1.1b shows an example of a complex car assembly line, which is capable of making Ford Escape cars (Automobile Newsletter 2012). Despite the difference in complexity, both of them are good examples of a manufacturing system since manufacturing refers to the production of merchandise for use or sale using labour and machines, tools, chemical and biological processing, or formulation (Wikipedia 2019a). Manufacturing is one of fundamental constitutions of a nation's economy. Manufacturing businesses dominate the secondary industry. Powerful countries in the world are those who take control of the bulk of the global production of manufacturing technologies. Over the past hundreds of years, advancing manufacturing has been the strategic achievement of the developed counties to sustain their national wealth and global power. The importance of manufacturing to a nation has been discussed by numerous of researchers and organizations. For example, a summary of the importance to the USA economy is given by Flows (2016) and Gold (2016) as follows:
1 Manufacturers contributed $2.2 trillion with ∼12% of gross domestic product (GDP) to the USA economy in 2015.
2 The manufacturing multiplier effect is stronger than in other sectors. For $1.00 spent in manufacturing, $1.81 is added to other sectors of the economy. Manufacturing has the highest multiplier effect. Gold (2016) argued that the impact of manufacturing has been greatly underestimated; it is supported by the findings of the Manufacturers Alliance for Productivity and Innovation (MAPI) Foundation that the total impact of manufacturing on the economy should be 32% of GDP and that the full value stream of manufactured goods for final demand was equal to $6.7 trillion in 2016.
3 Manufacturing employs sizeable workforces. The manufacturing sector provides ∼17.4 million jobs, or over 12.3 million.
4 Manufacturing pays premium compensation. Manufacturing workers earnt a high average of $81 289 annually in 2015.
5 Manufacturing dominates US exports; the United States is the No. 3 manufacturing exporter.
6 The US attracts more investment than other countries and foreign investment in US manufacturing grows; the foreign direct investment in manufacturing exceeded $1.2 trillion in 2015. New technologies allow manufacturers to alter radically the way they innovate, produce, and sell their products moving forward, improving efficiency and competitiveness.
Figure 1.1 A manufacturing system can be very simple or complex (a). Blacksmithing (Source weekly 2012), (b). Ford assembly line at Kansas City (Automobile Newsletter 2012).
1.1.2 Scale and Complexity of Manufacturing
From a system perspective, a manufacturing system can be described by the inputs, outputs, system components, and their relations, as shown in Figure 1.2. The system is modelled in terms of its information flow and materials flow, respectively. System inputs and outputs are involved at the boundaries of a manufacturing system in its surrounding business environment. For example, the materials from suppliers are system inputs and the final products delivered to customers are system outputs. System components include all of the manufacturing resources for designing, manufacturing, and assembling of products as well as other relevant activities such as transportations in the system. In addition, a virtual twin in the information flow is associated with a physical component in the materials flow for decision‐making supports of manufacturing businesses.
Figure 1.2 Description of a manufacturing system.
In the evolution of manufacturing technologies, the scale and complexity of manufacturing systems have been growing constantly. Note that both the scale and complexity of a system relates to the number and types of inputs, outputs, and system components that transform inputs to outputs. Figure 1.3 shows the impact of the evolution of system paradigms on the complexity of manufacturing systems (Bi et al. 2008). The evolution of system paradigms is divided into the phases of craft systems, English systems, American systems, lean production, flexible manufacturing systems (FMSs), computer integrated manufacturing (CIM), and sustainable manufacturing.
Figure 1.3 The growth of scale and complexity of manufacturing systems (Bi et al. 2014).
Historically, the manufacturing business began with craft systems where some crude tools were made from objects found in nature. The system inputs were simple objects and the requirements of the products were basic functions. In the 1770s, James Watt improved Thomas Newcomen's steam engines with separate condensers, which triggered the formation of English systems. In an English manufacturing system, machines partially replaced human operators for heavy and repetitive operations, the power supply became an essential part of the manufacturing source, and the production was scaled to make functional products for profit. In the 1800s, Eli Whitney introduced interchangeable parts in manufacturing that allowed all individual pieces of a machine to be produced identically. Thus, mass production became possible, the manufacturing processes began to be distributed, and system inputs in general assembly companies included parts and components. The criteria of system performance were prioritized with productivity and product quality. Mass production in the American system paradigm brought the rapid growth of manufacturing capacities that led to the saturation of manufacturing capacities in comparison with global needs. The global market became so competitive that the profit margin was such that without consideration of cost savings in the manufacturing processes profits would be insufficient to sustain manufacturing business. The lean production paradigm was conceived in Japan to optimize system operation by identifying and eliminating waste in production, thus reducing product cost to compensate for the squeezed profit margin. Most recently, sustainable manufacturing paradigms were developed to optimize manufacturing systems from the perspective of the product life cycle. This was driven by a number of factors, such as global warming, environmental degradation, and scarcity of natural resources. Manufacturing system paradigms are continuously evolving. The trend of the evolution in Figure 1.3 has shown that manufacturing systems are becoming more and more complicated in terms of the number of system parameters, the dependence on system parameters, and their dynamic characteristics with respect to time. The engineering education for human resources must evolve to meet the growth needs of the manufacturing industry.
1.1.3 Human Roles in Manufacturing
Computer aided technologies (CATs) in manufacturing are of the most interest in this book and are widely adopted to replace humans in various manufacturing activities and decision‐making supports. To appreciate the applications of CATs, the roles of the human being in manufacturing systems are firstly discussed to explore the possibilities of automated solutions.
As shown in Figure 1.4, the importance of human being in a manufacturing system has been widely discussed. In developing the Purdue system architecture, Li and Williams (1994) classified manufacturing activities into the activities in information/control flow and material flow, respectively. Human resources are needed to accomplish the tasks in both information and material flows. For example, human labourers are commonly seen in an assembly plant
