Key Concepts

Engineering Design Process:

• Identify the Problem:

  • Define the Problem or Need: Clearly state what the problem is that needs solving or what need is to be met.

  • Understand Requirements and Constraints: Identify what the users need, any budgetary constraints, time limits, and available resources.

  • Establish Design Criteria and Specifications: Create a list of must-have features and performance requirements that the solution must meet.

• Research and Generate Ideas:

  • Literature Reviews and Market Research: Investigate existing products and relevant technologies to understand the current market and previous solutions.

  • Investigate Existing Products and Solutions: Look at current designs to identify strengths, weaknesses, and potential improvements.

  • Brainstorming: Generate a wide range of ideas and initial sketches using creativity techniques like mind mapping and SCAMPER.

• Develop Solutions:

  • Create Detailed Design Proposals and Drawings: Develop detailed plans that illustrate your design ideas, including technical drawings and specifications.

  • Feasibility, Ergonomics, Aesthetics, and Functionality: Ensure that the design is practical, user-friendly, visually appealing, and functional.

  • Decision Matrices: Use tools like decision matrices to compare different design ideas and select the best one.

• Prototype and Test:

  • Build Prototypes: Create physical models of your design using various materials and methods.

  • Perform Functional Testing: Test the prototypes to see if they work as intended and gather feedback from users.

  • Refine Design: Make necessary changes based on test results and user feedback to improve the design.

• Evaluate and Refine:

  • Analyze Test Data and Performance: Look at the results of your testing to see how well the design meets the initial criteria.

  • Assess Design Against Criteria: Ensure the design fulfills all the requirements and specifications.

  • Document the Design Process: Keep detailed records of all stages of the design process and any changes made.

• Materials and Properties:

  • Metals:

Ferrous Metals:

• Steel: Known for its high strength and versatility. Types include carbon steel (strong, used in construction) and stainless steel (corrosion-resistant, used in kitchenware).

• Cast Iron: Known for its hardness and brittleness, used in engine blocks and pipes.

Non-Ferrous Metals:

• Aluminum: Lightweight and corrosion-resistant, used in aircraft and packaging.

• Copper: Excellent electrical conductivity, used in wiring and plumbing.

• Titanium: High strength-to-weight ratio and corrosion resistance, used in aerospace and medical implants.

• Plastics:

Thermoplastics:

• ABS: Tough and impact-resistant, used in toys and automotive parts.

• PVC: Durable and chemical-resistant, used in pipes and cable insulation.

Thermosetting Plastics:

• Epoxy: Strong adhesive and chemical-resistant, used in glue and coatings.

• Phenolic: Heat-resistant and hard, used in circuit boards and kitchenware.

• Composites:

Fiberglass: Lightweight and strong, used in boats and sports equipment.

Carbon Fiber: High strength-to-weight ratio and stiffness, used in aerospace and automotive industries.

• Wood:

Hardwoods:

• Oak: Strong and durable with an attractive grain, used in furniture and flooring.

• Mahogany: Stable and resistant to rot, used in high-quality furniture and boat building.

Softwoods:

• Pine: Light and easy to work with, used in construction and furniture.

• Cedar: Resistant to decay and aromatic, used in outdoor furniture and shingles.

• Material Properties:

Mechanical Properties:

• Tensile Strength: Resistance to being pulled apart.

• Compressive Strength: Resistance to being squashed.

• Hardness: Resistance to scratching or indentation.

• Toughness: Ability to absorb energy without breaking.

Physical Properties:

• Density: Mass per unit volume.

• Melting Point: Temperature at which a material changes from solid to liquid.

• Thermal Conductivity: Ability to conduct heat.

Chemical Properties:

• Corrosion Resistance: Resistance to degradation by chemical reactions.

• Reactivity: Tendency to undergo chemical changes.

• Mechanisms and Motion:

  • Types of Motion:

Linear: Straight-line motion, e.g., a piston in a cylinder.

Rotary: Circular motion, e.g., a spinning wheel.

Reciprocating: Back-and-forth motion, e.g., a sewing machine needle.

Oscillating: Swinging motion, e.g., a pendulum.

• Mechanisms:

Levers:

• First Class Lever: Fulcrum between effort and load, e.g., a seesaw.

• Second Class Lever: Load between effort and fulcrum, e.g., a wheelbarrow.

• Third Class Lever: Effort between load and fulcrum, e.g., tweezers.

• Mechanical Advantage: Ratio of output force to input force.

Linkages:

• Push-Pull Linkage: Transmits motion in a straight line.

• Bell Crank Linkage: Changes the direction of motion.

Cams and Followers:

• Cams: Convert rotary motion to linear motion, types include pear-shaped and eccentric cams.

• Followers: Move according to the cam's profile, types include knife-edge and roller followers.

Gears:

• Types of Gears:

  • Spur Gears: Straight teeth, used for parallel shafts.

  • Helical Gears: Angled teeth, smoother and quieter operation.

  • Bevel Gears: Conical shape, used for intersecting shafts.

  • Worm Gears: Screw-like, provide high reduction ratios.

• Gear Ratios: Ratio of the number of teeth on two gears, determining speed and torque.

Pulleys:

• Fixed Pulley: Changes the direction of force.

• Movable Pulley: Reduces the amount of force needed.

• Combined Pulley (Block and Tackle): Combines fixed and movable pulleys to further reduce effort.

Technical Knowledge

Engineering Drawing:

• Orthographic Projection:

  • Front, Top, and Side Views: Essential views that fully describe an object.

  • Drawing Conventions: Using line types (solid, dashed, center lines), scales, and annotations to convey information.

