NASA and FeatureCAM Team Up to Create Quality Aerospace Parts

NASA has used the full range of Delcam products for years for many different applications. FeatureCAM, in particular, has been used to drive experimental processes for creating near net shape prototypes for an array of parts. For example, NASA uses FeatureCAM to create a wind tunnel model of a Glide Back Booster (GBB), a reusable rocket booster. The GBB is used to learn about the response in flight characteristics (lift, drag, pitch, side-force, yaw, and roll) as a function of three inputs (Mach number, angle of attack, and side slip angle) when a vehicle is reentering the atmosphere.

The Process

First, the solid part file is imported into FeatureCAM. The toolpaths are created for constructing the rough part, which is then produced by using electron beamfree form fabrication (EB-FFF). Using FeatureCAM's solid modeling tools, NASA generated sliced-based toolpaths and post for the prototype machine.

EB-FFF uses 1/16" titanium wire and fuses a part into the required shape. A CNC Program applies 0.030" layer of titanium per pass, and creates a fully dense wall thickness of 5/16". The advantages of EB-FFF include speed, the ability to easily make hollow models, less required material, and the fact that the process may be applicable to zero-G space.

After the rough part is completed, NASA operators design and create the fixturing. Next, they semi-finish and finish the part on a mill.

The GBB blank produced on the EB machine is hollow to the nose, yet has fully solid wings.

Completing the Part

The GBB blank produced on the electron beam machine is hollow to the nose, but the wings are fully solid. The machining fixture is designed to position and fully support the blank while leaving enough room to machine the GBB. Using the fixture created with a 5-axis Huron mill, the GBB Blank is contour-locked in the cavity with Bendalloy, low melting-temperature metal. Bendalloy is used for its excellent support of the blank, and clamping for multiple machining areas is simplified. This method makes access to all upper model surfaces possible, and the blank is held with maximum rigidity.

The GBB blank is then semi-finish machined with a ½" diameter carbide ball endmill, with 0.025" left for finishing. A 10mm and a 6mm carbide ball endmill are used to finish the blank. Machining is then extended to below the model for full profile trimming cut. Because only 0.150" is removed from the entire blank surface, excellent tool life can be expected.

FeatureCAM ensures toolpath alignment with wing leading, trailing, and wingtip edges, allowing a relatively easily completed task. The EB-FFF technology produces excellent surface finish and mechanical qualities in the titanium model.

Electron beam-free form fabrication uses 1/16" titanium wire and fuses it into the required shape.

FeatureCAM 2008

FeatureCAM 2008 includes the same reliable technology that the software has previously offered, with plenty of upgrades and improvements in the areas of 5-axis machining, turning/milling, B-axis turning, and milling post development for major machine manufacturers, backplotting capability, automated testing framework, and other new features.

FeatureCAM 2008 offers support for both 5-axis milling machines and B-axis turn/mill machines. The software utilizes extensive 5-axis toolpath techniques and automatic tool axis control to allow complex, simultaneous 5-axis milling in an easy-to-use setting. Toolpath techniques include integration into FeatureCAM's wizards, and tool axis control is available for nearly every tool path: parallel, Z-level finish, isoline, 3D spiral, flowline, swarf, and 5-axis trim.

NASA utilizes FeatureCAM's solid modeling tools to generate sliced-based toolpaths and post for the prototype machine.

The tool axis control also gives the ability to specify simultaneous tool axes such as vertical or lead/lean. It also employs automatic gouge avoidance. The straight-forward user interface is simplified and consistent with other FeatureCAM modules.

Turning and milling improvements include a more intuitive pattern creation and enhanced Z-face rotation with limited Y movement. FeatureCAM 2008 has many more improvements to increase the ease-of-use and accuracy of projects.