Delcam’s stand (C05 in Hall 4) at the Milan EMO exhibition in October will feature a demonstration system for the polishing of turbine blades by robot. The system, which has been developed by Delcam Professional Services in association with Finland-based JOT Automation, uses an ABB robot driven by a combination of Delcam software including PowerMILL Robot and PowerINSPECT.
During the development of the process, simulations were undertaken in PowerMILL Robot to ensure that the robot could complete the progress of the blades around the cell without any collisions or any singularities resulting in erratic movements.
As well as showing how the use of a robot could replace manual operations, the cell provides an example of Delcam’s adaptive machining technology. As with other adaptive processes, the polishing operation is altered for each blade individually on the basis of inspection data collected at various stages in the process.
Each blade is transferred into the cell on a conveyor and picked up by the robot. The robot completes an initial pattern of measurements on the blade surface by lifting the blade towards a fixed probe. These measurements are passed into PowerINSPECT to determine the amount of stock material remaining on the blade. The information is used to produce the polishing paths in PowerMILL Robot.
For the polishing operation, the blade is moved against a disk within the cell. Once the routine is complete, a further series of probing measurements are taken to check that the required amount of material has been removed and that the blade is within the specified tolerances. If it isn’t, further polishing can be undertaken until the blade conforms to the standard.
A similar sequence is followed to machine the tip of the blade. Probing measurements are made along the tip and any excess material machined away by moving the blade against a milling cutter.
Typically, one or two passes across the grinding wheel and the milling cutter are sufficient to bring the blade into tolerance, although the loop can continue through more cycles until compliance is reached. The polished blade is then returned to the conveyor for removal from the cell.
