Granite platforms are essential reference tools for precision measurement, and their stability and reliability are directly related to the accuracy of measurement results. However, in actual use, the accuracy of granite platforms is affected by many factors, with temperature being the most critical.
Granite possesses excellent physical properties, but it can still undergo slight deformation due to changes in ambient temperature. If the platform is exposed to direct sunlight for extended periods or is near heat sources such as electric furnaces or heat exchangers, it will expand and contract, causing deviations in the working surface and affecting measurement accuracy. Therefore, granite platforms should be placed in a constant temperature environment and away from heat interference. Generally, the granite platform and the workpiece being measured should be kept at the same temperature, ideally at a constant temperature of 20°C. Otherwise, the thermal expansion of the metal workpiece can cause data errors and reduce measurement reliability.
In addition to temperature control, granite platform geometric accuracy inspection and calibration are also crucial. Marble measuring tools (machined from granite) are widely used to verify workpiece straightness, parallelism, and flatness. Thanks to granite's hardness and stability, these tools typically achieve a precision grade of 00 or 0.
During the design and processing process, marble measuring tools are often rectangular in shape, sometimes with round holes drilled in non-working surfaces for ease of handling and reduced weight. These holes do not affect the accuracy of the working surface, but their size and location vary depending on the tool specifications.
During the calibration process, different measuring instruments are required to check perpendicularity, straightness, and parallelism. Taking straightness as an example, for a Class 0 marble ruler, an electronic level or autocollimator can be used, with a typical tolerance of 0.001 mm/m. Verticality can be checked using a dial gauge and a stand, achieving an accuracy of up to 0.001 mm. Compared to traditional methods, electronic levels are easier to operate and offer higher measurement accuracy, making them widely adopted by manufacturers and users.
Thus, the accuracy of granite platforms depends not only on excellent machining but also on the combined influence of the operating environment, maintenance methods, and calibration methods. Through reasonable environmental control and scientific testing methods, the stability and accuracy of the platform can be maximized in long-term use.