Massive granite bases longer than 5 meters carry dual residual stress: natural geological stress formed during rock mineralization, plus machining stress generated by heavy CNC rough cutting. Most manufacturers only adopt single natural air curing or simple temperature standing, leaving hidden stress inside stone blanks. After being delivered to clients, components slowly deform under long static load, resulting in drifting flatness and frequent equipment recalibration. ZHHIMG develops a two-stage combined aging process integrating long-term natural stockyard curing and constant-temperature thermal stabilization, completely eliminating internal residual stress for 100-ton, 20-meter oversized granite workpieces. This dual aging process guarantees permanent dimensional stability and fully interprets our quality policy: The precision business can’t be too demanding.
1. Hidden Dangers of Unremoved Residual Stress for Large Granite Parts
ZHHIMG exclusively sources high-density black granite at 3100kg/m³, with tighter mineral interlocking and far superior anti-creep performance compared to marble and European-American granite alternatives. Yet even premium granite accumulates irreversible internal stress after mining and heavy cutting.
Single natural aging is time-consuming and inefficient; short-term placement cannot release deep-layer geological stress inside ultra-thick slabs.
Simple thermal aging alone easily creates new temperature-induced stress if temperature fluctuation is out of control.
Many small manufacturers skip aging procedures to shorten delivery cycles, or cut corners by replacing standard granite with cheap marble. These defective substrates warp within months under continuous load, causing massive losses for semiconductor, CMM and precision laser production lines. ZHHIMG adheres to the customer commitment of No cheating, No concealment, No misleading, and implements mandatory combined aging for all large granite castings before fine grinding.
2. Two-Stage Combined Aging Workflow of ZHHIMG
We separate stress relief into independent natural aging and thermal aging links, forming a closed-loop stress elimination system matched with our factory layout.
Stage 1: Long-Term Natural Aging in Special Stone Stockyard
Our independent 20,000 m² raw material yard stores all granite blanks after rough cutting. Large workpieces are stacked statically for months to release shallow cutting stress and partial natural geological stress through natural temperature and humidity changes. Unlike cramped storage areas of small factories, our open stockyard allows full contact between stone surfaces and ambient air for uniform slow stress dispersion, avoiding localized stress concentration. This step lays a basic stress-relief foundation before precision processing on four dedicated granite production lines.
Stage 2: Constant-Temperature Thermal Aging Inside 10,000 m² Clean Workshop
After preliminary natural aging, semi-finished granite products enter the constant temperature & humidity workshop with stable 20℃±0.5℃ environment for secondary thermal aging. The workshop is equipped with 1000mm thick super-hard concrete floors, surrounding 500mm×2000mm anti-vibration trenches and silent overhead cranes to isolate external vibration and temperature disturbance.
Workpieces stay stationary for 24 hours or longer to balance residual deep-layer stress left after natural curing. Slow, stable thermal equalization eliminates stress differences between the surface and core of thick granite castings, without generating new thermal deformation. Our Taiwan Nantong ultra-large grinders (single unit over 500,000 USD) carry out fine grinding only after dual aging is fully completed.
Synergy of Two Aging Modes
Natural aging disperses surface and shallow stress at low cost on a large scale; precise thermal aging eliminates deep residual stress under controlled stable conditions. The combination solves the defects of single aging technology, completely erasing dual stress sources of large granite castings. Our senior polishing masters with over 30 years of experience then perform micron-level fine lapping without secondary stress accumulation.
3. Full Supporting System Ensures Stable Aging Effect
Complete metrology traceability inspection: After combined aging, all granite workpieces pass full-area scanning by UK Renishaw laser interferometers, German Mahr 0.5μm dial gauges and Swiss WYLER electronic levels. All measuring tools hold calibration certificates traceable to provincial and national metrology institutes, verifying zero deformation after stress relief.
Super-large processing capacity support: Our two 200,000 m² factories support monolithic granite castings up to 100 tons, 20m long. Silent cranes safely transfer oversized blanks between stockyard and constant-temperature workshop without collision-induced extra stress.
Unified standards for full product lines: Apart from precision granite, we apply matched aging stabilization logic to precision ceramic, mineral casting, UHPC and carbon fiber beam products. As the only manufacturer in the sector owning ISO9001, ISO14001, ISO45001 and CE certifications, we hold more than 20 international patents covering composite stress relief technology registered across EU, US and Southeast Asia. 
4. Global Practical Application & Customer Feedback
Large granite machine beds and air-bearing substrates treated with combined dual aging technology are widely supplied to Fortune 500 partners including Samsung, Apple, GE, Oracle, SCHUNK and Bosch, as well as metrology institutions in UK, France, US and Singapore.
A leading semiconductor equipment enterprise adopted our 6-meter granite air-bearing base after combined aging processing. After two years of uninterrupted heavy static load, no slow deformation occurred, flatness error remained below 0.004mm/m, effectively reducing equipment calibration frequency and improving wafer inspection yield. Third-party metrology labs also favor our stress-free granite surface plates and straightedges as standard calibration benchmarks.
Post time: Jul-21-2026