TechFront New Developments in Manufacturing and Technology Taming Multiblade Parts Programming R
epetitive multiaxis manufacturing of complex parts poses a special challenge to CAM software manufacturers. Examples include Swiss-machined medical compo-
nents, cylinder-head ports, and multiblade parts used widely in aerospace, energy conversion, and other fluid movement ap- plications. When considering the possible alternative approach- es, Mastercam’s multidiscipline teams at CNC Software Inc. (Tolland, CT) came to the conclusion that the CAM software should be simple yet highly intelligent. It should be able to automatically ana- lyze the model and create the most efficient and safe manufacturing process with only a minimal amount of intervention from the end user. “Multibladed parts are difficult to machine because orientation of the tool must be continu- ally adjusted to reach all the surfaces that re- quire machining,” explains Karlo Apro, Master- cam multiaxis product manager. “Programming a complex multiblade part, even with full-fea- tured CAM software, must be done thoughtfully and carefully to avoid crashes and ruining an expensive part. It’s common for programming to take a couple of days. One approach blade manufacturers have relied on is the 3:2 pro- gramming technique in which the part is rotated to a new angle and then a three-axis program is used to clear out as much material as possible from that orientation. Then the part is moved to a new position and more material is cleared. These programs are tedious to write, and they result in very long machining cycles because there are many overlaps where the tool is doing nothing but air cutting.”
Multiblade parts come in a variety of shapes and sizes, but there is a significant amount of similarity in the way they are ma- chined. The workflow is almost always the same: rough out ex- cess material between the blades; semifinish the blades; finish the blades; and finish the base. “The initial iteration of our blade program makes it possible to apply this one workflow process
Blade Expert in Mastercam X6, developed for multiaxis programming of repetitively manufactured complex shapes, has reduced programming time needed from a matter of days down to an hour.
Some blade manufacturers have sidestepped this prob- lem by opting not to manufacture the blade out of a mono material but instead to manufacture blade segments and assemble them into a special manifold. This can result in a heftier design; however the problem of machining hard-to- access material is substituted for the problem of aligning and balancing blade components in a multiblade assembly.
to a wide variety of multibladed parts. All the user is required to do is identify the features on the part. After bringing in the blade model, the user is prompted to provide basic manufacturing in- formation from selecting the tool, toolholder, and tooling-related data to choosing the cut pattern and setting collision avoidance and noncutting gap motions,” Apro explains. Program simulation using Vericut software enables the user to visualize all of the complex machine movements. “Blade Expert reduces what would have taken two days with conventional programming techniques down to an hour,” says Apro. “We evaluated the expert blade program by dip-