In-Situ Metrology System for Laser Powder Bed Fusion Additive Process

TLDR

Additive manufacturing parts are difficult to dimensionally characterize, and measuring each layer during laser powder bed fusion is the most efficient approach. This paper describes the development of a non‑contact metrology system for a nickel powder laser fusion process. The system combines machine‑vision linear approximation for planar dimensions with a phase‑shifting fringe‑projection height measurement, producing a high‑density 3D point cloud that captures internal and obscured features. The project is ongoing, and results are incomplete.

Abstract

Complex metal parts produced by additive manufacturing processes are often very difficult to dimensionally characterize by traditional contact and non-contact metrology systems. The most efficient and effective approach to measuring metal additively produced parts, particularly those produced in a laser powder bed fusion process, is to measure each layer of the part as it is sintered. In this layer-wise measurement approach, what are internal and obscured features in the final part are accessible to measurement while the part build is still in process. This paper describes the development of a metrology system which performs non-contact measurement of a nickel powder laser fusion system. The metrology system discussed herein uses a traditional machine vision linear approximation to measure the planar dimensions of each build layer, and a phase shifting fringe projection system to produce an area height profile of each layer. The independent measurements can be combined to produce a high density 3D point cloud of the final part, including all internal and obscured features. This project is ongoing, and results are incomplete.