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To reduce time-to-market, most manufacturers demand suppliers import CAD data files to transfer information quickly. A blueprint is an after-thought--a document to archive for future reference. The CAD data file is not necessarily the end of the design cycle, but often an evolving code that, when imported, represents the point at which the manufacturer joins the design process. Some customers require suppliers to import CAD part files and then export final data back to the customer's system, either for verification and final part inspection, or to document the finished product specification.
Each CAD/CAM vendor has its own proprietary file format for storing part files in its database. Transferring a file from one system to another requires either the exporting CAD system or the importing CAM system use a file-data translator to ensure transfer integrity.
DIRECT VERSUS NEUTRAL
Methods for transferring part files between CAD and CAM systems are classified as direct translators and neutral file formats. A direct translator can accommodate the full product definition data because it uses the originating system's database format. Each CAD or CAM system, however, requires its own direct translator, so the cost to write and update direct translators to every possible system is prohibitive.
In the US, the Initial Graphics Exchange Standard (IGES)--a neutral file format--is recognized as the industry standard and monitored by the National Institute of Standards and Technology (NIST). If your CAD/CAM system has IGES input and output capability, itshould be able to transfer files between any CAD/CAM system with IGES neutral file format capability--but only theoretically. IGES came from an Air Force contract to a team from Boeing, GE, and the National Bureau of Standards (the predecessor of NIST). Work began in 1979 to develop a format for the exchange of product definition data, and has evolved into a standard, although imperfect, to exchange geometric data.
All neutral file formats, including IGES, require two translators: a preprocessor or out-translator, and a post-processor or in-translator, not to be confused with the CAM system's post-processor that converts toolpaths to a specific machine controller's G-code formats. IGES is widely accepted for transferring complex surface information, such as NURBS (Non-Uniform Rational B Splines) or trimmed surfaces. Nevertheless, many CAD software vendors have developed their own neutral file formats, such...