Octagonal gasket is a metal sealing gasket with a cross-sectional shape of octagon (like two squares stacked together), used for sealing flange connections.
To measure the thickness of the octagonal gasket, relevant tools need to be prepared first.
Priority should be given to using a micrometer or digital caliper (with an accuracy of 0.01mm) for direct measurement of gasket thickness; Optical projectors or 3D coordinate measuring machines can achieve high-precision automated measurement with small errors. In addition, a cleaning cloth and calibration block should be prepared to remove dirt from the gasket surface and verify the zero point error of the measuring tool.
The standardized operation method for measuring the thickness of octagonal gaskets is as follows:
1、 Multi point positioning measurement
Select 5 measurement points evenly on the circumference of the octagonal gasket (avoiding edges and deformation areas).
Adjust the diameter of the micrometer to 6mm and apply 0.83N pressure to the presser foot to ensure stable contact surface.
2、 Thickness data collection
Direct measurement method: Place the measuring tool perpendicular to the surface of the gasket and record the measured values at each point (avoiding the vertex of the pitch diameter and selecting a flat area).
Indirect calculation method: If direct contact with the thickness surface is not possible, the thickness can be calculated by measuring the outer diameter, inner diameter, and pitch diameter parameters, combined with formulas (with the assistance of trigonometric functions).
3、 Data Validation and Processing
Calculate the average of 5 measurement points and eliminate outliers with deviations exceeding ± 10%.
Compare the design drawings or API6A standard requirements (such as BX type octagonal gasket thickness tolerance usually ± 0.1mm).