GCr15 Steel 7 Sides Regular Polyhedron Prism Polished Surface Finish

Product Specification

Product introduction 

Regular Polyhedral prismPrism is a kind of high-precision angle measurement standard instrument, which takes the angle between the normal lines of adjacent working faces as the equivalent measurement angle and has a regular polygon angle standard instrument with accurate angle measurement. Prism andAutocollimator(Collimator or PhotoelectricAutocollimator), which is used to verify the indexing error of the circular indexing instrument. It is often used for angle indexing or positioning in machining and precision measurement.

Polyhedral prism As a standard instrument for angle measurement. It is mainly used to verify the dividing error of optical dividing head, dividing table, goniometer and other circular dividing instruments, and can also be used as the positioning datum of angle in high-precision machining or measurement. With the development of circular division technology, the positivePolyhedral prismIt has developed from the single even number plane (such as 12, 24 plane, etc.) To the odd number plane (such as 17, 23 plane, etc.) With comprehensive functions. The working angle of the former is an integral number, which is used to verify the large periodic error of the circular dividing instrument in the shafting, and can also be used for diameter measurement. The working angle of the latter is a non-integral number, which can comprehensively verify the large periodic error of the circular dividing instrument in the shafting and the small periodic error of the micrometer, and can accurately determine the uncertainty of the circular dividing instrument in the shafting.

If the total number of working faces of a prism can be equally divided into 360 degrees, it is called "integral number of degrees".Polyhedral prismIt is used for the verification of integral number error. Different specifications such as 4, 8, 12, 24, 36 and 72 are commonly used. If the total number of working faces of the prism can not be divided into 360 °, it is called "non-integral number of degrees".Polyhedral prismIt is used for comprehensive verification of integral number error and subdivision error. Different specifications such as 17 faces (adjacent angle 21 ° 10 ′ 35.3 ″) and 23 faces (adjacent angle 15 ° 39 ′ 7.8 ″) are commonly used.

Prism is classified into Grade I, Grade II, Grade III and Grade IV (corresponding to Grade 00, Grade 0, Grade 1 and Grade 2) according to the measurement uncertainty and deviation of working angle. Meanwhile, each grade of prism has corresponding requirements for the flatness of working surface and other properties of prism.

The prism is made of metal material, and the material is GCr15 high-carbon chromium bearing steel; After quenching and low temperature tempering, it has high hardness, uniform structure, good wear resistance and high contact fatigue performance.

Technical Indicators

1. Excircle diameter: φ 80-φ 150mm; 

2. Prism thickness: 17-20mm;

3. Rotating center aperture: φ25mm; Material: GCr15;

5. Hardness: HRC62-65;

6. Flatness of working face: Grade 0 (Grade II): ≤ 0.03um;  Grade 1 (Grade III): ≤ 0.05um;  Grade 2 (Grade 4): ≤ 0.1 um; [Customized class 00 (first class): ≤ 0.02 um;]

7,Flatness of datum plane: Grade 0 (Grade II): ≤ 1um;  Grade 1 (Grade III): ≤ 1.5 um;  Grade 2 (Grade 4): ≤ 1.5 um; [Customized Grade 00 (Grade I): ≤ 1um;]

8,Verticality of working surface to datum plane: Grade 0 (Grade II): ≤ ± 10 ″;  Grade 1 (Grade III): ≤ ± 15 ″;  Grade 2 (Grade 4): ≤ ± 20 ″; [Customized Grade 00 (Grade I): ≤ ± 5 ″;]

9. Surface roughness of working face: Ra ≤ 0.025um;

10. Surface roughness of datum plane: Ra ≤ 0.05 um;

11. Parallelism between the upper surface and the datum plane: 2 um;

12. Working angle deviation: Grade 0 (Grade II): ≤ ± 1 ″; Grade 1 (Grade 3): ≤ ± 2 ″; Grade 2 (Grade 4): ≤ ± 5 ″; [Customized Grade 00 (Grade I): ≤ ± 0.5 ″;]

13. Measurement uncertainty of working angle: Class 0 (Class II): ≤ 0.3 ″;  Grade 1 (Grade III): ≤ 0.5 ″;  Grade 2 (Grade 4): ≤ 1.0 ″; [Customized level 00 (first class): ≤ 0.2 ″;]

14,Effective working area of working face: circular area with S ≥ φ15mm (or 15mm * 15mm or D15mm);