Lecture - 1 Introduction (Handnote - I): Manufacturing Process I

Lecture 1 Introduction to Manufacturing Process Lecture outcomes: At the end of this lecture, students will be able to1. understand the fundamental concepts of manufacturing and production, including their definitions, differences, and the duality of manufacturing. 2. identify various manufacturing processes and types of industries. 1.1 Introduction Manufacturing is the backbone of any industrialized nation. All engineers, regardless of their specialization, should grasp the basic requirements for manufacturing activities. These include understanding the ‘6 Ms’: man, machine, material, methods, money, and management, as well as other essential infrastructure facilities and other support services. This holistic view enables them to effectively manage the total production of a manufacturing unit. However, a complete understanding of basic manufacturing processes and workshop technology is incredibly challenging for a single person who claims expertise over it. The duties and responsibilities of a manufacturing engineer are extensive and critical to efficient operations. They are tasked with facilitating smooth production within the manufacturing area, optimizing existing processes, implementing new ones, and ultimately ensuring that production goals are met. A manufacturing engineer also monitors the performance of equipment, machines, and tools. This includes overseeing maintenance and troubleshooting issues with equipment or process parameters to minimize defective products. They are dedicated to applying continuous improvement methodologies, such as lean tools, to enhance manufacturing quality, reliability, and effectiveness. Their responsibilities also extend to identifying new opportunities or implementing changes to improve products or reduce costs. Furthermore, they are crucial in fostering effective communication within the manufacturing environment and managing production schedules. 1 Lecture 1 Comprehensive lecture notes on Manufacturing Processes I This lecture will explore several aspects of manufacturing processes, primarily focusing on machining, casting, joining, and welding, examining their processing methods, merits, and limitations. 1.2 Description 1.2.1 Manufacturing The word ‘Manufacturing’ comes from two Latin words ‘manus’ means hand and ‘factus’ means to make or made. This origin reflects its initial meaning: to make something by hand. Today, manufacture and production are used synonymously, referring to the creation of goods and wares through industrial processes. The fundamental goal of the manufacturing process is to create a product with a useful form. It is a crucial step in the overall production process, primarily concerned with altering the form of a material or the dimensions of a part. The manufacturing process involves three main functions: 1. Changing the physical properties of the raw material. 2. Altering the shape and size of the workpiece. 3. Achieving the required dimensional accuracy and surface finish. Essentially, manufacturing is a complex activity involving people from diverse disciplines with varied expertise. It also requires a range of machinery, tools and equipment, often with various levels of automation, including computers, robots, and other specialized apparatus. Raw materials Transformation process Finished goods Fig. 1. Basic manufacturing process a product from raw materials to finished goods. Manufacturing is a branch of industry that involves applying tools and processing mediums to transform raw materials into finished goods for sale. Its operations must be adaptable to various needs and ongoing developments. As illustrated in Fig. 1.1, a material purchased as a ‘raw material’ begins its journey into becoming a product. This effort includes all intermediate processes necessary for the production and integration of a product's components. Essentially, manufacturing 2 can be defined as the transformation of raw materials into useful products using the most efficient and cost-effective methods available. Essentially, manufacturing can be defined as the transformation of raw materials into useful products using the most efficient and cost-effective methods available. During this process, a product that is only partially completed is known as ‘work in progress’ or a ‘semi-finished good’. Once the item is fully manufactured but not yet sold or distributed to the end-user, it’s called a ‘finished good’. 