Granite base for five-axis ultra-precision machine tools, featuring a core made of natural granite (Jinan Green / Zhangqiu Black) or artificial mineral casting to form an integrated bed body. This achieves high damping vibration reduction, low thermal expansion stability, and high rigidity load-bearing, serving as the foundation for micron/sub-micron level five-axis linkage.
I. Core Materials and Performance (Why Granite is Used)
Vibration Suppression (Most Critical): The damping ratio is 6–10 times that of cast iron, with a decay rate 3 times faster; the natural frequency is 10–20Hz, capable of absorbing 90% of external vibrations, controlling displacement error during linkage within ±0.5μm.
Thermal Stability: Thermal expansion coefficient (4–8)×10⁻⁶/℃ (about 1/20 of cast iron, 1/6 of aluminum alloy); a 0.1℃ fluctuation causes only 0.1μm/m deformation, maintaining micron-level accuracy even with a temperature control of ±2℃.
Rigidity and Load-Bearing: Compressive strength ≥200MPa, elastic modulus 45–55GPa; can bear a load of 1000kg/m² without deformation, suitable for five-axis heavy loads (single axis > 200kg).
Accuracy Retention: Wear-resistant, corrosion-resistant, and free of internal stress, with long-term geometric accuracy drift <1μm/year.
II. Typical Structure and Layout
Integrated Solid Base (Mainstream)
Material: Jinan Green / Zhangqiu Black (natural) or mineral casting (artificial), featuring a large overall block with slots, pre-embedded steel sleeves / guide rail mounting surfaces.
Layout: T-shaped structure, X/Z axis guide rails arranged vertically, Y axis on the X axis, and rotary axes (B/C) integrated into the Y carriage.
Support and Vibration Isolation System
Four-point Support: Support points are external to the base (large machines) or internal (small and medium machines), equipped with air springs / vibration isolation air cushions to isolate ground vibrations.
Leveling: Precision adjustable leveling feet, with a horizontal accuracy ≤0.02mm/m.
Application Scenario Structures
Ultra-precision five-axis machining (e.g., Precitech Freeform L): Sealed natural granite base, integrated TMC MaxDamp vibration isolation, suitable for diamond turning and micro-milling.
Domestic five-axis tool grinder (e.g., KToolG3515): Artificial granite integrated bed body, high damping, low thermal expansion, suitable for grinding cemented carbide / diamond tools.
III. Workshop Actual Shot (Long-distance view of a spacious workshop)
Scene: Large constant-temperature workshop (±0.5℃), epoxy floor, multiple five-axis machines with granite bases lined up, open space, and bright lighting.
IV. Selection Key Points
Material Priority: Natural Jinan Green (highest accuracy) > Artificial mineral casting (cost-effectiveness).
Structure: Integrated solid (avoid split splicing to prevent accuracy loss).
Vibration Isolation: Must be equipped with air springs active vibration reduction, with workshop vibration ≤0.1μm.
Accuracy: Base flatness ≤0.01mm/m, guide rail mounting surface parallelism ≤0.005mm/m.
