CIMdata PLM Industry Summary Online Archive
December 2005
Events News
Delcam to Show Latest Aerospace Machining Methods at Aerospace Asia
Delcam will demonstrate its latest developments in five-axis machining and adaptive machining on the Society of British Aerospace Companies stand at the Aerospace Asia exhibition to be held in Singapore from 21st to 26th February. The new techniques are based on Delcam's combination of expertise in software for both machining and inspection, which has been built up over many years of development of PowerMILL and PowerINSPECT.
Following the recent release of PowerMILL 6, Delcam now offers an extensive set of strategies for both positional and continuous five-axis machining of aerospace components. The full range includes machining through a point or to a point, or to or from a line or curve; programming using a reference surface; swarf machining; and five-axis trimming, pocketing and drilling.
For all the options, PowerMILL makes programming much easier than is possible with the more complicated software traditionally used in the aerospace industry. This combination of flexibility and ease of use has enabled the software to be used successfully in a wide variety of applications, including the manufacture of complex blades, blisks and aerostructures, finish machining of engine ports and pumps, and trimming and drilling of composite components.
Recent additions to the range of strategies includes the ability to program swarf machining with tapered tools. These types of tool are especially useful when machining undercut areas as they avoid the need to use a long, thin tool for finishing that would otherwise be needed. In addition, they allow more material to be removed than a tipped cutter, with less risk of rubbing on adjacent surfaces.
For all its five-axis machining options, PowerMILL incorporates automatic adjustment of tilt angles for both lead and lean (Lead is measured in the cutting direction; lean at right angles to the cutting direction.). Control of lead angle gives better cutting conditions, while the lean angle can be used to avoid collisions.
PowerMILL also includes many safety features to ensure that five-axis machining can be programmed easily and efficiently, without any risk of gouging. Furthermore, the machine simulation option for PowerMILL includes collision checking between the various parts of the machine tool and the model, as well as ensuring that the machine does not attempt to move outside its operating limits.
An important advantage of five-axis machining with PowerMILL is that the software works with the full range of different cutting tools, including end mills, tapered tools, and ball-nose, tipped-radius and off-centre, tipped-radius cutters. Many of the other systems currently available are limited to using only ball nosed and end mill cutters, which are not always the most efficient.
Delcam's unique set of adaptive machining techniques allow successful production and repair of the most complex components, by using in-process measurement to close the information gaps in the chain of operations.
The most common applications are those where the exact position of the workpiece on the machine tool bed is unknown. With larger components, achieving the correct position and orientation of the stock is a major challenge, taking many hours of checking and adjustment.
It is often easier to adjust the datum for the toolpaths to match the position of the workpiece, than it is to align the stock in exactly the desired position. This approach has been used in the machining of geometric features for some time. Delcam now offers an equivalent solution for the manufacture of complex shapes and surfaces that gives the same benefits of shorter set-up times and improved accuracy.
Adaptive machining can also be applied when the exact starting shape is unknown following near net shape manufacturing processes, like casting and forging, or imprecise repair techniques, such as welding. The main requirement here is to allow an even distribution of material to be removed around the stock to avoid over-machining in some areas and under-machining in others. Other benefits include the ability to give a smooth transition between machined and un-machined areas, a reduction in air cutting and improved control over the feed rate as the cutter enters and leaves the material.
The most challenging adaptive machining operations are those where the precise final shape of the component is unknown. This usually is needed when undertaking repairs to components that have been changed from their nominal CAD shape during service, for example, turbine blades that have been distorted by the high temperatures in aircraft engines.
The initial stage in these cases is to probe the component to determine the extent of its deviation from the nominal CAD data. Then, the morphing functionality in Delcam's PowerSHAPE hybrid modeler can be used to bring the CAD model into line with the actual geometry. Finally, toolpaths can be generated with PowerMILL for the areas to be machined.
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