Customized processing of marble square boxes

Customized processing of marble square boxesIt is a device used for inspecting or marking arbitrary angle lines of precision workpieces, mainly used for checking and marking the parallelism and perpendicularity of components. According to the different materials, square boxes can be divided into cast iron square boxes and marble square boxes. Cast iron square boxes are usually made of gray cast iron, with a dimensional accuracy within 0.01 millimeters. Adjacent planes are perpendicular to each other, and the allowable error is within 0.01 millimeters. ‌

According to their usage, they can be divided into: marking square box, inspection square box, magnetic square box, T-shaped groove square box, universal square box, etc. It is the basic equipment for component inspection and marking in mechanical manufacturing.

大理石方箱The core performance characteristics of

（1） Intrinsic properties of materials

1. Physical stability：
   • The main component is calcium carbonate (CaCO3), with a density of 2.6-2.8g/cm ³, a water absorption rate of<0.1%, and a size change rate of ≤ 1.5 × 10 ⁻⁶/℃ under temperature fluctuations (± 5 ℃), which is significantly better than cast iron (with a size change rate of about 11 × 10 ⁻⁶/℃);
   • Antimagnetic susceptibility<0.01 emu/g, not affected by electromagnetic interference, suitable as a measurement benchmark for precision equipment such as electron microscopes and nuclear magnetic resonance.
2. mechanical properties：
   • The compressive strength is 100-200MPa (equivalent to 70% of granite), the surface Mohs hardness is 3-5 levels, and it can withstand a uniform load of 20-50kg/cm ²;
   • Internal stress release (natural stone subjected to 10-20 years of geological action), no risk of aging deformation, superior to metal materials treated by artificial aging (residual stress release rate ≤ 90%).

（2） Environmental adaptability

2、 Accuracy level and measurement standards

（1） Geometric accuracy index

1. flatness error：
   • According to the GB/T 20428-2006 standard, the flatness of Class 00 accuracy is ≤ 3 μ m/m (1m × 1m surface), Class 0 is ≤ 5 μ m/m, and Class 1 is ≤ 10 μ m/m;
   • Detection method: Laser interferometer (resolution 0.1 μ m) or electronic level (division value 0.005mm/m), take the maximum difference between the diagonal and the grid points.
2. Verticality tolerance：
   • The verticality of adjacent working faces is ≤ 5 μ m/100mm (Class 00), and a square box square ruler is used in conjunction with a micrometer for detection. The micrometer has a range of 0-5mm and an accuracy of 0.001mm;
   • The diagonal perpendicularity error is ≤ 8 μ m (1m square box), and a coordinate measuring machine (CMM) is required for spatial vector analysis.

（2） Dimensional accuracy control

1. Side length tolerance：
   • The side length error of a 100mm × 100mm square box is ≤± 2 μ m, and the side length error of a 1000mm × 1000mm square box is ≤± 10 μ m. It is calibrated by comparing with a measuring block (accuracy level 0);
   • Parallelism error: The relative parallelism of the working surface is ≤ 3 μ m/m (level 00), measured by moving a micrometer along the diagonal, with a total difference of ≤ 3 μ m.
2. surface roughness：
   • Grinding surface Ra ≤ 0.1 μ m (mirror effect), precision grinding surface Ra ≤ 0.8 μ m, detected by a roughness meter (stylus type, resolution 0.01 μ m);
   • Special requirements can be processed to Ra ≤ 0.05 μ m (optical grade), suitable for laser interferometry measurement reference surfaces.

3、 Key points for precision maintenance and upkeep

（1） Key factors affecting accuracy