Computer-aided design (CAD), also known as computeraided design and drafting (CADD), is the use of computer software and systems to design and create 2D and 3D virtual models of goods and products. CADD provides an easy method to create designs for almost every engineering discipline. It can be used for architectural design, landscape design, interior design, civil works and surveying, mechanical design, electrical engineering, plant design, industrial design, duct design, electronic circuit design, plumbing design, textile design and product design.
 Computer-aided manufacturing (CAM) can be defined as all the support that can be provided by the computer in manufacturing any given product. CADD and manufacturing programmes are often integrated into one system called CAD/CAM. These systems import CADD drawings into CAM programmes to automate the manufacturing process. For example, an engineer can draw a machine part using CADD. The CADD drawing is brought into a computer-aided engineering (CAE) program for engineering analysis. When the design is finalised, the drawing is brought into a CAD/CAM system that uses numerical data from the CADD drawing for actual manufacturing. Types of CAD/CAM systems There are different types of CAD systems: 2D CAD, 2.5D CAD, and 3D CAD. The 2D and 3D CAD systems are more generally used. Another classification for CAD systems is into explicit and parametric CAD software.
Parametric approach: In the parametric approach, designers use features driven by dimensions and relationships to capture the design intent. The parametric approach is very powerful and rich, but it requires expert knowledge about how best to embed engineering constraints and relationships within a model. The data created can be easily modified and reused by changing the parameterised features. Explicit approach: With the explicit approach, designers quickly and easily create 3D designs, which they then modify through direct interactions with the model geometry. The explicit approach is flexible and easy to use, so it’s ideal for companies that create one-off or highly customised products—products that simply don't require all the extra effort of up-front planning and the embedding of information within models. Two basic types of CAM systems: Process-oriented CAM systems
: These are geared toward the process part of manufacturing engineering, which includes the effective use of tooling and machining operations, advantageous tool changes and the management of complex processes. This type of system is indeed for production machining work, where the geometry is not as big an issue as the overall process complexity and the need to maximise the process to compress overall machining time. Geometry-oriented CAM systems: These lean toward the geometric aspects of manufacturing engineering—complex part geometries, CAD models, and running process details through geometric conditions. This type of CAM system excels in mould, tool and die work.Here, the more difficult part of the job is the part of geometry, not process optimisation, since typically only a few parts are machined. Prime candidates for this type of CAM system would include a complex mould cavity for an injection-moulded part and the stamping die for a sheet metal automotive panel. Tushar Mehendale, Managing Director, ElectroMech, says, “At ElectroMech,we use CAM in a host of different applications.” First and foremost, the company uses CNC flame cutting machines for cutting steel profiles of several different shapes and sizes. These can be simple rectangular profiles or profiles having complex 2D geometries. The typical process of generating accurate cut pieces begins with a drawing on a CAD system like Solidworks. This drawing is later exported to the CNC machine controller which converts the drawing into G-M codes which give the necessary movement instructions to the servo motor driven plasma cutting torch. Adapting CNC flame cutting allows the company to get precise geometries, which increase the accuracy of the finished products. “In addition to this, nesting several pieces of the same plate thickness on one plate enables us to cut down drastically on scrap and increase the material utilisation,” says Mr Mehendale. “The rework due to grinding and finishing operations is also eliminated. Productivity levels are also enhanced as very few people are required to churn out large number of profiles, he adds.” All of these attributes help the company in reducing the fabrication costs to a large extent as well as speeding up the entire process. Another area of operations where CAM is used is in bending of plates on CNC press brakes. The basic advantage of CAM in fabrication is accuracy, consistency, a superb finish and high productivity levels. Judging CAD/CAM Choosing the right CAD/CAM software is critical for any design or manufacturing company. Some of the factors that one would consider while choosing a CAD/CAM system are:
Type of product being designed: The type and complexity of the product being created drives the selection of the CAD/CAM software. Productivity: The volume of data created, ease of use, and the ability to reuse design data has a significant bearing on the return on investment. Features and functionality: The features and functionality available in any CAD/CAM system play an important role—specific products like sheet metal components, plastic components and machined components need different types of features to create the geometry. Total cost of the system: Cost is a key driver that plays a significant role in selecting the required CAD/CAM tools. Vendor stability and longevity: Much software are taken over from the original creator for various business reasons, even though it is unpredictable as to which software would be sustained for a long time. The adaptability to changes would give a good indication while choosing the software. Maintenance, upgrade and training costs: To be competitive, it is imperative to stay up to date with the latest releases of CAD/CAM tools. These are repetitive costs necessary to keep the software up to date with the latest features and capabilities. Though software may cost less at the initial purchase, there may be a large repetitive annual maintenance cost associated with it and one needs to take this into consideration as well.
