Prediction of interlayer strength in material extrusion additive manufacturing

Coogan, Timothy Jerome; Kazmer, David O.

doi:10.1016/j.addma.2020.101368

Cited by 80 publications

(84 citation statements)

References 37 publications

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“…On the one hand, the compressive load was parallel with the interlayer bonding of scaffolds, and this might induce shearing force between adjacent layers. On the other hand, the strength of interlayer bonding of an FDM product is typically lower than that of the bulk materials, due to either poor interlayer contact or inadequate polymer diffusion [ 40 ]. Therefore, the interlayer debonding occurred before buckling of the scaffold.…”

Section: Discussionmentioning

confidence: 99%

Additive-Manufactured Gyroid Scaffolds of Magnesium Oxide, Phosphate Glass Fiber and Polylactic Acid Composite for Bone Tissue Engineering

Liu

Rudd

2021

Polymers

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Composites of biodegradable phosphate glass fiber and polylactic acid (PGF/PLA) show potential for bone tissue engineering scaffolds, due to their ability to release Ca, P, and Mg during degradation, thus promoting the bone repair. Nevertheless, glass degradation tends to acidify the surrounding aqueous environment, which may adversely affect the viability and bone-forming activities of osteoblasts. In this work, MgO was investigated as a neutralizing agent. Porous network-phase gyroid scaffolds were additive-manufactured using four different materials: PLA, MgO/PLA, PGF/PLA, and (MgO + PGF)/PLA. The addition of PGF enhanced compressive properties of scaffolds, and the resultant scaffolds were comparably strong and stiff with human trabecular bone. While the degradation of PGF/PLA composite induced considerable acidity in degradation media and intensified the degradation of PGF in return, the degradation media of (MgO + PGF)/PLA maintained a neutral pH close to a physiological environment. The experiment results indicated the possible mechanism of MgO as the neutralizing agent: the local acidity was buffered as the MgO reacted with the acidic degradation products thereby inhibiting the degradation of PGF from being intensified in an acidic environment. The (MgO + PGF)/PLA composite scaffold appears to be a candidate for bone tissue engineering.

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Section: Discussionmentioning

confidence: 99%

Additive-Manufactured Gyroid Scaffolds of Magnesium Oxide, Phosphate Glass Fiber and Polylactic Acid Composite for Bone Tissue Engineering

Liu

Rudd

2021

Polymers

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“…Extrusion-based additive manufacturing of thermoplastic polymers is a thermally driven process. Thermal history affects viscoelastic deformation [1][2][3], bonding [4][5][6][7][8], and residual stresses [9,10]. Consequently, dimensional accuracy and the strength of the manufactured part are driven by the thermal history of the part.…”

Section: Introductionmentioning

confidence: 99%

“…The temperature of each active element in the model is updated using the procedure described in Equations (2)- (7). When an element is added to the model, the neighbor information is updated to define the new boundary conditions.…”

mentioning

confidence: 99%

Discrete-Event Simulation Thermal Model for Extrusion-Based Additive Manufacturing of PLA and ABS

Bhandari

Lopez-Anido

2020

Materials

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The material properties of thermoplastic polymer parts manufactured by the extrusion-based additive manufacturing process are highly dependent on the thermal history. Different numerical models have been proposed to simulate the thermal history of a 3D-printed part. However, they are limited due to limited geometric applicability; low accuracy; or high computational demand. Can the time–temperature history of a 3D-printed part be simulated by a computationally less demanding, fast numerical model without losing accuracy? This paper describes the numerical implementation of a simplified discrete-event simulation model that offers accuracy comparable to a finite element model but is faster by two orders of magnitude. Two polymer systems with distinct thermal properties were selected to highlight differences in the simulation of the orthotropic response and the temperature-dependent material properties. The time–temperature histories from the numerical model were compared to the time–temperature histories from a conventional finite element model and were found to match closely. The proposed highly parallel numerical model was approximately 300–500 times faster in simulating thermal history compared to the conventional finite element model. The model would enable designers to compare the effects of several printing parameters for specific 3D-printed parts and select the most suitable parameters for the part.

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“…Although a combination of AM and injection molding is promising for the personalized medium-scale production of polymer and polymer composites, the weak point is bonding between the components, which is usually much weaker than the strength of a single-piece part. A number of papers focus on improving bonding strength by optimizing the processing parameters [ 22 , 23 , 24 , 25 ], surface treatment [ 26 ], or creating mechanical bonding between the coupled components [ 11 , 27 , 28 , 29 ]. However, all the above-mentioned studies focus on a bonding problem within a single manufacturing process and do not cover hybrid technologies.…”

Section: Introductionmentioning

confidence: 99%

Personalized Mass Production by Hybridization of Additive Manufacturing and Injection Molding

2021

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The new trend in the composites industry, as dictated by Industry 4.0, is the personalization of mass production to match every customer’s individual needs. Such synergy can be achieved when several traditional manufacturing techniques are combined within the production of a single part. One of the most promising combinations is additive manufacturing (AM) with injection molding. AM offers higher production freedom in comparison with traditional techniques. As a result, even very sophisticated geometries can be manufactured by AM at a reasonable price. The bottleneck of AM is the production rate, which is several orders of magnitude slower than that of traditional plastic mass production technologies. On the other hand, injection molding is a manufacturing technique for high-volume production with little possibility of customization. The customization of injection-molded parts is usually very expensive and time-consuming. In this research, we offered a solution for the individualization of mass production, which includes 3D printing a baseplate with the subsequent overmolding of a rib element on it. We examined the bonding between the additive-manufactured component and the injection-molded component. As bonding strength between the coupled elements is significantly lower than the strength of the material, we proposed five strategies to improve bonding strength. The strategies are optimizing the printing parameters to obtain high surface roughness, creating an infill density in fused filament fabrication (FFF) parts, creating local infill density, creating microstructures, and incorporating fibers into the bonding area. We observed that the two most effective methods to increase bonding strength are the creation of local infill density and the creation of a microstructure at the contact area of FFF-printed and injection-molded elements. This increase was attributed to the porous structures that both methods created. The melt during injection molding flowed into these pores and formed micro-mechanical interlocking.

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Prediction of interlayer strength in material extrusion additive manufacturing

Cited by 80 publications

References 37 publications

Additive-Manufactured Gyroid Scaffolds of Magnesium Oxide, Phosphate Glass Fiber and Polylactic Acid Composite for Bone Tissue Engineering

Additive-Manufactured Gyroid Scaffolds of Magnesium Oxide, Phosphate Glass Fiber and Polylactic Acid Composite for Bone Tissue Engineering

Discrete-Event Simulation Thermal Model for Extrusion-Based Additive Manufacturing of PLA and ABS

Personalized Mass Production by Hybridization of Additive Manufacturing and Injection Molding

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