Granite measuring platforms, as indispensable reference tools in precision testing, are renowned for their high hardness, low thermal expansion coefficient, and excellent chemical stability. They are widely used in metrology and laboratory environments. However, over long-term use, these platforms are not completely immune to deformation, and any problems can directly impact the reliability of measurement results. The causes of granite platform deformation are complex, closely related to the external environment, usage methods, installation methods, and material properties.
Primarily, fluctuations in ambient temperature and humidity are often significant contributors to platform deformation. Although granite’s linear expansion coefficient is relatively low, thermal expansion and contraction can still cause minor cracks or localized warping when temperature fluctuations exceed ±5°C. Platforms placed near heat sources or exposed to sunlight for extended periods are even more susceptible to deformation due to localized temperature differences. The impact of humidity is also significant. Although granite has a low water absorption rate, in environments with relative humidity exceeding 70%, long-term moisture penetration can reduce surface hardness and even cause localized expansion, compromising the platform’s stability.
In addition to environmental factors, improper load-bearing is also a common cause of deformation. Granite platforms are designed with a rated load capacity, typically one-tenth of their compressive strength. Exceeding this range can lead to localized crushing or grain spalling, ultimately causing the platform to lose its original precision. Furthermore, uneven workpiece placement can cause excessive pressure in a corner or area, leading to stress concentrations and, over time, localized deformation.
The platform’s installation and support methods also affect its long-term stability. If the support itself is not level or the support points are unevenly loaded, the platform will experience uneven loads over time, inevitably causing deformation. Three-point support is a suitable method for small and medium-sized platforms. However, for larger platforms weighing over one ton, using three-point support can cause the center of the platform to sink due to the large spacing between the support points. Therefore, large platforms often require multiple or floating support structures to distribute stress.
Furthermore, although granite undergoes natural aging, the release of residual stress over time can still cause minor deformation. If acidic or alkaline substances are present in the operating environment, the material structure may be chemically corroded, reducing surface hardness and further affecting the platform’s accuracy.
To prevent and mitigate these problems, multiple preventative measures should be implemented. The ideal operating environment should maintain a temperature of 20±2°C and a humidity level of 40%-60%, avoiding direct sunlight and heat sources. During installation, use vibration isolation brackets or rubber pads, and repeatedly verify levelness using a level or electronic tester. During daily use, the rated load capacity must be strictly adhered to. Workpieces should ideally be kept within 80% of the maximum load, and should be placed as dispersed as possible to avoid localized pressure concentration. For large platforms, using a multi-point support structure can significantly reduce the risk of deformation due to deadweight.
The accuracy of granite platforms requires regular inspection and maintenance. It is generally recommended to conduct a flatness inspection every six months. If the error exceeds the standard tolerance, the platform should be returned to the factory for re-grinding or repair. Minor scratches or pits on the platform surface can be repaired with diamond abrasive paste to restore the surface roughness. However, if deformation is severe and difficult to repair, the platform should be replaced promptly. When not in use, it’s best to cover the platform with a dustproof sheet to prevent dust accumulation and store it in a dry, ventilated environment. During transportation, use a wooden box and cushioning materials to prevent vibration and bumps.
In general, while granite measuring platforms offer excellent physical properties, they are not completely invulnerable to deformation. Through proper environmental control, appropriate mounting support, strict load management, and regular maintenance, the risk of deformation can be significantly reduced, ensuring consistent accuracy and stability over long-term use, providing reliable support for precision measurements.
Post time: Sep-10-2025