CAD/CAM is an abbrieviation of computer-aided design and computer-aided manufacturing.
Computer-aided design (CAD) is the use of a wide range of computer-based tools that assist engineers, architects and other design professionals in their design activities. It is the main geometry authoring tool within the Product Lifecycle Management process and involves both software and sometimes special-purpose hardware. Current packages range from 2D vector based drafting systems to 3D solid and surface modellers.
CAD is used to design, develop and optimize products, which can be goods used by end consumers or intermediate goods used in other products. CAD is also extensively used in the design of tools and macry used in the manufacture of components, and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures (hospitals and factories).
CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.
CAD has become an especially important technology, within CAx, with benefits, such as lower product development costs and a greatly shortened design cycle, because CAD enables designers to lay out and develop their work on screen, print it out and save it for future editing, saving a lot of time on their drawings.
Fields of Use :
The AEC industry- Architecture, engineering and construction
- Civil Engineering and Infrastructure
- Roads and Highways
- Water Supply and Hydraulic Engineering
- Mapping and Surveying
- Factory Layout
- Mechanical (MCAD) Engineering
- Bio-mechanical systems
- Electronic and Electrical (ECAD)
- Electrical Engineering
- Manufacturing process planning
- Industrial Design
- Apparel and Textile CAD
- Garden design
- Building engineering
- Railroads and Tunnels
- Storm Drain, Wastewater and Sewer systems
- (Chemical) Plant Design
- Heating, Ventilation and air-conditioning (HVAC)
- Automotive - vehicles
- Consumer Goods
- Ship Building
- Electronic design automation (EDA)
- Digital circuit design
- Power Systems Engineering
- Power Analytics
- Software applications
- Fashion Design
The capabilities of modern CAD systems include:
- Wireframe geometry creation
- 3D parametric feature based modelling, Solid modelling
- Freeform surface modelling
- Automated design of assemblies, which are collections of parts and/or other assemblies
- create Engineering drawings from the solid models
- Reuse of design components
- Ease of modification of design of model and the production of multiple versions
- Automatic generation of standard components of the design
- Validation/verification of designs against specifications and design rules
- Simulation of designs without building a physical prototype
- Output of engineering documentation, such as manufacturing drawings, and Bills of Materials to reflect the BOM required to build the product
- Import/Export routines to exchange data with other software packages
- Output of design data directly to manufacturing facilities
- Output directly to a Rapid Prototyping or Rapid Manufacture Machine for industrial prototypes
- maintain libraries of parts and assemblies
- calculate mass properties of parts and assemblies
- calculate mass properties of parts and assemblies
- Bi-directional parametric association (modification of any feature is reflected in all information relying on that feature; drawings, mass properties, assemblies, etc... and counter wise)
- kinematics, interference and clearance checking of assemblies
- sheet metal
- hose/cable routing
- electrical component packaging
- inclusion of programming code in a model to control and relate desired attributes of the model
- Programmable design studies and optimization
- Sophisticated visual analysis routines, for draft, curvature, curvature continuity...
Computer-aided manufacturing ( CAM) is the use of a wide range of Product Lifecycle Management computer-based software tools that assist engineers, Tool and die makers and CNC machinists, in the manufacture or prototyping of product components. 3D models of components generated in CAD software are used to generate CNC code to drive numerical controlled machine tools. This involves the user in selecting what type of tool, machining process and paths that are to be used.
Sometimes the CAM software is integrated with the CAD system, but not always. Every piece of CAM software must first solve the problem of CAD data exchange where in the CAD system which is producing the data often stores it in its own proprietary format, much as is the case with word processor software. Usually it is necessary to force the CAD operator to export the data in one of the common data formats, such as IGES or STL, that are supported by a wide variety of software. The output from the CAM software is usually a simple text file of G-code, sometimes many thousands of commands long, that is then transferred to a machine tool using a direct numerical control (DNC) program.
While it has long been the dream to make the CAM software that can run on its own, it generally requires a human operator with much knowledge and skill of machining to select the Milling cutters and define the necessary parameters and strategies that will generate an effective tool path.
Process of CAD & CAM :
Consider a Catia user that designs a simple part. Using STEP, that designer would pass his CAD file over to CAM, as usual, but would also export the AP 203 file, to be used later. Next, the CAM programmer decides what stock to use, defines contours and removal volumes, selects a tool and a machining strategy and creates all operations, again as usual. Each operation then is exported into the AP 238 file as a "working step." (Technically, the file is called the AP 238 Conformance Class, or CC1 file; see sidebar.)
Both the AP 203 (CAD) and AP 238 (CAM) data then go through a compositor, which essentially sews the two together to create an AP 238 CC2 file, with both the product geometry and toolpaths imbedded. That file, filtered through a STEP-NC interpreter, can be read directly by a modern machine controller with the right capability (reading TCP code). It eliminates the post processor, which means coordinates are "no longer fixed for a particular machine," Hardwick says.
With the STEP file, "you can perform a trace-forward on the CNC tool very effectively," he continues. "You can do just-in-time CNC verification, you've got the toolpath geometry, you've got the part geometry and the cutter geometry. Everything's there," he says. A simulation can be performed directly on the controller, using both the AP 238 CC2 file and the machine kernel data.
The result? The first part produced is very likely to be a good one. And if, by chance, a design or toolpath change is needed, the file can be transferred smoothly back up the manufacturing chain, from the CNC to CAM and CAD. Or, if desired, a design or toolpath change can theoretically be made right at the controller. This helps "break down the walls," so to speak, between design, engineering and the shop floor, Hardwick says.
At a demonstration during last year's Eastec, engineers added another wrinkle: In-process part inspection, with everything being measured in part coordinates, not machine coordinates, and creating another AP 238 superset with yet more information: The AP 238 CC3, adding machining features (pockets, bosses) needed for on-machine measurement.
"That's huge," Hardwick says, "because probing today is usually so intricate that it's tied to one machine, and you can't move it to another."