1.3 Production Production is the act of creating goods and services by transforming inputs (such as raw materials, labor, and capital) into finished outputs that satisfy human needs. It encompasses all activities that add value to inputs, making them useful for consumption. For instance, a car factory assembling vehicles. Here, inputs include metal, electronics, labor, while the output is a tangible physical car. This is a clear example of production within a manufacturing context. Conversely, a software company developing an application software (app) involves programming skills and tools as inputs, with a digital intangible product as the output, also falling under the umbrella of production. Inputs Materials • Men • Machine • Material • Methods • Money Transformation • • • • • Shape Size Forms Add/ Remove Remove Outputs • Finish goods • Service • Waste • Scrap Feedback Fig. 1.2 Basic production process. More specifically, the process of converting raw materials into finished products is termed as the production process, as illustrated in Fig. 1.2. In this process, different types of machines, tools, equipment are utilized to create the finished good. Several types of manufacturing processes are applied within the production process, depending on the nature of work and the characteristics of final product desired. Here, feedback in a system refers to the information or data collected about the performance of the system, such as quality, efficiency, delays, or defects, which is then used to make corrections or improvements in the process. 3 Lecture 1 Comprehensive lecture notes on Manufacturing Processes I Therefore, production decisions focus on: o o o o what goods to produce. how to produce them. the costs associated with their production. optimizing the mix of resource inputs used in their creation. Finally, there is slight difference in usage and origin of the terms ‘manufacturing’ and ‘production’, particularly British and American English, although the core meanings remain similar. The differences are summarized in Table 1.1. Table 1.1 Differences between Manufacturing and Production. Aspect Manufacturing Production Definition A subset of production, involves A broader term that includes all making tangible goods only. types of goods and services. Origin Comes from Latin manu and factus meaning ‘made by hand’. Historically used to refer to the physical creation of goods in factories. Output type Only tangible created. products are Products can be tangible (goods) or intangible (services). Sectors involved Mostly associated with secondary (industry) sector. the Includes primary, secondary, and tertiary sectors. Examples Making cars, building furniture, Producing electricity, writing assembling mobile phones. software, providing healthcare. Comes from Latin productio, meaning ‘bringing forth’ or ‘creation’. Broader term used both for making goods or services. 1.3 Duality of Manufacturing Manufacturing can be understood through intertwined subjects: (a) human’s discovery and invention of materials and processes to create goods, and (b) the development of production systems. More precisely, the duality of manufacturing refers to the two essential and complementary perspectives through which manufacturing is viewed and managed: technological manufacturing, and economic manufacturing. 1.3.1 Technological manufacturing This aspect focuses on the physical and technical processes involved in transforming 4 raw materials into finished goods, as illustrated in Fig. 1.3 (a). Key characteristics of technological manufacturing include: o It focuses on processes, equipment, and materials. o It involves core manufacturing activities such as machining, casting, welding, forming, etc., along with tooling automation, and robotics. o It concerned with how to make a product (technical feasibility). o It addresses product design and engineering, process planning and control, material selection and handling, etc. Men Machines Tooling Power Equipment Handling For example, for producing a metal gear using CNC machining, ensuring it meets specific tolerances and material properties requirements. Raw materials Manufacturing process Manufacturing processes in $ Raw materials Finished goods Value adding Materials processing in $$ Finished goods Scrap Waste (b) (a) Fig. 1.3 Dula nature of the manufacturing processes: (a) Technological aspects, and (b) Economic aspect. 1.3.2 Economic manufacturing This perspective addresses the cost-effective and efficient use of resources within the production process to maximize value and profit, as illustrated in Fig. 1.3(b). Key characteristics of economic manufacturing include: o It focuses on costs, productivity, and profitability. o It involves considerations such as labor costs, material costs, overhead, etc. o It is related to production scheduling, inventory control, supply chain management. o It concerned with how to make it profitably, i.e., its economic viability. o It addresses cost- profit analysis, waste reduction, cost-benefit optimization, etc. For example, deciding whether to produce a component in-house or outsource it, based on a comparative analysis of labor costs and delivery times. 5 Lecture 1 Comprehensive lecture notes on Manufacturing Processes I This duality is crucial in the production process because both views are essential and must be carefully balanced. A process might be technically perfect but economically unfeasible. Conversely, a low-cost method could compromise technical quality or product durability. Therefore, ideal manufacturing decisions combine both technical feasibility and economic viability. 