These are the terms with which one come across in the market. CADD which stands for Computer Aided Design and Drafting. In short this is termed as CAD. This involves any type of design activity which make use of the computer to develop, analyze, or modify an engineering design. It can be used to supplement or replace traditional drafting and designing tools i. e. scales, compass, T-square, drawing board etc. CAD ensures zero defect engineering.

The CAD system consists of a CAD software, a processor or a computer, a monitor used to display drawings, a keyboard  for data input, device such as mouse or stylus to control the location of drawing objects and a plotter or printer to take a hard copy output on paper.

The CAD operator interacts with the system with the help of series of commands to create, modify and edit a drawing. The software provides with predefined geometrical objects ( called objects or primitives) i. e. line, arc, circle etc. for 2D drafting and box, cylinder, cone etc. for 3D modeling. Operator can feed in the desired dimension to create the required objects and using an input device locate points to place objects on the screen. Combined with a library of symbol for repetitive work, it can reduce the lead time to complete a design project to few hr. as compared to weeks with manul designing.

Some high-end software allows user to perform engineering analysis on 3D models generated. The analysis may involve stress-strain calculations, heat transfer computations, analyzing dynamic behavior of a component, and calculation mass properties. The output of the analysis can also be presented graphically on the screen. This feature avoids creation of costly prototypes and time and money spent to analyze them. Design can be reviewed, evaluated and compared easily on the computer after the designer is through with the analyzing part.
Some of the graphics features of CAD system lend themselves especially well to the drafting process. 
These features include automatic dimensioning, generation of crosshatched areas, scaling of the drawing, and the capability to develop sectional view and enlarge views of particular part details. The ability to rotate the part or to perform other transformations of the image i. e. move, scale etc. can be of significant assistance in drafting.

Advantages of CAD are as follows :-
  1.            Better Designs.
  2. ·         Improved engineering productivity.
  3. ·         Shorter lead times.
  4. ·         Improved accuracy of design.
  5. ·         Provides better functional analysis to reduce prototype testing
  6. ·         Standardization.
  7. ·         Better documentation.
  8. ·         Better costing.
  9. ·         Faster and accurate NC Part programming with CAD Data.
  10. ·         Improved productivity in tool designing.
  11. ·         Better communication interface among engineers, designer, drafters, management and different project groups.

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                CAM stand for Computer Aided Manufacturing. This is use of computer systems to plan, manage and control the operations of a manufacturing plant through either direct or indirect computer interface with the plants production resources. In direct interface, computer is connected directly to the manufacturing process for the purpose of monitoring and controlling the process.
With the introduction of CAD and CAM, design and production department of industries have come closer, which used to be two far away departments earlier. CAD system allows designers to create, visualize draft and analyze their products on the screen in two or three dimensions. The same data can be transferred to production engineering as manufacturing data base. Production engineer can utilize the data to generate numerical part programming for CNC machines or for robotics etc. CAM system oversees the work flow on shop floors and controls the machine tools, conveyors and robots responsible for production.


                CAE stands for Computer Aided Engineering. It ties together such diverse interests as drawings, cost analysis, structural analysis, production process plans, material specification, tool design and quality control.

 What is AutoCAD

                             AutoCAD is developed and marketed by M/s Autodesk Inc. USA and most widely used CAD software worldwide. Currently releases of product are AutoCAD 2019. This was one of the software, which were launched on PC platform in initial years of eighties with few options. Before that all the CAD software used to be on mainframe machine only. Now it is one of the best selling software of the world. With AutoLISP, VB and VC++, accompanying high level programming languages, user can customize AutoCAD to their particular needs. A number of third party software are also evailable which work on AutoCAD platform to customize the software for specific usage i. e. Electrical, Civil, Architect, Piping, Ducting, etc.

Advantages of AutoCAD 

·         Flexible.
·         Availability on various platforms.
·         Availability and technical support.
·         Simple and ease of use.
·         Customizable.
·         Third party customized tools available.
·         Accepts and produces various file types.

Hardware requirement

·         Minimum Pentium 166MHz. Processor.
·         Minimum 32 MB of RAM.
·         VGA or higher graphics card.
·         Minimum 150 MB of free hard disk space.

Optional devices

·         Printer or plotter for hard copies.
·         Pointing device, mouse or tablet.
·         Color monitor or dual monitor.

Important commands of Autocad software   

  • Line: -The line is the basic object in AutoCAD. Line command allows you to draw straight lines by specifying two end points of line

    Xline (Construction Line):- Xline command draws lines of infinite length i. e. both ends remains invisible. Basic use of xline is to draw the construction line or grid lines used in layouts and construction drawings

    Mline(Multi-line):- Mline command creates multiple parallel lines at user defined distance. This is a shortcut to drawing a single line and then offsetting it on one side

    Circle:- Circle command allows user to draw the circle with different options. User may use any of the seven options available to draw the same circle, depending upon the type of data available and user personal preference

    Arc:- AutoCAD allows user to draw an arc with various options

    Polyline:- A polyline is connected sequence of wide line and arc segments. Polyline with all number of segments is treated as a single object by AutoCAD

    Polygon:- AutoCAD polygon command allows user to draw a polygon by specifying number of sides and length of sides

    Rectangle:- A rectangle is a special from of polyline which can be created by specifying two diagonally opposite corner points

    Ellipse:- AutoCAD RI. 14 allows user to create true ellipses with ellipse command

    Remove:- Remove option allows user to remove objects form selection set

    Add:- Add option allows user to add more objects to current selection set

    Erase:- Erase command allows user to erase the object, which are not required, from the drawing

    Copy/Move:- Both copy and move command work in similar fashion. With copy command user gets a duplicate copy of selected objects at required location while move command actually move the selected objects to new defined location

    Offset:- Offset command allows user to create objects parallel to the existing objects by defining the offset distance or through a specified point. User can quickly create the lines of similar length at defined distances and concentric circles of defined offset radius values with offset command

    Mirror:- Mirror command lets the user create a mirror copy of selected object. User will have to locate the mirror by specifying two points on mirror line. User can place mirror anywhere in the drawing. AutoCAD obeys the basic law of mirror that distance of image from the mirror line stands equal to distance of original object from mirror line

    Array:- The array command allows user to make multiple copies of selected objects in defined formats

    Fillet:- Fillet command removes the sharp edge corners of two objects and connects them with a smooth arc of defined radius

    Chamfer:- Joins the two line objects (only) with a straight line

    Trim:- Trim commands trims selected objects, which are projected out from an edge

    Extend:- Extend command lengthens the selected objects till the selected edge

    Rotate:- Rotate command allows user to rotate selected object around a specified base point

    Scale:- Scale command allows user to change the size of existing objects equally in both the coordinate directions

    Break:- Break command allows you to remove a portion of an object. You are prompted to select one or two points (depending upon the option) on the objects and AutoCAD removes the portion of object within the selected points

    Pedit (Polyline Edit) :- Pedit command edits the existing polyline with following options

    Join :- Prompts to select objects

    Zoom :- AutoCAD provides zoom command to take a closer look at required part of the drawing

    Pan :- Pan command you can displace whole drawing on one side and bring required area on the screen. All you have to do is pick two points on screen or specify coordinates of two points to specify the displacement. AutoCAD calculates the distance and angle between two points and performs displacement

    Regen :- The REGEN command regenerates the entire drawing and redraws it on the screen. Regeneration of drawing is reading the data from the database of AutoCAD and drawing it on the screen, which is same as opening a new file

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