Machine Design

Automatic feature recognition slashes CAM work

Here's the short review of FeatureCAM 2004 with Automatic Feature Recognition: Users import a CAD model and hit the AFR button. The NC program completes the toolpaths in a few minutes. That's it.



Of course, there is more to say about the software, such as its cutting-edge capability of machining parts directly from their CAD models. Solid models have all the information necessary to describe a part's shape so there is no reason for users to waste time recreating the part data in a CAM system. The program and others like it are transforming manufacturing by taking on more work better handled by computers. AFR is where the industry will head as more companies gravitate to midrange CAD products like SolidWorks and AutoDesk Inventor.

While the software has other features for production and custom manufacturing, this review focuses on its feature-recognition capabilities. I use AFR to recognize and program 2D parts for milling. Most 2D machining jobs are pockets, bosses, and holes. Other CAM systems make users define geometry, create features, and then specify cutting operations. AFR eliminates that. Typical 2D parts take less than 5 min to program and within 15 min finished parts are coming off the machine. That's incredible.

AFR uses the current-view orientation to analyze CAD models and recognize features. What's more, the software creates NC features that are fully associative to the CAD model. AFR also recognizes complex features that overlap, intersect, or contain 3D surfaces. I work with many different types of CAD files, but predominantly ACIS (.sat), Parasolids (.x_t) and SolidWorks (.sldprt). I've never had a problem with FeatureCAM recognizing features in any of these formats. Combining the CAM software's Direct Model Transfer with AFR makes work almost ridiculously easy. Direct Model Transfer works with SolidWorks and AutoDesk Inventor so it's just a button click to open the part file in the CAM program.

A three-step wizard creates the features. Users first select from a list of features and the software asks for information on shapes and sizes. Then the software displays machining information and lets users select a preferred machining strategy. The programmer can accept the strategies suggested based on the type of features for rough, semifinish, and finish passes, or make changes to fit the machining needs for that particular situation. Then, FeatureCAM analyzes the combination of feature dimensions, stock material, and cutting strategy to recommend the most efficient cutting tools, toolpaths and feeds and speeds for each cutting pass (rough, semifinish, and finish). The programmer can choose the recommended tool or search for another tool in the library. Users can accept or change the recommended feeds and speeds.

The toolpath is ready to go after creating the feature and it updates automatically after revising the feature. It doesn't get any easier than that.

Users retain control over how the software generates NC code. They can set machining preferences ahead of time and the CAM software remembers and applies them. It uses the preferences as it analyzes every feature that makes up the part. Then it recommends tools, feeds, and speeds based on the stock material, feature, and shape. Users can override any of the recommendations.

Because features are fully associative with the imported model, design revisions don't cause problems. With AFR, I don't start from scratch to program a revised model. When one is reimported into the same file, the CAM software compares the initial model with the revised one and displays a list of the added features, and those modified, removed, and unchanged. The software recognizes modified features and generates new toolpaths just for the revisions, leaving the unchanged features alone. The CAM software even notifies users when opening a file, whether or not changes have been made.

AFR also works well on complicated parts. A recent and fairly complex part file required machining on two sides. The first side was straightforward 2D machining. It had a series of bosses and a skirt around the outside of the part with a 0.062-in. wall thickness. The other side was another matter. It had a network of 0.050-in. seal grooves that overlapped and intersected. In addition, the part had over 20 through-holes of varying diameters. In the past, a part like that would have taken me two or three days to program. AFR let me program the first side in about 20 min. The second side took a couple of hours because I was trying different cutting strategies and tool sizes to cut the narrow grooves. It took me another hour to tweak the program just the way I wanted. In all, I spent less than half a day programming it. Reducing programming time from days to hours or even minutes is a huge improvement.

On parts that combine 2D milling with complex surfaces, AFR identifies the vertical and near-vertical walls and then, when it finds the intersection of the vertical wall and the surface, it creates a curve along the intersection. On the finishing pass, FeatureCAM machines up to the intersection. After that, surface machining handles the rest. It's a fast way to machine a die or mold cavity.

I've used other high-end CAD/CAM systems and, while these may be more mature products, their learning curve is too steep. It's frustrating to spend months learning a program while projects pile up. When I first started using FeatureCAM, I was making code the first day and parts within a few days. I used the product for a few months before taking a training class, and it was only to learn more-advanced techniques. Yes, high-end software has more bells and whistles, but I haven't run into any part I couldn't program with FeatureCAM.

When I started my own business in 1998, I purchased the software because I knew that other people would have to use the CAM software and I didn't want them on steep learning curves. For instance, I share floor space with another shop owner who uses a different CAM software system. He hired a CNC programmer and five months later, was still unable to program without assistance. On the other hand, the CNC programmer who works for me uses FeatureCAM. He was starting to program in two weeks, working solo in four, and programming complex 3D surfaces in six months. Now he's accelerating past me, and I consider myself a pretty good programmer.

Customer support is also good. They know how to talk to machinists so they walk you through any problem. In addition, the product diversity is excellent. We write programs all day, every day using FeatureMill2.5D and 3D, FeatureTurn, and others from the developer.
FeatureCAM comes from Engineering Geometry Systems Inc., 275 E. South Temple, Suite 305, Salt Lake City, UT 84111, (888) 393-6455, (

-Mike Maendl

Mike Maendl ([email protected]) is the owner of Protofab, a prototype and short-run production company in Novato, Calif. He has worked in the machining industry for 20 years and has used FeatureCAM products for the past six years.

FeatureCAM needs only a few minutes to generate the NC code for the simple flat plate.

Even for this fairly complex 2D part of pockets, holes, and walls, FeatureCAM needed only a few minutes more to complete after importing its solid model.

A more complex 3D part, an automotive brake actuator, takes a bit more user intervention. However, the software recognizes most of the part features and plans for them.

A complex brake actuator was machined from solid zinc using FeatureCam's 2D and 3D interfaces. Fifteen prototype actuators were produced by Protofab to qualify the product prior to building costly injection molds.


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