Black Granite Surface Plate

A high precision surface plate is an indispensable foundational metrology tool that provides an ultra-flat, stable reference plane for dimensional inspection, precision assembly, tool setup, and instrument calibration across advanced manufacturing and scientific research fields. It is available in premium cast iron (HT200/HT250) and fine-grained natural granite (black diabase being a top choice), each engineered through rigorous processes to eliminate internal stress and achieve extreme flatness.

Granite surface plates are widely favored for their exceptional thermal stability, low coefficient of expansion, non-magnetic properties, and excellent vibration-damping capability. With a Mohs hardness of 6–7, they resist corrosion from industrial fluids, avoid rusting, and maintain precision for decades with minimal maintenance. Cast iron plates, on the other hand, excel in heavy-load scenarios and can be manually scraped to form micro-oil reservoirs, ideal for continuous machining and assembly workflows.

Accuracy grading follows international standards (ISO 8512, ASME B89.3, GB/T 22095), with Grade 00/0 serving as the laboratory-level benchmark, boasting sub-micron to several-micron flatness tolerances. For example, a 500×500mm Grade 0 granite plate can achieve a flatness error ≤ 3.5μm, ensuring consistent and traceable measurements.

Key applications span aerospace, automotive, semiconductor, mold & die, and metrology labs. It acts as the base for coordinate measuring machines (CMMs), height gauges, dial indicators, and optical measurement systems. It is also critical for verifying the flatness, parallelism, and squareness of high-value components, such as turbine blades, precision gears, and electronic substrates.

To maximize service life, the surface plate should be installed on a rigid, level foundation, kept clean with lint-free cloths, and protected from heavy impacts and extreme temperature swings. Regular calibration by an accredited institution ensures compliance with global quality standards, making it an irreplaceable cornerstone of precision manufacturing and quality control.