--- title: "Classification of manufacturing processes; evolution" subject: "Manufacturing and Production Processes" chapter: 1 key: "semester_4/manufacturing_and_production_processes:classify-manufacturing-processes-evolution" source: https://www.bctengineer.com/q/semester_4/manufacturing_and_production_processes/classify-manufacturing-processes-evolution site: BCT Engineering --- # Classification of manufacturing processes; evolution Manufacturing and Production Processes · Chapter 1: Overview of Manufacturing - Asked in: year not given, 5 marks - Video: [How Things Are Made | An Animated Introduction to Manufacturing Processes](https://www.youtube.com/watch?v=Um_g8sQ_p3Y) — The Efficient Engineer - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_4/manufacturing_and_production_processes/classify-manufacturing-processes-evolution - Whole chapter: https://www.bctengineer.com/md/semester_4/manufacturing_and_production_processes/chapter-1 ## Question Classify manufacturing processes with one example of each class. Briefly describe how the organisation for manufacture has evolved from craft production to modern systems. ## Short answer Process classes: casting (sand casting), forming (rolling), material removal (turning), joining (welding), powder processing, property enhancing, and additive (3D printing). Organisation evolved from craft production to interchangeable parts, mass production, lean/flexible manufacturing, and finally integrated digital manufacturing with CAD/CAM and ERP. ## Answer Manufacturing is the conversion of raw material into useful products by processes that change shape, properties or form, usually followed by assembly. #### Classification of processes | Class | Principle | Examples | |---|---|---| | Casting (solidification) | Molten metal poured into a mould cavity | Sand casting, die casting | | Forming (deformation) | Plastic deformation without removing material | Rolling, forging, extrusion, deep drawing | | Material removal | Excess material removed as chips or by erosion | Turning, milling, grinding, EDM | | Joining | Parts joined permanently or temporarily | Welding, brazing, riveting, adhesive bonding | | Powder processing | Metal powder compacted and sintered | Gears, bearings by powder metallurgy | | Property enhancing | Heat treatment, surface treatment | Hardening, carburising, shot peening | | Additive | Material added layer by layer | 3D printing | Another useful grouping is **primary** processes (create the basic shape, e.g. casting, rolling) and **secondary** processes (finish or improve it, e.g. machining, heat treatment). #### Evolution of manufacturing organisation 1. **Craft production** - skilled artisan makes the complete product to order; high cost, high variety, no interchangeability. 2. **Interchangeable parts and factory system** (18th-19th century) - machine tools, division of labour and gauges allowed parts to fit without hand fitting. 3. **Mass production** (early 20th century) - moving assembly line, standardised products, low cost per piece, low variety. 4. **Scientific management and automation** - work study, transfer lines, numerical control, statistical quality control. 5. **Lean and flexible manufacturing** - just-in-time, small batches, cellular layout, CNC, FMS, continuous improvement. 6. **Integrated and digital manufacturing** - CAD/CAM, CIM, ERP, robots and networked machines giving mass customisation. The trend is from low volume and high variety by craftsmen, to high volume and low variety on lines, and then back to high variety at low cost through flexible automation. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Which pair is correctly classified? A. Rolling - material removal; turning - forming B. Rolling - forming; turning - material removal C. Rolling - casting; welding - forming D. Turning - joining; forging - casting Answer: B. Forming deforms plastically without removing material (rolling, forging); material removal cuts chips (turning, milling). (Key point: Forming vs material removal) 2. In the primary/secondary grouping, which is a secondary process? A. Sand casting B. Hot rolling C. Heat treatment or machining D. Pouring metal into a mould Answer: C. Primary processes create the basic shape (casting, rolling); secondary ones finish or improve it (machining, heat treatment). (Key point: Primary and secondary processes) 3. Which describes mass production in the evolution of manufacturing? A. Skilled artisan making a complete product to order B. Moving assembly line, standardised products, low cost per piece, low variety C. Small batches with just-in-time and cellular layout D. Networked machines giving mass customisation Answer: B. Early 20th century mass production used moving assembly lines for standard products with low cost and low variety. (Key point: Mass production features) 4. What is the overall trend in manufacturing organisation? A. Always from high volume to low volume B. Always towards lower variety C. Low volume high variety, then high volume low variety, then high variety again at low cost via flexible automation D. Constant high variety throughout Answer: C. Craft gave high variety at low volume, lines gave high volume low variety, flexible automation restores variety at low cost. 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