Metalworking № 6 (138)/2023

Material cutting

Ponomarev B. B., Nguyen Van Duc, Svinin V. M. Calculation of cutting force when machining complex surfaces with radius end mills. Part 1. Part 2

When forming complex surfaces with ball end mills, the cutting forces should not exceed the limit values at which the cutting edge of the tool tooth may be chipped or broken. Calculation of cutting force is carried out using the analytical method, which has been used so far for ball end mill with a flat rake face. Practical application of this method requires a large amount of preliminary experimental studies to obtain refining coefficients. The purpose of the research. Development of a method for calculating the cutting force when machining complex surfaces with ball end mills on a five-axis machine using analytical dependencies on the specific force and an epure distribution of its components. The research objectives. 1. Calculation of element tangential, radial and axial components of forces at the cutting point using specific force and determination of their values in the tool coordinate system. 2. Determination of total forces in the tool coordinate system using their epure of distribution. The research methods. Calculation of the cutting force using analytical dependencies of cutting theory and comparison of the results with the data obtained by measurements during the machining experiment. The novelty in research. Determination of cutting force for finishing milling of complex surfaces with a ball end mill, which have a helical cutting edge and a rake face on a spherical surface. The research results. The possibility of using the analytical method for calculating the cutting force when machining complex surfaces with ball end mills has been demonstrated. Conclusion. The results obtained by the analytical method showed that the magnitudes, directions and laws of change of the constituent forces correspond to the experimental values. The cutting force components reach their maximum values at the positions corresponding to the maximum uncut chip thickness, as in the real cutting process, the differences in their values did not exceed 20 %.

Keywords: cutting force, radius end mill, specific cutting force, force distribution epure.

Vologin N. A., Nikiforov I. P. Influence of cooling method of thin-walled workpieces dur-ing flat grinding on machining output parameters

The problem of flat grinding of thin-walled workpieces is outlined. The technique of experimental research on the influence of cooling method on the output parameters of machining: deviation from straightness in flatness and the number of visible burns is developed. The principle of operation of vortex Ranck — Hilsha tube designed for cooling of air flow is shown. A combined method including cooling by free-falling jet with low flow rate and air cooling by means of vortex Ranck — Hilsha tube is proposed and substantiated. Comparative characterization of different meth-ods of cooling of thin-walled billets is given. The change of profile of blanks at different methods of cooling is shown. The areas of visible burns on the surfaces of workpieces are determined by automated method.

Key words: surface grinding, thin-walled workpiece, cooling, Ranque — Hilsch vortex tube, deviation from straightness in the plane, burning.

Brus D. R., Alexandrov A. S., Colikova V. V. The relationship between the wear of turning carbide plates and surface roughness while cutting stainless 40Ch13 steel

The surface roughness directly determines the operating conditions of the products. A low roughness index determines the corrosion resistance of products, affects the density and tightness of joints, determines the abrasion resistance and sets the appearance of the product. The roughness index is influenced by a huge number of factors. These include: the rigidity of the technological system machine-tool-tool-part, the presence or absence of thermal temperature deformations, cutting modes, design features and geometric parameters of the cutting tool, wear of the working surfaces of the cutting blades and edges. The latter is exactly what will be discussed.

Key words: wear, quality, carbide tool, processing modes, tool life.

Kizhnyaev Yu. I., Nemtsev B. A. Determination of coolant consumption during deep drilling according to the condition of ab-sorption and removal of chip formation heat

A method for calculating the heat of chip formation released on the cutting surface during continuous deep drilling of holes with a diameter of 12–50 mm is presented. Dependencies have been compiled to determine the flow rate and coolant consumption according to the condition of absorption and removal of chip formation heat. The results of assessing the influence of diameter, drilling depth and cutting modes on coolant consumption for chip removal and heat of chip formation are presented.

Key words: deep drilling, heat of chip formation during drilling, flow rate and coolant con-sumption to absorb and remove heat.

Mikhalev O. N., Yanyushkin A. S. Automation of optimal cutting conditions taken into account of multicriterial processing conditions on metalcutting machines

Cutting conditions directly affect the productivity and tool life during machining of parts, which in turn affects the economic efficiency of the enterprise. Assigning such optimal cutting conditions that will ensure maximum productivity and low cost of processing parts is a difficult task. It is necessary to take into account many conditions of the cutting process, including those that are difficult to describe mathematically, as well as additional complex calculations. Assigning cutting modes from catalogs or from human experience leads to ineffective use of tools. The use of probabilistic methods and mathematical statistics makes it possible to more accurately assign optimal cutting conditions, which will not only allow more efficient use of metal-cutting tools and reduce their costs and other costs, but also significantly increase the efficiency of process design.

Keywords: cutting conditions, durability, productivity, prime cost, mathematical model.

New materials and technology

Mokritskiy B. Ya., Kosmyninin A. V., Serebrennikova A. G., Maryin S. B. Atomic force approach to the development of coatings for carbide metal cutting tools

The features of designing coatings for hard alloy VK8 are studied based on the atomic force interaction of the materials of the coating layers with each other and with the hard alloy.

The calculation of the energy of adhesion of materials was used. The most rational variants of coatings are selected. Conditions have been created for predicting the performance properties of the developed tool materials. A method for calculating the functionals of interatomic systems using the functional density of single atoms is applied. The relationship of the calculation results with the operational parameter of the metal-cutting tool in terms of the crack resistance coefficient K1s, MPa √m is established. The novelty of the work lies in the fact that the adhesion value for atoms stacked in different scale configurations was determined by the calculation method in order to use the adhesion value for diagnosing the tool system from the standpoint of ensuring maximum performance properties of the tool material

Keywords: selection of competitive coatings based on atomic force interaction, calculation of adhesion energy, prediction of operational properties.