redesign is performed to address issues and then retesting is conducted to verify improvements.
  • The cycle continues until the design satisfies the objective and passes all tests.

Examples, scenarios, and real-world relevance

  • Internal example: 3M posters emerged from brainstorming while workers were pursuing another project; led to a culture of idea capture and cross-pollination of concepts.
  • External example: US airports and border security needs led to leveraging external technology providers; demonstrates the value of identifying opportunities beyond the core business and engaging partners to meet critical needs.
  • Product concept example: a pen that functions as a mini computer while still enabling manual writing; demonstrates tradeoffs among performance (tech features), cost, and market demand.
    • Economic narrative: initial cost to produce a unit is $C1 = 1000$; as demand grows and production scales, the cost may increase to $C2 = 1.1 imes C1 = 1100$, while price increases to $P2 = 2000$ due to higher perceived value or market demand. Profit is
      extProfit=P<em>2−C</em>2=2000−1100=900,ext{Profit} = P<em>2 - C</em>2 = 2000 - 1100 = 900,
      and profit margin relative to revenue is
      extProfitMargin=P<em>2−C</em>2P2=9002000=0.45.ext{Profit Margin} = \frac{P<em>2 - C</em>2}{P_2} = \frac{900}{2000} = 0.45.
    • The discussion highlights that value (and thus potential price) can grow with demand, and the cost increase may be modest, improving profitability. In the narrative, there was mention of profitability moving from a lower percentage (about 5%) toward higher profitability as the product scales, with the suggestion that next-market opportunities might push price and value higher, while costs rise modestly due to economies of scale or design improvements.
  • Time and scheduling emphasis: a project might have a tight deadline (e.g., three weeks) versus a design that technically could take longer (ten weeks). In such cases, choosing a viable, faster alternative (even if not the absolute best concept) better serves the objective and meets the deadline.
  • Demonstrations and education: the instructor highlights the ethical and professional responsibility to test thoroughly to avoid embarrassment and to deliver working, reliable projects during class demonstrations.

Formulas and numerical references (LaTeX)

  • Basic economic relationships:
    • Revenue: R=PimesQR = P imes Q
    • Cost: CC
    • Profit: extProfit=R−C=PimesQ−Cext{Profit} = R - C = P imes Q - C
    • Profit Margin (relative to revenue): extProfitMargin=R−CR=PimesQ−CPimesQext{Profit Margin} = \frac{R - C}{R} = \frac{P imes Q - C}{P imes Q}
  • Example with unit costs and price progression:
    • Initial unit cost: C1=1000C_1 = 1000
    • Later unit cost after modest increase: C<em>2=1.1imesC</em>1=1100C<em>2 = 1.1 imes C</em>1 = 1100
    • Market-driven price: P2=2000P_2 = 2000
    • Resulting profit: extProfit<em>2=P</em>2−C2=2000−1100=900ext{Profit}<em>2 = P</em>2 - C_2 = 2000 - 1100 = 900
    • Resulting profit margin: extProfitMargin2=9002000=0.45ext{Profit Margin}_2 = \frac{900}{2000} = 0.45
  • Example time/delivery references mentioned: specific days like 11/30/202811/30/2028 and durations such as extweeksext{weeks} (e.g., three weeks vs ten weeks) to illustrate scheduling constraints.

Practical takeaways

  • Always start with the user need or opportunity and clearly specify constraints (Step 1–2).
  • Collect data thoroughly (Step 3) to ground the design in reality and reveal constraints that may alter earlier specifications.
  • Generate multiple design options (Step 4) to enable meaningful comparison (Step 5).
  • Use a structured evaluation framework (common sense, economic viability, and compatibility) to select the best design (Step 5).
  • Move to implementation, then rigorously test (Step 6–7) to ensure the design meets requirements and is safe and reliable.
  • Be prepared to redesign and retest (Step 8) based on test results.
  • Be mindful of time pressures and avoid procrastination; choose the best feasible option within the timeline when necessary.
  • Ethics and professional practice: prioritize safety, reliability, and the public good; ensure testing is thorough to prevent failures during demonstrations or real-world use.

Connections to broader themes

  • This design process aligns with foundational engineering principles: define, explore, test, and iterate toward a realizable, safe, and valuable solution.
  • It emphasizes the balance between technical feasibility, economic viability, and schedule constraints, which is critical in real-world product development, defense-related projects, and consumer technologies.
  • The discussion reinforces the importance of teamwork, documentation, and communication, as ideas move from concept to design to production and testing.

Summary of key steps (quick reference)

  • Step 1: Identify customer need or opportunity (internal vs external sources).
  • Step 2: Define problem/opportunity and list specifications/constraints (performance, economic, scheduling).
  • Step 3: Collect data and information; refine constraints as needed.
  • Step 4: Develop multiple alternative designs through brainstorming and creative problem solving.
  • Step 5: Evaluate designs using common sense, economic analysis, and compatibility analysis; select the best design.
  • Step 6: Implement the best design.
  • Step 7: Test and evaluate the design; ensure it meets requirements and safety standards.
  • Step 8: Redesign and retest if necessary; iterate until goals are met.