How CAD/CAM Programs Work
Ongoing refinements in CAD/CAM systems continue to save manufacturers tens of It was this source that resulted in the linkage between CAD and CAM. CAD Manufacturing Benefits: 3D CAD is most effective when integrated with the Do you have any problems between CAD design and production engineering, . Solid modeling also includes parameterization, in which the CAD system maintains a set of relationships between the components of an object so that changes.
Using CAD, it is possible to simulate in three dimensions the movement of a part through a production process. This process can simulate feed rates, angles and speeds of machine tools, the position of part-holding clamps, as well as range and other constraints limiting the operations of a machine. The continuing development of the simulation of various manufacturing processes is one of the key means by which CAD and CAM systems are becoming increasingly integrated.
This is of particular importance when one firm contracts another to either design or produce a component. For example, designs can be altered without erasing and redrawing. CAD systems also offer "zoom" features analogous to a camera lens, whereby a designer can magnify certain elements of a model to facilitate inspection.
Computer models are typically three dimensional and can be rotated on any axis, much as one could rotate an actual three dimensional model in one's hand, enabling the designer to gain a fuller sense of the object. CAD systems also lend themselves to modeling cutaway drawings, in which the internal shape of a part is revealed, and to illustrating the spatial relationships among a system of parts.
CAD systems have no means of comprehending real-world concepts, such as the nature of the object being designed or the function that object will serve. CAD systems function by their capacity to codify geometrical concepts.
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Thus the design process using CAD involves transferring a designer's idea into a formal geometrical model. Efforts to develop computer-based "artificial intelligence" AI have not yet succeeded in penetrating beyond the mechanical—represented by geometrical rule-based modeling. Other limitations to CAD are being addressed by research and development in the field of expert systems.
This field is derived from research done in AI. One example of an expert system involves incorporating information about the nature of materials—their weight, tensile strength, flexibility, and so on—into CAD software.
Other limitations to CAD are being addressed by research and development in the field of expert systems. This field derived from research done on artificial intelligence. One example of an expert system involves incorporating information about the nature of materials—their weight, tensile strength, flexibility and so on—into CAD software.
By including this and other information, the CAD system could then "know" what an expert engineer knows when that engineer creates a design. The system could then mimic the engineer's thought pattern and actually "create" a design. Expert systems might involve the implementation of more abstract principles, such as the nature of gravity and friction or the function and relation of commonly used parts, such as levers or nuts and bolts.
One of the key areas of development in CAD technologies is the simulation of performance. Among the most common types of simulation are testing for response to stress and modeling the process by which a part might be manufactured or the dynamic relationships among a system of parts. In stress tests, model surfaces are shown by a grid or mesh that distorts as the part comes under simulated physical or thermal stress.
Dynamics tests function as a complement or substitute for building working prototypes. The ease with which a part's specifications can be changed facilitates the development of optimal dynamic efficiencies both as regards the functioning of a system of parts and the manufacture of any given part.
Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) - benefits
Simulation is also used in electronic design automation, in which simulated flow of current through a circuit enables the rapid testing of various component configurations. The processes of design and manufacture are, in some sense, conceptually separable. Yet the design process must be undertaken with an understanding of the nature of the production process.
It is necessary, for example, for a designer to know the properties of the materials with which the part might be built, the various techniques by which the part might be shaped, and the scale of production that is economically viable. The conceptual overlap between design and manufacture is suggestive of the potential benefits of CAD and CAM and the reason they are generally considered together as a system.
The was the first plane Boeing produced that was completely designed by CAD systems.
Designing the took longer than theits predecessor. This occurred in part because the use of CAD incorporated a broader scope of considerations into the design process. The was made from parts produced by over 50 different firms. Additionally, Boeing engineers had scheduled ten days for the assembly of the fuselage and wing spars of the firstbut actual assembly took only two days.
Boeing estimated that the use of CAD throughout the design process lowered overall person hours for assembly by one-third.
