MANUFACTURING

1. MANUFACTURING

2. Introduction • Consumers are people who buy and use the items made in factories – soap, food, shoes, cars, and books • Industrial revolution in late 1700s – new methods of manufacturing • The first factories in the world made textiles in England and Scotland between 1750 and 1800 • Factory’s power usually came from rivers that turned water wheels • James Watt later designed a steam engine that could operate machines in factories • Manufacturing is the application of physical and chemical processes to alter the geometry, properties, and/or appearance of a starting material (raw or semi finished) to make parts or products • Manufacturing also includes assembly of multiple parts to make products • A sequence of operations adds value to the material by changing its shape or properties

3. People Information Materials Tools & Machines Capital Energy Time Starting Material Processed Part Manufacturing Process Introduction

4. Manufacturing Industries • An industry/company may not span the whole cycle of manufacturing – crude raw material to the finished product • Industry consists of enterprises and organizations that produce or supply goods and services • Industries can be categorized as basic producers, converter or fabricator and service industries • The first three categories form a connecting chain • Basic producers cultivate and exploit natural resources and transform these into raw materials – e.g. steel producers • Converters take the output of the basic producer and transform these raw materials into various industrial products and some consumer items – e.g. producers of sheet-metals and plastics • Fabricators fabricate and assemble final products – e.g. manufacturers of automobiles, appliances and garments

5. Manufacturing Industries • Service industry works in parallel with the other three and constitutes the service sector of the economy

6. Manufacturing Industries • Another classification of manufacturing firms may be by the quantity of the products they make • Job shop production, batch production and mass production

7. Resources for Manufacturing • Companies use a complex but coordinated setup of all the basic resources • People • Large companies employ a huge workforce because they manufacture several products at the same time • People to put forward the requirement of a new product • Research engineers and design engineers/drafters • Development engineers decide the steps of manufacturing the product • They make a prototype (a test version of the product ) of the new product before going onto the full scale or mass production • Production engineers implement the plan given by development department • Hundreds of laymen workers work in the production department • These workers may be working on or repairing and maintaining the machines • Skilled and qualified people are required for quality control • Planning, managing warehouses, dispatching etc • Marketing and distribution of the product in the local and international markets

8. Resources for Manufacturing • Information • Trends in the market • Different type of materials, their costs and quality standards • Mechanical drawings of different parts • Knowledge of manufacturing processes • Companies may launch new research projects in collaboration with universities • Materials • It is not always a raw material – materials in the natural state, e.g. iron ore, trees, and cotton • Steel sheets come from iron ingots made from coal, limestone and iron ore • Companies often make a trade-off between the cost and the quality of a material

9. Resources for Manufacturing • Tools and Machines • A tool changes the shape of material or fastens it together • Hand tools are those that use the power of our hand or arm – hammer and pliers • A power tool uses a small motor and is usually held in our hands – Electric drills • Jigs and fixtures facilitate the process of manufacturing – devices used to locate and hold work pieces. • Machines are usually operated by electric motors – bending, cutting, drilling, grinding, and hammering • Modern manufacturing processes run under program and feedback control A jig used in carpentry shop

10. Resources for Manufacturing • Energy • Mostly in the form of electricity • Thermal power – electricity from fossil fuels, i.e. coal, oil and natural gas • Own power source or near the government power supply – low transmission costs • A chemical plant can use its waste heat energy to generate steam – co-generation • Capital • Buy land, build factories, purchase equipment, pay workers, maintain machines, and advertise their products • A company may sell shares of stock • Capital may also come from a venture capitalist • Venture capital is money used to finance the costs of starting a new company • Time • Productivity is how quickly and cheaply a product is made • F. W. Taylor suggested the idea of scientific management – study every movement that a worker made

11. Industrial Materials • Four basic categories – metals, ceramics wood and polymers • Other useful materials are natural rubber/leather, glass, cotton, silk and wool • Criteria for selecting the right material – properties of the material, its deterioration-rate and its cost • Manufacturing process that can be used to make products depend on the mechanical and physical properties of the materials • Metals • Alloys are composed of two or more elements • Metals can be divided into two basic groups: (1) ferrous, and (2) nonferrous • Steel contains 0.02 to 2.11 % carbon. It may also have manganese, chromium and nickel to enhance the properties of the metal • Cast iron is an alloy of iron, carbon (2 to 4 %) and silicon (0.5 to 3 %) • Gray cast iron is used in blocks and heads of internal combustion engines

12. Industrial Materials • Ceramics • Compounds of metallic (or semi metallic) and nonmetallic elements – oxygen, nitrogen, ad carbon • Traditional ceramics – clay for brick, tile and pottery, silica for glass products and alumina and silicon carbide for abrasives used for grinding • Newer ceramics – tungsten carbide and titanium carbide for cutting tools and grinding abrasives • Crystalline ceramics are formed from powders and then sintered • Sintering – heating to a temperature below the melting point to achieve bonding between the powders

13. Industrial Materials • Wood • Natural wood can be classified into two forms – hardwood and softwood • Hardwood – trees that lose their leaves in winter, such as maple, oak and walnut • Softwood – evergreen trees such as fir, pine and redwood • Plywood is made by gluing together a number of thin veneers or plies of softwood or hardwood. There is always an odd number of veneers • Hardboard is made from wood fiber extracted from chips and pulped wood waste – a cheaper option than plywood Plywood Hardboard

14. Industrial Materials • Polymers • A compound formed of repeating structural units • They consist of carbon plus one or more other elements such as hydrogen, nitrogen, oxygen, and chlorine • Thermoplastic polymers soften when heated and when cooled, they are hard again – polyethylene bags, PVC pipes and nylon • Thermoset polymers char and burn when heated – plastic cups and dishes made of melamine.