reverse engineering
Å NVision’s 3D model of the “bathtub” required to repair the bird damage. The scan, modeling, part programming, machining, and repair were all completed within 24 hours.
Three Votes for Going All the Way to CAD On the other hand, there are knowledgeable users who do need to create a CAD file, and that may mean changing the measurement mix. The Naval Air Systems Command (NAVAIR), in Patuxent River, MD, runs a “reverse engineer- ing center of excellence” for the express purpose of keep- ing legacy aircraft flying. NAVAIR’s Danny Campbell said it usesseveral arm-based laser scanners (a Faro Edge 9' [2.7-m] arm with a Faro ES Laser Line Probe and a Faro Titanium 8' [2.4-m] arm). But he prefers using the touch probe when possible because the measured data is almost immediately usable in their CAD software. “The laser is really only used for complex or convoluted surfaces that don’t lend themselves well to touch-probing.” They use PolyWorks or Geomagic software to process their scanned point clouds into usable CAD data. Campbell takes advantage of any available drawings as they some- times provide design intent and critical dimensions, though he also says it’s common for airfoil drawings to have insuf- ficient detail. Recent projects have included critical safety items on the AV-8B Harrier jump jet and engine ductwork on the V-22 Osprey and Bell AH-1Z Viper attack helicop- ter. The latter two included computational fluid dynamics, requiring both laser scanning and translations to CAD files. The Corpus Christi Army Depot also typically creates CAD files, taking the scanned point cloud into their XOR software and then converting it to either an IGES/STEP Parasolid or a fully parametric model with history tree. They then check and tweak the resulting 3D CAD model in SolidWorks and finally go to a CAM package for the machining program.
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AdvancedManufacturing.org
Strand said API is getting lots of requests to use laser scanning to reverse engineer electronic components, in part because they’re harder to measure using other meth- ods. His first such project was for an aircraft circuit board and it’s another good example of when it makes sense to employ CAD.
“The critical factor in creating a replacement part was to be able to define the connection points and integrate the replacement with newer parts. The customer needed to change the layout a bit and reverse engineering helped make sure everything would fit with existing components. We captured the data using Polyworks and exported into DesignX to clean up the mesh and create the CAD. We modeled all the components separately. That way if we have any future requests with the same components we can use the CAD from our catalog, instead of wasting time rescanning and cleaning up the data and modeling over again.”
In-House or Outsource? If you’re still a bit bewildered by the options and trade-
offs in this area, take comfort in knowing that you can hire a company like NVision or API to come in to scan you parts and deliver an STL, CAD file, or another format on demand. If you’re ready to take the leap into doing it yourself, you can hire them to study your needs and deliver training and a complete turnkey solution. Or you can go straight to ven- dors like API, Wenzel America (Wixom, MI), and Basis Soft- ware Inc. (Redmond, WA) and assemble your own system. Just don’t stand too close to the B-52. |||
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