The method for inner surface finishing of bend and shaped pipe

In view of the tough problem about finishing and ultra-precision machining in inner surface of bend and shaped pipe, this paper proposes one new polishing method and technology, and accordingly develops not only the sphere rotating polishing head connected through the flexible wire which is suit for pipe bore surface finishing but also supporting technological equipment and fixtures. Polishing and micro-machining of chamfering in bent and shaped pipe bore surface are able to be achieved successfully the method, respectively. Therefore, other existing methods are incomparable with the advanced method. Inner interface roughness average (Ra) is chosen as criterion to evaluate the polishing method. As a result, original Ra is 10.3867μm, under the condition of velocity of polishing tool does not vary, Ra is 4.2444μm after 2 min polishing, Ra rate decreases 59.14%. After 4 min polishing, Ra is 3.4902μm, Ra rate decreases 66.40%. After 8 min polishing, Ra is 2.8574μm, Ra rate decreases 72.49%. It fully proves that the new polishing method proposed can efficiently address the problem on finishing and ultra-precision machining in inner surface of bent and shaped pipe.