A COMPARATIVE STUDY ON PRECISION METROLOGY SYSTEMS FOR ADDITIVE MANUFACTURING

Abstract

This paper presents a comparative study on precision metrology systems such as Coordinate Measuring Machine (CMM), 3-Dimensional Scanning (3DS) and Computed Tomography (CT) for polymer additive manufacturing. A special test sample was designed and manufactured by Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS) AM systems. The manufactured parts were then measured by three different precision metrology systems and the results were compared in terms of different measurement and AM methods. Uncertainty analyses were conducted based on the results of CMM measurements. The benchmark highlighted the difference between part characteristics manufactured by FDM and SLS, where FDM part represented higher surface roughness and more deviation to the nominal design. Furthermore, expanded uncertainties computed for the FDM manufactured part were almost three times of the uncertainties computed for the SLS manufactured part. It was also demonstrated that one of the major contributors to the expanded uncertainty occurred because of rougher surface of FDM manufactured part. Similar tendency of part to nominal deviations were observable in all metrology systems including CMM, CT and 3DS. Findings of the study revealed the need of standardized measurement for inspection and control of AM parts.