Дослідження впливу параметрів процесу хонінгування силікатними брусками на якість обробленої поверхні

Abstract

Numerous studies have shown that the kinematics of the honing process, which determines the trajectory of the cutting grain during machining, has a major impact on the parameters of macro- and microrelief. The complex working movement during honing of holes creates favourable conditions for the fuller use of the cutting capacity of the bars and uniform wear of the tool, which positively affects the machining performance and accuracy of the geometric shape of the surface. It is shown that, in this regard, there is a need to investigate the influence of the parameters of the honing process with silicate bars on the quality of the machined surface. The paper presents the results of a study of the effect of the contact pressure of the bars and the axial and circumferential speeds on the quality of the treated surface. The study was performed on a vertical single-spindle honing machine. The samples used were cylinder liners of car engines made of grey alloy cast iron. The evaluation was based on the roughness of the machined surface and the mass removal of metal during machining. The best performance was achieved by those bars that resulted in the lowest roughness of the samples. It was found that with an increase in the circumferential speed, the surface quality improves, and with an increase in the axial speed, it deteriorates after processing with diamond, abrasive and silicate stones. With an increase in the contact pressure of the bars, the surface quality deteriorates after machining with diamond bars and improves after machining with abrasive and silicate bars. It has been proven that the high surface quality after treatment with silicate blocks is due to the formation of amorphous silica during honing, which, under the influence of abrasive grains, falls into the cavities of the treated surface and adheres to the surface, thus saturating the treated surface with silicon oxide. It has been established that with an increase in the axial speed of the bars, metal removal increases, and with an increase in the circumferential speed, it decreases after machining with diamond, abrasive and silicate bars. With an increase in the contact pressure of the stones, metal removal increases after machining with diamond stones and gradually decreases after honing with abrasive and silicate stones. It was found that the metal removal after machining with silicate stones is 2 times less than after honing with diamond stones. It is proposed to set the allowance for finishing honing with silicate stones for cylinder liners made of alloy cast iron (HB 240) within 0.01-0.02 mm.