Last, the analysis functions of CAD enabled the number of working prototypes to be reduced to 3, down from 12 for the For example, in ship design manufacturers may use one CAD application for designing the vessel's steel structure and another for designing the propeller assembly. Such specialization ensures that designers have adequate layout and specification tools in the software to work with; however, the drawbacks are the need to learn multiple software packages and the need to eventually integrate pieces of the design that are coming from unlike systems.
The integration of CAD and CAM systems with the broader aspects of a firm's operations is referred to as simultaneous or concurrent engineering.
Concurrent engineering was adopted by the Ford Motor Co. For example, they enable users to save time, money, and other resources by automatically generating standard components of a design, allowing the reuse of previously designed components, and facilitating design modification.
Such systems also provide for the verification of designs against specifications, the simulation and testing of designs, and the output of designs and engineering documentation directly to manufacturing facilities. While some designers complain that the limitations of CAD systems sometimes serve to curb their creativity, there is no doubt that they have become an indispensable tool in electrical, mechanical, and architectural design.
CAM SYSTEMS The manufacturing process includes process planning, production planning involving tool procurement, materials ordering, and numerical control programmingproduction, quality control, packaging, marketing, and shipping. CAM systems assist in all but the last two steps of this process. In CAM systems, the computer interfaces directly or indirectly with the plant's production resources.
Process planning is a manufacturing function that establishes which processes and parameters are to be used, as well as the machines performing these processes. This often involves preparing detailed work instructions to machines for assembling or manufacturing parts.
Computer-aided process planning CAPP systems help to automate the planning process by developing, based on the family classification of the part being produced, a sequence of operations required for producing this part sometimes called a routingtogether with text descriptions of the work to be done at each step in the sequence.
Sometimes these process plans are constructed based on data from the CAD databases. Process planning is a difficult scheduling problem.
For a complex manufacturing procedure, there could be a huge number of possible permutations of tasks in a process requiring the use of sophisticated optimization methods to obtain the best process plan. Techniques such as genetic algorithms and heuristic search based on artificial intelligence are often employed to solve this problem.
The most common CAM application is numerical control NCin which programmed instructions control machine tools that grind, cut, mill, punch, or bend raw stock into finished products. Often the NC inputs specifications from a CAD database, together with additional information from the machine tool operator.
The MCU includes a data processing unit DPUwhich reads and decodes instructions from a part program, and a control loop unit CLUwhich converts the instructions into control signals and operates the drive mechanisms of the machine tool. The part program is a set of statements that contain geometric information about the part and motion information about how the cutting tool should move with respect to the workpiece.
- How CAD/CAM Programs Work
- CAD/CAM software
Cutting speed, feed rate, and other information are also specified to meet the required part tolerances. Part programming is an entire technical discipline in itself, requiring a sophisticated programming language and coordinate system reference points. Sometimes parts programs can be generated automatically from CAD databases, where the geometric and functional specifications of the CAD design automatically translate into the parts program instructions.
This technology involves three steps: This is a tool-less approach to manufacturing made possible by the availability of solid modeling CAD systems. Of course, machine control systems are often used in conjunction with robotics technology, making use of artificial intelligence and computer controlled humanoid physical capabilities e. These "steel-collar workers" increase productivity and reduce costs by replacing human workers in repetitive, mundane, and hazardous environments.
CAM systems often include components for automating the quality control function. This involves evaluating product and process specifications, testing incoming materials and outgoing products, and testing the production process in progress.
Quality control systems often measure the products that are coming off the assembly line to ensure that they are meeting the tolerance specifications established in the CAD databases. They produce exception reports for the assembly line managers when products are not meeting specifications.Lecture - 1 An Introduction to CAD
In summary, CAM systems increase manufacturing efficiency by simplifying and automating production processes, improve the utilization of production facilities, reduce investment in production inventories, and ultimately improve customer service by drastically reducing out-of-stock situations.