| Popis: |
The data on the labor intensity of manufacturing engineering products and the share of finishing and grinding operations in the total labor costs of their manufacture are presented. The list and the degree of mastering the technological operations of finishing and grinding processing, performed in the conditions of machine-building industries during the last years are given. The grounds are given for highlighting the method of vibration processing as the most promising for ensuring complete mechanization of the process of finishing and cleaning, as well as achieving high technological characteristics of the surface roughness of parts. An assessment was made of the influence of modes, the trajectory of the movement of the reservoir and the grain size of the granules of the abrasive medium on metal removal. It is indicated that the intensity and quality of vibration treatment is estimated quantitatively by the weight removal of metal and qualitatively by the roughness of the processed surface. It is indicated that the determining factor in this case is the speed of the oscillating movement of granules and parts, the difference of which represents the speed of vibration processing, depending on the speed of the oscillating movement of the medium. It is noted that in order to increase the productivity of the process, it is necessary to increase the speed of the medium by increasing the frequency and amplitude of the reservoir oscillations. The layer-by-layer transmission of a force impulse from the bottom of the reservoir to the bulk medium is considered. The physical meaning of increasing productivity by increasing the amplitude of the reservoir oscillations is indicated. The conditions for obtaining metal removal are indicated, which provide increased efforts for the interaction of granules with parts at high micro-cutting speeds. Experimental studies are described to determine the influence of the amplitude and frequency of oscillations on the results of vibration finishing and grinding. Graphic dependences of metal removal were obtained for various ratios of the sample weight to the weight of the medium granule. The dependence of metal removal on the ellipticity coefficient and the amplitude of the reservoir oscillations was obtained in a similar way. It is noted that the vertical component of the amplitude during in-plane oscillations of the reservoir is the determining factor of the complex influence of the parameters of the ellipse coefficient of the trajectory of the reservoir and its amplitude of oscillations. It has been established that when using a coarse-grained abrasive, the penetration of grains into the metal of the part occurs to a greater depth and larger metal chips are removed with a large metal removal. With a small grain size of the abrasive, small chips are removed with a small metal removal and a decrease in the height of micro-roughness. |
