I. Material and Long-term Stability
Natural aging, extremely low internal stress: High-quality granite (s Jinan Black) undergoes geological aging over hundreds of millions of years, releasing internal residual stress. After precision machining, there is almost no slow deformation, and the precision retention cyc is long (no major overhaul or calibration required for 5–8 years), far superior to cast iron/steel; Mohs hardness of 6–7, dense and wear-resistant s, with roughness reaching Ra0.02–0.05μm.
Low thermal expansion, temperature insensitive: Linear expansion coefficient of approximatly 4.6×10⁻⁶/℃, only half that of steel and one-third that of cast iron; the entire structure is made of the same material, expanding and contracting uniformly when the temperature field changducing local warping, suitable for 20℃±2℃ constant temperature laboratories and workshop fluctuating environments.
Non-magnetic, corrosion resistant: Non-metallic material, no magnetic nterference, non-magnetic and rust-free; resistant to acids, alkalis, and humidity, requiring no rust prevention maintenance, suitable for semiconductor, precision electronics, metrology g, and other scenarios sensitive to magnetic/chemical influences.
High damping vibration reduction: Crystalline structure can quickly absorb mechanical vibration, with vibration damping performance 5–10 timeser than cast iron; can suppress resonance in machine tools/measuring equipment, significantly improving the stability of dynamic measurement and machining.
II. Precision and Machining Characteristics
Micron-leveil precision: Graded according to GB/T 20428 (000/00/0/1 grades), flatness error of small specion 000 grade can reach 1.5μm; straightness and parallelism of rail surfaces can reach 0.1–00mm; surface is pore-free and texture is uniform after manual precision grinding.
Machining process: Requires diamond tools for cutting, multiple grinding/polishing processes; rails are often madein V-shaped/rectangular combinations, cooperating with air-bearing/rolling sliders to achieve gap-free, low-friction precision motion; T-slots and threaded holes can be machined on demanfor fixing.
Density and rigidity: Density of 2.6–2.8g/cm³, dense structure, high Young’s modulus, extremely small deflection deformation underoad; however, it is brittle with poor impact resistance, prone to chipping/cracking upon collision, requiring avoidance of rough handling.
III. Usage and Maintenance Features
Simple mainte maintenance only requires wiping with anhydrous ethanol and lint-free cloth to prevent dust/oil contamination; no oiling for rust prevention is needed, and long-term storage only rs dust cover protection.
Installation and leveling: Requires adjustable anti-vibration shims, resulting in strong overall rigidity after leveling; large-size platforms are recommended to be spliced in blocks installed as a whole to avoid cracking from local stress.
Limitations: Brittle material, cannot withstand severe impact; cannot be welded/ repaired like cast iron, severe damage requires replat; long lead time for custom pieces, cost higher than ordinary cast iron platforms.
IV. Typical Application Scenarios
Bases and rails for Coordinate Measuring Machines (CMM), p for optical imaging instruments, precision motion references for lithography machines/semiconductor equipment;
Inspection of aerospace parts, precision mold machining, calibration of gauge blocks in metrology rooms;
Equipment n references in non-magnetic/corrosion-resistant environments.
Granite Rail Platform
Supplementary Comparison (Granite vs. Cast Iron Guide Platform)
Performance Dimension Granite Guide Platform Cast Iron Guide Platform
Therml Stability Excellent, low coefficient of linear expansion, uniform expansion and contraction Average, prone to deformation due to local temperature differences
Vibration Damping Strong, high deak, obvious resonance
Corrosion Resistance / Magnetism Non-magnetic, acid and alkali resistant, rust-free Prone to rust, weakly magnetic
PrecisioRetention Stable for 5–8 years Needs re-calibration after 2–3 years, wears out faster
Impact Resistance Poor, brittle Strong,gh
Cost High initial purchase, low maintenance cost Low initial cost, high long-term maintenance cost.