1.4 Duties and Responsibilities of Manufacturing Engineers From the above descriptions and aligning with the activities outlined in Fig. 1.4, we can clearly identify the duties and responsibilities of a Manufacturing Engineer. These include: o designing products and their corresponding manufacturing processes o determining and defining the necessary equipment, tools, and processes required for efficient product realization. o Identifying the most appropriate and optimal combination of machinery, materials, and methods to achieve economical and trouble-free production. o Analyzing manufacturing costs and implementing strategies for cost reduction. o Driving quality assurance and continuous improvement initiatives. o Ensuring safety and maintaining regulatory compliance. o Developing analytical solutions and alternatives for complex, open-ended manufacturing challenges. Process design and development Process optimization Quality assurance Cost analysis and cost reduction Equipment selection and maintenance Continuous improvement Supply chain collaboration Supply chain collaboration Fig. 1.4 Duties and responsibilities of a manufacturing engineer. Therefore, a manufacturing engineer must have a strong background—both theoretical and practical —in materials and up-to-date machinery. They also need the critical ability to develop analytical solutions and alternatives for the multifaceted problems encountered in manufacturing. 1.5 Classification of Manufacturing Processes Manufacturing processes are primarily classified based on how materials are 6 transformed into finished products. Beyond the methods of transformation, manufacturing can also be categorized by the scale of the product being manufactured. As illustrated in Fig. 1.5, manufacturing is broadly divided into four groups based on product size: 1. Macro-manufacturing: This involves products with dimensions ranging from 10 mm to significantly larger scales. Examples include the construction of bridges, shipbuilding, air hangers, heavy machinery, excavators, industrial robots, etc. 2. Meso-manufacturing: This category covers products with sizes from 0.1 mm to 10 mm. This bridges the gap between large-scale and microscopic, often involving precision components that are still visible to the naked eye. Examples include mechanical components like tiny gears, springs, levers; small motors or bearings; medical stents and catheters; lenses for cameras and phones, etc. 3. Micro-manufacturing: This involves products size ranges from 0.1 µm to 0.1 mm. This realm often deals with components on the scale of human hair or smaller, frequently relying on techniques developed for integrated circuits. MEMs devices such accelerometers in smartphones, pressure sensors, and gyroscopes, several microfluidic devices, etc. 4. Nano-manufacturing: This is the smallest scale, involving manipulation at the atomic and molecular level to create materials and devices with novel properties. Examples include nanoparticles for coatings, quantum dots, carbon nanotubes, nano-sensors, targeted drug delivery systems, etc. 0.1 nm 1.0 nm 10 nm 0.1 µm 1.0 µm 10 um 0.1 mm 1.0 mm 10 mm 0.1 m 1 m Micro-manufacturing 10 m 100 m Macro-manufacturing Mesomanufacturing Nano-manufacturing Fig. 1.5 Types of manufacturing depending on product size. Manufacturing processes can be broadly categorized into two fundamental types: 1. processing operations, and 2. assembly operations. A processing operation transforms a work material from one state to a more advanced 7 Lecture 1 Comprehensive lecture notes on Manufacturing Processes I state, bringing it to the final desired product. This process adds value by altering the geometry, properties, or appearance of the raw materials. Conversely, an assembly operation joins two or more components to create a new entity. This new entity can be referred to as an assembly, sub-assembly, or a term specific to the joining process (e.g., a welded assembly is called a weldment). The final desired shape of manufactured component (i.e., final product) can be achieved through one or more of four following approaches: 1. Changing shape without adding or removing material: This approach involves altering the shape of the raw stock through plastic deformation without adding or removing material. Manufacturing processes based on this method are known as metal forming processes. Examples include bulk-forming processes like rolling, forging, drawing, and extrusion, as well as sheet metal forming operations such as bending, deep drawing, and embossing, are illustrated in Fig. 1.6. (a) (b) (c) (d) Fig. 1.6 The core principles of metal forming processes: (a) Rolling, (b) Forging, (c) Wire drawing, and (d) Extrusion process. 2. Adding or joining materials: This involves obtaining the required shape by adding metal or joining two or more metallic parts together. Common examples include welding, brazing, or metal deposition. 3. Molding molten or particulate metal: This method involves molding molten or particulate metal into a cavity that mirrors the shape of the final desired product. Processes such as casting and powder metallurgy fall into this category. 