Computer-aided technologies in engineering – terminology 1.
The major objectives of computer-aided technology (CAx) are to simplify and to improve human's work (engineer, architect, physician, surgeon, etc.), by using the computer as an indispensable tool to solve a problem in a certain field (engineering and production, medicine, architecture, business, teaching, economy, etc.) .
The advanced computer-aided technologies (CAx) are focused on solving specific problems by increasing human’s creativity and innovation obtained through collecting, using, and sharing information between interdisciplinary teams.
Computer-aided technologies in X field are general terms to define a technology, from a specific field of work, which is computed-aided. The substitute for X includes engineering (CAx-E), medicine (CAx-M), natural science (CAx-S), education (CAx-Ed), etc.
Nowadays, computer-aided technologies are not islands of automation, being integrated in general context of Lifecycle Management in X field. The concepts used to define the lifecycle management in engineering and medical field are the following (see Figure 1):
Product lifecycle management (PLM) in the industry field
Human lifecycle management (HUM) or health management across the human lifecycle
2. Computer-aided technologies in product lifecycle management
Product lifecycle management (PLM) is the process of managing the entire lifecycle of a product including conception, design, manufacturing, quality control, use, service, and disposal of products, having integrated people, data, methods, CAx tools, processes, and business systems [2, 3]. PLM is a digital paradigm, products being managed with digital computer, digital information, and digital communication .
The main benefits of product lifecycle management (PLM) for the industry field are faster time-to-market, improved productivity, better product quality, decreased cost of new product introduction, improved design review, and approval processes, identifying potential sales opportunities and revenue contributions and reducing environmental impacts at end-of-life. PLM emerged from tools such as CAD, CAM, and PDM, being viewed as the integration of these tools with innovative technologies (e.g., additive manufacturing, reverse engineering), methods, people, and the processes through all stages of a product’s life .
To improve the product lifecycle management, a lot of methods and techniques are used  such as concurrent engineering, bottom-up design, top-down design, both-ends-against-the-middle design, design in context, design for X (DFX), TRIZ, lean production, design for six sigma (DFSS), total quality management (TQM), and failure mode effects analysis (FMEA).
The most used design for X method is design for manufacture and assembly (DFMA) that is the combination of two methodologies: design for manufacture (DFM) and design for assembly (DFA), which mean the design of the parts for ease of manufacturing and the design of the product for ease of assembly.
Product data management (PDM) is the business function often within product lifecycle management (PLM) that is responsible for the management and publication of product data.
The tools used to access the information and knowledge regarding the product data are the computer-aided technologies (CAx). Computer-aided technologies (CAx) [7, 8] are the use of computer technology to aid in the design, analysis, production planning, manufacture of products, etc.
A CAx system can work like an “island of automation” or it can be integrated in the PLM system, interacting with other “islands of automation”. Thus, the advanced CAx tools merge many different aspects of the product lifecycle management, including design, manufacturing, etc. CAx can be integrated, also, with other computational systems of management and planning of trials and output, such as MRP (material resource planning), ERP (enterprise resource planning), EDM (electronic document management), and PDM (product data management).
A CAx system may be defined, in generally, having the following main components (see Figure 2):
Hardware component consisting in computer and interactive devices
Knowledge and human’s activities
Computer-aided design (CAD), computer-aided engineering (CAE), computer-aided manufacturing (CAM), computer-aided process planning (CAPP), and computer-aided quality assurance (CAQA) are the most known and mature computer-aided technologies.
Computer-aided design [1, 6, 9–12] is the computer-aided technology that involves the computer to assist in the creation, modification, analysis, and optimization of a design and design documentation.
Computer-aided engineering (CAE) [6, 9–12] is the computer-aided technology that involves the computer to analyze, simulate, and optimize the CAD geometry. CAE tools are available for a wide range of analyses: stress analysis, deformation, heat transfer, fluid flow, magnetic field distribution, kinematics, and dynamic analysis, etc.
Computer-aided manufacturing (CAM) [6, 9–12] is the computer-aided technology that involves the computer in planning, control, and management of manufacturing of any product. The most mature areas of CAM are the numerical control (NC) of the machine tools and programming of industrial robots that perform tasks as assembly, welding, etc.
