While CAD has certainly facilitated mechanical de-sign, engineers should not have to spend time creating standard parts for assemblies. Many part manufacturers have put their 2D part libraries onto CDs, but with the increased use of 3D CAD, designers clearly need 3D standard part options.

Trace Parts, a subsidiary of the French company Trace Software (Saint-Romain), offers designers a growing number of part libraries in native and neutral 3D CAD formats that can be downloaded free from the Web (www.traceparts.com/online) or by purchasing a CD. The company uses its own CAD parametric format written in JavaScript, which draws on an XML-based dimension database for part size. This method makes the library of hundreds of thousands of parts a manageable size to store on a CD, and it also lets users perform advanced queries with filter criteria and personal parameters to their searches. Databases from multiple manufacturers can also be associated.

Once the part has been selected in the CAD format, users can choose between 3D native formats for Inventor, Mechanical Desktop, SolidWorks, Solid Edge, thinkdesign, and TopSolid, or neutral formats (STEP, SAT, IGES, and XT). "All the parts in our libraries are available in 3D formats," says Gabriel Guigue, managing director of Trace Parts. "Part libraries today are one of the most asked for accessories to a CAD system, and they can cut design times by more than 60 percent."

German-based Cadenas (Augsburg) and its U.S. subsidiary PARTsolutions also offer a wide variety of parts on the Web, or by purchasing a CD, using a similar method of part geometry combined with a dimension database. "Our feature-based modeler applies a 'recipe,' or the variables for the specific part, to the basic geometry," explains Tim Thomas, general manager at PARTsolutions. "This means the file sizes are small because you only have to make the geometry once to have a large number of variations."

The company also offers 85 different formats including Catia V4, EAI, I-DEAS, Pro/ENGINEER, Solid Edge, SolidWorks, thinkdesign, and Unigraphics; plus IGES, SAT, and STEP neutral formats. When ordering free parts from the Web (www.partserver.com and www.partserver.de), the user will either receive a part in a native CAD format, or if the CAD format is not available, a macro "recipe" that will build the part within the user's CAD application. The CD offers additional applications, such as a bi-directional screw connector and an assembly generator.

Parts directly from the application. Add-on modules with direct interfaces for specific CAD applications give the user access to the part library directly in the application interface, as well as the direct transfer of a part into an assembly. In addition, the part can be automatically inserted in the bill of materials including the part name, reference, international standard, and supplier name.

Likewise Trace Parts is also available as an add-on for its native 3D formats, including its latest addition, Autodesk Inventor. Users can directly access the part library from within these applications and insert native parts into their assemblies. To do this, Trace Parts has written its own conversions from the CAD format to the specific application format. For Autodesk Inventor, this meant forming an agreement with Spatial, which owns the ACIS kernel that is used in Inventor and a large number of other CAD programs. The company is currently preparing Trace Parts for Catia V5 and Pro/Engineer, which have proprietary kernels.

Newtec Palettisation in France uses Trace Parts for both AutoCAD 2000 and Inventor Autodesk. The company, which makes robots to automatically position boxes onto palettes in preparation for distribution, has developed an extensive customized 2D library using parts both designed by the company and those from Trace Parts. With the addition of two seats of Inventor, Newtec is now starting to develop its 3D library. "It is important to have a part library available to speed design times, and Trace Parts is well integrated into the two CAD applications we use," states Laurent Ferre, manager of the Robotics Unit at Newtec Palettisation.

The test department of vacuum manufacturer Dyson (Malmesbury, England) has been using Trace Parts for Solid Edge for the last two years. Three engineers in the department use hundreds of standard parts every month to build testing equipment for the company products.

"The catalog works very well for generic parts that have international standards, but other parts that are 'generic,' yet not officially standardized, will vary from manufacturer to manufacturer," says Steve Evans, design engineering manager at Dyson. "We take a number of parts and load them into our own databases for future use. We usually only do simple searches, since it's a bit complicated to do anything really advanced."

Cadenas has agreements with a large number of CAD vendors to use their API (application program interface). The company can therefore set up a direct interface with the CAD system for all purchases of its CD, and the user receives a macro "recipe" for the part to be built within the system. Once built, the part can be listed within the data management system for future use.

Barmag AG (Remscheid/Lennep, Germany), which manufactures spinning machines for the textile industry, has used Cadenas in conjunction with SolidWorks for almost four years. The part database is installed in 100 seats, and CAD administrator Stefan Berlitz has found that the database is quite easy to use, though periodic updating of such a large installation can be cumbersome. However, he notes that Cadenas was one of the few part libraries available that could handle an installation of this size.

Local suppliers needed. Central to any part database is the number and location of the contributing suppliers. Cadenas boasts more than 150 suppliers that contribute to its part library, though many if not most of these are from German manufacturers with international distribution. Its new subsidiary, PARTsolutions, will be adding suppliers from North America. Trace Parts currently has parts from 25 different manufacturers and plans to bring that to 50 in the next six months. However, many of these are based in France.

"We never search for parts from unknown suppliers in the Trace Parts library," notes Ferre. "We make a point of taking parts from confirmed suppliers, or from the supplier specified in a customer's order, since there can be minor, but crucial variations in generic parts. Not all of our suppliers are in Trace Parts, but many more of them are slated to be in the next version."

"The user must be careful that a part used from the CD is from a supplier he or she can deal with," adds Evans. "As a U.K.-based manufacturer, it's important to have local suppliers that have a number of different parts that we need, to avoid opening an account for three hinges."

Barmag has filtered the Cadenas database access so users only see parts from the accepted supplier base. "However, we still have to be careful with the PDM interface," says Berlitz. "When assemblies that include standard parts are checked out of the PDM system, we have to be sure that the standard parts are not then modified by the engineer."

Finally, it is important to note that some part manufacturers have started creating their own portals for 3D part libraries, using tools such as Partdeveloper (Cadenas), Redspark (Autodesk), or CatalogCreator (Web2Cad). For those designers that have set suppliers, this is an alternative solution, however it requires a separate visit to each site and not necessarily the same number of CAD formats.