• Isometric Drawing:

  • 3D Representation: Drawing objects at 30-degree angles to create a three-dimensional effect.

  • Circles and Arcs: Techniques for representing circular features in isometric view.

• Dimensioning and Tolerancing:

  • Dimension Placement: Properly placing dimensions to communicate size and location of features.

  • Tolerances: Specifying allowable variations in dimensions to ensure proper fit and function.

• CAD (Computer-Aided Design):

  • Basic Functions and Tools:

    • Drawing Tools: Creating basic shapes (lines, arcs, circles).

    • Editing Tools: Modifying shapes (trim, extend, offset).

  • Creating and Editing 2D and 3D Models:

    • Sketching: Creating 2D profiles and shapes.

    • Extruding and Revolving: Turning 2D sketches into 3D models.

    • Assemblies: Combining multiple parts to create a complete product.

    • Simulation: Analyzing stress, strain, and motion in models.

  • Exporting and Printing Designs:

    • File Formats: Exporting designs in various formats (e.g., STL for 3D printing, DWG for 2D drawings).

    • Printing: Preparing technical drawings and specifications for manufacturing.

• Manufacturing Processes:

  • Traditional Methods:

    • Cutting:

      • Types of Cutting Tools: Hand saws, power saws, and shearing machines.

      • Techniques: Ensuring accuracy and safety while cutting.

    • Drilling:

      • Drill Types: Twist drills, spade bits, Forstner bits.

      • Techniques: Center punching, pilot holes, drilling speeds.

    • Milling:

      • Milling Machines: Vertical and horizontal milling machines.

      • Operations: Face milling, end milling, slotting, and drilling.

  • Modern Methods:

    • CNC Machining:

      • Basics: Understanding CNC programming and G-code.

      • Advantages: High precision, repeatability, and efficiency.

    • 3D Printing:

      • Technologies: Fused Deposition Modeling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS).

      • Materials: Plastics (PLA, ABS), metals (titanium, stainless steel), composites.

      • Applications: Prototyping, complex geometries, low-volume production.

    • Laser Cutting:

      • Types of Lasers: CO2 lasers, fiber lasers.

      • Applications: Cutting, engraving, marking various materials (metal, plastic, wood).

Practical Skills

Workshop Safety:

• Proper Use of Tools and Equipment:

  • Hand Tools: Proper handling and use of hammers, screwdrivers, wrenches.

  • Power Tools: Safe operation of drills, saws, grinders.

• Personal Protective Equipment (PPE):

  • Types of PPE: Goggles, gloves, aprons, ear protection.

  • Usage: Ensuring proper fit and condition of PPE.

• Workshop Safety Protocols:

  • Cleanliness: Keeping the workspace tidy to prevent accidents.

  • Emergency Procedures: Knowing the location of first aid kits, fire extinguishers, and emergency exits.

• Prototyping:

  • Techniques for Building Models and Prototypes:

    • Materials: Using cardboard, foam, wood, metal for prototyping.

    • Joining Methods: Adhesives (glue, epoxy), mechanical fasteners (screws, bolts), welding.

  • Use of Hand Tools and Power Tools:

    • Measuring and Marking: Using rulers, calipers, marking gauges for precision.

    • Cutting Tools: Using saws, cutters, and knives for shaping materials.

    • Shaping Tools: Using files, sanders, and rasps for finishing surfaces.

  • Evaluating Prototypes for Function and Form:

    • Testing: Conducting functional tests to evaluate performance.

    • User Feedback: Gathering feedback from potential users and making adjustments.

• Testing and Evaluation:

  • Methods of Testing Engineering Solutions:

    • Destructive Testing: Testing to failure to determine ultimate strength.

    • Non-Destructive Testing: Methods such as ultrasonic testing, X-ray, and magnetic particle inspection to detect defects without damaging the component.

    • Functional Testing: Ensuring the product performs as intended under expected conditions.

  • Collecting and Analyzing Test Data:

    • Data Recording: Keeping detailed records of test conditions and results.

    • Data Analysis: Using statistical methods to analyze data and identify trends or anomalies.

  • Making Design Improvements Based on Test Results:

    • Iterative Design Process: Refining the design based on test feedback and retesting.

    • Documentation: Keeping detailed records of design changes and justifications.

Sustainability and Ethics

Sustainable Design:

• Principles of Sustainable Design:

  • Reduce: Minimizing material usage and waste.

  • Reuse: Designing products for disassembly and reusability.

  • Recycle: Using recyclable materials and designing for end-of-life recycling.

• Life Cycle Analysis:

  • Stages: Raw material extraction, manufacturing, use, disposal.

  • Assessment: Evaluating environmental impacts at each stage.

  • Comparison: Comparing the environmental impacts of different design options.

• Reducing Environmental Impact Through Design Choices:

  • Eco-Friendly Materials: Selecting materials with lower environmental impacts.

  • Energy Efficiency: Designing for low energy consumption during manufacturing and use.

• Ethical Considerations:

  • Responsibility to Society and the Environment:

    1. Product Safety: Ensuring designs comply with safety standards and regulations.

    2. Social Impact: Considering the effects of products on communities and promoting inclusivity.

  • Ethical Use of Resources:

    1. Fair Trade: Sourcing materials from suppliers that adhere to ethical practices.

    2. Responsible Sourcing: Using materials that are sustainably harvested or recycled.

  • Impact of Engineering Solutions on People and Communities:

    1. Stakeholder Engagement: Involving stakeholders in the design process.

    2. Community Benefits: Designing products that provide positive social impacts.