A Granite Surface Plates is a precision reference measurement tool made from natural stone material. It is widely used in industries such as precision machinery, hardware, semiconductors, aerospace, automotive, and instrument manufacturing. Its key functions include:
1. **Serving as a reference for inspecting workpiece errors**:
Granite platforms are used to inspect errors in workpiece flatness, straightness, and contour measurements, ensuring that dimensions and shapes meet design specifications.
2. **Installation and calibration of equipment and workpieces**:
During the installation and calibration of mechanical equipment, granite platforms provide a stable reference surface to ensure precise alignment and setup.
3. **Flat and three-dimensional marking**:
For flat or 3D marking of components, granite platforms offer a stable base to guarantee marking accuracy.
4. **High-precision measurement**:
Owing to their exceptional precision and stability, granite platforms are ideal for high-accuracy measurements, such as inspecting instruments, precision tools, and mechanical parts.
Common sizes of granite measuring platforms are as follows:
| Items | Common size（mm） | Approximate weight | Flatness（μm） | |||
| Length-width-thickness | KG | Level 000 | Level 00 | Level 0 | Level 1 | |
| 1 | 300*300*80 | 21 | 1.5 | 3 | 6 | 11.5 |
| 2 | 400*400*80 | 38 | 2 | 3.5 | 6.5 | 13 |
| 3 | 400*500*100 | 60 | 2 | 3.5 | 7 | 13.5 |
| 4 | 500*600*100 | 90 | 2 | 4 | 7.5 | 14.5 |
| 5 | 630*1000*150 | 283 | 2.5 | 4.5 | 9 | 17.5 |
| 6 | 800*1000*150 | 360 | 2.5 | 5 | 9.5 | 18.5 |
| 7 | 800*1200*150 | 432 | 2.5 | 5 | 10 | 20 |
| 8 | 1000*500*150 | 225 | 2.5 | 4.5 | 8.5 | 17 |
| 9 | 1000*1000*150 | 450 | 2.5 | 5 | 10 | 19.5 |
| 10 | 1000*1200*150 | 540 | 3 | 5.5 | 10.5 | 20.5 |
| 11 | 1000*1200*200 | 720 | 3 | 5.5 | 10.5 | 20.5 |
| 12 | 1000*1500*200 | 900 | 3 | 6 | 11.5 | 22.5 |
| 13 | 1000*2000*200 | 1200 | 3.5 | 6.5 | 13 | 26 |
| 14 | 1200*1500*200 | 1440 | 3.5 | 7 | 13.5 | 27 |
| 15 | 1500*2000*250 | 2250 | 3.5 | 7 | 14 | 28 |
| 16 | 2000*2000*250 | 3000 | 4 | 8 | 15.5 | 31 |
| 17 | 2500*1600*300 | 3600 | 4 | 8 | 16 | 32 |
| 18 | 3000*2000*400 | 7200 | 5 | 9.5 | 18.5 | 37 |
Flatness Calculation Formulas for Granite Platforms
(According to JJG 117-2013 Standard)
Grade 000: 1 × (1 + d/1000) μm
Grade 00: 2 × (1 + d/1000) μm
Grade 0: 4 × (1 + d/1000) μm
Grade 1: 8 × (1 + d/1000) μm
Grade 2: 16 × (1 + d/1000) μm
Grade 3: 40 × (1 + d/1000) μm
(Where d = diagonal length in mm; measured at 20±2°C)
Physical Properties
Size: Customizable
Material: Natural granite
Reference Specific Gravity: 2800-3070 kg/m³
Compressive Strength: 230-254 kg/mm²
Elastic Modulus: 1.27-1.47 N/mm²
Linear Expansion Coefficient: 4.6 × 10⁻⁶ /°C
Water Absorption Rate: 0.13%
Shore Hardness: HS70 or higher
Accuracy Grades: 000, 00, 0, and 1