Engineering and Technology News
|Delcam's new PowerMILL includes a wider range of five-axis machining strategies|
Delcam has released the latest version of its PowerMILL CAM system, which is set to confirm the program's position as the world's leading milling software. The latest release, PowerMILL 7, includes new and improved functionality for roughing and finishing with both three-axis and five-axis machines. The enhancements include a wider range of five-axis strategies for both roughing and finishing, three-axis swarf machining and parametric surface finishing, together with faster calculation times, improved point distribution and easier data management.
The range of five-axis roughing strategies has been increased to match the wide list of options previously available for finishing. It now includes machining to or from a point, orientation through a line or curve, and programming using a reference surface. Using five-axis roughing can significantly reduce the number of set-ups needed to machine many components. It can also be used to give a more efficient cutting angle that will allow more material to be removed with each pass.
A new three-axis spiral roughing strategy can be used on suitable geometry instead of offset machining. Using a spiral toolpath allows the overall machining time to be reduced by minimising the number of air moves. In addition, a more consistent load can be applied to the cutter so limiting wear and reducing breakages.
For all roughing strategies, a new method has been introduced for ordering toolpaths so that air moves are further reduced. This enhancement will also make the ordering of rest roughing toolpaths more efficient.
New strategies for finish machining include parametric offset machining, three-axis swarf machining and interleaved constant Z. In parametric offset machining, the number of toolpaths used over a surface of varying width is kept constant. Instead of stopping and starting some paths, the stepover between the toolpaths is varied within preset limits. This approach gives a better finish by avoiding sudden changes of direction that can leave marks on the surface.
Three-axis swarf machining can be used to finish vertical walls. Using the side of the tool produces a better finish than cutting the wall in a series of operations at different Z levels. In addition, three-axis swarf machining with tapered tools can be used to finish flat walls with a draft angle of the same value as the angle of taper on the cutter.
For several releases, PowerMILL has been able to generate 3D offset toolpaths for finishing of flatter areas and constant-Z toolpaths for steeper surfaces in a single calculation. The new interleaved constant-Z option gives better control of the overlap between the two strategies and so avoids surface defects in the intermediate areas. In a related development, the calculation of shallow boundaries has been improved so that these areas are defined more accurately.
As mentioned above, PowerMILL's extensive range of five-axis finishing strategies can now be applied to the creation of roughing operations. In addition, PowerMILL 7 can now generate a five-axis equivalent of any three-axis toolpath. This might be necessary when a three-axis approach is being used for most of a job but where some five-axis moves might be needed to avoid an obstacle or to machine as closely as possible to a steep face.
Improved point distribution
The traditional approach with CAM programs was to reduce the number of points within any toolpath to the minimum needed to ensure that cutting tool remained within the specified tolerance. Adding excess detail could lead to data overload of the control, and so cause uneven machining.
Modern machine tool controls are, however, capable of handling much larger amounts of data. PowerMILL can take advantage of this increased capability by adding additional points to the toolpath, for example, by specifying a maximum distance between adjacent points. Increasing the number of points in the toolpath can give more even machining with less vibration and more consistent loading on the tool. Both these improvements allow faster machining with less wear of the cutter, especially with five-axis equipment, as well as giving a smoother surface finish with both three-axis and five-axis operation.
A number of enhancements have been made to the methods for managing data within PowerMILL. The most important of these is the ability for the user to create folders within the software's tree of operations. For example, roughing, semi-finishing and finishing toolpaths can be created and stored within separate folders. This makes it easier to keep track of the calculations already completed and those that still need to be undertaken.
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