Manufacturing Processes and History

• Most objects consist of numerous pieces built and assembled by manufacturing processes.
• Manufacture first appeared in English in 1567, derived from the Latin "manu factus", meaning "made by hand."
• Manufacturing first appeared in 1683 and production appeared in the 15th century.
• Discrete products are individual items (nails, bolts, paper clips).
• Continuous products are continuous materials cut to specific lengths (wire, tubing, aluminum foil).
• Manufactured items gain value through processing raw materials.
• High-value-added products include computer chips, electric motors, medical implants, machine tools, and aircraft.

Brief History of Manufacturing

• Manufacturing dates back to 5000-4000 B.C., predating recorded history.
• Early manufacturing includes cave drawings, markings on clay tablets and stone.
• Ironmaking began in the Middle East (1100 B.C.), steel production in Asia (600-800 A.D.).
• Diverse materials are available, including engineered materials, high-tech ceramics, reinforced plastics, composites, and nanomaterials.
• Until the Industrial Revolution in England (1750s), goods were produced in batches with manual labor.
• The Second Industrial Revolution began in the mid-1900s with solid-state electronics and computers.
• Mechanization began in England and Europe with textile machinery and machine tools.
• Interchangeable parts design began in the early 1800s by E. Whitney.
• Mass production and global markets characterized manufacturing from the 1940s-1990s.
• Digital manufacturing began around 1990, integrating computers and software across design and manufacturing.

Product Design and Concurrent Engineering

• Product design prescribes the shape and characteristics of an artifact.
• Design decisions determine 80% of product development and manufacturing costs.
• Successful design requires clear functions, performance expectations, and market analysis.
• Traditional design involved sequential activities, which may be wasteful.
• Concurrent engineering aims to bring products to market rapidly, involving simultaneous consideration of all disciplines.
• Communication among disciplines is critical in concurrent engineering.
• Concurrent engineering is applicable to companies of all sizes.
• Product life cycle has four stages: product start-up, rapid growth, product maturity, and decline.
• Life-cycle engineering considers the entire product life, from design to disposal.

Computers in Product Design

• Product design uses analytical and physical models for visualization and analysis.
• Models are simplified with computer-aided design (CAD) and computer-aided engineering (CAE).
• CAD systems enable rapid design analysis (e.g., Boeing 777 designed completely by computers).
• Computer-aided engineering simulates performance under various conditions.
• Computer-aided manufacturing involves all phases, utilizing stored information on materials and processes.
• Computers assist with programming, tool design, and quality control.
• Designers finalize geometric features, dimensional tolerances, and surface-finish.

Prototypes

• Prototypes are physical models reviewed for design/production modifications.
• Rapid prototyping enables quick and low-cost prototype creation.

Design for Manufacture, Assembly, Disassembly, and Service

• Design for manufacture (DFM) integrates design with production methods and materials.
• DFM requires understanding materials, processes, machinery, and variability.
• Quantitative relationships are essential for design optimization.
• Design for assembly (DFA), design for manufacture and assembly (DFMA), design for disassembly (DFD) are important.
• Assembly costs range from 10-60% of the total product cost, making ease and speed important.
• Disassembly is important for maintenance, servicing, and recycling.
• Design for service involves easy access to components needing service.

Green Design and Manufacturing

• Discarded items includes: 9 million cars, 300 million tires, 670 million lamps, and 5 billion kg of plastics annually in the US.
• Manufacturing processes and machinery impact the environment.
• Wastes produced by manufacturing include chips, slag, additives, hazardous waste, lubricants, liquids, and solvents.
• Environmental concerns include global warming, acid rain, ozone depletion, and pollution.
• Carbon footprint quantifies greenhouse gases produced.
• Green design and manufacturing considers environmental impacts of materials, processes, and operations.
• Design for recycling (DFR) involves biological or industrial cycles.
• Biological cycle: organic materials degrade naturally.
• Industrial cycle: materials are recycled and reused.
• Aluminum recycling from scrap reduces costs by 66% and energy consumption/pollution by 90%.
• About 75% of automotive parts are recycled in the U.S.

Selection of Materials

• A wide variety of materials are available with different properties, characteristics, advantages, and costs.
• Material selection is done with materials engineers and design engineers.
• General types of materials:
• Ferrous metals: Carbon, alloy, stainless, tool and die steels.
• Nonferrous metals: Aluminum, magnesium, copper, nickel, titanium, superalloys, refractory metals, beryllium, zirconium, low-melting-point alloys, and precious metals.
• Plastics (polymers): Thermoplastics, thermosets, elastomers
• Ceramics, glasses, glass ceramics, graphite, diamond, and diamondlike materials.
• Composite materials: Reinforced plastics, metal-matrix, ceramic-matrix composites.
• Nanomaterials
• Shape-memory alloys, amorphous alloys, semiconductors, superconductors.
• Material selection is challenging due to new developments and material substitution.
• Mechanical properties of interest include strength, ductility, hardness, toughness, elasticity, fatigue, and creep resistance.
• Physical properties of interest are density, specific heat, thermal expansion & conductivity, melting point, and electrical & magnetic properties.
• Optimal designs need a combination of mechanical and physical properties.
• Chemical properties like oxidation, corrosion, degradation, toxicity & flammability are important.
• Manufacturing properties indicate how a material can be cast, formed, machined, joined, and heat treated.

