Effect of surface roughness on uncertainty of X-ray CT dimensional measurements of additive manufactured parts

Determination of measurement uncertainty for CT dimensional measurements is a difficult task due to the amount of complex error sources affecting the entire process chain. One of the critical aspects to deal with is the presence of error components that must be taken into account additionally. Surface roughness has a strong influence, causing a considerable increase of uncertainty especially for parts characterized by high surface roughness, such as additive manufactured parts. The paper shows the influence of surface roughness on measurement uncertainty calculated for repeated CT measurements and investigates the relation between tactile CMM and CT measurements. The possibility to substantially decrease measurement uncertainty by correcting roughness systematic effects is outlined.