Computer Aided Design and Manufacturing. Zhuming Bi
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 to accomplish manual assemblies in the material flow; technicians are needed by small and medium sized companies (SMEs) to generate codes and run computer numerical controls (CNCs) in the information/control flow. From the perspective of a product lifecycle (Ortiz et al. 1999), human resources are needed at every stage from designing to manufacturing, assembling, inspecting, transporting, marketing, and so on.
Figure 1.4 Human's role in manufacturing (Ortiz et al. 1999).
Human resources will certainly play an essential role in the future of manufacturing where manufacturing technologies and human beings are being integrated more closely and more harmoniously than ever before. While the focus should be shifted to the effective human–machine interactions to synergize both strengths of human beings and machines, manufacturing technologies should be advanced to balance the strengths and limitations of human resources optimally.
With the rapid development of information technologies (IT), CATs are replacing human beings for more and more decision‐making support. The design and operation of a manufacturing system involves numerous decision‐making undertakings at all levels and domains of manufacturing activities. In any engineering decision‐making problem, one can follow the generic procedure with a series of design activities: (i) defining the scope and boundary of a design problem and its objective, (ii) establishing relational models among inputs, outputs, and system parameters, (iii) acquiring and managing data on current system states, and (iv) making decisions according to given design criteria. In the information flow of a manufacturing system, each entity normally has its capabilities to acquire the input data, process data, and make the decision as an output data.
1.1.4 Computers in Advanced Manufacturing
The performance of a manufacturing system can be measured by many criteria. Some commonly used evaluation criteria are lead‐time, variants, and volumes of products, as well as cost (Bi et al. 2008). Manufacturing technologies have advanced greatly to optimize system performances. Figure 1.5 gives a taxonomy of available enabling technologies in terms of the strategies, domains, and product paradigms of businesses to optimize systems against the aforementioned evaluation criteria. In the implementation of production, the majority of advanced technologies, such as CIM, FMS, Concurrent Engineering (CE), Additive Manufacturing (AM), and Total Quality Management (TQM), are enabled by CATs.
Figure 1.5 The strategies, domains, and production paradigms of advanced manufacturing technologies (Bi et al. 2008).
The advancement of CATs can be measured by their capabilities in dealing with the growing scales and complexities of systems and the autonomy of system responsiveness. Figure 1.6 shows the evolution of CATs from the perspective of these three measures (Bi et al. 2014), together with computer applications in manufacturing using numerical control (NC)/CNC workstations, FMSs, CIM, distributed manufacturing (DM), and predictive manufacturing (PM). Typical computer aided tools to support these enabling technologies are Quality Control (QC), TQM, Enterprise Requirements Planning (ERP‐I), Enterprise Resources Planning (ERP‐II), Product Lifecycle Management (PLM), Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS), respectively. Correspondingly, the capacities of software systems to deal with volume, variety, and velocity of the data have been increased gradually from stream data early in the digital era to big data now. IT hardware systems must be capable of processing data in a timely manner. The computing environments have evolved from Microchip, mainframe, servers, the Internet, to today's Cloud.
Figure 1.6 Evolution of computer aided technologies in manufacturing (Bi and Cochran 2014).
1.2 Computer Aided Technologies (CATs)
Computer aided technologies provide the aids for design, analysis, manufacture, and assembly of products and for design, planning, scheduling, controlling, and operations of production systems. Various CATs have been gradually known and adopted by engineers since CATs and tools were developed in the late 1950s. Wikiversity (2019) divides the historical development of computer aided design (CAD) into the stages of two‐dimensional, three‐dimensional, and parametric designs. Many other researchers discussed the development of CAD technologies by marking some significant theoretical contribution and products as milestones.
The first system of CATs in manufacturing was developed by Patrick Hanratty in 1957 as a programming system for numerical control. The major innovation in CATs occurred in 1963 when Ivan Sutherland, for his PhD thesis at MIT, created Sketchpad, which was based on a GUI (Graphical User Interface) to generate x–y plots. The innovation in Sketchpad pioneered the use of object‐oriented programming in modern CAD and CAE (Computer Aided Engineering) systems. In the 1960s, the extensive works were developed in the aircraft, automotive, machine control, and electronics industries for three‐dimensional modelling and the programming for numerical control. A few significant works were published as the fundamentals of the CAD theory, such as the mathematical representations of polynomial curves and surfaces by Bezier and Casteljau (Citroen Automotive Company) and Coons at MIT (Ford Motor Company).
Due to the rapid growth of computing power and reduction of hardware sources, three‐dimensional (3D) modelling techniques are now widely used in video games, robotics, simulation of discrete systems, medical imaging and diagnosis, and in computer‐controlled surgeries. As a milestone, the Manufacturing and Consulting Services Inc. (MCS) had developed CAD technologies in their commercially available Automated Drawing and Machining (ADAM) (Cadhistory 2019). The software was used and updated by McDonnell Douglas as Unigraphics and by Computer Vision as CADDs. Later, 3D printing technologies were developed and 3D printing technology evolved from 3D polygonal modelling to some objects with highly curvy surfaces, machine objects, and many other objects. 3D printing gave a boost to the development of computer aided manufacturing (CAM) technologies. As a few examples of successful companies in the CAM fields, (i) 3D Systems Corporation specializes in converting 3D solid or scanned models into physical objects; (ii) Stratasys Ltd. adopts additive manufacturing (AM) for direct manufacture of end parts; (iii) Intuitive Surgical Inc. designs, manufactures, and markets da Vinci surgical systems, as well as related instruments and accessories; and (iv) iRobot