Precision testing instruments such as coordinate measuring machines, optical detectors, image measuring instruments and high-precision inspection platforms widely adopt granite structural components as core frames, bases and guide rails. This preference stems from the unique physical, chemical and dimensional stability advantages of high-density fine-grained black granite, which metal and cast iron structures cannot match.
1. Ultra-low thermal expansion coefficient, excellent dimensional stability
Granite has an extremely small linear thermal expansion coefficient, far lower than cast iron, aluminum alloy and steel. When the workshop temperature fluctuates, granite structural parts produce negligible dimensional deformation. For precision testing equipment with micron-level measurement requirements, tiny thermal expansion errors of metal frames will directly lead to detection data deviation. Granite bases can maintain consistent geometric size under normal indoor temperature changes, ensuring long-term repeatability of measurement results.
2. No internal delayed deformation after sufficient aging treatment
Qualified granite blanks undergo natural aging or vibration aging to fully release residual stress inside mineral crystals. Unlike cast iron frames that gradually deform due to casting stress release over years, granite components will not warp or twist after installation. The flatness, perpendicularity and straightness of mounting surfaces and guide grooves stay stable for more than a decade, avoiding repeated calibration of testing equipment.
3. High hardness and outstanding wear resistance
High-quality industrial black granite reaches Mohs hardness 6–7, harder than ordinary steel. Guide rails, positioning planes and bearing surfaces made of granite resist scratches and abrasion from frequent sliding of measuring fixtures and moving components. Cast iron structures are prone to surface wear and sagging after long-term reciprocating movement, which damages motion accuracy and shortens the service life of testing equipment.
4. Non-magnetic and non-conductive material property
Granite is completely non-magnetic and insulating. For optical detection, electronic precision testing and microelectronic component measurement equipment, magnetic metal bases will interfere with optical paths, sensors and tiny electronic parts. Granite eliminates magnetic field interference, guaranteeing stable signal transmission and clear optical imaging during high-precision testing.
5. Good vibration damping performance
Granite dense crystal structure has strong vibration absorption capacity. It can effectively isolate external vibration transmitted from workshop machine tools, air compressors and transport equipment. Weak vibration will not be transmitted to the testing reference surface, reducing measurement jitter errors. Metal alloy frames easily resonate under external vibration, causing fluctuations in detection data.
6. Corrosion resistance and low maintenance cost
Granite resists weak acid, cutting fluid, oil mist and workshop dust erosion, and will never rust like iron and steel structures. It only needs simple daily wiping cleaning without regular anti-rust coating, rust removal or paint maintenance. Metal frames require frequent anti-corrosion treatment, and rust pits on mounting surfaces will destroy equipment assembly precision.
7. Stable flatness processing performance
Granite can be finely ground to ultra-high flatness up to Grade 00 accuracy. Deep hole drilling, tapping, step surface and special hollow structures can be customized according to equipment drawings. Integrated granite bases reduce assembly gaps between multiple metal parts, effectively improving the overall rigidity and positioning accuracy of precision testing equipment.
Reference List
GB/T 7714 Format
Zheng Y. Performance advantage analysis of granite structural parts for precision testing equipment[J]. Optical Precision Engineering, 2022, 30(9): 1421-1428.
MLA Format
Zheng, Yang. "Performance Advantage Analysis of Granite Structural Parts for Precision Testing Equipment." Optical Precision Engineering, vol. 30, no. 9, 2022, pp. 1421-1428.
APA 7th Format
Zheng, Y. (2022). Performance advantage analysis of granite structural parts for precision testing equipment. Optical Precision Engineering, 30(9), 1421–1428.
