Modern computer technology enables the designer to manage the enormous number of design, material, and process applications available when designing with composites for example. In the past, the designer had to limit the material, process, and design choices to those that were familiar. Now, with the help of a computer, one can develop a number of design concepts, quickly evaluate them against established functional and performance criteria in a wide range of materials and processes, and make the necessary design modifications. Finished drawings and specifications can be provided with increased accuracy and confidence-often in less time than ever before possible. For example, if one dimension is changed that alters many other dimensions, all the dimensions will be changed automatically by the computer at the same time the initial changes are made.
Admittedly, entering the initial three-dimensional geometry for various concepts into the computer is often more time consuming than developing concept sketches with conventional methods. However, subsequent revisions and analyses of that geometry can be performed many times faster than with manual methods.
CAD/CAM design and development database sharing.
It is this concept of database sharing that has made CAD a tremendous time- and work-saving tool for the designer. In the past, the evaluation of design concepts to determine their viability was a long and tedious task. By utilizing a CAD system, the three-dimensional geometry initially entered can be redefined, manipulated, and edited quickly, and preliminary finite-element analyses and economic analyses for various materials and processes can be performed. In addition, the database can be copied for numerically controlled tool paths already scaled for shrink factors to enable a mould designer to prepare a preliminary mould design.
Design and development models.
Three-dimensional wire frame mockups and models can be constructed to help visualize the product and to serve as a framework for many other modelling programs. These wire frame models are constructed in three dimensions and can normally be viewed in orthographic, isometric, or perspective views, often at the same time. Changing one view alters all the other views. Wire frames are easily modified, and many design variations can be constructed in a relatively short period of time. With this wire frame model, the designer can iteratively blend one shape into another while holding given parameters. Thus, a wall section or volume of a part can be held constant, while the shape can change incrementally over a given number of iterations. This process often yields a potential configuration that may not have been possible to find with time-consuming manual methods.
The ability to reposition the parts of an assembly is a great aid in refining and checking some of the operations and functional uses of the product. Parts can be lined up on a common centre and clearances edited and verified from the data base. Many hours of cumbersome calculations can be eliminated. Moving parts can be incrementally or dynamically rotated about an axis, and the interferences can be checked at each position. Colour raster technology is of further benefit in the checking process. Interferences are more readily found when each part or position is in a different color.