Core Features of Granite Machine Base for CMMs
- Excellent Thermal Stability
Granite has an extremely low coefficient of thermal expansion, is minimally affected by workshop temperature changes, and is resistant to thermal expansion and contraction deformation. This ensures long-term stable measurement accuracy, with significantly less thermal drift compared to cast iron or cast aluminum bases. - High Structural Rigidity and Low Internal Stress
Naturally crystalline and dense with uniform texture, it possesses high rigidity and is resistant to bending deformation. After natural aging, internal stresses are thoroughly released, ensuring no creep or deformation during long-term use, making it suitable for high-precision benchmarks. - Excellent Shock Absorption and Vibration Damping
The internal crystalline structure of granite has good damping properties, absorbing vibrations from equipment operation and workshop floors. This reduces interference with the probe and measurement path, improving repeatability. - Strong Dimensional Stability
It is rust-proof, oxidation-free, and free from aging deformation. Precision remains stable year-round, eliminating concerns about rust or stress rebound found in cast iron. It is suitable for long-term use in constant-temperature metrology rooms and precision workshops. - Easy Machinability and Wear Resistance
It can be precision ground to ultra-high flatness and surface finish. With high hardness, it is wear-resistant and resistant to scratches. The table can be precisely drilled for threaded holes, dowel holes, and air-bearing holes, facilitating the installation of guides, gratings, and tooling fixtures. - Corrosion Resistance and Non-Magnetic
Resistant to acids, alkalis, and oil stains, it is unaffected by cutting fluids and coolants. It is non-magnetic, does not attract metal chips, and does not interfere with the operation of precision sensors or optical measurement components. - High Flatness and Benchmark Quality
The entire table is precision machined as a single piece, offering excellent flatness, straightness, and perpendicularity benchmarks. It is the ideal base for installing the X/Y/Z three-axis guides of a CMM. - Good Aesthetic Texture and Easy Cleaning
With a dense texture and minimal pores, it is oil-proof, water-proof, and easy to clean. Daily maintenance is simple, and its neat appearance suits the overall quality of high-end inspection equipment.
Supplementary Material Selection Points
For CMM bases, priority should be given to dark-colored fine-grain granite (such as Jinan Green, Mount Tai Green, Absolute Black, etc.): These have uniform particles, minimal color variation, extremely low stress, and optimal thermal stability and rigidity, making them the industry-standard material.
