| 摘要 |
A fluid having magnetorheological (MR) properties and including a finely-divided abrasive material is directed through a non-ferromagnetic nozzle disposed axially of the helical windings of an electric solenoid. The MR fluid may contain magnetosoft or magnetosolid particles or mixtures thereof. A magnetic field created by the solenoid orients and aligns the magnetic moments of the particles to form fibrils thereby stiffening the flowing MR fluid which, when ejected from the nozzle, defines a highly-collimated jet. Collimation of the MR material persists for a significant time outside the magnetic field, permitting use of the abrasive jet to shape and/or polish the surface of a workpiece at some distance from the nozzle. The jet is directed into a shroud against a workpiece mounted for multiple-axis rotation and displacement to meet predetermined material removal needs for shaping. The solenoid may be similarly mounted to also move the jet over the surface of the workpiece. The apparatus may be provided with a plurality of independently-powerable electromagnets disposed in a plane orthogonal to the jet for deflecting the jet as desired to a specific target area on the workpiece or to move over the surface of the workpiece in a complex, predetermined pattern. The shapes and locations of anomalies to be removed may be pre-programmed into a computer-operated controller which calculates and controls the intensity and dwell time of the jet as it traverses repeatedly over the workpiece to achieve the desired result. |
