Improving the quality of critical tractor parts through the dynamic stabilisation of the manufacturing process in regard to CNC machines
¹Estonian University of Life Sciences, Chair of Biosystems Engineering, Kreutzwaldi 56, EE51006 Tartu, Estonia
²Saint-Petersburg Mining University, Department of Mechanical Engineering, 2, 21st Line, St Petersburg RU199106, Russia
*Correspondence: jyri.olt@emu.ee
Abstract:
This article focuses on the evaluation of a rod improvement which is considered in detail below. The rod in question is part of an hydraulic cylinder manufacturing process which takes place on CNC machines. The need for ensuring a process improvement in this area arose because the rod often breaks down under operational conditions. It was found that the cause of this is a finishing operation in the existing production process. The effect of charging which occurred during the grinding process brings about the embedding of abrasive particles into the workpiece surface layer. Therefore, at the running-in stage, the mating surfaces on the rod and the system being used to seal the rings both experience intense wear in their contact areas, with this being caused by abrasive microparticles which serves to reduce the performance characteristics of the part in question. However, even if we dispense with the grinding process, ensuring the necessary roughness of Ra = 0.63 μm at the machining stage alone will present problems of their own for a number of reasons. First and foremost is the connection with the phenomenon that results in an auto-oscillation processes which is generated by the manufacturing system, as well as the formation of flow chips during machining on CNC machines. In this regard, in order to avoid any negative factors creeping into the process, we propose that a new approach be taken in achieving the necessary surface roughness, one which is based on the suppression of the auto-oscillation process during machining by means of creating a selective metastable structure. At the machining stage, any inhomogeneous structure in the local chip formation area will be destroyed, thereby suppressing the auto-oscillation process and reducing the surface roughness. Eventually, the proposed method will allows the grinding operation to be dispensed with entirely from the manufacturing process.
Key words:
auto-oscillation processes, chip formation, local laser impact, machining process system, metastable structure, production process, surface roughness