Availability of Materials

• Economic aspects are important for material selection.
• Supply reliability is important to maintaining production schedules, particularly in automotive industries.
• Geopolitics and a country's self-reliance on resources must be considered.
• Shortened product service life can result from material selection, production methods, control of variables, or defects.
• A product fails when it stops functioning, does not perform, or becomes unsafe.

Selection of Manufacturing Processes

• There are multiple methods to produce a component from a material.
• Broad categories of manufacturing:
• Casting: Expendable mold and permanent mold.
• Forming and shaping: Rolling, forging, extrusion, drawing, sheet forming, powder metallurgy, molding.
• Machining: Turning, boring, drilling, milling, planing, shaping, broaching, grinding, ultrasonic, chemical, electrical, electrochemical machining, and high-energy-beam machining.
• Joining: Welding, brazing, soldering, diffusion bonding, adhesive bonding, and mechanical joining.
• Finishing: Honing, lapping, polishing, burnishing, deburring, surface treating, coating, and plating.
• Microfabrication and nanofabrication: Fabrication of microelectromechanical and nanoelectromechanical systems.

Net-Shape and Near-net-Shape Manufacturing

• Net-shape and near-net-shape manufacturing make a part close to the final dimensions, tolerances, and surface finish.
• Additional operations such as machining or grinding may be needed, contributing to product cost.

Computer-Integrated Manufacturing

• Computer-integrated manufacturing (CIM) integrates software and hardware for graphics, modeling, design, and manufacturing.
• CIM began in the 1970s and enhances responsiveness, material use, and production control.

CIM Elements

• Computer numerical control (CNC): controlling machine movements with coded instructions.
• Adaptive control (AC): automatically adjusting parameters to optimize quality and minimize costs.
• Industrial robots: replacing humans in repetitive or dangerous tasks.
• Automated materials handling: using computers for material and component handling.
• Automated assembly systems: replacing humans in assembly.
• Computer-aided process planning (CAPP): optimizes process planning for productivity and consistency.
• Group technology (GT): grouping parts based on design and manufacturing similarities.
• Just-in-time production (JIT): delivering supplies and producing parts just in time.
• Cellular manufacturing (CM): utilizing workstations with manufacturing cells.
• Flexible manufacturing systems (FMS): integrating manufacturing cells with a central computer.
• Expert systems (ES): computer programs with problem-solving capabilities.
• Artificial intelligence (AI): computer-controlled systems that learn from experience.
• Artificial neural networks (ANN): simulating human thought processes for production and financial planning.

Quality Assurance & Total Quality Management

• Product quality influences satisfaction and success.
• Quality must be built into the product from design through manufacturing.
• Continuous control of processes (online monitoring) is critical.
• Quality assurance and total quality management (TQM) is a shared responsibility.
• Product integrity is the degree to which a product functions reliably, is suitable, and can be maintained.
• Designing and manufacturing safe products is a manufacturer's responsibility, as is avoiding failure due to misuse.
• A product's malfunction or failure causes bodily injury, death, or financial loss.
• Product Liability is the laws governing product failure and its consequences.

Lean and Agile Manufacturing

• Lean production minimizes waste at all levels by eliminating unnecessary operations.
• Lean production focuses on manufacturing steps, machinery, and personnel.
• Agile manufacturing requires agility and flexibility to respond to changes in product demand.
• Achieving flexibility: with people, equipment, computer hardware, software, and communications systems.

Methodologies

• Lean and agile production require benchmarking.
• Benchmarking: assessing competitive position (product quality, production time, manufacturing costs) and setting realistic goals.

Manufacturing Costs

• The economics of manufacturing are critical, with global competition and demand for high-quality, low-priced products.
• Manufacturing cost represents 40% of the selling price.

Cost Components

• Materials: raw-material costs depend on the material itself and on supply and demand.
• Tooling: costs for cutting tools, dies, molds, work-holding devices, and fixtures.
• Fixed, costs include: energy, rent for facilities, insurance, and real-estate taxes.
• Capital, costs include: Production machinery, equipment, buildings, and land.
• Labor, cost consists of: direct and indirect costs.