Investigation on Process Stability and Part Positioning Influence on the Relative Density of Designed Materials via Laser‐Based Powder Bed Fusion of Metals on a Multi‐Laser Machine

Abstract

Component production via laser‐based powder bed fusion of metals (PBF‐LB/M) is becoming reality for multiple applications. Especially for sophisticated parts, as in case of gas turbines, assurance of repeatable properties involves control of process and machine parameters. PBF‐LB/M is used to build configurable open‐porous structures—designed materials (DMs)—out of the high temperature superalloy Haynes 282 with relative densities from 35 % to 65 % . The objective is investigating positioning influence and process stability based on their relative densities in discrete scan fields and build jobs. As DMs made from Haynes 282 are not yet scientifically investigated, first the process boundaries are identified. The used PBF‐LB/M machine—EOS M 400‐4—works with four lasers in four quadrants—a quadrant benchmarking is carried out. The experiment is repeated in a second build job. Scatter is identified in quadrant and build job benchmarking. A further aspect under investigation is positioning within laser quadrants. However, keeping laser and parameter combinations constant, sample locations are assessed. A relative density dependency on the laser deflection angle—as a positional measure—is observed. The results of positioning influence and scatter are used to formulate a tolerance equation for relative densities of DMs.

Pre‐Print‐Prediction of Morphological Properties for Designed Materials Manufactured via Laser‐Based Powder Bed Fusion of Metals on a Multi‐Laser Machine

“…[2,3,8,9] Process adaptations-either modifying the powder feedstock, or process and machine parameters-can be used to provoke randomly distributed porosity into PBF-LB/M components. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] For the approach of process parameter adaptions, the formation of pores is driven by the controlled introduction of defects, e.g., lack of fusion. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] In two previous studies so-called designed materials (DMs) were produced from the nickel-based superalloy Haynes 282 -UNS N07208 ).…”

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] For the approach of process parameter adaptions, the formation of pores is driven by the controlled introduction of defects, e.g., lack of fusion. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] In two previous studies so-called designed materials (DMs) were produced from the nickel-based superalloy Haynes 282 -UNS N07208 ). [9,22,26] Their open porosity was fabricated by lowering laser power, increasing scan speed, hatch distance, or layer thickness in comparison to a standard process parameter set.…”

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] In two previous studies so-called designed materials (DMs) were produced from the nickel-based superalloy Haynes 282 -UNS N07208 ). [9,22,26] Their open porosity was fabricated by lowering laser power, increasing scan speed, hatch distance, or layer thickness in comparison to a standard process parameter set. [9,22,26] Multiple studies analyzed DM's morphology regarding porosity (or RD), pore, and strut size.…”

“…[9,22,26] Their open porosity was fabricated by lowering laser power, increasing scan speed, hatch distance, or layer thickness in comparison to a standard process parameter set. [9,22,26] Multiple studies analyzed DM's morphology regarding porosity (or RD), pore, and strut size. [9][10][11][12][13][14][15][16][17]20,21,[23][24][25]27] These investigations focus on process parameter influences and have not assessed the property's scatter.…”

“…[9][10][11][12][13][14][15][16][17]20,21,[23][24][25]27] Determining the RD (or porosity) by calculating the ratio of dimensions and weight is a commonly used method for porous samples. [14,16,[20][21][22][23][24]26] For the pore and strut size, the digital assessment via microcomputed…”