4. Removing material: This approach involves removing portions from the stock material to achieve the final desired shape. A cutting tool, which is harder than the stock material and possesses specific geometric characteristics, is used to remove undesired material in the form of chips. This group includes several chipforming (machining) operations, exemplified by turning, milling, and drilling. Processing operations utilize various forms of energy, including mechanical, electrical, thermal, chemical, or combination of them. These operations are further distinguished into three main categories as: 8 a. shaping operations, alter the geometry of the starting work material using various methods. b. property enhancing operations, improve the physical properties of the material without changing its shape. c. surface finishing operations, involve processes that improve the surface characteristics of a product. A general model of the processing operations is illustrated in Fig. 1.7. Casting and molding, etc. Shaping process Property enhancing process Processing operations Surface processing operations Manufacturing processes Particulate processing Deformation process Material removal Heat treatment Cleaning and surface treatment Coating and deposition process Welding Permanent joining processes Brazing & soldering Adhesive bonding Assembly operations Mechanical fastening Thread / fasteners Permanent fastening Fig. 1.7 Classification of manufacturing processes. [Source: Groover, 5e, pp. 12.] Common shaping operations include casting, forging, and machining. These processes can be categorized into four main types: 1. Casting, molding, and similar processes: In these methods, raw materials are 9 Lecture 1 Comprehensive lecture notes on Manufacturing Processes I heated to a liquid or semi-fluid state and then poured into a mold to achieve the desired shape, as illustrated in Fig. 1.8(a). 2. Particulate processing: This involves using a powder as the starting material. The powders are formed into a specific shape and then heated to create the final part. 3. Deformation processes: A ductile solid, typically a metal, is deformed to shape the part. Examples include forging and rolling, or bending, as illustrated in Fig. 1.8(b). 4. Material removal processes: A solid material, which can be either ductile or brittle, has material removed from it to create the desired shape or geometry. Machining is prime example of this type of process. F Pouring Ladle Punch Molten Metal Sheet Metal Die Mold (Sand) (a) (b) Fig. 1.8 Metal shaping processes: (a) Casting of metals, and (b) Bending of sheet. Property enhancing operations add value to the material by improving its physical properties without changing its shape. Heat treatment is the most common example. These processes do not alter the shape of the party, such as annealing, strengthening, sintering of powdered metals, etc. Property-enhancing operations improve a materials’ physical properties without altering its shape. Heat treatment is the most common example. These processes, such as annealing and strengthening, add value to a material by enhancing its characteristics, rather than changing its form. Sintering of powdered metals can also be considered a property-enhancing operation as it fuses particles together to create a stronger, more solid component. Surface finishing operations are performed to clean, treat, coat, or deposit material onto the exterior surface of a workpiece. Common examples of coating include electroplating, anodizing of aluminum, and organic coatings like painting and porcelain 10 enameling. The second basic type of manufacturing operation is assembly, which involves joining two or more separate parts to form a new entity. The components can be connected either permanently or temporarily. Permanent joining methods, such as welding, brazing, soldering, and adhesive bonding, create a bond between components that cannot be easily disconnected. In contrast, temporary assembly methods use threaded fasteners like screws, bolts, and nuts, which are traditional and important methods that allow for parts to be easily separated. Two different types of joints are illustrated pictorially as in Fig. 1.9. (a) (b) Fig. 1.9 Assembly processes: (a) Permanent assembly by welding, and (b) Temporary joining by using nuts and bolts. 1.6 Types of Industries Industries are a key part of the economic system, comprising a group of businesses or organizations that produce similar goods or provide related services. They are typically categorized into five types (as shown in Fig. 1.10) based on the nature of their activities. Types of Industries Primary Industries Secondary Industries Tertiary Industries Quaternary Industries Quinary Industries Fig. 1.10 Types of industries based on their activities. 1. Primary industry: The first is the primary industry, which is involved in the cultivation or extraction of natural resources directly from the Earth. Examples include agriculture, forestry, fishing, and mining. 11 Lecture 1 Comprehensive lecture notes on Manufacturing Processes I 2. The second is the secondary industry, which involves the manufacturing and processing of raw materials from the primary sector into finished or semi-finished products. This process often requires machinery and technology. Examples include textile manufacturing (turning cotton into clothing), steel production (converting iron ore into steel), construction engineering (building houses, roads, and bridges), and food processing (making packaged foods from raw crops). 