Dimensional and Form Characterization of a Benchmarking Specimen Subjected to Different Post‐Processing Technologies for Metal Additive Manufacturing

The major interest for the use of Metal Additive Manufacturing (MAM) in precision tooling have led to a large demand of increased dimensional and form accuracy. In order to characterize both the manufacturing process itself as well as the subsequent postprocessing that is inevitable in many cases, a benchmarking specimen has been designed and manufactured. The benchmarking specimen consists of several geometries including external and internal features. The external features include protruding as well as intruding geometries while the internal features range in two different categories relating to channels with square and circular crosssections respectively. Several identical units of the benchmarking specimen have been manufactured using MAM with stainless steel 316L. After the characterization of selected geometrical parameters including measurands like dimensions and form, the specimens have been subjected to different post‐processing technologies such as Functional Coatings (Sol‐Gel), Electrochemical Polishing, Dry Electro Polishing and Plasma Electrolytic Polishing. Following post‐processing of the specimens the geometrical characterization has been repeated and compared to the initial characterization. The results show that geometrical dimensions are largely dependent on the subjected post‐processing technology while form parameters deviate less with different post‐processing technologies. By implementing post‐processing correction factors, it would be possible to manufacture parts with an increased final accuracy thereby increasing the final quality of specimens manufactured using MAM technology.