Characterization of PA12/PBT specimens prepared by selective laser sintering

Salmoria, Gean Vitor; Lauth, Victor R.; Cardenuto, M.R.; Magnago, Rachel Faverzani

doi:10.1016/j.optlastec.2017.07.044

Cited by 32 publications

(22 citation statements)

References 21 publications

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“…Parts consisting only of a single layer could be produced with laser sintering, but no mechanical properties were tested. The performance of dry blends of PA12 mixed with up to 30% PBT was investigated by Salmoria et al [12]. The authors reported a minimal increase of flexural modulus upon blending PA12 with 10% Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

2019

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This work describes the production of a spherical polybutylene terephthalate (PBT) powder and its processing with selective laser sintering (SLS). The powder was produced via melt emulsification, a continuous extrusion-based process. PBT was melt blended with polyethylene glycol (PEG), creating an emulsion of spherical PBT droplets in a PEG matrix. Powder could be extracted after dissolving the PEG matrix phase in water. The extrusion settings were adjusted to optimize the size and yield of PBT particles. After classification, 79 vol. % of particles fell within a range of 10–100 µm. Owing to its spherical shape, the powder exhibited excellent flowability and packing properties. After powder production, the width of the thermal processing (sintering) window was reduced by 7.6 °C. Processing of the powder on a laser sintering machine was only possible with difficulties. The parts exhibited mechanical properties inferior to injection-molded specimens. The main reason lied in the PBT being prone to thermal degradation and hydrolysis during the powder production process. Melt emulsification in general is a process well suited to produce a large variety of SLS powders with exceptional flowability.

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Section: Introductionmentioning

confidence: 99%

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

2019

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“…Although there has been much investigation on the influence of process parameters and material compounds on the mechanical properties of polymers such as PA12 [4,5,6,7], the effect of the powder deposition process is not yet well understood. For this purpose, a number of experimental and numerical related approaches helped to gain new insights into the topic of creating dense packings and made it possible to better evaluate the powder flow properties [8,9,10,11,12].…”

Section: Introductionmentioning

confidence: 99%

Influence of Powder Deposition on Powder Bed and Specimen Properties

et al. 2019

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Three-dimensional printing used to be a rapid prototyping process, but nowadays it is establishing as an additive manufacturing (AM) process. One of these AM techniques is selective laser sintering (SLS), which most often involves partial melting of the particles and therefore belongs to the category of powder bed fusion processes. Much progress has been made in this field by research on process parameters like laser power, hatch distance, and scanning speed while still lacking a fundamental understanding of the powder deposition and its influence on parts. A critical issue for economic manufacturing is the building time of parts with good mechanical properties, which can be reduced by lower surface roughness due to less or missing post processing. Therefore, the influence of three blade shapes on powder bed surface roughness has been evaluated for PA12 powder with three different grain size distributions by using advanced X-ray micro computed tomography (XMT) and a confocal laser scanning microscope (LSM). Along with those methods, new techniques for powder characterization were tested and compared. Lowest roughness has been achieved with a flat blade, based on a higher compression due to a larger contact zone between blade and powder bed. Furthermore, an anisotropic effect of the mechanical properties resulting from different building directions has been detected which can be explained by varying amounts of solid contact paths through the powder bed depending on powder application direction. In addition, an optimal combination of process parameters with an even compression of the powder bed leads to low surface roughness, complementing the advantages of additive manufacturing.

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“…Figure presents the cryogenic fracture of the specimens observed by SEM. Different from polyamides parts prepared by SLS, UHMWPE powder seems to be stacked up to each other inside the sintered parts. To some extent, each particle is equivalent to an independent unit.…”

Section: Resultsmentioning

confidence: 98%

An investigation of post treatment on properties and structure of ultrahigh molecular weight polyethylene parts prepared by selective laser sintering for biomedical application

Zhao

Yang

et al. 2020

Polymers for Advanced Techs

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Combined with customization advantage of selective laser sintering (SLS) and excellent performance of ultrahigh molecular weight polyethylene (UHMWPE), it is possible to meet the requirements of artificial joints for biomedical application. However, high viscosity of UHMWPE melt limits the strength of UHMWPE sintered parts. Inspired from metal and ceramic materials, this work aims to improve the performance of UHMWPE parts prepared by SLS using post treatment methods, including heat treatment and hot isostatic pressure (HIP) treatment. Consequently, HIP treatment shows superiority on promoting the performance of UHMWPE sintered parts compared with heat treatment. With the condition of temperature and isostatic pressure, a novel definition of "bonding neck" is given to explain the enhancement of cohesion between each UHMWPE particle in different post treatment. Without any fortifier, the biological safety of artificial joints manufactured by SLS is further guaranteed. Under the isostatic pressure of 12 MPa and temperature of 185 C in HIP treatment, the mechanical strength, tribological performance and other properties are improved dramatically. The tensile strength of the specimen is up to 8.0 MPa, the elongation at break is 99.3%, the impact strength is 8.8 MPa, the friction coefficient is 0.11, the wear rate is 9.3 × 10 −4 mm 3 /Nm and samples do not show cytotoxicity at the same time. K E Y W O R D S heat treatment, HIP treatment, posttreatment, selective laser sintering, UHMWPE

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Characterization of PA12/PBT specimens prepared by selective laser sintering

Cited by 32 publications

References 21 publications

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

Influence of Powder Deposition on Powder Bed and Specimen Properties

An investigation of post treatment on properties and structure of ultrahigh molecular weight polyethylene parts prepared by selective laser sintering for biomedical application

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