Metalloobrabotka № 3 (123)/2021

Metal cutting

Alexandrov A. S., Brigadnov I. A., Vasilkov D. V., Golikova V. V. Cutting forces when milling screw surfaces

A method for determining the cutting forces during milling with disc shaped cutters of the working part of the rotor of a screw compressor is proposed. The calculation scheme for determining the cutting force acting on the milling cutter tooth is considered. The main assumptions that simplify the calculations are adopted. With different deepening, the components of the cutting force are determined for individual sections of the milling cutter tooth. For single and multi-tooth milling, the projections of the cutting force on the coordinate axis are determined. It is established that in a disk shaped cutter with a number of teeth of 10, almost one tooth is involved in cutting and there is a small overlap of the teeth. At the same time, there is a very high unevenness of milling, which practically corresponds to single-tooth cutting. When the number of milling cutter teeth increases to 15, the angle of displacement between the teeth decreases from 36° to 24°. As a result, a significantly larger overlap is obtained, providing simultaneous cutting with two teeth. The use of a disc shaped milling cutter with a number of teeth of 15 allows to reduce the unevenness of the load on the machine’s actuators by 60 % and reduce the level of vibrations caused by the variability of the disturbing action of the milling cutter, which in turn eliminates vibration traces on the treated surface of the profile of the working part of the rotor.

Keywords: milling, screw surface, screw compressor rotor, disc shaped milling cutter, milling tooth, cutting forces, unevenness of milling.

Maksarov V. V., Minin A. O., Brigadnov I. A. The use of ultrasonic vibrations in the machining of difficult-to-machining materials

The article discusses the methods of processing difficult-to-machine materials using ultrasonic vibrations, which contribute to ensuring the quality of manufacturing products, as well as the problems arising in the process of processing these materials.

Keywords: difficult-to-machine materials; ultrasonic vibrations; cutting processing; cutting parameters; cutting tool.

Schipachev A. M., Vardanyan E. L., Mukamadeev V. R., Mukamadeev I. R. Investigation of changes in the surface hardness of coated cutting tools

The results of the study of the hardness in the surface layers of the cutting tool are presented. In this work, the influence of the cutting process during the run-in period and the initial stage of normal wear on the change in microhardness in the near-surface layers of the cutting tool with a composite coating was studied. For this purpose, a process close to the run-in period and the initial stage of normal wear was modeled. Samples made of TT8K6 alloy with TiAlN coating were examined, which were annealed at a temperature of 700°C under a pressure of 0.5 GPa for 20 minutes. A decrease in hardness was found in the heated sample, but there was no sharp jump in hardness in comparison with the initial sample.

Keywords: tool, coating, hardness, wear, titanium, aluminum.

New materials and technology

Konovalov A. M., Kugushev V. I. Mathematical model of free energy carrier in dynamic processes of non-destructive testing

The article presents a mathematical model intended to describe a process of generation and accumulation of elastic energy in parts under dynamic action. It is demonstrated, that presently there is no specific mechanism of a number of dynamic processes observed experimentally, and the proposed model bridges the gap. This has been achieved by introducing into the model the virtual Riemannian space, interacting with the real Euclidean space. The article shows, how the proposed mathematical model is actually explaining virtually all dynamic processes, associated with excitation of natural oscillations of a part, which gives reason to consider it as a carrier of “free energy”. The model also substantiates simulation of crack effect in the course of non–destructive testing based on natural oscillations.

Keywords: excitation of oscillations, specific model, Riemannian space, free energy.

Sokolov Yu. A., Gusev S. A. Modelling of industrial system for synthesis of products on technology of selective electron beam alloying

The organisation’s questions of additive manufacture, formalisation of designing’s process of industrial systems with use of the UML (Unified Modelling Language) are considered in the article. The basic development cycles of the equipment for realisation of technology selective electron beam alloying are resulted.

Keywords: industrial systems, the object-oriented approach, simulation language, design stages, types of models, selective electron beam alloying, management of technological process, the software.

Maksarov V. V., Filipenko I. A., Sheglova R. A., Brigadnov I. A. Technological quality assurance of the edges of flat products by means of magnetic abrasive finishing of aluminium and its alloys

The article considers the problems that arise when achieving the surface quality of products made of aluminum alloys. A method of magnetic abrasive treatment as a finishing method is proposed. The choice of the method is due to low temperatures in the cutting zone, which has a favorable effect on the surface layer of the product. Two methods of magnetic abrasive processing are considered: with the use of three synchronously rotating pole tips and with pole tips that do not rotate synchronously. According to the results of the study, a method of magnetic abrasive processing of the edges of flat products has been developed and justified, which allows for defect-free uniform processing of the edges of products while maintaining the accuracy of the geometric shape.

Keywords: magnetic-abrasive finishing, aluminum products, edge processing.