👷🏼‍♂️Intro to Mechanical Prototyping Unit 1 – Intro to Mechanical Prototyping

Key Concepts and Terminology

• Prototyping involves creating a preliminary model or sample to test and evaluate a design concept
• Iterative design is a cyclic process of prototyping, testing, analyzing, and refining a product or process
• Fidelity refers to the degree to which a prototype accurately represents the final product in terms of functionality, appearance, and materials
  • Low-fidelity prototypes are simple, quick, and inexpensive to create (cardboard, foam, or sketches)
  • High-fidelity prototypes closely resemble the final product and are more time-consuming and costly to produce (3D-printed parts, functional electronics)
• Rapid prototyping techniques enable quick fabrication of physical models, such as 3D printing, CNC machining, and laser cutting
• Tolerance is the permissible limit of variation in a dimension, often represented as a plus or minus value (±0.5mm)
• Constraints are limitations or restrictions on the design, such as material properties, budget, or manufacturing capabilities
• Design for Manufacturing (DFM) is the process of designing products with manufacturing in mind to optimize cost, quality, and efficiency

Tools and Materials

• Hand tools for measuring, marking, cutting, and shaping materials include calipers, rulers, squares, saws, files, and sandpaper
• Power tools for more efficient fabrication include drill presses, band saws, circular saws, and sanders
• 3D printers use additive manufacturing to create objects layer by layer from digital models, using materials such as PLA, ABS, and resin
• Laser cutters use a high-powered laser to cut and engrave various materials, such as wood, acrylic, and cardboard
• CNC (Computer Numerical Control) machines, such as routers and mills, use subtractive manufacturing to cut and shape materials based on digital designs
• Microcontrollers (Arduino, Raspberry Pi) enable the integration of electronic components and sensors into prototypes
• Breadboards and jumper wires allow for quick and easy prototyping of electronic circuits without soldering
• Common prototyping materials include cardboard, foam board, wood, acrylic, and 3D printer filament

Design Principles

• Form follows function emphasizes that the shape and appearance of an object should primarily relate to its intended purpose
• Simplicity in design often leads to improved usability, manufacturability, and aesthetics
• Ergonomics considers human factors and user comfort in the design process to optimize user experience and safety
• Modular design involves creating independent, interchangeable components that can be easily replaced or upgraded
• Aesthetics play a crucial role in product design, as they influence user perception, emotional response, and market appeal
• Sustainability considers the environmental impact of a product throughout its lifecycle, from material sourcing to disposal
• Accessibility ensures that products can be used by people with a wide range of abilities and disabilities
• Affordability balances the cost of materials, manufacturing, and development with the target market and intended use

Prototyping Techniques

• Sketching and drawing by hand can quickly communicate design ideas and concepts in the early stages of prototyping
• Cardboard modeling is a low-cost and efficient method for creating rough 3D models to test form, fit, and basic functionality
• 3D printing enables rapid fabrication of complex geometries and functional parts directly from digital models
• Laser cutting is ideal for quickly creating precise, flat parts from sheet materials like wood, acrylic, or cardboard
• CNC machining uses computer-controlled tools to cut, drill, and shape various materials with high precision
• Breadboarding allows for the quick assembly and testing of electronic circuits without the need for soldering
• Soldering is used to create permanent electrical connections between components in more advanced electronic prototypes
• Molding and casting techniques enable the creation of multiple copies of a part using materials like silicone, resin, or plaster

CAD and 3D Modeling

• Computer-Aided Design (CAD) software is used to create, modify, and optimize 2D and 3D digital models of products and components
• Parametric modeling allows for the creation of designs with adjustable dimensions and constraints, enabling easy modification and iteration
• Sketching in CAD involves creating 2D profiles that can be extruded, revolved, or lofted to create 3D geometries
• Assembly modeling enables the virtual combination of multiple components to check for proper fit, interference, and motion
• Rendering generates photorealistic images of 3D models, simulating materials, textures, and lighting for visual presentation
• Finite Element Analysis (FEA) is a numerical method used to simulate and analyze the behavior of 3D models under various loading and boundary conditions
• STL (Standard Tessellation Language) is a common file format used for 3D printing, representing 3D models as a series of triangular facets
• Slicing software converts 3D models into layer-by-layer instructions (G-code) for 3D printers to follow during the printing process

Fabrication Methods

• Additive manufacturing, such as 3D printing, builds objects by depositing material layer by layer based on a digital model
  • Fused Deposition Modeling (FDM) is a common 3D printing technology that extrudes molten plastic through a nozzle to create layers
  • Stereolithography (SLA) uses a laser to cure and harden liquid resin layer by layer to create high-resolution prints
• Subtractive manufacturing involves removing material from a larger block or sheet to create the desired shape
  • CNC milling uses rotating cutting tools to remove material from a workpiece, creating complex 3D geometries
  • Laser cutting focuses a high-powered laser beam to cut, engrave, or etch flat sheet materials
• Forming techniques shape materials without adding or removing material, such as bending, stamping, or forging
• Joining methods combine separate components using adhesives, fasteners, welding, or soldering
• Injection molding is a manufacturing process that injects molten plastic into a mold cavity to create identical parts in large quantities
• Casting involves pouring liquid material (metal, resin, or plaster) into a mold and allowing it to solidify, creating a replica of the mold cavity

Testing and Iteration

• Functional testing evaluates the performance and operation of a prototype under various conditions to ensure it meets design requirements
• Usability testing involves observing users interacting with a prototype to identify areas for improvement in ergonomics, user experience, and intuitive design
• Stress testing applies forces, pressures, or loads to a prototype to assess its strength, durability, and failure points
• Environmental testing exposes prototypes to different environmental conditions (temperature, humidity, vibration) to evaluate their performance and reliability
• Collecting user feedback through surveys, interviews, or focus groups provides valuable insights for iterative design improvements
• Analyzing test results helps identify design flaws, potential improvements, and areas requiring further investigation or refinement
• Iterative design involves making incremental changes and improvements to a prototype based on testing results and user feedback
• Documentation of testing procedures, results, and design changes is essential for tracking progress, communicating with stakeholders, and informing future design decisions

Safety and Best Practices

• Always wear appropriate personal protective equipment (PPE) such as safety glasses, gloves, and closed-toe shoes when working with tools and materials
• Read and follow the manufacturer's instructions and safety guidelines for all tools, machines, and materials used in the prototyping process
• Ensure proper ventilation when working with materials that produce fumes, dust, or particles, such as 3D printer filaments or solvents
• Maintain a clean and organized workspace to reduce the risk of accidents and improve efficiency
• Properly store and handle materials, especially flammable or hazardous substances, in accordance with safety regulations and guidelines
• Regularly inspect and maintain tools and equipment to ensure they are in safe working condition and calibrated correctly
• Use appropriate clamping and fixturing techniques to securely hold workpieces during cutting, drilling, or shaping operations
• Be aware of pinch points, sharp edges, and moving parts when working with machinery and tools to avoid injuries
• Develop and follow standard operating procedures (SOPs) for common prototyping tasks to ensure consistency and safety
• Collaborate with team members, share knowledge, and seek guidance from experienced professionals when faced with unfamiliar or challenging prototyping tasks