Cadalyst - September 2008 - (Page 37)

mcadmodeling fact, that I have heard some companies say that the days of drafters are coming to an end. They say that engineers and designers will be creating their own drawings. I have to question the logic of this thinking. The fact is, drafters are trained to know drawing standards and can present work in ways that most people will understand. Engineers are trained in many areas but seldom have more than a semester of drafting education. Besides, engineers are paid more than drafters. It makes more business sense to move drafting work to lesser-paid people who have more specific training for the job. What’s Going On? Figure 2. CAM is a great thing indeed. There is no more accurate way to build a physical model. Modern CAM programs take a 3D model and calculate the path its tools must follow to machine a part. We still create 2D drawings, but their function has changed. When I was fresh out of college, drawings were necessary for building not only the parts but the tools to make the parts. The model shop relied on my 2D drawings. That’s not necessary in today’s world, or even preferred. Nowadays, many companies cut steel by using their wonderfully accurate 3D models. The modern machine shop can take a 3D model file and pass it into its computer-aided manufacturing (CAM) program to tell its tools what to do (figure 2). These systems work directly from the 3D geometry. They are limited only by the size of their cutters. Rapid prototyping (RP) is a 3D model application that bypasses the need for drawings (figure 3). In fact, except for some finishing work — and even that is getting less and less necessary — you don’t even need tools for RP. Some RP machines tout resolutions on the order of 16 micrometers. Lastly, there is simulation (figure 4). It used to be that you drew layouts so you could show the complete range of motion of the parts in your design. Now, you build the parts, put them in an assembly, then push or pull them around. If you’ve properly constrained them, they will act like the real parts. It’s actually fun to watch. Answers and Perspective Figure 3. Rapid prototyping is the most exciting technology in the manufacturing world. With it, you can turn a virtual part into a reallife 3D prototype. Drawings and tooling are unnecessary. If a feature is in the digital model, it’ll be in the RP part. So how do we use 2D drawings nowadays? At the risk of oversimplifying the answer, I would conclude that 2D drawings today are used mostly for inspection. You have to make sure the parts your vendor hands you are within specification. To fully use the 3D models we’ve spent so much time and effort creating, it only makes sense that we would keep everything in the digital realm until the very last stage of production — when parts pop out of the factory. There’s also history. If the government audits you, it’s nice to have the drawings required. But in all likelihood, 2D drawing for specification is probably doomed — like so many other human activities. We have to grow and mature. It’s natural. I prefer to think that 2D drawings will live on — but in new ways. Mike Hudspeth, IDSA, is an industrial designer, artist, and author based in St. Louis, Missouri. Figure 4. If created properly, simulated assemblies will perform just as you would expect real objects to do. September 2008 cadalyst www.cadalyst.com 37 http://www.cadalyst.com

Table of Contents Feed for the Digital Edition of Cadalyst - September 2008

Cadalyst - September 2008 Contents Editor's Window Cad Central Tech Trends: Genie Out of the Bottle Cadalyst Labs Reviews: Big Tools for Big Jobs — Wide-Format Scanners and Printers Make Small Work of Large Projects Cadalyst Labs Reviews: AutoCAD 2009 — General-Purpose CAD Software Cadalyst Labs Reviews: AecBatchStylesEditor 2009 — CAD Standards Management Software for AEC Cad manager: Synchronize CAD Files over a Wide Area MCAD Modeling: Is 2D Drawing Doomed? Plm Strategies: More Bang for Your Truck Aec Insight: Works and Plays Well with Others Cad Cartoon Issue Indexes Hot Tip Harry: VBA Hints for Customizing AutoCAD

Cadalyst - September 2008

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