Improving the dimensional accuracy of downfacing surfaces of additively manufactured parts

In this study the accuracy of downfacing surfaces of small LPBF (Laser Powder Bed Fusion) fabricated features is investigated. Calibration geometries with downfacing angles ranging from 75° to 25° are printed in three different layer thicknesses to quantify the dimensional error due to dross formation and other melt pool phenomena in the downfacing area. Their dimension is measured with a digital microscope and compared with the CAD model: all geometries show a negative mismatch which is proportional to the downfacing angle, therefore a correction parameter is calculated. To validate the effectiveness of this offset, microchannels with diameter ranging from 1 mm to 0.6 mm were printed both with and without the correction. Their deviations from the nominal diameter were investigated through the use of micro Computed Tomography. Results show less deviation from the nominal cylindrical CAD when the offset is applied, while the dross formation remains almost unaffected.

ISBN:978-0-9957751-5-2

Jaar van publicatie:2019

Toegankelijkheid:Open