cad cam machine
CAD/CAM technologies have continued to evolve. The current trend is feature-based systems. Features play a key role in the recent integration of CAD/CAM systems. Automatic feature recognition has been successful to a certain extent and applied to Computer Aided Process Planning (CAPP) systems. Featurebased CAPP interprets the product model in terms of machining features and uses the features to generate manufacturing instructions to produce the product. With the help of automatic feature recognition, CAPP systems can recognize features directly from solid models created by CAD systems and generate process plans for the solid models. A product has to be manufactured to bring it to life. However, the process plans generated from CAPP systems cannot serve as a starting point for CAM systems to generate tool paths and NC programs. The user still needs to manually create the machining steps and define geometry for each Machining step. The situation must be improved to achieve a seamless CAD/CAM integration.
CAD/CAM systems have helped speed many tedious steps in the concept to production cycle since they were employed in industry. They replace or assist many decision-making functions and dramatically increase productivity. Soon after CAD and CAM systems were developed, users realized that the communication between CAD and CAM systems became the bottleneck for the improvement of productivity, so the integration of CAD and CAM systems started drawing researchers attention. For the purpose of the research conducted in this dissertation, only mechanical CAD and CAM systems and their integration are discussed.
By Min Hou “CAD/CAM Integration Based on Machining Features for Prismatic Parts”
Computers have been greatly involved in product development throughout the product lifecycle, from design, analysis, to manufacturing. Since the concept of Computer Aided Design (CAD) emerged in early 1950s, it has extended into every aspect of product design and development. CAD systems were developed from simple two-dimensional (2D) drafting tools to currently much more powerful systems based on solid modeling technology. Around the same time, Computer Aided Manufacturing (CAM) was inspired by Numerical Controlled (NC) machines. CAM systems were developed separately from CAD systems by different user groups. The development of CAD and CAM technology significantly increased efficiency in each individual area. The independent development, however, greatly restrained the improvement of overall efficiency from design to manufacturing. The communication between CAD and CAM systems has become a bottleneck for further improvement of production efficiency.
The first effort to break the isolation of CAD and CAM systems was to reuse the product model designed in CAD systems in CAM systems. It made CAM systems able to directly manipulate CAD models, either the wire frame or solid model. But the model given by CAD systems is only the product model of the final shape. The traditional CNC machines used in machine shops take NC programs, i.e.
G/M codes, as input to drive CNC machines. NC programmers need to know the intermediate shapes of the product to create machine codes for each Machining step. Intermediate shapes of intermediate processes in manufacturing are not available from CAD systems and have to be obtained from creating new models or editing the final model. It requires a great amount of user interactions and knowledge of the CNC machine and processes to generate machine codes.
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