TABLE OF CONTENTS Regardless of what is being produced, the fabrication process nearly always begins with a computer-aided design drawing. While paper prints are still a necessity in some instances, the machining and metalworking industries have been transformed by the evolution of computer-aided design (CAD) and computer-aided manufacturing (CAM) systems. Two-dimensional drafting packages are largely giving way to three-dimensional solid-modeling packages. Although mechanical design typically is not the responsibility of the machinist or metalworker, machinists and metalworkers increasingly are required to be fluent in the use of a solid-modeling system for purposes of designing tooling, generating toolpaths, and conducting engineering analysis studies.
Given the widely distributed nature of design and manufacturing, it is often the case that the machinist will not be working with the same CAD package as the mechanical designer. In these cases, either the machinist's CAD system must be capable of importing the CAD format used by the mechanical designer, or the two must agree on a neutral interchange format.
Some of the more commonly encountered CAD file formats can be found in Table 6.1. Of the formats shown on this list, IGES and STEP are examples of neutral data-exchange file formats developed by standards committees. The Parasolid and ACIS formats are commercial formats, but they are also of interest in the sense that most of the CAD systems represented in Table 6.1 are built on either the Parasolid or the ACIS kernel. If the mechanical designer and machinist both happen to use...
