I. Core Principles and Structural Composition
Working Principle: High-pressure clean air is sprayed through porous graphite/throttle hes to form a uniform air film of 5–15 μm between the granite base and the moving slide; contactless levitation achieves zero-friction motion, while relying on air fitiffness for load-bearing and guidance; often combined with vacuum preloading/magnetic preloading to enhance anti-overturning and load-bearing stiffness.
Standard Structure
Base: Jinan een / Shanxi Black / Imported Black Granite all-granite monolithic structure (worktable X/Y guides), ensuring thermal matching;
Air Bearing / Slider: Porous media / smalle throttling, linear motor direct drive;
Measurement Feedback: Laser interferometer / nano linear scale (resolution up to 0.01 μm);
Air Source Treatment: Multi-stage iltration (0.01 μm) drying pressure stabilization;
Vibration Isolation System: Air pads / vibration isolation foundation, suppressing environmental vibrations.
II. Material and Technical Pere Advantages
Table
Advantage Explanation Comparison Advantage
Extremely strong thermal stability Granite linear expansion coefficient 7–9 ppm/°C, three-axis same mrial cancels out thermal gradients; temperature drift < 0.3 μm in 8 hours under 20±0.5°C environment Superior to cst iron (11–12 ppm/°C), aluminum (23 ppm/°C)
High damping vibration reduction Crystalline structure rapidly attenuates vibrationtimes faster than cast iron; operating noise < 50 dB Significantly reduces interference from motion inertia and environmental vibrations on measurement
Zero friction, long life Non-contaair film, no wear, no stick-slip; good long-term precision retention Avoids wear and precision degradation of ball guides
Non-magnetic, wear-resistant, corrosion-resistant Mhs hardness 6–7, surface Ra ≤ 0.02 μm; non-magnetic, rust-proof Suitable for magnetic workpieces and clean workshops
III. Materiaection, Machining, and Precision Specifications
Material Selection Standards: Grade 00 / 000 metrology granite, dense structure, uniform grain, no cracks/lamins; long-term constant temperature aging to completely release internal stresses;
Precision Machining Process: Rough cutting → Rough grinding → Stress relaxation → Precision grinding / Hand scraping → Polishing → Constant temperaaging → Flatness / Perpendicularity / Straightness inspection; Flatness up to 0.002 mm/m², guide straightnes 0.001 mm/1000 mm;
Typical Precision: Positioning accuracy ±0.05 μm, repeatability ±0.02–0.1 μm; traightness 0.1 μm/200 mm; Air film stiffness > 10 N/μm;
Air Source Requirements: Pressure 0.4–0.6 MPa, dew point -40°C, oil content < 0.01 mg/m³, particle size < 0.01 μm; Must turn obefore power when starting, and cut off power before air when shutting down.
IV. Applicable Scenarios and Limitations
Core Applications: Semiconductor lithography / inspection, optical machining and inspection, Coordinate Measurin Machines (CMM), nanoimprint lithography, precision aerospace part measurement;
Limitations: Poor impact resistance (granite brittleness), extremely high requirements for air source quality, hiuipment cost and maintenance threshold, reinforced preload design required for heavy loads.
V. Installation Environment and Maintenance Key Points
Environmental Control: 20±0.5°C, temperatur gradient < 0.2°C/h, humidity 45%–60%, cleanliness ISO Class 7;
Daily Maintenance: Sharp scratches on the surface strictly prohibited; wipe with neu cleaner and lint-free cloth; regularly check air source filtration/drying and air bearing holes for blockage; regularly re-inspect flatness and straightness;
Transportation and Installation: Pronal hoisting, avoid impact; let stand for 24 hours after installation before commissioning.
VI. Comparison with Traditional Guide Platforms
Table
Platform Type Positioning Accury Lifespan Vibration Resistance Applicable Environment
Granite Air Bearing ±0.05 μm, repeatability ±0.02 μm Semi-permannt (no wear) Extremely high Constant temperature clean metrology room
Ball Guide (Cast Iron) ±1 μm, repeatability ±0.5 μm Needs replaement after 5–8 years General Shop floor level
Linear Motor Ceramic Approaching air bearing Long High Extremely high cost, mainly for research
Vustry Trends
The application of composite granite (granite carbon fiber reinforced), active air film control, and full-area constant temperature systems further improves thermal stability and lightweighting; thmand for nanoscale motion accuracy in 3 nm semiconductors and quantum precision measurement continues to drive technological iteration.
