In-depth comparison of polyamide 12 parts manufactured by Multi Jet Fusion and Selective Laser Sintering

Rosso, Stefano; Meneghello, Roberto; Biasetto, Lisa; Grigolato, Luca; Concheri, Gianmaria; Savio, Gianpaolo

doi:10.1016/j.addma.2020.101713

Cited by 56 publications

(50 citation statements)

References 41 publications

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“…The average values of crystallinity are in line with previous literature on MJF (Mele et al , 2020a; Rosso et al , 2020). The comparison with powder crystallinity demonstrates that a significant reduction of crystallinity degree was induced by the process.…”

Section: Resultssupporting

confidence: 91%

On the effect of irradiance on dimensional accuracy in multijet fusion additive manufacturing

Mele

Campana

Monti

2021

RPJ

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Purpose The amount of radiated energy is known to be a crucial parameter in powder-bed additive manufacturing (AM) processes. The role of irradiance in the multijet fusion (MJF) process has not been addressed by any previous research, despite the key role of this process in the AM industry. The aim of this paper is to explore the relationship between irradiance and dimensional accuracy in MJF. Design/methodology/approach An experimental activity was carried out to map the relationship between irradiance and dimensional accuracy in the MJF transformation of polyamide 12. Two specimens were used to measure the dimensional accuracy on medium and small sizes. The experiment was run using six different levels of irradiance. For each, the crystallinity degree and part density were measured. Findings Irradiance was found to be directly proportional to part density and inversely proportional to crystallinity degree. Higher irradiance leads to an increase in the measured dimensions of parts. This highlights a predominant role of the crystallisation degree and uncontrolled peripherical sintering, in line with the previous literature on other powder-bed AM processes. The results demonstrate that different trends can be observed according to the range of sizes.

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Section: Resultssupporting

confidence: 91%

On the effect of irradiance on dimensional accuracy in multijet fusion additive manufacturing

Mele

Campana

Monti

2021

RPJ

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“…Some specific phenomena, valid only for some specific samples, depending on their thickness or build orientation, were also observed and discussed below. All studied surfaces contain ductile and brittle fracture regions ( Figure 21 a–c), similarly as observed in [ 48 ]. However, the ratio of ductile to brittle area was found to be dependent mainly on the print thickness.…”

Section: Resultssupporting

confidence: 76%

“…Then, by increasing the wall thickness, the mixed, ductile, and brittle mode of fracture was observed (Figure 21b), while for the thickest prints the fracture was mainly brittle (Figure 21c). The mixed fracture mode was also observed by Rosso et al [48] but instead was linked to specific regions in the print, i.e., more ductile in the upper part of fracture surface and more brittle in the lower parts. Furthermore, other powder bed fusion processes, like SLS, show rather more brittle behavior [49], which may suggest that MJF provides prints with higher toughness and capable to absorb more energy before final failure.…”

Section: Microstructural Analysis Of Fractured Surfacessupporting

confidence: 66%

Study on Geometry, Dimensional Accuracy and Structure of Parts Produced by Multi Jet Fusion

Adach¹,

Sokołowski

Piwowarczyk

et al. 2021

Materials

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Multi Jet Fusion (MJF) is one of the newest additive manufacturing technologies for polymer powders, introduced in recent years. This fully industrial technology is gaining big interest as it allows fast, layer-by-layer, printing process, short production cycle, and very high printing resolution. In this paper, twelve thin-walled, spherical PA12 prints were studied in terms of geometry, dimensional accuracy, and fracture surface characteristics. The various characteristic features for MJF prints were observed here for parts produced according to four various print orientations and having different thicknesses, i.e., 1, 2 or 3 mm. The study showed that MJF technology can print such difficult shapes. However, the set of parameters allowing producing parts with highest geometrical and dimensional accuracy causes at the same time some microstructural issues, like great interlayer porosity or high number of non-processed powder particles embedded in the print structure.

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“…The algorithm produces a surface with continuity in curvature (C2 surface), except at extraordinary vertices where they are C1. This allows to reduce stress concentration, especially at nodal points, enhancing the mechanical properties and the fatigue life of the lattice [56][57][58].…”

Section: Design Workflowmentioning

confidence: 99%

An Optimization Workflow in Design for Additive Manufacturing

et al. 2021

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Additive Manufacturing (AM) brought a revolution in parts design and production. It enables the possibility to obtain objects with complex geometries and to exploit structural optimization algorithms. Nevertheless, AM is far from being a mature technology and advances are still needed from different perspectives. Among these, the literature highlights the need of improving the frameworks that describe the design process and taking full advantage of the possibilities offered by AM. This work aims to propose a workflow for AM guiding the designer during the embodiment design phase, from the engineering requirements to the production of the final part. The main aspects are the optimization of the dimensions and the topology of the parts, to take into consideration functional and manufacturing requirements, and to validate the geometric model by computer-aided engineering software. Moreover, a case study dealing with the redesign of a piston rod is presented, in which the proposed workflow is adopted. Results show the effectiveness of the workflow when applied to cases in which structural optimization could bring an advantage in the design of a part and the pros and cons of the choices made during the design phases were highlighted.

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In-depth comparison of polyamide 12 parts manufactured by Multi Jet Fusion and Selective Laser Sintering

Cited by 56 publications

References 41 publications

On the effect of irradiance on dimensional accuracy in multijet fusion additive manufacturing

On the effect of irradiance on dimensional accuracy in multijet fusion additive manufacturing

Study on Geometry, Dimensional Accuracy and Structure of Parts Produced by Multi Jet Fusion

An Optimization Workflow in Design for Additive Manufacturing

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