CAD (computer-assisted design) and CAM (computer-assisted manufacturing) software has replaced manual drafting of shapes and objects and the manual control of machines to produce the desired parts. Instead, engineers and technicians use CAD software to create accurate dimensional drawings using standard shapes, previously created drawing elements and programmed curves. CAM software translates these drawings into instructions for CNC machines (computer numerical controlled machines) to allow machine tools to physically create the parts. The CAD/CAM process is accurate, repeatable, efficient and reliable, delivering substantial benefits over manual drafting and machine control.
The CAD/CAM process is accurate, repeatable, efficient and reliable, delivering substantial benefits over manual drafting and machine control.
CAD/CAM software is used universally in design shops and industrial plants throughout manufacturing, equipment production, research facilities, prototype testing and architecture. An important area of use is in machining and metal fabrication where punching and cutting machines are programmed to shape metal according to CAD drawings. Integrated metal fabricators can design and manufacture metal parts from basic raw materials, turning out standard and custom metal components for a variety of industrial customers.
Key factors for high-quality output are the accuracy of the drawings, the maintenance of specified tolerances in dimensions and shapes and the quality of the machined surfaces. For CAD software, the computerized drawings will contain elements such as circles, ellipses and arcs that are precisely drawn according to input parameters such as radius and curvature. The lengths of sides and other dimensions are always exactly as specified. Where elements from previous work are used, the shapes are exactly as seen on the older work. The most important skill of the designer becomes the ability to use and assemble drawing components quickly and effectively rather than precision drawing.
CAM software translates the vector drawings into instructions for the machines. As long as the machine tool is appropriate and the material suitable, the fabrication machine will produce a sheet metal part corresponding to the drawing, although often further fabrication steps such as bending, welding, shaping and polishing may be required to produce a finished product. The output quality no longer depends on the skill of the machine operator but rather on the quality of the machine and the raw material.
The output quality no longer depends on the skill of the machine operator but rather on the quality of the machine and the raw material.
The key advantages from using CAD/CAM software come from the digital processing and storage of numeric entries for drawings and numeric commands for machine control. Quality output results from correct design and data entry. While the design process is still a source of errors, designs can easily be tested in prototypes and, once a design is validated, the CAD/CAM parameters are stored and the design can be re-used repeatedly.
For example, a flat sheet-metal part for industrial equipment could be designed on CAD software and created using CNC machines with CAM software. When a prototype is machined and tested, the metal develops cracks. An analysis shows that a sharp corner results in stresses that exceed the strength of the metal. The designer can reduce the amount of stress by using a larger radius for the corner, avoiding the concentration of stress.
Using CAD software, it is easy to replace the tight corner radius with a larger one, shifting the corresponding lines and maintaining all critical dimensions. Everything else stays the same and the CNC machine can cut the new part without major modifications. Further adjustments to the prototype can similarly be carried out quickly and easily. When the test results for the prototype are acceptable, the required quantity of the part can be produced using the same CAD/CAM settings.
At this point, the use of CAD/CAM software can result in another major advantage by optimizing material use and machine time. Operators can enter raw material inventory into the software and the program can use material and allocate parts to minimize waste and keep machines working efficiently. Parts can be grouped to use the same material or placed on waiting lists until enough parts are on the list to use a specific material with a minimum of off-cuts.
The production line can handle increased throughput, output quality is higher, waste is reduced, the rate of defective parts is lower and operator productivity rises.
Most of the benefits due to using CAD/CAM sheet metal software result directly from the accuracy and reliability of the programs and their ability to digitally store past work. When the programs generate drawings with high dimensional precision with accurately rendered curves and shapes, the basis for machining is reliable. The CAM software controls the machines to create a part exactly corresponding to the drawing and stores the instructions. The parts are exactly as designed, within the tolerances of the machine, and the same or similar parts can be produced at any time from the stored instructions.
This means manufacturers can fill a software library with past work and can draw on the instructions and parts drawings to fill repeat orders, to carry out changes on existing parts and to create new parts similar to ones in the library. A database can keep track of parts so operators can quickly find what they need.
The combination of an increasingly efficient drawing and manufacturing process with a growing library of past work has concrete benefits for manufacturers. The production line can handle increased throughput, output quality is higher, waste is reduced, the rate of defective parts is lower and operator productivity rises. The resulting lower costs and higher customer satisfaction are powerful arguments for putting CAD/CAM software into most manufacturing facilities.