Many precision inspection tasks are vulnerable to magnetic interference. Conventional metal gantries act as hidden error sources under such working conditions. Steel and cast iron gantries are magnetically conductive. Even without external magnetic fields, weak magnetic fields generated by surrounding motors, cables and electromagnetic drive components can be absorbed and transmitted by metal frames, resulting in local magnetic field distortion. For inspection tasks sensitive to magnetic fields, such magnetic disturbance will skew sensor readings, interfere with optical detectors or alter the magnetic state of test samples, leading directly to inspection failure. The inherent non-magnetic property of granite moving gantries avoids magnetic interference from the supporting frame, making them ideal carriers for magnetically sensitive inspection scenarios.
Granite is an aggregate of natural silicate minerals and contains no ferromagnetic substances. It cannot be magnetized and retains no residual magnetism. Unlike metal frames, granite gantries will not alter the original magnetic field distribution, nor converge or refract magnetic fields under alternating or static weak magnetic fields around equipment. When inspection machines are equipped with sensitive components such as magnetic sensors, Hall probes and magnetic force microscopes, the supporting gantry will not introduce extra magnetic noise. Signals collected by probes only come from the tested samples instead of magnetic interference from the frame. This natural non-magnetic feature requires no extra shielding coating, so there is no performance degradation caused by coating aging or peeling. It remains stably non-magnetic over long-term service.
Some wafer inspection processes in the semiconductor industry impose strict control over ambient magnetic fields. Precise circuit structures inside wafers are extremely susceptible to stray magnetic fields, which not only affect signal acquisition during inspection, but may damage microcircuits on wafers in severe cases. For scanning platforms built with metal gantries, magnetic fields generated by linear motors and servo cables form eddy currents and magnetic loops on metal frames and amplify local magnetic fluctuations. Granite moving gantries do not participate in magnetic loop formation and help maintain a pure magnetic environment within the inspection zone. When the gantry drives optical or magnetic detection modules for large-range scanning, frame movement will not trigger instantaneous magnetic disturbance and ensures consistent inspection data across the whole wafer.
Non-destructive testing of magnetic materials is another scenario heavily reliant on non-magnetic bases. Performance testing of permanent magnets, soft magnetic films and magnetic sensors requires accurate capture of faint magnetic signals from samples. If magnetically conductive gantries are adopted, the frame will attract magnetic lines emitted by samples, distort the magnetic field shape around samples and lead to distorted readings of magnetic flux and magnetic field intensity. As the load-bearing body, granite moving gantries do not interfere with the path of magnetic lines. Data collected by probes can truly reflect the intrinsic magnetic properties of samples. Large-span moving gantries can carry probes to complete scanning over large magnetic material surfaces. During continuous dynamic inspection, the non-magnetic frame will not introduce dynamic magnetic interference as the slide moves.
Weak magnetic defect inspection of electronic components also benefits from the non-magnetic advantages of granite gantries. Tiny precision components such as chip lead frames, miniature relays and sensor magnetic cores need inspection for subtle magnetic anomalies during production. Magnetic signals corresponding to such defects are extremely faint, and any extra magnetic noise will submerge valid signals. Metal gantries also produce tribo-magnetization and eddy current effects during movement, further raising background noise. Granite moving gantries have no such issues. The frame will not generate extra magnetic signals during high-speed reciprocating motion and start-stop switching, so faint defect magnetic signals can be steadily captured by detection equipment. 
Some integrated vacuum and low-temperature inspection equipment also prefer non-magnetic granite gantry structures. Such equipment has limited internal cavity space with densely arranged drive and sensing components, creating a complex electromagnetic environment. The magnetic permeability of metal frames changes under low temperature, and the degree of magnetic interference fluctuates with temperature, bringing extra uncertainty to inspection results. The physical properties of granite remain stable over a wide temperature range, and its non-magnetic characteristic is unaffected by low temperature or vacuum environments. The gantry frame can be integrated inside vacuum chambers to drive detection mechanisms for sample scanning without introducing variable magnetic interference as environmental conditions change.
On top of the non-magnetic frame, granite itself features high rigidity and low deformation, satisfying dual precision requirements for magnetically sensitive inspection. Many non-magnetic non-metallic materials lack sufficient rigidity, and gantry slides tend to elastically shake during high-speed movement and cause positioning errors. Integrated granite structures deliver adequate rigidity and minimal deformation during motion. While maintaining a magnetically clean environment, they preserve micron-level motion positioning, combining stable magnetic conditions and high motion accuracy. Local magnetic isolation can be applied to metal parts such as guide rails and fasteners. Cooperating with the non-magnetic granite main body, the overall magnetic interference of the whole gantry system can be kept at an extremely low level to meet strict requirements of various special inspection scenarios.
Post time: Sep-20-2026