Residual Stress Build-Up in Aluminum Parts Fabricated with SLM Technology Using the Bridge Curvature Method

Abstract

In metal 3D printing with Selective Laser Melting (SLM) technology, due to large thermal gradients, the residual stress (RS) distribution is complicated to predict and control. RS can distort the shape of the components, causing severe failures in fabrication or functionality. Thus, several research papers have attempted to quantify the RS by designing geometries that distort in a predictable manner, including the Bridge Curvature Method (BCM). Being different from the existing literature, this paper provides a new perspective of the RS build-up in aluminum parts produced with SLM using a combination of experiments and simulations. In particular, the bridge samples are printed with AlSi10Mg, of which the printing process and the RS distribution are experimentally assessed with the Hole Drilling Method (HDM) and simulated using ANSYS and Simufact Additive. Subsequently, on the basis of the findings, suggestions for improvements to the BCM are made. Throughout the assessment of BCM, readers can gain insights on how RS is built-up in metallic 3D-printed components, some available tools, and their suitability for RS prediction. These are essential for practitioners to improve the precision and functionality of SLM parts should any post-subtractive or additive manufacturing processes be employed.

Topology Optimization of the Clutch Lever Manufactured by Additive Manufacturing

“…During the SLM process, the residual stress occurs in the components and it affects the final shape distortion. According to the previous study [29], the authors made the appropriate printing adjustments (mainly usage of supports or part orientation and design changes, etc.) to minimize the residual stress.…”

Assessment of Residual Stresses in Laser Powder Bed Fusion Manufactured IN 625

“…One of the most common techniques used to study residual stress in PBF-LB/M is the bridge curvature method (BCM) which is a technique for measuring the deflection (curl-up angle) caused by residual stress in bridge specimens [1,5,11,14,[30][31][32] or cantilever specimens [5,11,15]. The bridge curvature method has become a widely used technique in the additive manufacturing community due to its sensitivity, simplicity, non-destructive nature, and applicability to various materials [3,21].…”

Microstructural Investigation of Process Parameters Dedicated to Laser Powder Bed Fusion of AlSi7Mg0.6 Alloy

“…The idea of creating a mathematical model showing the theoretical porosity using these printing parameters seems to be very advantageous. Aluminum materials are known for their high thermal conductivity and, thus, the occurrence of residual stress and warping [1,9,20]. Today's aluminum alloy research deals with printed PBF-LB/M technologies, mostly addressing quality depending on the printing orientation [4,8,11], research on material properties and production of metal powder [3,21], the formation of defects, corrosion, stress corrosion, and the effect of heat treatment [4,5,10,18,20,22] or by modeling and predicting the properties of printed parts [17].…”

“…Aluminum materials are known for their high thermal conductivity and, thus, the occurrence of residual stress and warping [1,9,20]. Today's aluminum alloy research deals with printed PBF-LB/M technologies, mostly addressing quality depending on the printing orientation [4,8,11], research on material properties and production of metal powder [3,21], the formation of defects, corrosion, stress corrosion, and the effect of heat treatment [4,5,10,18,20,22] or by modeling and predicting the properties of printed parts [17]. In the case of research on the effect of changing the printing parameters, the articles bend in the range of different values of printing parameters than in our research [1,6] or dealing with other specifications [12,13,15,16,22,23].…”