The following are the most known commercial software tools for computer-aided technologies:
CATIA by Dassault Systemes, Creo by PTC, NX by Siemens, PowerShape/ PowerMill by Delcam etc., in the field of CAD/CAM
Materialise Magics and Netfabb Studio, in the field of 3D-printing/ additive manufacturing
RapidForm and Geomagic in the field of computer-aided reverse engineering
Ansys, Abaqus, COMSOL Multiphysics, Adams, LMS Virtual.Lab are focused on CAE
|CAx in engineering field||X=design, analysis, process planning, manufacturing, quality, innovation, etc.|
|CAD||Computer-aided design [6, 9–12].|
|CAM||Computer-aided manufacturing [6, 9–12]. Software to control machine tools and related machinery in the manufacturing of workpieces.|
|CAPP||Computer-aided process planning [9–12] system is the bridge between CAD and CAM.|
|CAE||Computer-aided engineering. Software to aid the simulation of mechanical, strength, temperature, pressure, etc.|
|FEA||Finite element analysis is the practical application of the finite element method (FEM), which involves the use of numerical methods in structure analysis, dynamics, thermal analysis, etc.|
|CFD||Computational fluid dynamics uses numerical analysis and algorithms to analyze problems that involve fluid flows.|
|MBDS||Multibody dynamics simulations.|
|CAQA||Computer-aided quality assurance.|
|CAI||Computer-aided innovation  is an emerging domain in the array of computer-aided.|
|CARE||Computer-aided reverse engineering  has the aim to capture the geometry of an existing physical model, through digitization, and to create a 3D virtual model that is used then in different applications.|
|CATAM||Computer-aided technologies for additive manufacturing. Supporting the design, simulation and process planning for additive manufacturing.|
|RapidX||RapidX [15, 16] is a generic term for rapid technologies, e.g., rapid prototyping (RP), rapid tooling (RT), and rapid manufacturing (RM) .|
|CADComposite||Computer-aided design in composite material technology.|
|CAMComposite||Computer-assisted manufactured composite .|
|CAMT||Computer-aided manufacturing technologies.|
|CAPE||Computer-aided production engineering .|
|CAMSE||Computer-aided manufacturing system Engineering . CAMSE is defined as the use of computerized tools in the application of scientific and engineering methods to the problem of the design and implementation of manufacturing systems.|
|CAT||Computer-aided techniques for tolerance analysis|
computer-aided tolerancing .
|CAAD||Computer-aided architectural design|
|CAID||Computer-aided industrial design .|
|CAWFD||Computer-aided welding fixture design.|
|CAFD||Computer-aided fixture design .|
|CAMAP||Computer-aided mechanical assembly planning.|
|Integrated Cax in engineering field||Remarks|
|CADM||Computer-aided design and manufacture.|
|CAD/CAM/CAQ||Integrated CAD/CAM/CAQ system.|
|CIM||Computer integrated manufacturing [9–12] has the purpose to tying “the separate islands of automation” together, including the computer-aided design, computer-aided planning, computer-aided manufacturing, and computer-aided quality assurance into an efficient system.|
The most known standards used in the product data exchange between computer-aided technologies systems are presented in Table 3.
|CAD geometry translator standards||The neutral file format allows to exchange files containing 2D/3D product data models between different CAx software:|
|STEP (standard for the exchange of product model data) is an ISO 10303-21 standard|
|IGES (initial graphics exchange specification)|
|DXF (drawing exchange format)|
|STL (stereolithography, standard triangle language, or standard tessellation language)|
|VRML (virtual reality modeling language)|
|AMF (additive manufacturing file format) is an ISO/ASTM52915 standard |
Some terms, connected to computer-aided technologies, are shown in the Table 4.
|PLM||Product lifecycle management [2, 3].|
|PDM||Product data management [2, 3].|
|PPLM||Product and process lifecycle management.|
|ERP||Enterprise resource planning.|
|DF||Digital factory is the foundation of the factory of the future, consisting in a digital mock-up of the factory.|
|MPM||Manufacturing process management.|
|CPD||Collaborative product development.|
|DMU||Digital mock-up is a concept that allows the description of a product, usually in 3D, for its entire life cycle.|
|ICT||Information and communication technologies.|
3. Computer-aided technologies in health management across the human life cycle (human lifecycle management)
Medical technology is the type of technology which is used to extend and improve human life. Medical technology is used to diagnose infections, treat diseases, and to make research on diseases affecting humans. Computer-aided technologies play an important role in health management across the human life cycle. The main applications of computer-aided technologies in the medical field are the following:
Computer-aided design (CAD)
Computer-aided detection and diagnosis
Computer-aided medical interventions or computer-aided surgery
Computer‐aided clinical decision
CAD systems play an important role in medical applications, allowing to simulate and analysis, prosthesis design, surgical implant design, blood flow analysis, preoperative planning for surgical operations, and computer-assisted surgery .
Virtual reality (VR) enables physicians and surgeons to interact, manipulate, and simulate the geometric 3D CAD models of anatomical structures directly in a virtual environment, with 3D displays and haptic devices.
Rapid prototyping (RP), 3D printing (3DP), and additive manufacturing (AM) technologies allow us to obtain a real copy of anatomical structures, before a medical implant is inserted or a surgical procedure is performed.
