The present AutoCAD reference guide is, basically, an extension of our teaching, training and working experience in the CAD (Computer Aided Design) field and covers only ~200 commands of AutoCAD. In a productivity war, not only fewer weapons (tools and commands) force us to imbibe the defeat, but more than enough weapons are also suicidal (because we have less time for selection of weapon, too). So a compromising balance has been tried to achieve the optimum.

The available average good books on AutoCAD are horribly containing 2-3 thousands of pages for main text, with dozens of pages, only for their contents. All these mess is full of unnecessary details of even very simpler commands, which user can easily learn intuitively. Even after the bulk of pages they skip some really useful commands, which could otherwise boost the productivity of end user. 

While this reference guide is intended to provide a compact guide of AutoCAD to a wide range of working CAD professionals and students, ranging from engineering streams (architectural, civil, mechanical, electrical, etc.) to non-technical streams. We are relying heavily on the AutoCAD’s user friendly interface while writing the reference guide, as after entering the command alias in AutoCAD, it,  itself, tells ‘n asks for minimum ‘n necessary details through command line. So, practically, there is no need of written procedural details.

As this reference guide book is complimentary with the ‘AutoCAD-Advanced’ and ‘AutoCAD-Professional’ courses of ‘4Dimensions’, most commands given in this guide need at least one time lab training on real projects by an experienced tutor/professional. Each command, once mastered, doesn’t need the whole procedure to be remembered exactly (as different versions may have different procedures).

Content Development Team

4 Dimensions

This Ebook is a master's dissertation on 'Cam Profile Analysis and Simulation using Synthetic Curves' submitted in September, 2013.

Cam follower mechanisms are versatile mechanisms for obtaining complex motion outputs. Cams are also having vast range of applications due to their flexibility in operations, as they may easily be replaced, are adjustable and changeable for timing or for different motion requirements.

The kinematic behavior of follower establishes the basic suitability of cam for the given application. The cam profile curves are mainly responsible, at the core, for proper operation of the cam follower mechanism, as they are the main input of the cam follower system. Synthetic curves, which are generated, parametrically, through a set of known data points with desired number of curve segments, may be proved to be a major improvement over the traditional trigonometric and polynomial cam profile curves.

In present work Hermite and Bèzier curves are studied for their effect on the kinematic behavior of follower, when used as cam profile curves. Both the curves are generated by varying their different curve parameters, viz. length and direction of tangent vector for Hermite curves, and number of control points with their different positions for Bèzier curves. The kinematic behavior of follower is simulated for cam profiles using these synthetic curves in MATLAB. The resulting follower displacements, velocities, accelerations and jerks are analyzed and comparative study is performed with the kinematic behavior of cycloidal cam profile.

It is observed that the Hermite curve, when used as a cam profile, has caused 28.32% improved (i.e. reduced) maximum acceleration of follower than that obtained for cycloidal curve, while deviating from cycloidal cam profile by a maximum instantaneous difference in displacement of follower by 4.95 %. At the same time Bèzier curve has facilitated continuous jerk of follower, which is not, at all, possible by using a cycloidal curve.

Thus, it is finally concluded that the synthetic curves, when used as cam profile, are providing better kinematic behaviour of cam follower mechanism, with lower maximum velocities, lower maximum accelerations, and lower maximum values of other undesirable higher order kinematic characteristic terms with the flexibility of shape control and better support for CAD/CAM applications.

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