7. Discuss the advantages of CAD. How CAD is different from CAM? Illustrate how design process is made simple with a CAD workstation?

Monday, 10 February 2014

7. Discuss the advantages of CAD. How CAD is different from CAM? Illustrate how design process is made simple with a CAD workstation?


It is the use of computers to assist in the creation, modification and analysis of a product plan. CAD is a technology that interrelates with so many of other production systems.

Advantages of CAD

1.Improved Productivity
2.Better costing
3.Fewer errors in numerical control programming
4.Reduced tool costs
5.Possibility of easy modifications
6.Better design for manufacture
7.Improved design accuracy
8.Operation at optimal conditions


It is the use of computer systems to plan, manage and control the operations of the manufacturing plant.

Both CAD & CAM systems are now widely used and have transformed much of our country's manufacturing processes. CAD and CAM are fundamentally different.
• In product development, computer-aided design (CAD) automates the design process while computer-aided manufacturing (CAM) automates the manufacturing of CAD-generated product designs.
• The use of CAD then led to the use of CAM, which utilizes data from   CAD generated prints to manufacture a part.
• While CAD defines design features, CAM identifies manufacturing features. In other words, with CAD systems, you are creating something digital—the product's computer image—and with CAM, you are creating something physical—the actual product.
• Workflow and time are not important factors in CAD, while CAM is concerned with workflow because the sequence in which various processes are carried out can be crucial.
• CAM is almost effortless. CAD you need to be around all the time.
• CAD Software examples = AutoCAD, Pro-Engineering,   CADKEY, Pro-CAD, Turbo-CAD, Visio.
  CAM Software examples = SmartCAM, Master CAM, BOBCAD


Need for CAD

The 3 primary phases of the product design are
1.Product identification
2.Design and Optimization engineering

How CAD helps in each of these is mentioned as separate paragraphs below.

Product Concept Development is aided in CAD modeling. A large no. of alternative designs can be generated on the computer screen and the best one out of this can be selected using CAD.

Design and Optimisation done on a CAD terminal can be explained with an example. Proposed product is divided into triangular shaped elements. The effect of loading the structure is seen, deflections & stresses at various nodal points are defined by the vertices of the triangle. Stress concentrated points can be displayed through colour graphics.

Drafting can be performed effectively on a CAD terminal. Any line drawing can be done and stored/displayed by the computer on the CRT screen.


The design related tasks performed by modern CAD system can be grouped into 4 areas.

1.Geometric Modeling   
    It involves computer compatible mathematical description of geometry of an object, using this images of objects are displayed. It can be manipulated on a graphics terminal from CPU of CAD s/m. Different types of commands are used to generate basic geometric elements like line, circle, to accomplish transformations like rotation, scaling, to join various elements to give desired object. In this objects are represented using wireframe, surface, solid models.

2.Engineering Analysis
     Some kind of analysis is required in the formulation of any design project.   Analysis can be stress-strain calculations, heat transfer computations or use   of differential eqns to describe dynamic behavior of s/m being designed.   The computer can be used to assist this work.

3.Design Review & Evaluation
      The accuracy of the s/m can be checked conveniently on graphics terminal. Dimensioning, tolerance routines are there to reduce errors. The designer can zoom in on any details & closely scrutinize the magnified image. Animation, Gear simulation, tooth hole checking etc can also be done which helps in the evaluation process. 

4.Automated Drafting
This procedure helps in saving lot of time & labour.Computer aided drafting is known as Design workstation. CAD workstation is the s/m Interface with the outside world. A good CAD workstation must accomplish 5 functions. They are:
a.Interface with the CPU of the computer
b.Generate a steady graphic image for the user
c.Provide digital description of the image
d.Be user friendly
e.Translate computer commands into operating function.




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