The computer-aided technology tools used in the medical field are shown in Table 5.
|CAx in medical field||X=design, diagnosis, detection, surgery, manufacturing (RP, 3D printing), etc.|
|CADMF||Computer-aided design in medical field [25–27].|
|CAMD||Computer-aided manufactured devices [26–28].|
|CAL||Computer-aided learning .|
|CADiagnosis||Computer-aided diagnosis .|
|CADetection||Computer-aided detection is a technology designed to decrease observational oversights of physicians interpreting medical images .|
|CAMS||Computer-aided modeling and simulation.|
|CAClinical DSS||Computer-aided clinical decision support systems .|
|DSS||Decision support systems.|
|CAMI||Computer-aided medical interventions.|
|CASurgery||Computer-aided surgery  is focused on surgical planning and simulation, and for guiding or performing surgical interventions.|
|CAOSurgery||Computer-aided orthopedic surgery .|
|CATSurgicalG||Computer-aided technology of surgical guide.|
|CATE||Computer-aided tissue engineering or computer-aided technologies in tissue engineering applies many CAx techniques including computer-aided design, medical image processing, reverse engineering, finite element analysis, computer-aided manufacturing, and additive manufacturing for multiscale biological modeling, biophysical analysis and simulation, and design and manufacturing of tissue and organ substitutes .|
|AM||Additive manufacturing .|
|RP||Rapid prototyping [11, 15, 17].|
|CARE||Computer-aided reverse engineering.|
|MRI||Magnetic resonance imaging.|
|PET||Positron emission tomography.|
|SPECT||Single photon emission computed tomography.|
|CAT||Computerized axial tomography.|
Table 6 shows some computer-aided technology tools used in other fields.
|CAx in other fields|
|CAS||Computer-aided technology in sport training  is such a scientific training method that will improve athlete’s training level when it is applied in athletics training.|
|CAT3DAnim||Computer-aided technology applied in 3D animation.|
|CATDecorD||Computer-aided technology applied in decoration design.|
|CATArt||Computer-aided technology in art.|
4. Conclusion and new trends
Nowadays, some computer-aided technology systems have reached the maturity, especially in engineering, and other CAx systems in medicine field are areas of research. The future of computer-aided technologies is focused on their integration in the smart factory, which is part of the fourth industrial revolution, Industry 4.0  (Figure 3). The fourth industrial revolution supposes the introduction of the Internet of Things and Services into the manufacturing environment . A sketch of Internet of Things is shown in Figure 4. The new concepts related to Industry 4.0 are presented in Table 7.
|Virtual reality (VR)||Virtual reality  refers to computer technologies that use interactive software and hardware to generate a realistic and immersive simulation of a three-dimensional environment controlled by movement of the body.|
|Virtual enterprise (VE)||Virtual enterprise consists in “a group of people who work together on a project, communicating mainly by phone, e-mail, and the internet, rather than regularly going to a central office to work providing operations as competitive as those in a traditional enterprise” .|
|Factory of the future||Factory of the future is the combination of virtual and real in order to get a full view of the complete value chain that it will allow factories to produce more rapidly, more efficiently and with greater output using fewer resources .|
|Smart factory||Factory of the future.|
|Industry 4.0||Industry 4.0 or the fourth industrial revolution [37, 42] creates a virtual copy of the physical world called "smart factory" including cloud computing, cyber-physical systems that communicate and cooperate with each other and with humans in real time, via the Internet of Everything and Services.|
|Cloud computing||Cloud computing store, manage, and process data, rather than a local server or a personal computer by using a network of remote servers hosted on the Internet.|
|CMfg (Cloud manufacturing)||Cloud manufacturing  uses cloud computing, the Internet of Things, service-oriented technologies, and high performance computing for solving manufacturing applications.|
CAx software can be supplied as a service on the Manufacturing cloud (MCloud).
|Cyber-physical production systems||Cyber-physical production systems “comprise smart machines, warehousing systems, and production facilities that have been developed digitally and feature end-to-end ICT-based integration, from inbound logistics to production, marketing, outbound logistics, and service” .|
|IoT (Internet of Things)||Internet of Things comprises an intelligent interactivity, via Internet, sensors and actuators, etc., between human and things to exchange information and knowledge.|
|IoTS (Internet of Things and Services)||Internet of Things and Services  comprises the infrastructure, technologies, and applications that connect the real world and the virtual world. IoTS interconnects via the Internet, human, things, and services.|
|IoE (Internet of Everything)||Internet of Everything joins people, process, data, and things.|
|Industrial Internet||Industrial Internet “is the integration and linking of big data, analytical tools, and wireless networks with physical and industrial equipment, or otherwise applying metalevel networking functions to distributed systems” .|