10 Most Important Things You Need To Know About CAD CAM

INTRODUCTION

1. In engineering practice, CAD/CAM has been utilized in different ways by different people.
2. Some utilize it to produce drawings and document designs.
3. Others may employ it as a visual tool by generating shaded images and animated displays.
4. A third group may perform engineering analysis of some sort on geometric models such as finite element analysis.
5. A fourth group may use it to perform process planning an generate NC part programs. In order to establish the scope and definition of CAD/CAM in an engineering environment and identify existing and future related tools, a study of a typical product cycle is necessary
6. CAD tools can be defined as the intersection of three sets: geometrical modeling, computer graphics and the design tools.

Reasons for Implementing a CAD System

1. To increase in the productivity of the designer The CAD improves the productivity of the designer to visualize the product and its components, parts and reduces time required in synthesizing, analyzing and documenting the design.
2. To improve the quality of design CAD system permits a more detailed engineering analysis and a large no. of design alternatives can be investigated. the design errors are also reduced because of the greater accuracy provided by system.
3. To improve communication in design the use of a CAD system provides better engineering drawings, more standardization in drawing, better documentation of design, few drawing errors.
4. To create a data base for manufacturing In the process of creating the documentation for the product design, much of the required data base to manufacture the product can be created.
5. Improves the efficiency of design It improves the efficiency of design process and the wastages at the design stage can be reduced.

Conventional Design Process

1. Recognition of need

• The first step in the designing process is to recognize necessity of that particular design. • The condition under which the part is going to operate and the operation of part in that particular environment.
• The real problem is identified by knowing the history and difficulties faced in system.

2. Definition of problem

• The design involves type of shape of part, its space requirement, the material restrictions and the condition under which the part has to operate.
• The basic purpose of design process has to be known before starting the design.
• A problem may be design of a simple part or complex part.
• It may be problem on optimizing certain parameters.

3. Synthesis of design

• In this, it may be necessary to prepare a rough drawing of design part.
• The type of loading conditions imposed on the parts.
• The type of shapes which the part section can require and approximate dimension at which the different forces are located has to be provided on the sketch of part.
• The stresses to which the part is likely to be subjected must be analyzed and relevant formulas should be prepared.
• A mathematical model of design may be prepared to synthesize the parts of design.

4. Analysis and optimization

• The design can be analyzed for the type of loading condition as well as the geometric shape of the part.
• In the first stage it will be necessary to check the design of the part for safe stresses.
• If it is not satisfactory, then the dimensions of the part can be recalculated.
• The part can further be optimized for acquiring minimum dimensions, weight, volume, efficiency of the material and cost.
• The optimization depends on the definition of the problem and importance of a parameter.
• It may be sometimes necessary to optimize the part for certain operating parameters like efficiency, torque, etc.

5. Evaluation

• It is concerned with measuring the design against the specifications established in the problem definition phase.
• The evaluation often requires the fabrication and testing of model to assess operating performance, quality and reliability.

6. Presentation

• The design of component must be presented along with necessary drawings in an attractive format.

Conventional Design vs CAD

1. Geometric modelling

• Geometric modelling is concerned with the computer compatible mathematical description of the geometry of an object.
• The mathematical description allows the image of the object to be displayed and manipulated on a graphics terminal through signals from the CPU of CAD system.
• The software that provides geometric modelling capabilities must be designed for efficient use both by the computer and human designer.
• The basic form uses wire frames to represent the object.
• The most advanced method of geometric modelling is solid modelling in three dimensions.

2. Engineering Analysis

• The analysis may involve stress-strain calculations, heat transfer computation etc.
• The analysis of mass properties is the analysis feature of CAD system that has probably the widest application.
• It provides properties of solid object being analyzed, such as surface area, weight, volume, center of gravity and moment of inertia.

• The most powerful analysis feature of CAD system is the finite element method.

3. Design Review & Analysis

• A procedure for design review is interference checking.
• This involves the analysis of an assembled structure in which there is a risk that the components of the assembly may occupy same space.
• Most interesting evaluation features available on some CAD systems is kinematics.
• The available kinematics packages provide the capabilities to animate the motion of simple designed mechanisms such as hinged components and linkages.

4. Automated Drafting

• This feature includes automatic dimensioning, generation of crosshatched areas, scaling of the drawing and the capability to develop sectional views and enlarged views of particular part details.

Benefits of CAD

• Improved engineering productivity
• Reduced manpower required
• More efficient operation
• Customer modification is easier to make
• Low wastages
• Improved accuracy of design
• Better design can be evolved
• Saving of materials and machining time by optimization
• Colors can be used to customize the product