Linear motors and air bearing guideways are core components enabling high-speed, frictionless motion for ultra-precision CNC equipment. However, many machinery manufacturers encounter an easily overlooked problem during commissioning: magnetism from the base material disturbs linear motor magnetic fields, or metallic impurities inside the substrate trigger local magnetic distortion. This leads to thrust fluctuation and positioning jitter. Such defects cannot be detected in static inspection and only emerge during high-speed synchronized operation, undermining nano-level positioning performance. Non-magnetic CNC granite bases are developed for high-end magnetic-sensitive equipment such as linear motors and air bearing stages, eliminating magnetic interference at the substrate level and stabilizing the entire motion system.
1. Magnetic interference: hidden precision killer for linear motors and air bearing equipment
Linear motors generate thrust through magnetic interaction, while air bearing guideways rely on micron-scale air films for contactless movement. Both are highly sensitive to ambient magnetic fields and material impurities. If the machine base contains ferromagnetic mineral particles, it continuously distorts the magnetic field of linear motors, resulting in uneven thrust and increased repeat positioning error. Magnetic fluctuations also disturb optical grating readers and cause signal drift.
Air bearing guideways are also sensitive to impurities on base surfaces. Detached ferromagnetic particles from the base may enter air gaps, scratch air bearing surfaces and break stable air films. Traditional cast iron and steel bases are inherently magnetic. Even after demagnetization treatment, alloy bases risk re-magnetization over time. Some low-cost stone contains iron-bearing minerals and carries weak magnetism, making them unsuitable for ultra-precision motion units such as linear motors and air bearing stages.
2. Naturally non-magnetic granite substrate eliminates magnetic disturbance at source
ZHHIMG high-density black granite is carefully screened for mineral composition with ferromagnetic impurities removed. The raw material is inherently non-magnetic without magnetic conductivity. No extra demagnetization coating or thermal demagnetization treatment is required. The substrate will not attract magnetic powder or warp the magnetic circuit of linear motors.
When linear motors operate, the base preserves uniform magnetic field distribution. Thrust output becomes smoother and micro-jitter caused by thrust ripple is reduced. When paired with air bearing guideways, the non-magnetic stone does not attract metal dust, lowering the risk of scratches on air bearing surfaces and preserving uniform air films. Air bearing stages can reliably maintain micron or sub-micron motion gaps.
3. Combined superior properties meet strict working conditions of linear motors and air bearing guideways
Non-magnetic performance is only the baseline. Linear motors and air bearing stages impose multiple strict requirements on base substrates. Continuous vibration from high-speed reciprocating motion demands high damping to absorb oscillation; heat generated by motors requires minimal thermal deformation to prevent reference plane shift.
This non-magnetic granite base features a low thermal expansion coefficient and excellent vibration damping. Vibration from high-speed movement is quickly absorbed by the stone matrix to suppress resonance. Subject to heat from motors, the base undergoes negligible dimensional change and keeps the reference plane of air bearing guideways flat for long periods. In addition, blanks go through full aging treatment to release residual internal stress. No slow deformation occurs during long service, preventing air bearing gap drift. 
4. Integrated custom machining for assembly of air bearing and linear motors
Custom fabrication is available to match assembly characteristics of linear motor and air bearing guideway equipment. Reference planes for air bearing installation, slots for linear motor stators, grating mounting references, vacuum holes and locating pin holes can be processed in one go inside temperature-controlled and vibration-isolated workshops. All reference surfaces are lapped to high precision with guaranteed flatness and parallelism for air bearing assembly.
Before shipment, finished bases undergo full geometric inspection with international metrology instruments to guarantee accuracy of reference surfaces and hole positions. Machine builders can directly mount linear motor stators and air bearing guide components after delivery. No on-site secondary machining is needed, avoiding iron scrap contamination to air bearing surfaces.
5. Application scenarios and benefits
Such non-magnetic granite bases are widely used for XY linear motor stages, air bearing motion platforms, semiconductor inspection equipment, optical scanning systems, high-precision 2D and CMM measuring machines. For these devices, magnetic interference or damaged air films directly cause machining or measurement failure.
Adopting non-magnetic granite bases eliminates hidden magnetic errors and reduces risks of air bearing surface damage. Motion smoothness of linear motors improves significantly, helping equipment steadily achieve sub-micron positioning accuracy. Meanwhile, maintenance frequency drops and service life of air bearing guideways and linear motors extends, suiting research laboratories and high-end semiconductor mass production lines.
Conclusion
The precision bottleneck of linear motor and air bearing equipment lies not only in moving components. Magnetic properties and material purity of the base also determine overall machine performance. Featuring natural non-magnetism, high stability and strong vibration damping, ZHHIMG non-magnetic CNC granite bases remove magnetic interference and protect air bearing gaps. They provide a clean and stable reference platform for ultra-precision equipment built around linear motors and air bearing guideways.
Post time: Sep-18-2026