Downloading CAD drawings saves time

Component manufacturers have been making CAD drawings available for downloading for a long time, originally through a central database for in-house use, then through CD-ROM for customers. Now, they are available on the Internet for mass distribution to anyone who might want them--for free.

The natural progression has been to make CAD file downloads available from each manufacturer's site, as well as provide the same downloads via links from distributor sites and catalog sites. Although the wide availability of downloadable CAD drawings may increase the visibility of suppliers, or get their components specified into designs they might not have known about in the past, the primary reason to provide CAD downloads is to service and maintain loyal customers. That's why fastener suppliers Southco and Penn Engineering, as well as companies like PHD, Adept, and many others, make them available from their sites. So, how often do design engineers use downloaded CAD files? Ask some who use them.

Travis Pedley, a design engineer for Electro-Mechanical Specialties out of Sanford, NC, says, "I primarily download standard products at a rate of about two per week." Crawford Turner, CAD manager for Advanced Automation says he downloads over ten standard products per week, "often to help out the50-plus engineers in my department." Turner has downloaded from numerous sites, including SMC, Effector, Allen-Bradley, PHD, and others. Most of the engineers in his department download components regularly. Both Pedley and Turner expect they will be performing more downloads in the future.

Do they ever make changes to the CAD files they download? Pedley, whose company makes custom machine designs, says he often makes minor adjustments to large CAD files. "For example, we might change the stroke for an electric slide to fit a specific design," he says. Advanced Automation, which designs and manufactures automated assembly equipment, says, "We use AutoCAD and would rather download a .DWG file. We're only producing 2D drawings. The .DXF files most suppliers provide have to be converted (which only takes a minute or two), but then have to be checked for accuracy. Checking to see if the file is dimensionally correct can take as long as 20 minutes. To repair the drawing, it might take another hour."

Most manufacturers offer their product downloads in either .DXF for 2D or IGES for 3D files, both of which easily transfer to most CAD software. Pedley downloads standard product drawings directly into Autodesk's Mechanical Desktop program. "About 30% of each application I work on is made from standard products," he says. "I download 90% of those products directly into my drawing. I can't tell you how many hours it saves me, but engineers will be able to translate it for their own applications."

Turner, on the other hand, claims to use almost 50% standard components and 50% custom designs. Out of the standards, about 20% are downloaded directly from the manufacturer's site. "They have the latest drawings," Turner says. "Our CD's are often a year or more old, plus are hard to keep track of," he adds. "Since supplier web sites always have the most updated downloads, we don't have to store files here and let them go out of date."

Downloading CAD drawings does more than just save time for Pedley. "There is much less risk of error when you download a component drawing because the data doesn't have to be translated from catalog copy and redrawn by hand," he says. "Besides, the greater detail offered by most CAD downloads makes my main drawing look more professional." When asked if the downloads themselves take up much time, the answer was a definitive no. "Downloads take from five to about thirty minutes, and run in the background while I perform other operations," he says.

Compare this with Turner's concern over checking and repairing files. Turner goes on to say that complex components may not be worth the time to repair if they don't transfer properly to the format he needs.

Other engineers, who asked to remain anonymous, agree with the ease and speed of CAD file downloads. Most engineers interviewed for this column work on a PC running either Windows 98 or Windows NT. When asked about the accuracy of downloads available, one engineer said that literally every file has been 100% useable. "I've never gotten a bad file from a download," he said.

The availability of CAD downloads for custom designs offers manufacturers another interesting inroad to new applications. To get more custom work, PHD provides engineers with the ability to produce CAD files for custom designs. The company's Parametric CAD Configurator provides accurate PHD model number selection, which reflects both option compatibility and travel increments. The Configurator actually creates a 2D and/or 3D CAD file of the exact model number selected. Once again, the most significant advantage is the time savings. There are fewer risks for errors when a CAD drawing does not have to be modified. As mentioned above, a peripheral advantage would be the sophistication of the drawing itself.

PHD provides its Parametric CAD Configurator application on CD-ROM or as downloadable software from their site, so customers can create their designs on- or off-line. Once configured, all options that affect the unit's size are reflected in the parametrically created geometry, including stroke, rod end, cushions, shock pads, shock absorbers, mounting styles and much more. According to PHD's Steve Gilliom, "All calculations leading to a valid part number and a clean CAD drawing in 2D or 3D are performed on-the-fly." PHD now has 3D files available that can be imported into most solid modeling CAD packages, as well.

Electro-mechanical Specialities' Pedley says he uses PHD's Parametric CAD Configurator regularly. "The Configurator is resident on my hard drive, so it is always available," he says. "Our machines vary so much from design to design, and the Parametric Configurator saves us a lot of time." Advanced Automation's Turner also uses PHD's Configurator, except that Turner would like to see the CAD files available in .DWG rather than .DXF. "Whenever we can get CAD files in the language our CAD package uses, we do it," he says.

11th Annual HP Technology Trends in Computational Engineering

On March 28th, 2000, HP will present the 11th Annual HP Technology Trends in Computational Engineering Symposium at the Laurel Manor in Livonia, MI. This outstanding annual seminar uniquely brings together chief technologists from the leading MCAE software companies who share their insights into the dynamic world of computational engineering.

Additional presentations will be made by HP technologists and strategists, outlining HP's vision for the role of the Internet in engineering enterprises. A special guest speaker from the motor sports world will also share his view of engineering from the race tracks.

Featured topics of the seminar will include:

- Structural Engineering

- Crash and Stamping Analysis

- Noise Vibration and Harshness (NVH)

- Computational Fluid Dynamics (CFD)

More information and seminar registration can be found at http://www.hp.com/go/auto.