Research on surface quality measurement technology for small surface structure

Surface roughness is a key factor to evaluate the machining quality of parts and affect the sealing performance of products, especially for aerospace propulsion valve products with high sealing performance requirements. In this paper, a multi region sampling stitching method and multiple sampling mean methods are proposed to evaluate the surface roughness of small surface structures. And the uncertainty of micro size measurement is systematically analyzed. And three measuring methods on different structural sealing parts are compared and analyzed. The test results show that the roughness measurement method proposed in this paper is accurate and effective. The relative error of this measurement is less than 1%. It meets the high sealing surface quality requirements of aerospace products. This measurement method has important guiding significance and engineering application value for aerospace propulsion products with high sealing requirements.