L-PBF in-situ process monitoring instrumentation

点击翻译按钮获取中文摘要

A laser powder bed fusion (LPBF) device with in-situ emission spectroscopy, vacuum chamber, and package space reduction is proposed to gain understanding of (nanoparticle-additivated) metal powder processing. Tracking the chemical composition during the LPBF process by in-situ spectroscopy and reconstructing it in three dimensions is critical to correlate compositional changes with microstructure formation and 3D device properties. Concomitantly, X-ray fluorescence (XRF) and energy dispersive X-ray spectroscopy (EDX) are used for elemental analysis after LPBF-fabrication of parts. However, such ex situ methods require tedious and time-consuming preparation and are hardly suitable for full 3D reconstruction. The proposed LPBF instrument with integrated optical emission spectroscopy (OES) provides a fast method for in situ elemental analysis. The OES, which has already been successfully demonstrated for laser welding, enables in-situ metal vapor analysis of the respective two-dimensional position of the melting laser beam in the powder bed, which is to be assembled into 3D information by software. In addition, the correlation of the in situ measured emission spectra (especially element ratios) and the bulk composition will be worked out by means of non-destructive ex-situ XRF and EDX mapping of transverse sections. The additive laser powder bed fusion (L-PBF) process is predestined for the use of OES, since here three-dimensional components are built up in layers of about 20 µm to 100 µm by local melting and solidification of metallic powder material. The layer building principle of the L-PBF process and the digital nature of the layer generation will be exploited in the proposed device to analyze the laser-induced emissions in real time during the process and to obtain a complete spatial analysis of the composition of the manufactured part. The instrument will enable better understanding of the processes along the chain of powder properties, LPBF processing and microstructure/part properties. The proposed L-PBF in-situ process observation instrument thus occupies a key position that exerts a leverage effect on the materials science, manufacturing and physics research spectrum of the participating chairs.