The early failure period is the initial stage of CNC machine tool usage, from the installation and debugging of the entire machine to about one year of operation. The characteristics of failures during this stage are high frequency and a rapid decline with the increase of usage time. The reasons for the frequent failures in the initial stage are roughly as follows.
(1) Although the CNC machine tools for mechanical parts have undergone a brief磨合 run prior to shipment, it mainly focuses on the spindle and guide rail alignment. Due to the microscopic and macroscopic geometric shape errors on the machined surfaces of the parts, the surfaces are relatively rough before full磨合. This may result in assembly inaccuracies, leading to significant wear during the initial use of the CNC machine tools. This excessive wear can create larger gaps between the relative moving parts of the equipment, potentially causing malfunctions.
(2) The control system of the CNC machine tools for electrical parts utilizes a large number of electronic components. Although these components have undergone a considerable amount of aging tests and other types of screening at the manufacturing plant, some of the components with poor performance fail to withstand the test during actual use. This is due to factors such as heat generation in the circuit, alternating loads, surge currents, and back electromotive force shocks. As a result, these components may be scrapped due to current surges or voltage breakdown, or their characteristic curves may change, leading to the entire system's inability to function normally.
(3) Due to the extended transportation and installation period after manufacturing, certain parts of the hydraulic system remained oil-free for extended periods, resulting in dried lubricant in the cylinders. Since oil mist lubrication could not take effect immediately, it led to potential rusting in the hydraulic or pneumatic cylinders. Additionally, if the newly installed air pipes are not cleaned thoroughly, debris and moisture may enter the system, causing initial malfunctions in the hydraulic and pneumatic components.
