Basic Concepts of Computer Aided Design and Computer Aided Manufacturing
Computer-aided design and computer-aided manufacturing (CAD/CAM) is a comprehensive and technically complex systems engineering discipline that incorporates diverse fields such as computer science and engineering, computational mathematics, geometric modeling, computer graphics display, data and databases, simulation, numerical control, robotics and artificial intelligence technologies, as well as specialist knowledge related to product design and manufacturing.
It represents a new technology that allows product designers and process technology personnel to design and manufacture products with the help of computer systems by following product design and manufacturing procedures.
It is an organic combination of traditional techniques and computer technologies. Currently, CAD/CAM technology is not only widely used in the aerospace, electronics and mechanical manufacturing sectors, but is also gradually expanding into areas such as clothing, decoration, furniture and footwear.
Looking at the product manufacturing process, it typically involves drawing or 3D modeling and process design before starting machining. Consequently, CAD/CAM can be subdivided into CAD/CAPP/CAM, where Computer Aided Process Planning (CAPP) serves as the bridge that connects CAD and CAM.
1. Computer Aided Design (CAD)
Computer Aided Design refers to a system consisting of humans and computers in which engineers use computers as auxiliary tools to conduct the ideation and validation of product design, overall product design, technical design, and component design.
Includes analysis and calculation of component strengths, stiffness, heat, electricity, magnetism, and output of component manufacturing information (engineering drawings or numerical control machining information, etc.), as well as the preparation of technical documents and technical reports related. The goal is to improve the quality of product design, shorten product development cycles, and reduce product costs.
The main features of a CAD system include sketch design, component design, assembly design, complex surface design, engineering drawing, engineering analysis, realism, and rendering and data exchange interfaces, among others.
2. Computer Aided Process Planning (CAPP)
Computer Aided Process Planning involves a system composed of humans and computers where, based on information provided from the product design phase, product machining methods and process flow are determined interactively or automatically.
Within an integrated CAD/CAM environment, process designers can often control the component machining process and simulate machining conditions based on information provided by the CAD process and the capabilities of the CAM system, thereby generating information to control the machining process. component machining.
The basic functions of CAPP mainly include blank design, machining method selection, process routing, operation and step design, and tool and fixture design.
3. Computer Aided Manufacturing (CAM)
In the mechanical manufacturing industry, Computer Aided Manufacturing refers to the use of computers to automatically complete the manufacturing processes of discrete products, including machining, assembly, inspection and packaging through various machine tools and numerical control equipment. CAM can be defined broadly or narrowly.
Broadly speaking, CAM refers to the use of computers to assist in activities from production preparation to product manufacturing, including process design, fixture design, automatic CNC programming, production job planning, production control and quality control. Strictly, CAM generally refers to CNC programming, which includes tool path planning, cutter location file generation, tool path simulation, and CNC code generation.
Key technologies in CAD/CAM research
The architecture of CAD/CAM systems can be divided into three layers: the base layer, the support layer and the application layer. The base layer consists of computers, peripheral devices and system software, which includes various supporting software, tools for system development and maintenance.
The support layer includes CAD/CAM support software, product data management, graphics display, etc. With the widespread use of the Internet/intranets, distributed collaborative design and manufacturing in the CAD/CAM environment is becoming an important part of the support layer. The application layer consists of various CAD/CAM application systems developed according to the different needs of the application field.
1. Integrated Technology
Product design, as a creative activity, has evolved into a comprehensive technology with the development of natural sciences, technical sciences, environmental sciences and humanities.
The concept of CIMS emerged through the introduction of systems and information perspectives into manufacturing. With more than 40 years of CAD/CAM technology development, its individual technologies (such as CAD, CAPP, CAM, PDM, ERP, etc.) have matured and play increasingly important roles in their respective fields.
However, these independent subsystems cannot transmit and exchange information automatically, resulting in repetitive work between subsystems. For example, a product feature model needs to be established in CAPP, and the product model needs to be reestablished in the CAM system, while the regular CAD model is mainly used for drawing generation and product simulation.
Integration typically refers to the seamless integration of systems and modules, enabling information transmission, response, analysis and feedback based on a unified product data model and engineering database.
2. Smart Technology
Intelligent production systems integrate artificial intelligence into all aspects of the production process, replacing or expanding activities normally carried out by specialists. In an intelligent production system, the system has some of the “intelligence” of human experts.
For example, the system can automatically monitor its operational status and adjust its parameters to adapt to the external environment, ensuring optimal performance. The research and application of intelligent production systems largely depends on the development of artificial intelligence technology.
3. Network technology
Network technology includes hardware and software implementation, various communication protocols and manufacturing automation protocols, communication interfaces, and system operation control strategies. It forms the basis for the automation of various production systems.
Particularly since the 1990s, with the development of the Internet/intranets, it has provided a platform for remote and collaborative design research and application, and CAD/CAM technology has evolved into networks. Current research in this area focuses mainly on the following aspects:
1) Establishment of remote collaborative design platforms in internet/intranet environments.
2) Principles and technologies for implementing parallel collaborative work (including collaborative problem solving, cooperative operation mechanisms and management control).
3) Product modeling issues in a collaborative work environment.
4) Network-based enterprise manufacturing resource management.
4. Visualization technology
Using virtual reality technology, multimedia technology and computer simulation technology, geometric simulation, physical simulation, manufacturing process simulation and work process simulation are carried out in product design and manufacturing process.
Various media are used to store, express and process various information, integrating text, voice, images and animation to give a sense of reality and immersion. Typical applications include virtual manufacturing and virtual reality. It is specifically reflected in the following aspects:
1) Digital and graphical dynamic data display of scientific computing results.
2) Geometric simulation and simulation of the assembly process of products and their parts.
3) Physical and mechanical simulation of product performance.
4) Simulation of the product's work process to give a feeling of immersion and controllability.
In summary, the degree of automation in the manufacturing process is one of the main indicators of the advancement of manufacturing technology and is one of the most active links in modern manufacturing technology in the 21st century. The development of manufacturing automation will meet rapidly changing market demands with its flexible, integrated, agile, intelligent and global characteristics.
The development of factory automation in our country is based on national conditions, aiming at the global advanced level and improving competitiveness.
Adopts moderate automation technology that combines humans and machines, organizes equipment with high degrees of automation (such as CNC machine tools, industrial robots) and equipment with low degrees of automation effectively, and realizes a people-centered manufacturing automation system and computers as important tools, which are flexible, intelligent, integrated, quick to respond and rapidly reconfigurable.
Clearly, production automation technology is an important technological field that our country must develop vigorously.