Trends in CAD/CAM Some of the areas that are currently the leading trend setters in CAD/CAM are:
Offshoring: After proving itself in IT outsourcing, India is emerging as the hub for engineering outsourcing as well. With a qualified pool of engineers who speak English fluently and work at cheaper rates than their western counterparts, India is fast emerging as a major player in engineering outsourcing. Companies in developed economies outsource a major chunk of their engineering activities and India has the lion’s share of this business. Mass customisation: Companies no longer maintain large inventories as they did five years ago. CAD/CAM has made it feasible and easy to tailor products to meet customers’ specific needs in order to become more competitive. Growing popularity of 3D modelling: 3D models not only give engineers more design flexibility, they also offer realistic images of products and allow downstream tasks, such as analysis, to be more easily integrated. Solid modelling supports a decades-long push by the CAD/CAM industry to give manufacturing customers “art-topart” capabilities—bringing a design from the concept to the tooling stage in a completely digital world. CAM software’s increasing functionality: CAM is becoming more automated, better integrated with design software and increasingly user-friendly. According to CIM data’s NC software market assessment report, some recent enhancements include intelligent user interfaces, programming guidance, commands integrating multiple steps, automatic re-machining, and automatic selection of cutting parameters, tools and toolpaths.  The online training route CAD/CAM training can be conducted via online training. Sridharan Balaiyan, Partner & Director—Engineering Services, Barry-Wehmiller International Resources (BWIR), says, “Training DVDs and online training are gradually gaining popularity over the traditional classroom training, as these offer the convenience of learning at a leisurely pace, and can be perused either at work or home. Online and training DVDs also ensure consistency of Instruction.” Understanding this trend, tools like SolidWorks today offer detailed integrated tutorials with the software licenses, and this has contributed to the their success.
Impact of CAD/CAM The user is ultimately benefited because he obtains a quality product at a much lower cost. As simulation and testing has superseded physical or destructive testing, the costs of testing have come down significantly. The user also gets a renovated product quickly as the lead time for companies to bring the product to market is reduced.
Visualisation of the product before actual development enhances customer experience. The following are some CAD/CAM systems which have the strongest impact on the end-user. Fully integrated CAD/CAM/CAE systems—from concept design to product design, manufacture and customer service Collaborative design—virtually co-located teams spread out in different geographic locations can collaborate on design of a single product Configured to order product design—integrating requests for product configuration by sales group Virtual prototyping—reduce need to build expensive prototypes for testing Finite element analysis—static and dynamic testing of physical characteristics of the product.  Future prospects Since the early development of computer-aided design we have seen a trend towards increasing accessibility. When CAD applications became available for product development in the 1960s, it was only the largest of enterprises that could afford to make use of the technology, the aerospace and automobile industries, for instance. As computer technology developed, computer-aided design made the move from dedicated systems to general-use personal computers, opening the door for smaller enterprises and individual users. Today it is possible to run most CAD software (and even some highend 3D packages) on a typical desktop PC. Though the CAD/CAM industry still faces the challenges of cost, flexibility, reliability and modularity, there has been a manifold increase in the number of manufacturers switching over to using 3D CAD/CAM systems over the past couple of years. Easy availability of various CAD/CAM software tools and trained manpower have also contributed to this cause. This trend will surely continue and both the CAD and CAM industries will grow significantly in the coming years. About 30 per cent of manufacturers use CAD/CAM today. A large percentage of manufacturers continue to use 2D CAD tools and have limited access to CAM software tools. However, awareness about the use of 3D CAD for design and its inherent advantages for downstream applications like CAM and FEA has been increasing by the day. To stay competitive, manufacturers are definitely bound to adopt CAD/CAM technologies, if they have not already done so. In India, our expectations for the use of CAD/CAM is 30 per cent, which is similar to the global level. Silky Verma, International Business Development Executive, L&T Infotech—IES says, “In the future, we can expect further advances in 3D software packages, allowing users a more simple and intuitive experience. Perhaps the most exciting fact for CAD users is that the cost of 3D printing will steadily decline, opening up a whole new avenue in the product development process.” Not only will CAD users be able to make instant modifications to their conceptual designs, but they will also be able to instantly create a physical prototype—solving an inherent drawback of virtual product development. |
