A Preliminary Investigation on Surface Roughness Assessment of Complex Additive Manufactured Parts Scanned by X-ray Computed Tomography

The additive manufacturing (AM) technologies bring in a number of benefits over traditional subtractive manufacturing technologies. However as-built surface finish of AM produced components is often not satisfactory and usually needs further post-process. Surface roughness is vitally important to the product’s functional performance. However, the measurement and characterization of the complex functional AM surfaces is difficult due to their complicated shape or intricate internal geometries. XCT is current the only valid method that can measure complete internal and external geometry without constraints of traditional tactile and optical techniques. Nonetheless, XCT measurement posts two obstacles to standard roughness characterisation: the measured surface form and the non-uniform sampled measurement data structure. Aiming for a holistic and reliable roughness assessment, it is proposed to use the linear diffusion equation to achieve a Gaussian filtering effect on complex surfaces and to extend the roughness areal parameters on a triangular mesh.