PowerMILL 6.5 incorporates new and improved functionality for roughing and finishing with both three-axis and five-axis machines, including a wider range of five-axis strategies for both roughing and finishing, intelligent plunge milling, three-axis swarf machining and parametric surface finishing, together with faster calculation times and easier data management.
The range of five-axis roughing strategies has been increased to match the wide list ofoptions 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 tool path allows the overall machining time to be reduced by minimizing 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 tool paths so that air moves are further reduced. This will also make the ordering of rest roughing tool paths more efficient.
Intelligent plunge milling
Plunge milling removes bulk material by a series of plunging moves, similar to a network of drilling operations. The technique should give faster clearance of deep pockets than conventional roughing strategies. However, it has seen limited application because of the potential damage to the spindle and the cutter resulting from the severe increases in load as the cutter enters and leaves the material.
Both these potential problems can be overcome with PowerMILL’s new “intelligent” programming methods. The software updates the stock model after each cutting operation so that each subsequent move is based on the remaining material on the job. This ensures that an even amount of material is under the cutter before each plunge and so keeps the load on the tool and spindle at safe levels. It also prevents small upstands being left on the job that can wrap around the cutter. Once the cutting move is completed, the stock model is used to calculate safe retract moves, without any rubbing of the cutter on the remaining walls of the material.
New strategies for finish machining include parametric offset machining, three-axis swarf machining and interleaved constant Z. In parametric offset machining, the number of tool paths used over a surface of varying width is kept constant. Instead of stopping and starting some paths, the stepover between the tool paths 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 6.5 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.
Better control over the point distribution within five-axis toolpaths has been provided to take advantage of the improved ability of modern machine tool controls to handle large amounts of data. 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 give a better surface finish and less wear of the cutter.
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.
These management tools are especially important for companies that operate multiple shifts as staff on the new shift can immediately find out exactly what work has been completed on the project and what remains to be done. They are also helpful in tracking information when duplicate or related components or tooling have to be produced long after the original project was completed. By providing a clearly-structured record of the processes followed in the earlier project, PowerMILL allows the knowledge and experience gained to be applied to the new task.
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