Under standardized use and regular maintenance, qualified granite structural parts made of high-density fine-grained black granite maintain stable precision for more than ten years with barely measurable deviation. However, precision degradation will occur after long-term service if improper operating conditions or human damage exist.
1. Scenarios with almost no precision loss
High-quality granite blanks go through natural aging and artificial vibration aging to release internal residual stress before precision machining. The compact, uniform crystal structure has ultra-low thermal expansion coefficient, no internal layered gaps and no hygroscopic expansion. When placed in a vibration-isolated workshop without heavy impact, chemical corrosion or concentrated high-temperature baking, flatness, perpendicularity and linear accuracy will not drift significantly over long-term use. Daily light contact with measuring tools and ordinary workpieces only creates tiny wear marks without changing overall geometric tolerance.
2. Factors causing long-term precision deterioration
Continuous heavy impact and overload compression
Frequently dropping heavy metal workpieces directly onto granite surfaces produces pits and local indentations. Long-term placement of ultra-heavy components beyond the platform load limit causes slow micro-deformation of stress-concentrated areas, breaking the original flatness benchmark.
Severe temperature alternation and local overheating
Long-term local high-temperature welding or cutting on the stone surface creates uneven thermal expansion, generating permanent micro-distortion. Frequent drastic temperature swings between cold and hot seasons enlarge minor internal mineral gaps and gradually reduce positioning precision.
Corrosion and long-term oil penetration
Uncleaned cutting fluid, acid cleaning agents and welding slag residue erode grain boundaries over years, forming pockmarks and uneven surface textures. Deep oil absorption changes local stone density, leading to inconsistent flatness across the table surface.
Incomplete aging treatment of inferior raw stone
Low-cost coarse-grained grey granite or unaged blanks retain massive internal stress. Even without external damage, slow stress release will cause gradual warping and precision decline after several years of placement.
Unstable support and long-term uneven force
Irregular foot pad adjustment, single-point long-term bearing and tilting placement make the component bear asymmetric stress, triggering slow geometric deformation over time.
3. Degree of precision change classification
Slight precision drift: Only surface wear scratches appear; overall flatness deviation stays within the original grade tolerance, recoverable via simple surface grinding and calibration.
Moderate precision loss: Local pits, thermal deformation or oil corrosion expand flatness error beyond the original grade; re-finishing can restore it to lower qualified accuracy grades.
Irreversible precision failure: Deep cracks, severe thermal warping or large-area collapse of the working surface; the granite component cannot be repaired to original precision and needs replacement.
4. Measures to lock long-term precision
Strictly avoid direct heavy collision and local high-temperature operation; clean oil, slag and corrosive liquid every shift; adjust support foot pads to keep uniform stress distribution; place precision granite structural parts in constant-temperature low-vibration environments; conduct regular flatness calibration once every 6 to 12 months to track tiny accuracy changes timely.
Reference List
GB/T 7714 Format
[1] Feng S. Long-term precision stability research of granite measuring structural parts under workshop service conditions[J]. Metrology and Test, 2022, 49(8): 59-64.
MLA Format
Feng, Shu. "Long-term Precision Stability Research of Granite Measuring Structural Parts Under Workshop Service Conditions." Metrology and Test, vol. 49, no. 8, 2022, pp. 59-64.
APA 7th Format
Feng, S. (2022). Long-term precision stability research of granite measuring structural parts under workshop service conditions. Metrology and Test, 49(8), 59–64.
