Improvement and Research of a Machine for the Pre-Finishing of Leather and Fur

The article provides a systematized overview of technological machines and devices, as well as technologies for grinding and finishing leather and fur leather fabrics. A grinding machine has been developed that ensures the processing of leather and fur semi-finished products, taking into account the full use of abrasive materials. On the working drum, due to the ability to overturn and quickly replace the grinding sheets, conditions are created for conducting the grinding process in an optimal mode depending on the type and properties of the leather raw material. Furthermore, the rational justification of the geometric, kinematic, and control parameters of the grinding drum machine contributes to increasing its economic efficiency and ensuring its safety. This work analyzes the strength of the working drum of the drum-type leather grinding machine. A cylindrical shaft rotating under the action of a load is considered a drum. During the leather grinding process, friction forces and sometimes unevenly distributed loads act on the drum surface. Since the drum is constantly operating in rotational mode, a centrifugal force arising from rotation, contact pressure with the skin, bending caused by loads transmitted to the drum axis, and torque caused by a moment transmitted through the shaft arise on its wall. Therefore, it is necessary to analyze the drum as a complex mechanical system. The conducted theoretical and computational study of the fabricated grinding drum showed that, at a rotational speed of 1200 rpm and an average calculated radius of 0.145 m, the circumferential normal stress is approximately 2.61 MPa. Verification of the computational model in the limiting case showed that, in the absence of rotation, the circumferential stress tends to zero. It was also established that the stress depends linearly on the material density and quadratically on the angular velocity and radius. The obtained computational results confirm the consistency of the adopted analytical model with the parameters of the fabricated grinding drum.