When selecting granite bases, many manufacturers of ultra-precision equipment focus heavily on the flatness index at factory acceptance, yet tend to overlook long-term risks caused by residual stress inside the stone. During quarrying and cutting, large granite blanks retain substantial internal stress. Without adequate stress relief aging treatment, stress will release gradually over time under continuous impacts from ambient temperature and vibration. The base will warp, and the originally qualified reference precision will drift, directly undermining the measurement and processing stability of the whole machine. ZHHIMG adopts multi-stage stress relief aging processes to release residual stress within granite and ensure machine bases maintain stable geometry throughout their service life.
Natural granite is not a perfectly homogeneous ideal material. Rock masses fracture under force during quarrying, leaving primary stress inside large raw blocks. Subsequent sawing and rough grinding further introduce machining stress. Such stress remains hidden inside the stone and invisible to the naked eye. Granite bases that only undergo simple cutting and grinding may pass precision inspections in the short term. However, after commissioning, under combined stimuli of workshop temperature fluctuations and continuous equipment vibration, internal stress releases slowly, gradually altering the flatness and straightness of the base. This type of deformation is progressive and hard to detect during equipment commissioning. It often emerges months or even years after operation, triggering equipment precision drift and raising maintenance costs.
ZHHIMG’s stress relief aging is not a single operation, but a progressive multi-stage process. After raw blanks arrive at the factory, they first undergo natural static aging to allow sufficient time for releasing primary internal stress generated during quarrying. After rough cutting and rough grinding, the blanks enter a secondary aging phase to eliminate mechanical stress induced by material removal and rough machining. During the aging cycle, geometric changes of the stone are continuously monitored. Semi-finished products with excessive deformation are screened out, and only blanks with stabilized deformation are transferred to the constant-temperature workshop for subsequent fine grinding. After multiple rounds of aging, most internal stress of the granite is released, greatly improving the finished base’s resistance to long-term deformation.
It is necessary to distinguish aging stress relief from surface grinding, as they are two completely separate procedures. Grinding only corrects the current geometric precision of the stone surface and cannot remove residual stress trapped inside. Even if a base achieves excellent precision upon delivery, slow deformation will still occur later if residual stress remains. ZHHIMG arranges aging processes before rough machining. Ultra-precision grinding is performed to lock the reference surface only after internal stress reaches a stable state. Granite bases manufactured in this way will not suffer continuous deformation of the reference surface due to subsequent stress release. 
Even with complete aging stress relief, on-site working conditions still affect the long-term stability of the base. Improper support layout during installation or uneven foundation settlement introduces additional external stress, which may also bend the stone. At the customization stage, ZHHIMG technical team optimizes support schemes according to equipment load distribution to avoid external stress impacting granite bases. Bases with full aging treatment, paired with a proper installation solution, can maintain stable benchmarks even in workshops with vibration and minor temperature fluctuations. They are widely used in high-end equipment including semiconductor inspection systems, optical measuring instruments and precision laser processing machines.
The key to long-term dimensional stability of granite machine bases is not merely achieving ultra-high precision at the time of delivery, but thorough stress relief aging treatment. ZHHIMG’s multi-stage aging process gradually releases residual stress from granite blanks and machining operations, lowering the risk of slow deformation in later service from the source. This enables granite bases to retain consistent reference precision over extended periods and deliver reliable load-bearing benchmarks for ultra-precision equipment.
Post time: Sep-15-2026