If you have done drafting by hand, or used simple CAD programs such as Autocad you are used to a different approach to technical drawing. In drafting based programs you picture the part in your mind, and then draw lines and arcs for two, three or more views that represent the edges of the part. For example to draw a cube you draw three squares (front, top, right side views) using four lines for each square. The line dimensions must be correct, and then dimensions can be added after. When you are done the only major use is to print/plot the drawings.
With solid modeling based systems you start by entering the geometry of the object. For example a cube is a cube, not a set of lines. The solid modeler stores this geometry internally as a mathematical model of the surface and volume of the part. After entering the geometry it can be used for various tacks such as creating 3 view drafted drawings, creating NC codes so that it may be machines, doing finite element analysis. Most CAD packages now offer some level of solid modeling, including Autocad.
Pro/Engineer has its own method for entering the geometry that tends to focus on cross section profiles. You draw a profile of the part and then extrude or rotate it. This approach is well suited to parts that will be manufactured. The creation of the profile is the most like traditional drafting. For example to create a cube, you would first draw a square, and then extrude it into a cube. If the same square was rotated it would produce a cylinder. After the base part has been created, it can be added to or features can be cut out. The geometry of the part is not fixed, and it can be changed and manipulated at any time.
Note: When using the solid modeler be prepared to use 3D coordinate systems to define and manipulate parts.
1. Use the book “Pro/Engineer Tutorial and Multimedia CD” by Toogood and Zecher. Insert the CD and follow through a few until you feel comfortable. Then work through the book up to and including lesson 8.
2. Create a geometry for a die cavity (a simple box shaped cavity is sufficient). Use the Pro/E machining module to convert this to CL values. Look at the text file that was produced. This file is not yet ready for an NC mill. It requires post processing, which we will do later.