Open AccessKeeping up the product competitiveness continually requires solving the problems of reducing time for product creation and material costs for its production and ensuring the maximum conformity of the product quality with the individual requirements of a particular consumer. It is especially difficult to implement these tasks in product manufacturing from the hard-to-machine steels and alloys with extremely low production rate in machining (often 10-20 times lower than when cutting the ordinary structural steels).
Currently, one of the promising ways to improve the cutting process of hard-to-machine materials and quality of parts made from these materials is development and application of combined processing methods, which use additional energy sources to act on the machined material in the cutting zone. A BMSTU-developed cutting method with leading plastic deformation (LPD), which acts to raise the production rate, gain the cutting tool-life, reduce the surface roughness, improve the accuracy of processing and the performance characteristics of products, ensure the reliable flow chip control, and improve the labor conditions, belongs to such sort of methods.
One of the most important indicators of processing quality that has a great impact on the operation and cost characteristics of the product and on the machining rate as well is the accuracy of processing. In cutting, the processing errors largely arise from the elastic deformations of a technological system when the cutting force, and, in particular, the radial component of the cutting force, acts on it.
The deforming devices, used in cutting with LPD, being located as a rule, on the diametrically opposite side with respect to the cutting zone, act on the technological system as vibration dampers. In addition, as studies have shown, the choice of a rational direction for applying LPD load helps to compensate partially or completely the cutting force radial component effect on the technological system, thereby raising the accuracy of processing through reducing a value of the elastic deformations of a work-piece in the cutting zone.
The paper presents the comparative test results of the work-piece shape accuracy in cutting with LPD and in conventional cutting in two respects: profile deviation of the longitudinal section of the cylindrical surface and circularity deviation. The studies were carried out using a special BMSTU-designed installation, which allows us to regulate direction of the angle of LPD force action, and, consequently, the load values in direction perpendicular to the surface to be machined. The experiments were carried out on soft samples, made from the low rigid hard-to-machine materials, belonging to different groups of machining property. It is found that when cutting with LPD there is a significant reduction of shape errors. For the processing conditions, assumed in the experiments, as compared to the ordinary cutting a deviation of the profile of the longitudinal section and a circularity deviation were decreased by 2.4-3.3 times and 1.2-1.6 times, respectively.