Delcam’s Vortex high-speed roughing headed for China
Delcam will demonstrate its new Vortex strategy for high-speed area clearance at the CIMT exhibition in Beijing from 22nd to 27th April. Vortex will be the major enhancement for the next release of Delcam’s PowerMILL CAM system for high-speed and five-axis machining. Other developments in the new release will include better control of five-axis machining, smoother spiral machining and more efficient programs.
Vortex, for which Delcam has a patent pending, has been developed by the company specifically to gain the maximum benefit from solid carbide tooling, in particular those designs that can give deeper cuts by using the full flute length as the cutting surface. It can be used for two- and three-axis roughing, three-plus-two-axis area clearance and for rest machining based on stock models or reference toolpaths.
Like other Delcam roughing strategies, Vortex toolpaths are calculated to give more efficient machining by following the shape of the part and by keeping air moves to a minimum. This is particularly important for rest machining operations.
One fundamental problem with conventional area-clearance strategies is that the optimum cutting conditions only occur during a straight-line cut. Any internal corners within the model significantly increase the engagement angle of the cutter. To protect the cutter, this increase needs to be balanced by setting a lower feed rate. The user then has the choice of using this lower rate over the whole toolpath, which increases the machining time, or varying the feeds and speeds as the cutter moves around the model and so increasing wear on the cutter.
Unlike other high-speed roughing techniques that aim to maintain a constant theoretical metal-removal rate, the Vortex strategy produces toolpaths with a controlled engagement angle for the complete operation. This maintains the optimum cutting conditions for the entire toolpath that would normally be possible only for the straight-line moves. As a result, the cutting time will be shorter, while cutting will be undertaken at a more consistent volume-removal rate and feed rate, so protecting the cutter and the machine.
Because Vortex toolpaths have a controlled engagement angle, tools will never be overloaded and so will achieve the maximum tool life. Shock loading caused by changes in the contact angle is minimised, preventing chipping of the flutes. In addition, the stability of the cutting conditions gives more consistent edge temperatures, so prolonging the life of the tool coating and removing heat damage to the surface of the part. Finally, the ability to use stepdowns of up to two, or even three times, the tool diameter spreads the tool wear evenly over the cutting surface of the tool, again contributing to longer tool life.
The main change in five-axis machining in the new PowerMILL release will be to increase the number of options for tool-axis definition. For raster toolpaths, the lead and lean angles can now be defined relative to a contact normal. In addition, better control is now possible for the tool-axis definition when using the To or From a Point, Line or Curve strategies. These improvements will make it easier for users to control the contact angle between the cutter and the part, and so set the optimum cutting conditions for efficient machining and quality of surface finish.
The new algorithm for spiral machining produces smoother toolpaths that give a better surface finish and more consistent machine-tool motion. This change will improve area clearance, steep-and-shallow finishing, 3D-offset finishing and optimised constant-Z finishing.
NC programs generated in PowerMILL can be made more efficient by automatically reordering the toolpaths, using the tool number or tool diameter, to reduce the number of tool changes, or using a specific workplane, to minimise set-up changes.
03 April 2013