Relaxation of residual stress in fused filament fabrication part with in-process laser heating

Han, Pu; Zhang, Sihan; Tofangchi, Alireza; Hsu, Kuo Chin

doi:10.1016/j.promfg.2021.06.080

Cited by 11 publications

(7 citation statements)

References 26 publications

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“…The orthotropic stiffness matrix in Equation ( 13) consists of nine components that are dependent on Young's moduli, Poisson's ratios, and shear moduli of the material as defined in Equations ( 14)- (17). These properties are time and temperature-dependent and represented by a fitted Prony series model obtained from the experimental master curves [31].…”

Section: Determination Of the Model Parametermentioning

confidence: 99%

“…From a physical perspective, the FDM process is notably complex, involving a multitude of thermal phenomena. Heat transfer assumes a pivotal role throughout the process, particularly in determining the temperature distribution within the model, subsequently influencing the evolution of residual stresses and deformation, ultimately affecting the final integrity of the printed part [14][15][16][17]. Parts manufactured using FDM with semicrystalline materials frequently exhibit residual stresses and shrinkage during the cooling phase following disposition [18].…”

Section: Introductionmentioning

confidence: 99%

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Additive Manufacturing of Composite Polymers: Thermomechanical FEA and Experimental Study

Behseresht,

Park

2024

Materials

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This study presents a comprehensive approach for simulating the additive manufacturing process of semi-crystalline composite polymers using Fused Deposition Modeling (FDM). By combining thermomechanical Finite Element Analysis (FEA) with experimental validation, our main objective is to comprehend and model the complex behaviors of 50 wt.% carbon fiber-reinforced Polyphenylene Sulfide (CF PPS) during FDM printing. The simulations of the FDM process encompass various theoretical aspects, including heat transfer, orthotropic thermal properties, thermal dissipation mechanisms, polymer crystallization, anisotropic viscoelasticity, and material shrinkage. We utilize Abaqus user subroutines such as UMATHT for thermal orthotropic constitutive behavior, UEPACTIVATIONVOL for progressive activation of elements, and ORIENT for material orientation. Mechanical behavior is characterized using a Maxwell model for viscoelastic materials, incorporating a dual non-isothermal crystallization kinetics model within the UMAT subroutine. Our approach is validated by comparing nodal temperature distributions obtained from both the Abaqus built-in AM Modeler and our user subroutines, showing close agreement and demonstrating the effectiveness of our simulation methods. Experimental verification further confirms the accuracy of our simulation techniques. The mechanical analysis investigates residual stresses and distortions, with particular emphasis on the critical transverse in-plane stress component. This study offers valuable insights into accurately simulating thermomechanical behaviors in additive manufacturing of composite polymers.

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Section: Determination Of the Model Parametermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Additive Manufacturing of Composite Polymers: Thermomechanical FEA and Experimental Study

Behseresht,

Park

2024

Materials

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“…This means that the gap between the layers is filled due to the surface reflow to a certain degree. Nonetheless, there is not enough time for relaxation [18] or complete reptation [46], as observed from the tensile strength data, to form a region that is isotropic and solid. Surface reflow is driven by surface tension.…”

Section: Mechanical Strength and Fracture Behaviormentioning

confidence: 99%

“…The extrusion-based fabrication process itself gives rise to poor surface smoothness because of the multi-layer deposition of the material, with a thickness of 0.1 or 0. for each layer [18]. The nozzle, due to its shape, determines the roundness of the material extruded.…”

Section: Introductionmentioning

confidence: 99%

In-Process Orbiting Laser-Assisted Technique for the Surface Finish in Material Extrusion-Based 3D Printing

et al. 2023

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Material extrusion-based polymer 3D printing, one of the most commonly used additive manufacturing processes for thermoplastics and composites, has drawn extensive attention due to its capability and cost effectiveness. However, the low surface finish quality of the printed parts remains a drawback due to the nature of stacking successive layers along one direction and the nature of rastering of the extruded tracks of material. In this work, an in-process thermal radiation-assisted, surface reflow method is demonstrated that significantly improves the surface finish of the sidewalls of printed parts. It is observed that the surface finish of the printed part is drastically improved for both flat and curved surfaces. The effect of surface reflow on roughness reduction was characterized using optical profilometry and scanning electron microscopy (SEM), while the local heated spot temperature was quantified using a thermal camera.

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“…As PEEK finds increased utilization in ME manufacturing, the importance of understanding how residual stress release manifests will be integral to assigning part lifetimes and developing material formulations and print protocols that can improve structural fidelity. Han et al 11 conducted experiments with FFF-printed PEEK in which inprocess laser heating was utilized to "heal" residual stress during the printing process. The laser treatment increased the strength of tensile samples, an improvement the authors ascribed to intralayer relaxation of polymer chains from a shear-induced extended conformation to a relaxed, clustered conformation.…”

Section: Introductionmentioning

confidence: 99%

Multiple Molecular-Level Processes in the Evolution of Residual Strain in 3D Printed Poly(ether ether ketone)

Riggins,

Dadmun

2024

ACS Appl. Polym. Mater.

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The processing that occurs during material extrusion (ME) 3D printing imparts residual stress in printed parts, which is released during annealing and manifests as an irreversible thermal strain. Our group seeks material-based solutions that control the release of residual stress through molecular-level processes, decrease the magnitude of observed strain, and produce structures that can be annealed without loss of structural fidelity. This work describes an examination of the release of residual stress in 3D printed monoliths made from poly(ether ether ketone) (PEEK) filaments using nanographene sheets as an additive, in situ illumination with an appropriate wavelength light source, and thermal annealing close to the melting temperature. The extent of strain release of the PEEK monoliths is far suppressed relative to that of those made from poly(lactic acid) for all formulations. Moreover, there is a consistent pattern of a transition from positive-to-negative residual strains with annealing time that is independent of the annealing temperature and material formulation. This is interpreted to indicate that multiple competing processes drive the development of residual stress in the ME-printed PEEK samples. Short time relaxation of molecular alignment compels macroscopic expansion, while increased polymer crystallization at longer times forces macroscopic contraction due to densification. These results, therefore, provide crucial insight into molecular-level processes that guide macroscopic structural changes and will inform the development of PEEK annealing protocols to form robust structures by ME without sacrificing structural integrity.

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Relaxation of residual stress in fused filament fabrication part with in-process laser heating

Cited by 11 publications

References 26 publications

Additive Manufacturing of Composite Polymers: Thermomechanical FEA and Experimental Study

Additive Manufacturing of Composite Polymers: Thermomechanical FEA and Experimental Study

In-Process Orbiting Laser-Assisted Technique for the Surface Finish in Material Extrusion-Based 3D Printing

Multiple Molecular-Level Processes in the Evolution of Residual Strain in 3D Printed Poly(ether ether ketone)

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