3. The third is the tertiary industry, which provides services rather than goods. These services support both consumers and businesses. Examples include retail shops (selling products), healthcare (hospitals and clinics), education (schools and colleges), banking and finance (banks and insurance), tourism, and entertainment. 4. In addition, the fourth is the quaternary industry, also known as the knowledge sector. This industry focuses on intellectual and knowledge-based activities. It involves the generation, analysis, and dissemination of information and often requires a highly educated workforce. Examples include information technology (IT) services, research and development (R&D), consulting services, and media. 5. The fifth is the quinary industry, which includes the highest-level decisionmakers in a society or economy. Often referred to as ‘gold collar’ professions, these individuals are responsible for creating policies and making critical decisions that have a significant impact on their respective fields. Examples include top executives in major corporations, government officials, and leaders in fields such as healthcare, education, and science. Based on nature of products, industries can be classified as: 1. Manufacturing industry: This industry produces tangible goods using raw materials and machines. Examples include the production of steel, electronics, and processed foods. 2. Construction industry: This industry is involved in building physical structures and infrastructure, such as roads, bridges, houses, and commercial buildings. 3. Service industry: This industry provides intangible products or services. Examples include banking, insurance, hospitality, and consulting. Based on scale of operation, industries may be categorized into: 1. Cottage industry: These are small-scale, home-based industries that often rely on family labor. Examples include handicrafts, weaving, and pottery. 2. Small-scale industry: These industries operate with limited capital and fewer 12 employees. Examples include furniture making, printing presses, and bakeries. 3. Large-scale industry: These industries require heavy capital investment and focus on mass production. Examples include shipbuilding, automobile manufacturing, and oil refineries. Based on the ownership of industries, they are grouped into three categories. They are: 1. Public sector industries: These industries are owned and operated by the government. Examples include railways and power generation authorities. 2. Private sector industries: These industries are owned and managed by private individuals or companies. Examples include Tata Motors and Samsung. 3. Joint sector industries: These industries are jointly owned by the government and private entities. An example is Padma Oil Company Limited, Jamuna Oil Company Limited, Meghna Petroleum Limited, are all subsidiaries of Bangladesh Petroleum Corporation (BPC). --------• Manufacturing transforms raw materials into finished goods using efficient, cost-effective methods. • The ‘6 Ms’ (Man, Machine, Material, Methods, Money, Management) are essential elements in manufacturing. • Manufacturing has a dual perspective: technological (how to make) and economic (how to make profitably). • Manufacturing processes are classified into processing and assembly operations, each using methods like shaping, property enhancement, and surface finishing to transform raw materials into finished products. • Core manufacturing processes include machining, forming, casting, joining, and surface finishing. • Manufacturing engineers play a critical role in designing, optimizing, and managing production processes to ensure cost-effective, high-quality, and efficient manufacturing. • Industries can be classified based on activity (primary, secondary, tertiary, etc.), scale (cottage, small, large), and ownership (public, private, joint). Self-study 1. Review the classification of manufacturing processes with examples from real industries. 2. Explore case studies of manufacturing in Bangladesh, including local manufacturing sectors and their challenges. 13 Lecture 1 Comprehensive lecture notes on Manufacturing Processes I Short questions 1. What are the ‘6 Ms’ in manufacturing? 2. Define manufacturing in short. 3. What is the difference between manufacturing and production? 4. Name any two shaping processes. 5. What is meant by ‘work-in-progress’, or semi-finished goods? 6. What is a secondary industry? Give an example of a secondary industry. 7. Mention one property-enhancing operation. 8. What is the difference between permanent and temporary joining methods in manufacturing? 9. What is the role of feedback in production? 10. What does the term ‘dual nature of manufacturing’ refer to? Broad questions • Explain the dual aspects of manufacturing: technological and economic. • Describe the differences between manufacturing and production with examples. • Discuss the duties and responsibilities of a manufacturing engineer. • Classify manufacturing processes and explain each with examples. • How are industries categorized based on activity and scale of operation? • Describe the role and importance of assembly operations in manufacturing. • Explain the significance of property-enhancing and surface-finishing operations. 14