| 摘要 |
A system for machining a piston blank 10 to a predetermined profile includes means for rotating the blank at a predetermined speed and means for moving the tool 22 axially with reference to the blank 10. Digital processing means 70, 72 and 74 receives input data defining the required profile (or part only of the profile if the profile is symmetrical). In response to this data, to digital information on channel 20 corresponding to the instantaneous angular position of the blank 10, and to digital data on the channel 34 corresponding to the instantaneous axial position of the tool 22, processor 72 outputs digital data defining the required position of the tool 22 in the direction perpendicular to the surface of the blank 10 in order to produce the required profile. The actuator control processor 74 outputs a corresponding digital signal which, via a digital-to-analogue convertor 92, drives a tool actuator 24 so as to position the tool correspondingly. Processor 74 also receives digital tool position feedback signals on the channel 38. An adaptive control loop 98 senses and compensates for changes in the transfer function between the input of the processor 74 and the tool 22. Sensors 40 and 44 sense dimension distortion and temperature changes, respectively, of the blank 10 and produce corresponding compensating changes in the digital output signals. |
