Management of the quality characteristics of the working surfaces of complex profile products during mechanical processing

Abstract

The paper considers the temperature field model, which is formed in the surface layer of complex profile products during their processing in finishing operations. These operations are associated with defects in the surface layer of products, such as burns, cracks, and tensile stresses. Which significantly affects the reliability and durability of these parts during their operation. These defects, being local stress concentrators in operational conditions, lead to premature failure of products, even though the load on them forms stresses, the value of which does not exceed the limit values. The model is built based on the solution of the product's initial boundary value problem of thermal conductivity. Functional relationships of technological parameters with the grinding temperature obtained based on the model reflect the state of the treated surfaces for products with complex profiles and allow using appropriate techniques to eliminate burns on the treated surfaces. The study of the conditions for improving the quality of the treated surfaces by eliminating defects such as cracks and burns was carried out mainly at the level of identifying the connections of the temperature fields that are formed with technological parameters, physical and mechanical properties of the polished materials and the geometry of the products. It was established that when grinding complex profile products from a larger radius in the direction to a smaller one, the temperature increased in proportion to the angle of inclination of the treated surface. The adequacy of the built model was checked on the example of grinding conical products made of steel with known physical and mechanical characteristics, the choice of tool, and the designation of processing modes. Analysis of the simulation results shows that the temperature of the machined surface increases as the machining tool approaches a smaller diameter along the conical surface. This area of conical products' machined surface is most prone to defect formation during finishing operations. Therefore, when assigning treatment modes for such surfaces, they should be assigned with the condition that when the processing tool approaches the part of the conical surface with a smaller diameter, the temperature formed on it should not exceed the permissible values that ensure the required quality. Analysis of the results of numerical calculations of temperature fields showed sufficient accuracy according to the boundary conditions of the simulation.