Technical Requirements for Marble and Granite Mechanical Components

Marble and granite mechanical components are widely used in precision machinery, measuring equipment, and industrial platforms due to their excellent stability, high hardness, and wear resistance. To ensure accuracy and durability, strict technical requirements must be followed during the design and manufacturing process.

Key Technical Specifications

1. Handling Design
   For Grade 000 and Grade 00 marble mechanical components, it is recommended that no lifting handles be installed in order to maintain structural integrity and accuracy.

2. Repair of Non-Working Surfaces
   Minor dents or chipped corners on non-working surfaces may be repaired, provided that the structural strength is not affected.

3. Material Requirements
   Components should be manufactured using fine-grained, high-density materials such as gabbro, diabase, or marble. Technical conditions include:

   • Biotite content less than 5%

   • Elastic modulus greater than 0.6 × 10⁻⁴ kg/cm²

   • Water absorption rate below 0.25%

   • Working surface hardness above 70 HS

4. Surface Roughness

   • Working surface roughness (Ra): 0.32–0.63 μm

   • Side surface roughness: ≤10 μm

5. Flatness Tolerance of Working Surface
   Flatness accuracy must comply with the tolerance values specified in corresponding technical standards (see Table 1).

6. Flatness of Side Surfaces

   • The flatness tolerance between side surfaces and working surfaces, as well as between two adjacent side surfaces, shall comply with Grade 12 of GB/T1184.

7. Flatness Verification
   When flatness is tested using diagonal or grid methods, the fluctuation value of the air level plane must meet the specified tolerance.

8. Load-Bearing Performance

   • The central load-bearing area, rated load capacity, and allowable deflection must meet the requirements defined in Table 3.

9. Surface Defects
   The working surface must be free of serious defects that affect appearance or functionality, such as sand holes, air pores, cracks, inclusions, shrinkage cavities, scratches, dents, or rust marks.

10. Threaded Holes and Grooves
    For Grade 0 and Grade 1 marble or granite mechanical components, threaded holes or slots may be designed on the surface, but their position should not be higher than the working surface.

Conclusion

High-precision marble and granite mechanical components must adhere to strict technical standards to guarantee measurement accuracy, load-bearing capacity, and long-term stability. By selecting premium materials, controlling surface quality, and eliminating defects, manufacturers can deliver reliable components that meet the stringent demands of global precision machinery and inspection industries.