After leveling the plate, it was found to be uneven after using it for a period of time. What could be the reason?

Firstly, the most common reason is the failure of the installation foundation and support system. Slow settlement due to insufficient ground load-bearing capacity, or loosening of support pads and anchor bolts due to long-term vibration, will directly damage the original horizontal benchmark. When inspecting, these external factors should be excluded first to ensure that the foundation is stable and all support points are in a tight and evenly stressed state.

Secondly, the release of internal stress or structural deformation within the fixed plate itself is a deep-seated cause. There are residual internal stresses in cast iron parts after casting and processing, and re balancing the stresses during use can lead to "aging deformation". In addition, long-term exposure to uneven heavy loads (such as placing heavy workpieces locally for a long time) may also cause trace plastic deformation beyond the elastic range, resulting in permanent loss of flatness.

Finally, environmental changes and improper use are direct triggers. Severe temperature fluctuations in the workshop (such as large temperature differences between day and night) can lead to uneven thermal expansion and contraction of the fixed plate. More commonly, improper operation, such as heavy hammering on the platform, illegal dragging of workpieces causing hard scratches or impacts, can directly damage their plane accuracy. Corrosion caused by lack of daily maintenance can also affect local smoothness.