How to make a spur gear using AutoCAD

You can make a spur gear using AutoCAD following this simple tutorial Step 1: Lunch AutoCAD.

• Step 2: Draw 2 circles of 50mm radius and 35mm radius respectively To draw circle in the command line type circle, or c and press enter Choose r for radius and enter 50 for the first circle repeat again for the second circle.

 • Step 3: Make the gear tooth spaces profile

. • Step 4: Trim the circles side ways.

 • Step 5 Now enter "bo" command. It will show the boundary creation dialogue. Click Pick point. This command is going to be used for creating the polyline.

 • Step 6: Click inside the region and then press enter.

 • Step 7 Now we have the polyline created. Remember bo command doesn't join the lines but creates a polyline bounded by a region. Therefore the lines and arcs are also there.

 • Step 8 Make a circle of 50mm radius.

 • Step 9 Extrude it by 15mm.

 • Step 10 Now extrude the tooth polyline by 25mm.

 • Step 11 Array>>polar array>> and select the tooth profile extruded to array and the center point be origin and no. of items let be 12. Click OK

 • Step 12 Now subtract the tooth profile arrayed from the cylinderical disc and we have the gear body.

CHAPTER 3: Drawing Your First Objects in Autocad

Introduction

This tutorial is designed to show you how all of the AutoCAD Draw commands work. If you just need information quickly, use the QuickFind toolbar below to go straight to the command you want or select a topic from the contents list above. Not all of the Draw commands that appear on the Draw toolbar are covered in this tutorial. Blocks, Hatch and Text for example are all tutorial topics in their own right!

The Draw commands can be used to create new objects such as lines and circles. Most AutoCAD drawings are composed purely and simply from these basic components. A good understanding of the Draw commands is fundamental to the efficient use of AutoCAD.

The sections below cover the most frequently used Draw commands such as Line, Polyline and Circle as well as the more advanced commands like Multiline and Multiline Style.  As a newcomer to AutoCAD, you may wish to skip the more advanced commands in order to properly master the basics. You can always return to this tutorial in the future when you are more confident.

In common with most AutoCAD commands, the Draw commands can be started in a number of ways. Command names or short-cuts can be entered at the keyboard, commands can be started from the Draw pull-down menu, shown on the right or from the Draw toolbar. The method you use is dependent upon the type of work you are doing and how experienced a user you are. Don't worry too much about this, just use whatever method feels easiest or most convenient at the time. Your drawing technique will improve over time and with experience so don't expect to be working very quickly at first.

If you are working with the pull-down menus, it is worth considering the visual syntax that is common to all pull-downs used in the Windows operating system. For example, a small arrow like so " " next to a menu item means that the item leads to a sub-menu that may contain other commands or command options. An ellipsis, "…" after a menu item means that the item displays a dialogue box. These little visual clues will help you to work more effectively with menus because they tell you what to expect and help to avoid surprises for the newcomer.

Before we start any drawing it is mandatory and professionally that we must set up a layer for the drawiong

AutoCAD Lesson from the Book Teach Yourself AutoCAd in 30 Days For Dummies

Computer-aided design (CAD) is the use of computer technology to aid in the design and particularly the drafting (technical drawing and engineering drawing) of a part or product, including entire buildings. It is both a visual (or drawing) and symbol-based method of communication whose conventions are particular to a specific technical field.

CAD was first created in the early 1960s and today is used to design almost every product on the market in the world.  There are many types of CAD software existing for different applications.

Drafting can be done in two dimensions ("2D") and three dimensions ("3D"). Drafting is the integral communication of technical or engineering drawings and is the industrial arts sub-discipline that underlies all that is involved in technical endeavors. In representing complex, three-dimensional objects in two-dimensional drawings, these objects have traditionally been represented by three projected views at right angles.

Current CAD software packages range from 2D vector-based drafting systems to 3D solid and surface modelers. Modern CAD packages can also frequently allow rotations in three dimensions, allowing viewing of a designed object from any desired angle, even from the inside looking out. Some CAD software is capable of dynamic mathematic modeling, in which case it may be marketed as CADD — computer-aided design and drafting.

CAD is used in the design of tools and machinery used in the manufacture of components, and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures (hospitals and factories).

CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.

17

CAD has become an especially important technology within the scope of computer-aided technologies, with benefits such as lower product development costs and a greatly shortened design cycle. CAD enables designers to lay out and develop work on screen, print it out and save it for future editing, saving time on their drawings.

Types of CAD Software

2D CAD

Two-dimensional, or 2D, CAD is used to create flat drawings of products and structures. Objects created in 2D CAD are made up of lines, circles, ovals, slots and curves. 2D CAD programs usually include a library of geometric images; the ability to create Bezier curves, splines and polylines; the ability to define hatching patterns; and the ability to provide a bill of materials generation. Among the most popular 2D CAD programs are AutoCAD, CADkey, CADDS 5, CATIA v4 and Medusa.

2.5 D CAD

In between 2D and 3D CAD is 2.5-D CAD. The models created in this type of CAD are prismatic, that is, they represent the depth of the objects. Like 2D CAD, these objects are made up of geometric objects.

3D CAD

Three-dimensional (3D) CAD programs come in a wide variety of types, intended for different applications and levels of detail. Overall, 3D CAD programs create a realistic model of what the design object will look like, allowing designers to solve potential problems earlier and with lower production costs. Some 3D CAD programs include Autodesk Inventor, CoCreate Solid Designer, Pro/Engineer SolidEdge, SolidWorks, Unigraphics NX and VX CAD.

3D Wireframe and Surface Modeling

CAD programs that feature 3D wireframe and surface modeling create a skeleton-like inner structure of the object being modeled. A surface is added on later. These types of CAD models are difficult to translate into other software and are therefore rarely used anymore.

Solid Modeling

Solid modeling in general is useful because the program is often able to calculate the dimensions of the object it is creating. Many sub-types of this exist. Constructive Solid Geometry (CSG) CAD uses the same basic logic as 2D CAD, that is, it uses prepared solid geometric objects to create an object. However, these types of CAD software often cannot be adjusted once they are created. Boundary Representation (Brep) solid modeling takes CSG images and links them together. Hybrid systems mix CSG and Brep to achieve desired designs.

CAD Hardware and OS technologies

Today most CAD computers are Windows based PCs. Some CAD systems also run on one of the Unix operating systems and with Linux. Some CAD systems such as QCad or NX provide multiplatform support including Windows, Linux, UNIX and Mac OS X.

Generally no special basic memory is required with the exception of a high-end OpenGL based Graphics card. However for complex product design, machines with high speed (and possibly multiple) CPUs and large amounts of RAM are recommended. CAD was an application that benefited from the installation of a numeric coprocessor especially in early personal computers. The human-machine interface is generally via a computer mouse but can also be via a pen and digitizing graphics tablet. Manipulation of the view of the model on the screen is also sometimes done with the use of a spacemouse/SpaceBall. Some systems also support stereoscopic glasses for viewing the 3D model.